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f^ ^ ^ cornell university. 
 
 BG^ the 
 
 the gift of 
 RO SWELL R FLOWER 
 
 FOR THE USE OF 
 
 THE N. Y. STATE VETERINARY COLLEGE. 
 
 1897 
 
Cornell University Library 
 RA 425.B66 
 
 A manual of public health 
 
 3 1924 000 319 776 
 

AMAl^UAL OF PUBLIC HEALTH 
 
A MANUAL 
 
 OF 
 
 PUBLIC HEALTH 
 
 BY 
 
 A. WYNTER BLYTH, M.E.C.S., L.S.A 
 
 FELL. CHEM. SOC, FELL. INST. CHBM. 
 
 BABK.ISTEB-AT LAW 
 
 MEDICAL OFFICER OF HEALTH AND PUBLIC ANALYST 
 
 FOR ST. MARYLEBONE, ETC 
 
 Uontfon 
 MACMILLAN AND CO. 
 
 AND NEW YOEK 
 1890 
 
 The Right of Trajislation and BeprOd/uction is Reserved 
 
RTCHAiti) Clay and Sons, Limited. 
 
 LONlX)N AND BONGAT. 
 
 KA 
 
 dU 
 
PREFACE 
 
 In the following pages the author has interwoven knowledge 
 compiled from various sources with his personal official experience 
 in hoth urhan and rural districts. 
 
 In the plan of the work and in its treatment he may perhaps 
 claim some originality ; at all events it is intended to convey the 
 author's idea of the suhjects of special knowledge necessary for 
 those engaged in either an administrative or subordinate capacity 
 in the Public Health Service to be acquainted with. 
 
 The author has to thank Mr. Henry Law, M. Inst. C.E., for 
 revising the statistical section and the mathematical formulae, 
 and for the useful tables at pages 217 and 218 ; to Professor 
 Fuller the author is indebted for the scale at page 36 ; to Dr. 
 Richard Budd, of Barnstaple, for the loan of original photographs 
 and drawings ; to Professor Stewart, of the Royal College of 
 Surgeons, for facilities for copying pathological specimens in the 
 Museum ; and to Mrs. Wynter Blyth for drawing and colouring 
 most of the lithographs. 
 
The original of this book is in 
 the Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/cletails/cu31924000319776 
 
CONTENTS 
 
 SECTION 1.— STATISTICS. 
 CHAPTER I. 
 
 THE CALOCLATION AND SIGNIFICANCE OF VITAL STATISTICS. 
 
 PAGE 
 
 (1) Methods of Calculating Populations between the Census Periods 3 
 
 (2) Local Censuses .... ... 5 
 
 (3) Death Returns .... . .5 
 
 (4) Causes of Death ..... . . 7 
 
 (6) Addresses. The Mortality Ledger 11 
 
 (6) Sex ... 12 
 
 (7) Age 12 
 
 (8) Calculation of Birth and Death-Eates . 12 
 
 (9) Age Distribution ... . 15 
 
 (10) Zymotic Death-Eate . . . 18 
 
 (11) Proportion of Deaths from certain Causes of Disease to the Total Deaths . 18 
 
 (12) Proportional Distribution of Deaths 19 
 
 CHAPTER n. 
 
 MEAN AGE AT DEATH — MEAN DUEATION OF LIFE — FROBABLB DITEATION OF LIFE 
 — CONSTKUCTION OF LIFE TABLES. 
 
 (13) Mean Age at Death .... 22 
 
 (14) Calculation of Mean Duration of Life .... 23 
 
 (15) The Probable Duration of Life .... .23 
 
 (16) Construction of Life Tables ... . .24 
 
 (17) Construction of Short Life Tables ... 27 
 
 (18) The Construction of an Extended Life Table . . 30 
 
 CHAPTER IIL 
 
 AIDS TO CALCTTLATION. 
 
 (19) Tables . 35 
 
 (20) Professor Fuller's Spiral Rule . . 35 
 
 (21) Multiplication by the Spiral Rule . . . 37 
 
 (22) Division by the Spiral Rule . 37 
 
 (23) The Arithmometer . . . . . . ■. 40 
 
CONTENTS. 
 
 SECTION 11.— AIR— VENTILATION— WARMING. 
 
 CHAPTER IV. 
 
 AIR. 
 
 PAGE 
 
 (24) General Nature of Air ^' 
 
 (25) Atmospheric Pressure . ' ^' 
 
 (26) The Weight of a Volume of Air *8 
 
 (27) Percentage Composition of the Atmosphere 50 
 
 (28) The Fixation of Carbon by Plants. Maintenance of the Composition of 
 
 the Atmosphere . ^° 
 
 (29) Other Gases more or less constantly present in Air 5i 
 
 (30) Other Substances Floating in Air. Micro-organisms 56 
 
 (31) The General Difference between Town and Country Air "56 
 
 CHAPTER V. 
 
 THE GENERAL PRINCIPLES OF VENTILATION. 
 
 (32) The Mechanism by which the Air of Rooms is made Impure 58 
 
 (33) Composition of Expired Air 60 
 
 (3i) The Contamination of Air by Animals . 61 
 
 (35) Quantity of Air Required per Head per Hour 63 
 
 (36) Atmospheric Impurity from Combustion ... 65 
 
 (37) Velocity of Air which can be Borne without Discomfort . 67 
 
 (38) Principles Governing Air Movement . . 68 
 
 (39) Inlets afid Outlets . 69 
 
 Methocis of Ventilation. 
 
 (40) Simple Openings . ... 73 
 
 (41) Accepted Principles to be Applied to Simple Natural Ventilation . 74 
 
 (42) Appliances Connected with Windows . . .74 
 
 (43) Appliances Connected with Walls and Chimneys 76 
 
 (44) Special Shafts or Tubes ... ,77 
 
 (45) Cowls and Extraction Shafts Generally 78 
 
 CHAPTER VI. 
 
 SYSTEMS OF VENTILATION. COMBINED WITH WARMING OR DEPENDENT ON 
 MECHANICAL AGENCIES. 
 
 (46) Gas as an Aspirating Agent . , .79 
 
 (47) Pritchett's Miniature Hot Water Apparatus ... 79 
 
 (48) Ventilation Depending on Water Power ... 80 
 
 (49) The Ventilation of Underground Passages and Mines 80 
 
CONTENTS. 
 CHAPTER VII. 
 
 WARMING. 
 
 PAGE 
 
 (50) General Principles of Warming Rooms 87 
 
 (51) "Warming by Open Fireplaces 87 
 
 (52) Stoves 88 
 
 (53) Systems Applicable for Schools and Public Buildings 80 
 
 (54) Tbe High Pressure System .. 90 
 
 (55) Steam Heating . . 91 
 
 (56) Hot "Water System 91 
 
 CHAPTER VIII. 
 
 PEACTICAL EXAMINATION OF AIR. 
 
 (57) Examination by the Senses 95 
 
 (58) Dust. Bacteria .... ; . 95 
 
 (59) Chemical Method of Estimating Organic Matter in tlie Air 96. 
 
 (60) Estimation of Carbonic Acid in the Air 96 
 
 (61) Nephalometric Methods . 98 
 
 (62) Pettenkofer's Volumetric Method . . 101 
 
 (63) Estimation of Carbon Monoxide, CO 102 
 
 (64) Sulphuretted Hydrogen . ] 03 
 
 CHAPTER 15. 
 
 HOW TO MEASURE CUBIC SPACE AND TO EBPOET ON VENTILATION. 
 
 (65) Cubic Space Allowed by Law or by Local Regulations . . 104 
 
 (66) The Cube of Rectangular and Triangular Spaces . . ,104 
 
 (67) Cubic Space of Rooms, the Ground Plan of which is an Irregular Figure. 106 
 
 (68) The Cube of Cylinders such as Pillars . .107 
 
 (69) Area of Ellipses . . . . . . . 110 
 
 (70) The Cube of Rectangular Prismoids and Frustums of Cones or Pyramids 111 
 
 (71) To Find the Cubic Content of Irregular Spaces . . 112 
 
 (72) Example of Reports on Ventilation . . 112 
 
 SECTION 111.— METEOROLOGY. 
 CHAPTER X. 
 
 THE BAROMETER. 
 
 (73) Principle of the Barometer 119 
 
 (74) The Glycerin Barometer . 120 
 
 (75) Mercurial Barometers . 121 
 
 (76) Reading a Mercurial Barometer 123 
 
 (77) CoiTcction of Barometer Reading.s 124 
 . (78) The Aneroid Barometer 125 
 
 (79) Hygrometers. . 127 
 
s CONTENTS. 
 
 CHAPTER XI. 
 
 THE DEW-POINT — KAINFALL — SUNSHINE — WIND. 
 
 PAGE 
 
 (80) Determination of the Dew-point 129 
 
 (81) Measurement of Rain. Rain Gauges . . . • 1^* 
 
 (82) Registration of Sunlight . . , - ■ 136 
 
 (83) Wind Anemometers . * l®'^ 
 
 SECTION IV.—WAmE SUPPLY. 
 CHAPTER XII. 
 
 SOUKCES OF WATEE SUPPLY. 
 
 (84) Rivers . ... . 141 
 
 (85) Wells .... . 141 
 
 (86) Artesian Wells . 142 
 
 (87) Lakes ... . . . . . .142 
 
 (88) Quantity of Water per Head ; . . .143 
 
 (89) Catchment Areas, Contour Lines, Ridge Lines . 144 
 
 (90) Rainfall in Relation to Water Supply . . 145 
 
 (91) General Principles of a Town Water Supply 146 
 
 (92) Water Meters .... 147 
 
 (93) Constant and Intermittent Water Supply . . . 147 
 
 (94) Fittings for Constant Water Supply ... 148 
 
 CHAPTER XIII. 
 
 THE WATEE SUPPLY OF THE METKOPOLIS. 
 
 (95) The London Water Companies . . . . 150 
 
 (96) Kent Waterworks Company . . 150 
 
 (97) The New River Company . . . 151 
 
 (98) The East London Water Supply ... . . 151 
 
 (99) The Southwark and Vauxhall Company 152 
 
 (100) The West Middlesex Company . . 152 
 
 (101) The Grand Junction Company ... . . . 153 
 
 (102) The Lamheth Company Waterworks . .... - . . 153 
 
 (103) The Chelsea Company ... . . . ... 153 
 
 (104) Summary of the London Water Supply 154 
 
 (105) Purification of the London Water Supply. Filter Beds . . . 154 
 
 CHAPTER XIV. 
 
 THE SCIENTIFIC EXAMINATION OF WATEE. 
 
 (106) Purity of Water 156 
 
 (107) Examination and Analysis of Water . . I57 
 
 (108) Examination by the Senses . . . I57 
 
 (109) Microscopical and Biological Methods 158 
 
 (110) Qualitative Examination of Water . . . 161 
 
 (111) Quantitative Chemical Examination . . . 163 
 
CONTENTS. xi 
 
 (112) Solutions Required for the Analysis . . 
 
 PACE 
 
 164 
 
 (113) The Operation of Weighing . . 
 
 165 
 
 (114) Relation between the Litre and the Gallon . 
 
 166 
 
 (115) Solid Residue . . 
 
 167 
 
 (116) Ammonia 
 
 . 167 
 
 (117) Chlorine 
 
 169 
 
 (118) Nitrates 
 
 169 
 
 (119) Hardness ... . . 
 
 . 170 
 
 (120) Alkalinity •. 
 
 . 171 
 
 (121) Sulphates ... 
 
 . . . . 171 
 
 (122) Classification of Natural "Waters and the Interpretation 
 
 of a Chemical 
 
 Analysis 
 
 172 
 
 (123) Interpretation of an Analysis 
 
 : 173 
 
 (124) Purification and Softening of "Water . . . 
 
 175 
 
 SECTION V. DRAINS SEWERS SEWAGE 
 
 DISPOSAL. 
 
 CHAPTER XV. 
 
 
 DEAINS. 
 
 
 (125) Legal Distinction between Drains and Sewers 
 
 181 
 
 (126) Brick Drains and their Defects . 
 
 , 182 
 
 (127) "Varieties of Drain Pipes . . . . 
 
 185 
 
 (128) Fall of House Drains . 
 
 . . . 186 
 
 (129) General Method of House Drainiige . . 
 
 187 
 
 (130) Traps . . 
 
 188 
 
 (131) The "Water Seal 
 
 189 
 
 (132) Examples of Traps . . 
 
 190 
 
 (133) Grease Traps . . 
 
 192 
 
 (134) Inspection of Drainage . ... ... 
 
 192 
 
 (135) Special Drain Tests ... 
 
 193 
 
 CHAPTER XVI. 
 
 SEWBES. 
 
 (136) Drain-Sewers .... ..... 195 
 
 (137) The Flushing of Sewers ■ 196 
 
 (138) Dead Ends of Sewers .197 
 
 (139) The Size of Sewers. The Separate System . . . . . 197 
 
 (140) The Shape and Construction of Sewers . 198 
 
 (141) Capacity of Sewers . . 200 
 
 (142) Steep Gradients .... . . . ' 201 
 
 (143) Inverted Syphons 201 
 
 (144) Storage Sewage Reservoirs . 202 
 
 (145) Road Gullies . 202 
 
 (146) Ventilation of Sewers ... . . .202 
 
 (147) The Outfall of Sewers . . . 204 
 
xii CONTENTS. 
 
 CHAPTER XYII. 
 
 THE SEWBEAGB OF THE METEOPOLIS. 
 
 PAGE 
 
 (148) Interception . 205 
 
 (149) Size of the Main London Sewers .... 205 
 
 (150) General Principle of the Metropolitan Sewer System 206 
 
 (151) Northern Interception 207 
 
 (152) Southern Interception . . . 208 
 
 (153) Arrangements at the Main Outfalls . 211 
 
 CHAPTER XVIII. 
 
 CALCTTLATIONS OF THE DISOHABGE OF SEWASB OB WATER OE OTHEK LIQUIDS. 
 
 (154) Eytelwein's FormulEe 216 
 
 (155) Head of Water . 219 
 
 (156) Kutters' Formula 220 
 
 CHAPTER XIX. 
 
 DISPOSAL OF SEWAGE. 
 
 (157) Irrigation of Land ... 223' 
 
 (158) Chemical Processes for the Treatment of Sewage . 225 
 
 (159) Composition of Sewage ... . . . . . 226 
 
 (160) General Reactions on the addition of Lime, Iron, or Alumina . 227 
 
 (161) Lime Process 227 
 
 (162) Alumina Process . . . .228 
 
 (163) Salts of Iron . . 228 
 
 (164) Various Mixtures . . 228 . 
 
 (165) Sewage Sludge , . 229 
 
 (166) Summary of Precipitation Processes .... . 229 
 
 Special Systems of Sewerage. 
 ,(167) The Shone System . ... 230 
 
 (168) The Liermur System .... .230 
 
 (169) The Treatment of Sewage by Electrolysis . . 231 
 
 (170) Dry Systems of Sewage Disposal ... . . 231 
 
 (171) The Pail System ... . 232 
 
 (172) "Water Closets 233 
 
 (173) Soil Pipes . 236 
 
 SECTION Yl.— NUISANCES. 
 CHAPTER XX. 
 
 ORDINARY NUISANCES DEALT WITH BY .SANITARY AUTHORITIES. 
 
 (174) Distinction between Private and Public Nuisances . . 241 
 
 (175) Leading Cases as to Nuisance ... . 243 
 
 (176) Nuisances under the 91st Section of the Public Health Act, 1875 . 244 
 
CONTENTS. xiii 
 
 PAGE 
 
 (177) Offensive Businesses specifically mentioned in the Public Health and 
 
 Sanitary Acts . . . 248 
 
 (178) Blood Drier, Blood Albumin, Blood Boiling 248 
 
 (179) Fat Melting, Dip Candle Making .... .250 
 (ISO) Bone Boiling ... ... 253 
 
 (181) Soap Boiling, Soap Making .... . . . .253 
 
 (182) Manufacture of Manure . . ... 254 
 
 (183) TheTradeofaFellmonger .... ... 255 
 
 (184) Gut Scraping. Gut Spinning. Preparation of Sausage Skins . 256 
 
 (185) The Boiling of Tripe . .... 261 
 
 (186) Slaughter Houses . . 263 
 
 (187) Knackers' Yards ... 268 
 
 CHAPTER XXI. 
 
 EFFLUVIUM NUISANCES CONNECTED VflTH TRADES. 
 
 (188) Classification of Effluvium Nuisances . . 271 
 
 (189) Pig Keeping ... . . . . 272 
 
 (190) Bacon Curing .... . 273 
 
 (191) Nuisance from Stables. Horse Keeping 273 
 
 (192) Cow Keeping. Dairies 274 
 
 (193) Dairies, Cowsheds' and Milkshops' Order 275 
 
 (194) Tanning . 280 
 
 (195) Leather Dressing . . .282 
 
 (196) Manufacture of Chamois Leather 282 
 
 (197) Glue Making 283 
 
 (198) Nuisance from Fried Fish Shops 286 
 
 (199) Roasting of Vegetable Substances, such as Malt, Chicory, Coffee 287 
 
 (200) Nuisances from the Manufacture of India-rubber . 287 
 
 (201) Flax Betting 288 
 
 (202) The Manufacture of Oxalic Acid from Sawdust . 288 
 
 (203) The Manufacture of Paper from Esparto Grass . 289 
 
 (204) The Manufacture of Wood Pulp 289 
 
 (205) Distillation of Wood for the purposes of obtaining Wood Naphtha and 
 
 Pyroligneous Acid . ... ... 289 
 
 (206) Nuisances depending chiefly on the Production of Acrolein 290 
 
 (207) The Manufacture of Coal Gas '. 291 
 
 (208) The Manufacture of Sulphate of Ammonia and of Sal Ammoniac 293 
 
 (209) DistUlation of Tar . . . 294 
 
 (210) The Manufacture of Carbolic Acid 295 
 
 (211) The Manufacture of Alkali 296 
 
 (212) The Manufacture of Picric Acid and the Manufacture of Aniline and 
 
 AniUne Colours . .... .... 298 
 
 (213) The Manufacture of Sulphuric Acid . . 298 
 
 (214) The Manufacture of Salt .299 
 
 (215) The Manufacture of Chloride of Lime (Bleaching Powder) , . 300 
 
 (216) The Manufacture of Glass 301 
 
 (217) The Calcining of Ironstone and Tap Cinder 302 
 
 (218) Hardening of Steel Springs and Saws 302 
 
xiv. CONTENTS. 
 
 PACK 
 
 (219) The Calcining of Spelter 302 
 
 (220) Galvanizing Iron . . 302 
 
 (221) Tin Plate Manufacture 303 
 
 (222) Tin Burning • ... 301 
 
 (223) The Calcining of Arsenic and Arsenical Ores . . . . . 304 
 
 (224) The Smelting of Copper Ores 304 
 
 (225) Lime Burning 305 
 
 (226) Manufacture of Coke and Breeze . . . 305 
 
 (227) Brick Burning ... 306 
 
 (228) Ballast Burning 307 
 
 (229) The Manufacture of Portland Cement 307 
 
 (230) The Firing of Pottery . . . . . 309 
 
 SECTION Yll.—DISIN'FEGTION'—DISINFECTAN'TS. 
 CHAPTER XXIJ. 
 
 EXPEEIMENTAL METHODS FOR TESTING THE VALUE OF A DISINFECTANT. 
 
 (231) Distinction between Disinfectants and Antiseptics . 313 
 
 (232) Temperature . 313 
 
 (233) Experimental Methods . . 314 
 
 (234) The Drop Method . 314 
 
 (235) The Thread Method . . ,315 
 
 CHAPTER XXIII. 
 
 DISINFECTION BY HEAT. 
 
 (236) Experiments of Parsons and Klein . 318 
 
 (237) Experiments with Dry Heat . 318 
 
 (238) Experiments with Moist Heat ... . 319 
 
 (239) On the Penetration of Heat into Articles Submitted for Disinfection 319 
 
 (240) Explanation of the Superior Penetrating Power of Steam . 321 
 
 (241) On the Liability to Injury of Articles Disinfected by Heat . . . 323 
 
 (242) Scoi?ching ... . 324 
 
 (243) Over Drying ... ... . . 326 
 
 (244) The Fixing of Stains . ... 327 
 
 (245) Melting of Fusible Substances such as "Wax and Varnish 328 
 
 (246) Alterations in Colour, and Shrinking . . 329 
 
 (247) Wetting ' . 33O 
 
 (248) The Different Forms of Apparatus for Disinfection by Heat 331 
 
 (249) Washington Lyon's Patent Disinfector . 33I 
 
 (250) Bradford's Patent Disinfecting Apparatus . 332 
 
 (251) The Nottingham Self- Regulating Disinfecting Apparatus 333 
 
 CHAPTER XXIV. 
 
 CHEMICAL DISINFECTANTS. 
 
 (252) List of Practical Disinfectants . . . , 33^ 
 
 (253) Mercuric Chloride. Corrosive Sublimate. Bichloride of Mercury HgCl^ . 334 
 
CONTENTS. XV 
 The Halogens. 
 
 PAGE 
 
 (254) Chlorine. . . .336 
 
 (255) Iodine . . 337 
 
 (256) Bromine . . . . 337 
 
 (257) The Experiments of Cash on the Halogens ... . 337 
 
 (258) The Experiments of Fischer and Proskaner .... . 343 
 
 (259) Iodine Trichloride ... . . 345 
 
 (260) Phenol. Carbolic Acid . 346 
 
 (261) Cresol. Cresylio Acid . . 347 
 
 (262) Estimation of Impvirities in Commercial Carbolic Acid 347 
 
 (263) Carbolic Acid Powders are Powders which should contain Free Tar Acids 848 
 
 (264) The Author's Experiments on the Disinfecting Powers of Phenol and 
 
 Cresol 348 
 
 (265) Experiments on the Disinfecting Action of Phenol and Cresol on Sewage . 350 
 
 (266) Koch's Experiments on Phenol ... ... . . .351 
 
 (267) Schill and Fischer on the Action of Phenol on Tuberculous Matters . . 351 
 
 (268) Summary of the Action of Phenol and the Cresols as Disinfectants . . 352 
 
 (269) Creasote. ... 352 
 
 (270) Phenyl-Propionic and Phenyl-Acetio Acids . . . 352 
 
 (271) Sulphur Dioxide {Sulphurous Acid Gas) ... 353 
 
 (272) "Wolfhugel's Researches on the Disinfecting Properties of Sulphurous 
 
 Acid Gas ... ... . . . 354 
 
 (273) Cash's Experiments on Sulphurous Acid ... . 357 
 
 (274) The Practice of Disinfeption. The Disinfection of the Sick Boom 358 
 
 (275) Disinfection of House Drains and Closets . . 359 
 
 SECTION YI11.—2YM0TIC {MJCRO-PARASITIG) DISEASES. 
 
 CHAPTER XXV. 
 
 THE MODBEN THEOET OP MIOKO-PAEASITBS. 
 
 (276) Micro-strife . . 363 
 
 (277) Acquired Immunity . ... 364 
 
 (278) Classification of Micro-parasitic Diseases . . 365 
 
 CHAPTER XXVI. 
 
 BBTJPTIVE FEVEES, SMALL-POX, MEASLES, SOAELBT FEVEE AND TYPHUS. 
 
 Small-Pox. 
 
 (279) Incubation and Eruption. . . 366 
 
 (280) Mortality of SmaU-Pox. . . ... 368 
 
 (281) Seasonal Prevalence of Small-Pox. . . . 368 
 
 (282) The Infection of Small-Pox . . 369 
 
 (283) The Duty of the Sanitary Authority and of its Medical Officer in Small- 
 
 Pox Outbreaks. ... . . . . 370 
 
 (284) Vaccination and Small- Pox . ... 372 
 
xvi CONTENTS. 
 
 Measles. 
 
 PAGE 
 
 (286) Statistics • -374 
 
 (286) Seasonal Prevalence. 375 
 
 (287) Symptoms , , 376 
 
 (288) Etiology. ..... 377 
 
 (289) Measures to be taken in Outbreaks of Measles. 377 
 
 Scarlet Fever. 
 
 (290) General Course of Scarlet Fever. Incubation. 378 
 
 (291) Seasonal Prevalence of Scarlet Fever 380 
 
 (292) Mortality of Scarlet Fever 380 
 
 (293) Sex and age 381 
 
 (294) Sequels and complications of Scarlet Fever . . . 388 
 
 (295) Period during which it is necessary to isolate Scarlet Fever Patients S90 
 
 (296) The Connection of Scarlatina with Disease in Milch Cows 391 
 
 Ty]}hus. 
 
 (297) Statistics 395 
 
 (298) Incubation Period 395 
 
 (299) Symptoms . . 396 
 
 (300) Etiology of Typhus . 398 
 
 (301) Mortality 400 
 
 (302) Seasonal Prevalence 401 
 
 (303) Race .402 
 
 (304) Prevalence of Typhus in 1886 402 
 
 (305) The Nazareth House Outbreak . 404 
 
 (306) The Isolation and Prevention of Typhus . 405 
 
 CHAPTER XXVII. 
 
 MICEO-PAKASITIC DISEASES AFFECTING THE NEEVOUS SYSTEM — KABIBS — TETANUS — 
 
 WHOOPING COUGH. 
 
 (307) Rabies 408 
 
 Tetanus. 
 
 (308) Researches on the Bacteriology of Tetanus . 408 
 
 (309) The Prevention of Tetanus ' 412 
 
 Whooping Cough. 
 
 (310) General Nature of "Whooping Cough 412 
 
 (311) Statistics 412 
 
 (312) Etiology . 412 
 
 313) Duty of the Medical Ofiacer of Health 413 
 
 CHAPTER XXVIII. 
 
 MIORO-PARASITIO DISEASES MAINLY AFFECTING THE BESPIEATOEY OEGANS. 
 
 Pneumonia. 
 
 (314) Epidemic Pneumonia . . 414 
 
 (315) Evidence of the Infectious Character of Pneumonia . 414 
 
 (316) The Middlesborough Epidemic ... . 416 
 
CONTENTS. xvii 
 
 PAGE 
 
 (317) Etiology of Pneumonia. Gamaleia's Views . 416 
 
 (318) Pathogenic Role of the Streptococcus Lanceolatns 418 
 
 (319) Streptococcus Lanceolatns in Healthy Persons 421 
 
 (320) Bacteriology of the Middlesborough Pneumonia Cases . 424 
 
 (321) Preventive Measures . ... 425 
 
 CHAPTER XXIX. 
 
 SEPTIOa)MIC MALADIES. 
 
 Erysipelas. 
 
 (322) Mortality from Erysipelas . . . 426 
 
 (323) Mortality as Influenced by Season , . . . 427 
 
 (324) Bacteriology . ... 427 
 
 (325) Etiology ... 427 
 
 (326) Disinfection after Erysipelas .... 428 
 
 Diphtheria. 
 
 (327) Mortality from Diphtheria ... . 429 
 
 (328) Geographical Distribution of Diphtheria in England and "Wales 429 
 
 (329) Researches on the Bacteriology and Pathology of Diphtheria . 431 
 
 (330) The Nature of the Diphtheritic Poison 433 
 
 (331) Klein's later Researches on Diphtheria . . . 435 
 
 (332) The Prevention of Diphtheria . 439 
 
 Puerperal Fever — Septiccemia — Pycemia — Blood-Poisoning. 
 
 (333) Influence of Season on Septic Diseases . . . 440 
 
 (334) Statistics of Puerperal Mortality 441 
 
 (335) Bacteriology of Septic Diseases . . . 442 
 
 (336) The Duty of the Health Of&cer in Relation to Puerperal Fever . . 442 
 
 (337) Disinfectants in the Puerperal Condition . 443 
 
 CHAPTER XXX. 
 
 TUBEEOULAR MALADIES. 
 
 Tuberculosis. 
 
 (338) Statistics of Tubercular Mortality . . 444 
 
 (339) The Influence of Age and Sex . . . 445 
 
 (340) Probability of a Person Dying from Consumption . 448 
 . (341) Influence of Occupation on Tubercle Infection . 449 
 
 (342) Influence of Soil . 450 
 
 (343) Influence of Season on Tubercle Fatality . 451 
 
 (344) Bacteriology and Pathology of Tuberculosis 451 
 
 (345) Characteristics of the Tubercle Bacilli . . . 453 
 
 (346) Artificial Cultivation of Tubercle Bacilli .... . 454 
 
 (347) The Universal Presence of the Bacilli in true Tubercle . . . 456 
 
 (348) Experimental and Clinical Proofs of the Contagious Nature of Tuberculosis 457 
 ,(349) The Production of Tubercles in Animals by Feeding them with Tubcrcu- 
 
 ''W lous Products 462 
 
 6 
 
xviii CONTENTS. 
 
 PAGE 
 
 (350) Unequal Susceptibility of different Animals to the Tubercular Infection . 463 
 
 (351) Giant Cells ... .464 
 
 (352) Pathology of Tuberculosis • *^^ 
 
 (353) The Pathology of Pulmonary Tuberculosis . . 465 
 
 (354) The Pathology of Acute Miliary Tuberculosis . ... 475 
 
 (355) The Eelations of Scrofula, Lupus, and Tuberculosis .... .476 
 
 (356) Propagation of Tubercle through the agency of Milk derived from a 
 
 Diseased Cow ... .... . 476 
 
 (357) Propagation of Tuberculosis from consuming the Flesh of Tuberculous 
 
 Animals ... . ■ ■ 4^" 
 
 (358) Disinfection of Tuberculous Products ... 482 
 
 (359) The Prevention of Tuberculosis . 485 
 
 CHAPTER XXXI. 
 
 MA.LAEIA — MALAKIOtrS DISEASES. 
 
 (360) The Effects of Malaria . 487 
 
 (361) Bacteriology of Malarious Diseases . 487 
 
 (362) Geographical Distribution of Malarious Tracts 488 
 
 (363) Malaria from Local Causes . . 488 
 
 (364) Prevention of Malaria . . 489 
 
 CHAPTER XXXII. 
 
 MIOEO-PAKASITIC DISEASES MAINLY ATTACKING THE INTESTINE. 
 
 Enteric (yr Typhoid Fever. 
 
 (365) Statistics of Mortality from Enteric Fever . 490 
 
 (366) Case Mortality of Enteric Fever . 491 
 
 (367) Incubation Period 491 
 
 (368) Seasonal Prevalence . . 492 
 
 (369) Bacteriology of Enteric Fever 493 
 
 (370) Symptoms . 498 
 
 (371) Predisposition . . 500 
 
 (372) Pathological Appearances after Death , 500 
 
 (373) Diagnosis of Typhoid 503 
 
 (374) Theory of the Propagation of the Disease 503 
 
 (375) The Ground "Water Theory . 504 
 
 (376) Propagation of Typhoid . 505 
 
 (377) Prevention of Typhoid ' . 507 
 
 Asiatic Cholera. 
 
 (378) History of Cholera in England 508 
 
 (379) Epidemic of 1848-9 509 
 
 (380) Epidemic of 1854 510 
 
 (381) The Broad Street Pump ... 511 
 
 (382) Lessons learnt from the 1849 and 1854 Epidemics 512 
 
 (383) The Cholera of 1866 512 
 
 (384) The East London "Water Company and the Cholera of London 512 
 (885) The Relation of Altitude to Cholera Mortality 514 
 
CONTENTS. xix 
 
 PAGE 
 
 (386) Mortality of Cholera in Relation to Age and Sex 514 
 
 (387) Symptoms . .... 516 
 
 (388) Post-mortem Appearances . 518 
 
 (389) Bacteriology of Asiatic Cholera . . 519 
 
 (390) The BaciUus of Finkler and Prior 522 
 
 (391) The Recognition of the Comma Bacillus hy Chemical Tests 523 
 
 (392) Klein's Objections to the " Comma " Theory . . . . . 523 
 
 (393) Experiments on the Communicability of Cholera before the Discovery of 
 
 the Comma Bacillus . . . . ... . . 524 
 
 (394) Modem Experiments on Animals with Cultivations of the Comma Bacillus 527 
 
 (395) Propagation of Cholera by "Water and otherwise . . . . 529 
 
 (396) Propagation of Cholera by Clothes soiled with the Discharges , . 531 
 
 (397) Pettenkofer's Theory ... 532 
 
 (398) Preventive Measures as Formulated by Koch . 532 
 
 (399) OfScial Memorandum as to Prevention of Cholera . . 534 
 
 (400) Order Prohibiting Importation of Rags 539 
 
 Diarrhma. — English Cholera. 
 
 (401) Mortality and Sickness from Diarrhoea 539 
 
 (402) Symptoms . 540 
 
 (403) Seasonal Influences . 540 
 
 (404) Predisposition . 542 
 
 (405) Bacteriology of DiarrhcEa . 542 
 
 (406) General Results of Ballard's Inquiry . . . 543 
 
 (407) Practical Action to be taken as Preventive of Diarrhoea 553 
 
 SECTION IK.— ISOLATION HOSPITALS. 
 CHAPTER XXXIII. 
 
 THE PEINOIPLES OF CONSTKUOTION OP ISOLATION HOSPITALS. 
 
 (408) Infectious Hospitals 557 
 
 (409) Site. ... . 557 
 
 (410) Hospital Construction . , 558 
 
 (411) The Wards . . 558 
 
 (412) Ventilation. 559 
 
 (413) Warming 560 
 
 (414) Closets . 560 
 
 (415) Sinks. — Drainage. , 560 
 (416; Furniture ... 561 
 
 (417) Disposal of the Dead . . 561 
 
 (418) The Local Government Board Hospital Plans. . . 561 
 
 (419) The Superintendence and Management of Hospitals . 562 
 
 (420) Duties of Nurses 563 
 
 (421) Duties of the Laundry Superintendent. . 563 
 
 (422) Duties of the Gate Porter . . . . 563 
 
 (423) General Regulations. . . . . 564 
 
 (424) Regulations as to the Condition of Patients 564 
 
 (425) Visiting . ... . . . 564 
 
CONTENTS. 
 
 SECTION a.— FOOD— DIET. 
 GHAPTEE XXXIV. 
 
 THE PRINCIPLES OF DIET. 
 
 PAGE 
 
 (426) Water in Food ... 569 
 
 (427) Albuminous Materials 570 
 
 (428) The Relation of Nitrogen to work . 571 
 
 (429) Quantity of Nitrogen required 572 
 
 (430) Carbohydrates 573 
 
 (431) Fats . . 573 
 
 (432) Mineral Matters 574 
 
 (433) Digestibility of Foods . . . ... 575 
 
 (434) The Standard Diet 578 
 
 (435) Construction of Dietaries 578 
 
 SECTION XI.— THE DUTIES OF SANITARY OFFICERS. 
 CHAPTER XXXV. 
 
 DUTIES AiJD QUALIFICATIONS OF MEDICAL OFFICERS OF HEALTH. 
 
 (436) Qualifications of Medical Officers of Health . . 587 
 
 (437) Duties of Medical Officers of Health . . 588 
 
 (438) Duties of a Port Medical Officer of Health . . ... 597 
 
 (439) The Report of a Port Medical Officer of Health 598 
 
 (440) The Duties of a Medical Officer of Health . ... 599 
 
 (441) The Reports of a Medical Officer of Health to a Combined District . 600 
 
 (442) Duties of Medical Officers of Health as laid down by the Local Government 
 
 Board . . . . 60O 
 
 (443) Duties and Qualifications of Inspectors of Nuisances . 602 
 
 (444) Duties of Port Sanitary Inspector . . . 604 
 
 (445) Duties of Inspectors as laid down by Order of the Local Government Board 606 
 
 SECTION XII.— INSPECTION OF FOOD. 
 CHAPTER XXXVI. 
 
 THE INSPECTION AND SEIZURE OF UNWHOLESOME FOOD. 
 
 (446) Powers of Inspecting Food . g-^-^ 
 
 CHAPTER XXXVII. 
 
 POISONOUS FOOD. 
 
 (447) The Development of Poison in Food 613 
 
 (448) Pork-Pie Poisoning at Retford 613 
 
CONTENTS. xxi 
 
 PAGi: 
 
 (449) The Arlford Sausage Poisoning Case . \ . . . . 615 
 
 (450) Diarrhoea from Milk or Cheese — Tyro-toxioon ... . . 616 
 
 (451) Method of Investigating Outbreaks of Diarrhoea or Illness supposed to 
 
 result from Bad Food . . . ... 617 
 
 CHAPTER XXXVIII. 
 
 "UNFIT VEGETABLE SUBSTANCES. 
 
 (452) Decomposed Vegetables . . . . . . 620 
 
 (453) Unhealthy Condition of Flour or Bread . . ... 620 
 
 (454) Ergot in Flour . . . .620 
 
 (455) Corn Cockle Seeds in Flour . . . 621 
 
 CHAPTER XXXIX. 
 
 INSPECTION OF FISH AND MEAT. 
 
 (456) Inspection of Fish . , 622 
 
 (457) Inspection of Meat . . .622 
 
 (458) Characteristics of Good Meat ... . . . .623 
 
 (459) The Detection of the Tubercle Bacilli . . .624 
 
 CHAPTER XL. 
 
 DISEASES OF ANIMALS KENDERINQ THEIR FLESH MORE OR LESS UNFIT FOR 
 
 FOOD. 
 
 (460) Measles in the Pig and the Ox . . . ...... . ., . . . 626 
 
 (461) Trichinae— Trichinosis . . .... 627 
 
 (462) Examination of Meat for Trichina ... .... 629 
 
 (463) Vitality of Trichinae . . 630 
 
 (464) Glanders and Farcy ... . . 630 
 
 (465) Variola of Sheep 630 
 
 (466) Paeumo-Enteritis of the Pig , 631 
 
 (467) Swine Plague 632 
 
 (468) St. Anthony's Fire 632 
 
 (469) Foot and Mouth Disease . .... ... 633 
 
 (470) Pleuro-Pneumonia 633 
 
 (471) Cattle Plague 634 
 
 (472) Tuberculosis . 635 
 
 (473) Actinomycosis . . 635 
 
 (474) Anthrax .... 636 
 
 (475) Charbon Symptomatique . 639 
 
LIST OF ILLUSTRATIONS 
 
 PIG. PAGE 
 
 1 FnLLBE's Spiral Rttlb ... 36 
 
 2 Scale of Fuller's Spiral Rule ... 36 
 
 3 The Cirotjlae Arithmometer 41 
 
 4 The Straight Arithmometer . 44 
 
 5 Lunge and Zeokendoef's Apparatus foe the estimation of Carbonic 
 
 Acid in Air . . . 97 
 
 6 Schrottbr's Apparatus for the Estimation of Carbonic Acid ... 99 
 
 7 Triangle . . . 
 
 8 Section of House 
 
 9 A Trapezoid 
 
 10 Ground Plan of a Room . 
 
 11 A Circle 
 
 105 
 105 
 106 
 106 
 108 
 
 12 Ground Plan of a Room hating a Bow-Window 109 
 
 13 A Polygon . . .110 
 
 14 A Roof . . Ill 
 
 15 A Frustum . . .111 
 
 16 Section of a Drain . 112 
 
 17 An Anemometer . . . . .... 114 
 
 18 Diagram showing how the Values from a Glycerin Barometer 
 
 ARE Plotted . . 121 
 
 19 Fortin's Barometer . ... . , 122 
 
 20 The Mercurial Barometer Scale . . 123 
 
 21 An Engineering Aneroid . . ... . 126 
 
 22 Hygrometer (horizontal form) 128 
 
 23 ,, (vertical form) ... 128 
 
 24 Rain Gauge . ... i^^ 
 
 25 Glass Measure for Measuring Rain-fall 134 
 
 26 The Whipplb-Cassella Sunshine Recorder . 13g 
 
 27 Wyntee-Blyth's Deposit Tube . ^^53 
 
 28 Drop Bottle . . jgO 
 
 29 Diagram Illustrating Deposit in a Sewee caused by the deliveet 
 
 of Liquid from a Soil Pipe . _ 183 
 
 30 A Flat Beick Drain .... ■ 183 
 
LIST OF ILLUSTRATIONS. xxiii 
 
 PIG. PAGE 
 
 31 A CiECULAE Brick Drain .... ... 183 
 
 32 Diagram Ili,ustrating the Stphoning of Traps 190 
 
 33 A Bell Trap . . . . . . 190 
 
 34 Buchan's Disconnecting Chamber . . 191 
 
 35 A Grease Trap . ... ... 192 
 
 36 Outline of Older Form of Egg-shaped Sewer . . 199 
 
 37 Outline OF New Form OF Egg- SHAPED Sewer 199 
 
 38 Section of Brick Sewer . . 199 
 
 39 A Road Gully 202 
 
 40 Keeling's Gas Exhauster . . 203 
 
 41 A Pan Closet . 234 
 
 42 The Bramah Closet . . . . 234 
 
 43 The Hopper Closet . . . . 235 
 
 44 The Washout Closet . . ...... 235 
 
 45 Hetwood and Lloyd's Apparatus for Condensing the Vapours from 
 
 Varnish Making ... . . 291 
 
 46 Diagram showing Apparatus in use at Mr. Lowe's Works 295 
 
 47 Drop Bottle .... 315 
 
 48 Buohan and Mitchell's Curve of Small-Pox Mortality . . . 369 
 
 49 Slightly Magnified Culture of the Streptococcus Scarlatina . ■ 393 
 
 50 Photograph of a Highly Magnified Preparation of the Strepto- 
 
 coccus Scarlatina . 393 
 
 51 Tubercle Bacilli ... . . 454 
 
 52 Stab Culture of Gaffky's Bacillus, aud a similar Bacillus derived 
 
 FROM A case of Diarrhcea . .... 497 
 
 53 Tank in a Calcutta Busteb, with Huts and Privies on its Edge 596 
 
 54 A Magnified Tuft of Actinomycosis . . 636 
 
PLATES AND DIAGRAMS 
 
 Tofacejiage 
 
 GeneKAl Map of the Main Drainage System of the Metropolis 208 
 
 Diagram showing the Curves Representing the Monthly Admissions of Fever 
 
 Cases into the Metropolitan Asylum Board Hospitals ... . 3S0 
 
 Plate I. (A) Section of the Spleen of a Cow which had been Inoculated 
 with Streptococcus Scarlatinse. (B) Section of a Bronchial Gland. (C) A 
 Portion of the Lung from the same Cow 393 
 
 Plate II. (a) A Giant Cell containing numerous Bacilli arranged in a Radiating 
 Form X 700. (J) A few Colonies from the Artificial Culture Represented 
 in Plate III. (S). (c) The Spleen of a Rabbit Infected with Tuberculosis 
 by Injection of an Artificial Culture into the Anterior Chamber of the Eye 
 (after Koch) . . 453 
 
 Plate III. [a) JTaked Eye Appearance of a Culture of Tubercle Bacilli on 
 Coagulated Blood Serum. (6) The same X 80. (c) The Lungs of a 
 Guinea-Pig Infected with Miliary Tuberculosis by Inhalation (after Koch) . 454 
 
 Plate IV. (a) A Portion of the Human Ileum Afiected with Typhoid Ulcera- 
 tion. (6) A Portion of the Small Intestine of a Cariama Afiected with 
 Tuberculous Ulceration, (c) A Tuberculous Ulcer of the Human Ileum . 465 
 Plate V. (1) Appearance of the Human Ileum in an Early Stage of Typhoid 
 Fever, probably before the Seventh Day. (2) The Human Ileum at a 
 Later Stage of Typhoid showing Typical Ulcers . . 501 
 
 Plans of Small Isolation Hospitals as Recommended by the Local Government 
 
 Board . ... ... 562 
 
 Plate V"I. Cystioercus Bovis (Beef Measles) .... . . . 627 
 
 Plate VII. Encysted Trichinae in Human Muscle 629 
 
 Plate VIII. A Portion of the Mucous Membrane of the Ileum of a Pig which 
 
 had Died of Pig Typhoid 631 
 
 Plate IX. Sections of the Tongue of an Ox Affected with Actinomycosis . 635 
 
SECTION I. 
 ST A TISTICS. 
 
A MANUAL OF PUBLIC HEALTH. 
 
 CHAPTER I. 
 
 THE CALCULATION AND SIGNIFICANCE OF VITAL STATISTICS. 
 
 Vital Statistics have been defined as the science of figures 
 applied to life ; the term was first invented by Professor Achenwall, 
 of Gottingen; the science itself by Sir William Petty, who died 
 in 1687. 
 
 The materials for the statistics of the health officer are the 
 census returns, any local census which he may make, and returns 
 from the registrars or other persons. 
 
 (1) Method of Calculating Populations between the Census Periods. 
 
 The ten-year period census is far too long, and in certain 
 rapidly growing or decreasing localities, causes great errors in the 
 calculated rates, whenever such increase or decrease is irregular. 
 If, however, the change is fairly uniform, the population may in 
 any year in the interval between two censuses, be approximately 
 calculated by the following rule. 
 
 From the logarithm^ of the most recent census subtract the 
 logarithm of the previous census, and divide the number so ob- 
 tained by the number of intervening years ; the quotient will be 
 
 ' It is difficult and oumberaome to use ordinary arithmetic in the calculation of 
 a variety of data which the sanitarian requires, hence a knowledge of the use of 
 logarithms is essential. Law's Mathematical Tables (Crosby, Lockwood, and Son) are 
 very clear and the directions simple. Woodward's Logarithms and Chambers's Tables 
 may also be recommended. 
 
 B 2 
 
4 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 the logarithm of the ratio of annual increase. By adding this 
 logarithm to the logarithm of the population at any period, the 
 logarithm of the population at the end of the succeeding year will 
 be obtained ; and by continually adding the logarithm of the ratio, 
 the logarithm of the population in each successive year will be 
 obtained.^ 
 
 For example, supposing that in 1886 it is required to calculate 
 the population of a town, for each year from 1881, the census in 
 1871 giving 156,000, and in 1881 giving 171,000. Then 
 
 Logarithm of 171,000 = 5-232996 
 156,000 = 5-193125 
 
 0-039871 -=-10 = -003987 =the logarithm of 
 ratio of increase. 
 Then log. of 171,000 = 5-232996 
 0-003987 
 
 5-236983 No. 172,580 population in 1882 
 
 0-003987 
 
 5-240970 „ 174,170 „ „ 1883. 
 
 0-003987 
 
 5-244957 „ 175,780 „ „ 1884. 
 0-003987 
 
 5-248944 „ 177,400 „ „ 1885. 
 0-003987 
 
 2 
 
 5-252931 „ 179,030 „ „ 1886. 
 
 ^ Let jj denote the population at anytime ;y the population at any previous time 
 
 ■n the number of intervening years ; then \/^ = r = 1 + the annual rate of 
 
 increase. The division of the logarithm of 2 or 3 by the logarithm of r gives the 
 number of years in which at that rate the population will double or triple, &c. 
 (Farr). 
 
 2 The census is taken in March, therefore the numbers obtained would be the 
 presumed population in the March of the different years ; but if it is req^uired to esti- 
 mate for the middle of each year, we must begin by adding Jth of the logarithm 
 •0039871 to the 1881 population, which will then represent the logarithm of the 
 population in the middle of 1881 ; by then adding to the logarithm of each succeeding 
 year the logarithm -0039871, the logarithms of the population in the middle of each 
 year are obtained. Similarly, if the population in the September quarter is required, 
 then we must begin by adding half the logarithm -0039871 to the 1881 population. 
 
I.] STATISTICS. 6 
 
 Or, if any one year is required, all that is necessary is to multiply 
 the logarithm of the ratio of annual increase by the number 
 of years elapsed from the census, and add it to the logarithm 
 of the population; thus, if the population is required for 1888, 
 ■0039871 X 7 and added to 5-232996 gives the logarithm 5-260906, 
 that is 182,350. 
 
 On the other hand, supposing the census of 1881 gave a lower 
 figure than that of 1871, the population for the years subsequent 
 to 1881 may then be similarly calculated upon the assumption of 
 a uniform decrease. 
 
 (2) Local Censuses. 
 
 These may be made in small areas, such as a crowded street, 
 model artisans' dwellings, and villages, by the inspector of nuisances, 
 and will be found of value, the more especially if made at short 
 intervals. 
 
 If an accurate enumeration of persons be made in 100 houses 
 of the same size and class, trustworthy averages may be obtained ; 
 and such averages may be used for the purpose of calculating the 
 population of small areas. The number of houses can be got from 
 the rate-books, and the number of empty houses from the rate- 
 collectors ; the inhabited houses are then multiplied by the average. 
 It is obvious that this method does not give age distribution, and 
 is inferior to personal inquiry, but it is nevertheless useful, for it is 
 not always practicable to make an actual local census. 
 
 (3) Death Returns. 
 
 It is the duty of every sanitary authority to cause the local 
 registrars to supply the ofiScer of health regularly with copies of 
 the death returns and also the number of births. These returns 
 are usually made weekly, but deaths from zymotic diseases should 
 of course be communicated as soon as the registrar has notice of 
 the fact ; this is the more necessary in those places in which the 
 compulsory notification of disease is not in force ; where infectious 
 disease is systematically notified, the health ofiicer will be early 
 acquainted with the nature and locality of the disease. 
 
A MANUAL OF PUBLIC HEALTH. [cHAt. 
 
 An example of the most useful form of return is the following : — 
 
 DISTRICT- 
 
 5.— This Retuin Is to lie posted 
 a secure its delivery 
 FIRST POST ON 
 MORNING. 
 
 A Eeturn of the number of Births and of Deaths registered in the Sub-District during 
 the Week ending Saturday, the day of 189 . 
 
 SuB-DlSTRIOT. 
 
 BiKTHS. 
 
 Males 
 
 Females 
 
 Total 
 
 Write " NIL " if no Birth was 
 Registered in the week. 
 
 Deaths. 
 
 Males 
 
 Females 
 
 Total 
 
 Write " NIL " if no Death was 
 Registered in the week. 
 
 Partioulaes of the Deaths Eegistbeed in the Week. 
 
 la 
 
 When Died and 
 
 Whkre. 
 State also in Col. 
 9 the previous 
 residence of in- 
 mates of Insti- 
 tutions : See 
 General Instruc- 
 tion No. 3, and 
 Special Instruc- 
 tion No, 9. 
 
 i 
 
 Aqe. 
 
 Occupation or 
 Profession. 
 
 Cause of 
 Death. 
 
 (3 
 
 Oeservatioks. 
 
 (See Instruc- 
 tions, General 
 
 - No. 3, and 
 Special No. 9.) 
 
 Ur-I 
 
 o 
 
 m 
 
 i 
 
 Cols. 
 
 1. 
 
 2. 
 
 3. 
 
 4. 
 
 5. 
 
 6. 
 
 7. 
 
 8. 
 
 9. 
 
 
 
 
 
 
 
 
 
 
 
 This return gives the following items of information : — 
 Total number of births, male and female, for the week; 
 total number of deaths, male and female; date of death; 
 address of place of death; sex, age, and occupation of person 
 dying ; — added to which the registrar notes when an inquest has 
 been held. All these different facts admit of tabulation and 
 arrangement. 
 
I-] 
 
 STATISTICS. 
 
 (4) Causes of Death. 
 
 The causes of death and the ages at death are usually collected 
 together and tabulated in the following form : — 
 
 Mortality of the District of 
 
 Table I. 
 
 for tlie "Weeks ending 
 
 18 
 
 Causes of Death. 
 
 I. ZYMOTIC. 
 
 Order 1— MIASMATIC. 
 
 Small-pox 
 
 Measles 
 
 Scarlatina (Scarlet Fever) 
 
 Diplitheria . 
 
 Quinsy . 
 
 Croup . . . . 
 
 Whooping Cough . 
 
 Typhus . 
 
 Enteric or Typhoid Fever . 
 
 Simple Continued Fever 
 
 Erysipelas (Rose) 
 
 Puerperal Fever (Metria) . 
 
 Carbuncle . . . . 
 
 Influenza 
 
 Dysentery .... 
 
 Diarrhoea (Bowel Complaint) 
 
 Cholera (Simple) .... 
 
 Ague 
 
 Remittent Fever .... 
 
 Rheumatism 
 
 Other Zymotic Diseases 
 
 Order 2— ENTHETIC. 
 Syphilis ... 
 Stricture of Urethra . 
 Hydrophobia .... 
 Glanders 
 
 Order 3— DIETETIC. 
 Privation .... 
 Want of Breast Milk 
 Purpura and Scurvy . 
 
 {Delirium Tremens 
 Intemperance 
 
 Carried forward 
 
 Alcoholism \ 
 
 Ages. 
 
 
 fC) «0 >^ CO 
 
 %t gf 
 
 Total. 
 
A MANUAL OF PUBLIC HEALTH. 
 Table I. (continued). 
 
 [chap. 
 
 Causes of Death. 
 
 t3 00 
 a to 
 
 rf o 
 
 Total. 
 
 Thrush 
 Worms, dkc. 
 
 Brought forward 
 Obder 4— parasitic. 
 
 II. CONSTITUTIONAL. 
 
 Order I— DIATHETIC. 
 
 Gout 
 
 Dropsy .... 
 
 Cancer . 
 
 Noma (Cancrum Oris) 
 
 Mortification 
 
 Abscess or Tumour 
 
 Order 2— TLTBERCULAR. 
 
 Scrofula 
 
 Tabes Mesenterica .... 
 Phthisis (Consumption) 
 Hydrocephalus (Water on the Brain) 
 
 III. LOCAL. 
 
 Order 1— NERVOUS SYSTEM. 
 Cephalitis 
 Apoplexy 
 Paralysis 
 Insanity 
 Chorea . 
 Epilepsy 
 Convulsions 
 Brain Disea, 
 
 Order 2— ORfiANS OF CIRCULA- 
 TION. 
 
 Pericarditis 
 
 Aneurism 
 
 Heart Disease, &c 
 
 e, (be. 
 
 
 Order 3— RESPIRATORY ORGANS. 
 
 Laryngitis 
 
 Bronchitis 
 
 Pleurisy ... . . . 
 
 Pneumonia 
 
 Asthma 
 
 Lung Disease, <Ssc. . . . . 
 
 Carried forward . 
 
!•] 
 
 STATISTICS. 
 Table I. {continued). 
 
 Causes of Death. 
 
 Brought forward 
 
 Okder 4— DIGESTIYE ORGANS 
 
 Gastritis 
 
 Enteritis 
 
 Peritonitis 
 
 Ascites 
 
 Ulceration of Intestines 
 Hernia (Eupture) 
 
 Ileus 
 
 Intussusception 
 
 Stricture of Intestines . . ■ . 
 
 Fistula 
 
 Stomach Disease, &c. . 
 
 Pancreas Disease, &c. . 
 
 Lead Colio , 
 
 Jaundice 
 
 Hepatitis 
 
 Liver Disease, &c. 
 
 SpUen Disease, die. 
 
 Oedee 5— IIEINARY ORGANS. 
 
 Nephritis ... 
 
 Ischuria 
 
 Nephria_(Bright's Disease) 
 
 Diabetes 
 
 Stone (Calculus) . 
 
 Cystitis . 
 
 ~" cfcc. . 
 
 Order 6— ORGANS OF GENERATION. 
 
 Ovarian Dropsy ... . . 
 
 Uterus Disease, &c. . . 
 
 Oedbk 7— ORGANS OF LOCOMOTION. 
 
 Arthritis (Synovitis) 
 
 Joint Disease, t&c 
 
 Obdek 8— INTEGUMENTARY 
 SYSTEM. 
 Phlegmon 
 Ulcer 
 Skin Disease, <Sic, 
 
 Carried forward . 
 
 Ages. 
 
 ^ o 
 
 Id (M 
 
 
 a u 
 
 OS O 
 
 S f^ 
 
 as 
 
 00 ca 
 
 Total. 
 
10 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 Table I, (contimbed). 
 
 Causes of Death. 
 
 Brought forward 
 
 IV. DEVELOPMENTAL. 
 
 Oedek 1— diseases of CHILDREN. 
 
 Premature Birth . 
 
 Cyanosis . . . . 
 
 Spina Bifida . . . . 
 
 Other Malformations 
 
 Teething ... . . 
 
 Obdbe 2— DISEASES OF ADULTS. 
 
 Childbirth (see Puerperal Fever) 
 
 Oedee 3— DISEASES OF OLD 
 PEOPLE. 
 Old Age 
 Premature Decay 
 
 Oedee 4— DISEASES OF NUTRITION. 
 Atrophy and Dehility 
 
 V. VIOLENT DEATHS. 
 
 Oedee 1— ACCIDENTS OR NEGLI- 
 GENCE. 
 Fractures and Contusions . 
 
 ^°-^={8uTltat' 
 Burns and Scalds 
 Poison . 
 Drowning 
 Suffocation . 
 Otherwise 
 
 Oedee 3— HOMICIDE. 
 Murder and Manslaughter 
 
 Oedee 4— SUICIDE. 
 
 Poison . 
 
 Drowning 
 
 Hanging 
 
 Otherwise 
 
 Violent Deaths not Classed 
 
 Not Specified, or ill Defined . 
 Total 
 
 P h 
 OS QJ 
 
 §1 
 
 a PI 
 0-2 
 
 rr^'Xl 
 
 ■=•9 
 CO oa 
 
 Total. 
 
1.] STATISTICS. 11 
 
 To those acquainted with the recent great advances in etiology 
 the table has little commendable in either arrangement or classi- 
 fication. For example, neither phthisis nor cancer can properly be 
 called constitutional ; the former most decidedly has affinities with 
 zymotic maladies, being caused by a definite parasite ; tabes is 
 produced by the same parasite ; pneumonia, syphilis, and possibly 
 tetanus, should be also classified among parasitic maladies. In a 
 few years there will of necessity be a different and more scientific 
 classification,^ but the subject is too large to be discussed here, and 
 the table will do as well as any other for the purpose of exempli- 
 fying the usual methods of tabulating statistics. 
 
 In extracting individual deaths from the returns it is convenient 
 in the first place to denote them by single strokes, with a cross 
 stroke for the fifth, thus 12 deaths from pneumonia of persons • 
 between 20 and 40 would be represented thus : [j«I| ||jj ||. In the 
 final sheet these marks are, of course, exchanged for ordinary 
 figures. It will also be found useful after entry of any death to 
 put a pencil tick or cross opposite the entry in the return, other- 
 wise mistakes in enumeration may occur. 
 
 (5) Addresses — The Mortality Ledger. 
 
 A mortality ledger is an essential for every district. A mortality 
 ledger is a large bound volume, each page of which is similarly 
 tabulated to the registrar's returns. To each street, village, or 
 small definite locality is assigned one or several pages, in which 
 the deaths of that particular locality are copied. On the top of 
 the page is written clearly the name of the street or locality, and 
 it is convenient to put also the character of the houses, -the general 
 nature of the inhabitants, and the actual or presumed popu- 
 lation. From 25 to SO deaths should fill a page, and every 
 fifth line should be double, so that deaths can then be easily 
 enumerated. The ledger is, of course, indexed. A properly kept 
 mortality ledger is of the greatest use, for by its means the health 
 officer is able at any moment to refer to the mortality statistics 
 of the smallest hamlet, court, or street in his district. The following 
 
 ^ For an essay at scientific classification the reader may consult Public Health, 
 vol. ii. p. 289. 
 
12 
 
 A MANUAL 0¥ PUBLIC HEALTH 
 
 [CHAT". 
 
 is a copy of a portion of a single sheet from one of the author's 
 " mortality ledgers " : — 
 
 ■ff . „„ q™„„„ / No. of houses 105. Most of the street let out in tenements. 
 jiAbi aiREET. I -j^^_ ^j j,^^^g g^Q_ g.^^j^^ ^^^ 5 yg^^g gj^^jjjg 1885 = 377. 
 
 Population by local census in 1883 — 
 
 Adults 1016 
 
 Children below 15 . 626 
 
 1642 
 
 No. of 
 House. 
 
 Date. 
 
 Sex. 
 
 Age. 
 
 Occupation or Profession. 
 
 Cause of Death. 
 
 Under 1. 
 
 1 and 
 
 under 
 
 60. 
 
 60 and 
 wards. 
 
 97 
 10 
 89 
 55 
 14 
 
 1877. 
 
 21.6 
 6.7 
 9.7 
 
 12.7 
 3.8 
 
 F. 
 
 M. 
 M. 
 M. 
 
 M. 
 
 5 months 
 
 22 
 2 
 
 69 
 
 75 
 
 Carman's daughter. 
 
 Carman. 
 
 French polisher's son.' 
 
 Plumber. 
 
 Carman. 
 
 Diarrhoea. 
 
 Phthisis. 
 
 Pertussis. 
 
 Paralysis. 
 
 Phthisis. 
 
 (6) Sex. 
 
 If so desired, the causes of death or other facts can be collected 
 for each sex separately. In certain districts it is well this should 
 be done, the more especially where there are industrial influences 
 affecting unequally the health of males and females. The death- 
 rate is also affected by inequality in numbers between males and 
 females, the latter having a lower normal death-rate than the 
 former (see Table II., p. 16). 
 
 (7) Age. 
 
 A division into a few age periods only, as in the table at 
 p. 7, is sufficient for general purposes, but if a life table is to 
 be constructed, then a further division is necessary. 
 
 (8) Calculation of Birtli and Death Bates. 
 In the first place the data must be made as correct as pos- 
 sible. Should there be a lying-in institution in the district, the 
 births of strangers must be eliminated ; similarly persons who are 
 strangers to the district, but die there, whether in hospitals or 
 private houses, must also be eliminated ; and residents who, having 
 contracted their fatal maladies in the district and die elsewhere 
 must be added, so far as such deaths can be ascertained. In the 
 
I.] STATISTICS. 13 
 
 metropolis there is an excellent arrangement in force, by means of 
 which, for a small payment, each local authority obtains returns 
 direct from the Eegistrar-General's Office, of extra-parochial deaths 
 in various hospitals, infirmaries, asylums, and similar public 
 institutions. 
 
 Birth and death rates are expressed in terms per 1,000 per 
 year of the known or calculated population. If the whole of the 
 statistics relate to a single year, the calculation is a simple rule of 
 three sum, the rule being — multiply the number of deaths by 
 1,000, and divide by the population. For example, in a popu- 
 lation of 156,290 there were in one year 2,989 deaths ; then 
 
 ' -. 'r, = 19'1. The death-rate is therefore 19'1 per 1,000 per 
 
 156,290 tr ' r 
 
 annum ; or, if done by logarithms, subtract the logarithm of the 
 deaths from the logarithm of the population multiplied by 1,000; 
 thus — 
 
 Logarithm of 2,989,000 = 6-4.7553 
 
 Logarithm of 156,290 = 519393 
 
 1-28160, or 19-1. 
 
 The same result is of course obtained by the multiplication 
 of a factor (reciprocal) obtained by dividing 1,000 by the popu- 
 lation and multiplying the quotient by the number of deaths ; 
 
 thus, in the example given : ' ^ = -006398, and -006398 X 
 
 2,989 = 19-1 ; or, by the use of logarithms, the logarithm of the 
 factor is added to the logarithm of the deaths ; thus — 
 
 Logarithm of -006398 = 3^80607 
 Logarithm of 2,989 = 3-47553 
 
 1-28160 = 19-1. 
 
 The operation is not so simple if it is desired to express accurately 
 the mortality of a. week, a month, or a quarter, as a yearly rate, 
 for it is necessary to take into account that a week is not exactly 
 the fifty-second part of a year, that a month varies in length, and 
 that the number of days in a quarter is from 90 to 92. The 
 number of days in a natural year is 365-24, the number of 
 weeks 52-177 ; therefore the number of deaths in a week, multi- 
 plied by this number, and then by 1,000, and lastly divided by 
 
14 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 the population, gives the annual rate. A more convenient method 
 is to divide the estimated population by 52-177, and in this way 
 a number is obtained which represents the weekly population, 
 and which serves as a constant throughout the year. To 
 obtain the death-rate, the number of deaths is divided by this 
 number, and the resulting fraction multiplied by 1,000 ; e.g. in a 
 population of 132,450 persons there died, in the week ending 
 July 28, 51 persons ; required the annual death-rate for the 
 week. 
 
 First method — 
 
 Second method — 
 ' ^,- = 2,366 weekly population, and — „ ' — = 21 '55 death- 
 rate. 
 
 It must, however, be confessed that for practical purposes the 
 deaths in a week may be calculated on the basis of 52 weeks in 
 the year, the errors of delayed registration far outweighing the 
 refinements of the decimals given above. 
 
 But with regard to rates based upon monthly returns, to multiply 
 births or deaths by 12 will always produce a considerable error, 
 because some months have four weeks, others five. 
 
 The method generally adopted is to divide the population by 
 the number of days in the year, which then gives the daily 
 
 population, or 365-24 ^ ^^^^^ population. This number must 
 
 then be multiplied by the number of days in a month, 28 or 31 
 as the case may be, which will give the theoretical population for 
 that month. For example, if in a population of 123,450 persons 
 there should die, in the four weeks ending February 28, 210 
 
 persons, the calculation proceeds as follows : • '■ — - = 338 the 
 
 daily population. Then 338 x 28 = 9,464, which is the population 
 
 for 28 days ; then comes the usual calculation ^ 1.000 _ oo.i q . 
 
 9,464 - ^^ ^y . 
 
 or get. out the factor ^^ = -1056, and -1056 X 210 = 22-18, 
 
 which is near enough. 
 
I.] STATISTICS. 15 
 
 Factors (reciprocals)^ will in all these cases be found most 
 convenient, and the factor need seldom be more than three figures. 
 For instance, the month of 28 days gives a factor for All Souls, in 
 the writer's district, of "4879, and supposing in the month there 
 are 56 births, then 56 x '4879 = birth-rate 2732, but the same 
 result is obtained by multiplying by '488 ; similarly a factor of 
 ■8909 may be transformed into "891, or a factor of '561 may even 
 be made into two figures, viz. '56, without introducing inaccuracy 
 of great moment.''' 
 
 In the same way the daily population may be converted into the 
 population for a quarter by multiplying by either 90 or 92 as 
 the case may be ; but the error in taking three months as exactly 
 a quarter of a year, is immaterial, and rates may for this purpose 
 be calculated by simply multiplying the births or deaths by 
 4 X 1000, and dividing by the population. 
 
 (9) Age JDistrihution. 
 
 A rate derived from a population of every age from the newly- 
 born to the limit of human existence gives but scanty information. 
 The normal death-rate below 5 is something like 66 per 1000, 
 between 10 and 15 it sinks to 5, persons over 85 die at the rate of 
 294 per 1000 ; it is therefore evident that should a district from 
 the presence of institutions for the aged or the very young have a 
 number of the less vital members of the community in excess of 
 other districts, the death-rate will be large ; but such a rate, 
 unless beyond or below the normal rates for those age-periods, affords 
 
 ^ A table of reciprocals of numbers from 1 to 100,000, with their differences, by 
 which the reciprocals of numbers may be obtained up to 10,000,000, by Lieut.-Col. 
 "W. H. Oakes, is published by Messrs. C. and E. Layton, London, and will be found 
 most useful. 
 
 " Mr. Sydney Luptou writing in Nature observes : — " It is convenient to bear 
 in mind the following simple rules, due I believe to De Morgan. If two numbers, 
 a and i, each true to the first decimal place, are multiplied together, the result is 
 
 true to — ^zr- only ; a second true decimal in each number makes the result ten 
 
 times more correct, and so on. In dividing -r where each is true to the first place, 
 
 the result is true to -^ ^ , and so on. Any attempt at greater accuracy in cal- 
 culation than is indicated by these results should be avoided, since it only precludes 
 the use of cheap and handy tables, tires the calculator, making him more liable to 
 error in the important figures, and tends to give a false idea of the accuracy of thg 
 experiments on which the calculations are based," 
 
16 
 
 A MANUAL 0¥ PUBLIC HEALTH. 
 
 [chap. 
 
 no guide to sanitary condition — it will depend upon " the age dis- 
 tribution"; similarly in localities in which from various industrial and 
 other causes, there is an excess of persons between the ages 10 and 
 35, the mortality will seem very low if compared with more mixed 
 populations. It follows, then, that all rates of mortality should be 
 dissected up and expressed in terms per 1000 of various groups of 
 ages. This is done in the following table, which exhibits the death- 
 rates at different age -periods (calculated from the numbers living 
 at each age-period) amongst males and females in England and 
 Wales during the ten years 1871-1880 : — 
 
 Table II. 
 
 Annuai, Moktalitt pee 1,000. 
 
 
 
 
 Males. 
 
 Females. 
 
 All ages , 
 
 22-61 
 
 20-00 
 
 Under 5 years . . ' . 
 
 68-14 
 
 58-10 
 
 5 to 10 , 
 
 
 6-67 
 
 6-20 
 
 10 „ 15 , 
 
 
 3-69 
 
 3-70 
 
 15 „ 20 , 
 
 
 5-23 
 
 5-43 
 
 20 „ 25 , 
 
 
 
 7-32 
 
 6-78 
 
 25 „ 35 , 
 
 
 
 9-30 
 
 8-58 
 
 35 „ 45 , 
 
 
 
 13-74 
 
 11-58 
 
 ■45 „ 55 , 
 
 
 
 20-05 
 
 15-59 
 
 55 „ 65 , 
 
 
 
 34-76 
 
 28-54 
 
 65 ,, 75 , 
 
 
 
 69-57 
 
 60-82 
 
 75 and upwards .... 
 
 169-08 
 
 155-83 
 
 (Supplement to the ihtli Annual Report of the Megistrar- General.) 
 
 The following table gives the age-distribution amongst 1,000 
 persons in England and Wales (mean of the censuses of 1871 and 
 1881) :— 
 
 Table III. 
 
 All Ages 
 1,000 
 
 Under -5 
 
 5—10 
 
 10—15 
 
 15—20 
 
 20—25 
 
 25—35 
 
 136 
 
 120 
 
 107 
 
 97 
 
 89 
 
 147 
 
 All Ages 
 1,000 
 
 35—45 
 
 45—55 
 
 55—65 
 
 65—75 
 
 75 and upwards. 
 
 113 
 
 86 
 
 59 
 
 33 
 
 13 
 
T.] STATISTICS. 17 
 
 That is, persons under 5 forna 13'6 percent, of the total populations ; 
 persons aged 5 to 35 form 75'9 per cent. ; and persons aged 55 and 
 upwards form 10'5 per cent. 
 
 Since 1883 the Registrar-General, in his annual summaries for 
 London and other great towns, has given the corrections which 
 must be applied to the death-rates for age and sex distribution, so 
 as to make the urban death-rates comparable with that of the 
 country (England and Wales) as a whole. Out of the 28 towns, 
 the correction adds in 26 a certain quantity to the recorded rate, 
 varying from 0'5 to 3 per 1000 ; whilst in two towns — Norwich and 
 Plymouth — a small subtraction must be made from the recorded 
 rates. The correction for London is -I- 1"3 per 1,000 ; or the death- 
 rate in any year must be multiplied by the factor 1'0615. The 
 method pursued by the Registrar-General is as follows : — The mean 
 annual death-rate for each sex, at each of the 12 age-periods, in 
 England and Wales in 1871-80, is applied to the population of each 
 of the 28 towns, with age and sex distribution as shown at the last 
 census (1881). The result is a number called the standard rate, 
 which varies in every town according to the age and sex distribu- 
 tion of the population of the town. The mean annual death-rate 
 of England and Wales from 1871-80 (21-27) is then divided by this 
 standard, and a factor is obtained for each town by which the 
 recorded death-rate of any year must be multiplied. The factor 
 exceeds unity in 26 towns, and is less than unity for two towns only 
 out of the 28 (Annual Sitmmary for 1883). 
 
 It is not necessary to fractionate up the routine statistics of a 
 district into so many divisions as represented in the foregoing 
 table. I am content with regard to the statistics of my own dis- 
 trict with five groups of ages. The following, for instance, is a 
 "table of rates at different ages for St. Marylebone during 1886 ; 
 the natural values taken from the English life table being added 
 for comparison. 
 
 These numbers are obtained in a similar manner to the death- 
 rates of the whole population already detailed at p. 14. The popu- 
 lation at the groups of ages dealt with are extracted from the census 
 returns ; the deaths at that particular age-period collected from such 
 a table as at p. 7, X 1,000, and divided by the population for that 
 age. If the calculation is made for any fraction of a year, the rules 
 given at p. 14 equally apply. For example, the deaths for the 
 
18 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 Table IV. 
 
 Comparing the Dbath-Rates tor 1886 at Vabiotts Ages, with Death- 
 Rates at the Same Age given in the English Life Iaele. 
 
 English Life Table . . 
 
 Under 5 
 
 years of 
 
 age. 
 
 6 and 
 under 20. 
 
 20 and 
 under 40. 
 
 40 and 
 under 60. 
 
 60 and 
 upward.s. 
 
 657 
 
 71 
 
 10-3 
 
 18-3 
 
 717 
 
 The whole district . 
 All Souls .... 
 CaTendish Sq^uare 
 Rectory . 
 St. Mary . . 
 Christ Church . 
 St. John 
 
 70-2 
 73-8 
 41-9 
 70-6 
 72-3 
 89-4 
 60-1 
 
 3-3 
 
 4-3 
 2-0 
 3-5 
 1-9 
 4-1 
 3-0 
 
 6-8 
 9-1 
 2-2 
 7-4 
 6-3 
 8-2 
 6-4 
 
 20-8 
 21-1 
 13-8 
 23-1 
 20-8 
 23-9 
 17-6 
 
 68-3 
 72-8 
 68-4 
 46-1 
 60-4 
 81-6 
 70-5 
 
 whole district between the ages of 20 and 40 were 395, the calcu- 
 lated population at those ages was 57,746, hence 
 
 6-8. 
 
 57,746 
 
 In the intervals between the census the population at any age 
 
 in increasing or decreasing populations must be calculated. For 
 
 example, a population in 1881 of 154,910 contained 15,900 under 
 
 5 years of age ; in 1886 the same population was presumed from 
 
 calculation to be 156,290 : then by an ordinary rule of three sum 
 
 15,900x156,290 tc^qk i +• j k • -.oo^ j 
 
 — — = lb,0d5 population under 5 years in 1886, and so 
 
 XO^^tj j.\J 
 
 on for the remaining groups. 
 
 (10) Zymotic Death-Eate. 
 What is called the zymotic death-rate, is the rate of mortality per 
 1,000 of the population from the principal zymotic diseases — that 
 is, small-pox, measles, scarlet fever, diphtheria, whooping cough, ery- 
 sipelas, typhoid, typhus, and other forms of fever and diarrhoea. The 
 calculation is precisely the same as that of an ordinary death-rate. 
 For instance, in a population of 156,000 there died 123 from zymotic 
 
 maladies ; required the zymotic rate : ^^^ x 1,000 ^ ^.^ 
 
 156,000 
 
 (11) Proportion of Deaths from certain Classes of Disease to the 
 
 Total Deaths. 
 This is a very frequent method of tabulating deaths, and in 
 
!•] 
 
 STATISTICS. 
 
 sub-districts in whicli the age-distribution is fairly equal, affords a 
 good basis of comparison. 
 
 The calculation is simple ; the deaths from any class are multi- 
 plied by 1,000, and divided by the total deaths. The annexed table 
 is an example of the classes usually selected. Taking the first 
 column, to show its construction, the total deaths were 3,087, the 
 
 zymotic deaths 381, then §5L^J_^'^ =• 123, which are the first 
 
 figures in column 1. 
 
 The deaths from pulmonary complaints were 763, then 
 
 — ' — =247, which are the second figures in column 1, and 
 so on with the other numbers. 
 
 Table Y. 
 
 Giving the Compaeative Moexalitt of the Six Registration Disteicts 
 
 FROM certain CLASSES OF DISEASE, IN PROPORTION TO A THOUSAND 
 
 Deaths from All Causes. 
 
 1. Chief Zymotic 
 
 Diseases . . 
 
 2. Pulmonary, other \ 
 
 than Phthisis f 
 
 3. Tubercnlar . . . 
 
 4. "Wasting Diseases "l 
 
 of Infancy . . / 
 
 5. Convulsive Dis- 1 
 
 eases of Infancy J 
 
 The 
 . whole 
 District. 
 
 All 
 Souls. 
 
 Caven- 
 dish 
 Square. 
 
 Rectory. 
 
 St. 
 Mary. 
 
 Christ 
 Church. 
 
 St. 
 John. 
 
 123 
 
 247 
 
 137 
 
 67 
 
 58 
 
 109 
 
 278. 
 
 150 
 
 67 
 
 47 
 
 72 
 
 230 
 
 114 
 
 48 
 
 60 
 
 102 
 
 227 
 
 136 
 
 47 
 
 80 
 
 130 
 
 231 
 
 158 
 
 63 
 
 38 
 
 157 
 
 264 
 
 159 
 
 73 
 
 66 
 
 143 
 
 245 
 
 108 
 
 47 
 
 63 
 
 NOTES. 
 1, includes Smallpox, Measles, Scarlet Fever, Diphtheria, "Whooping Cough,Erysipelas, 
 Croup, Fever, and Diarrhoea. 
 
 3, includes Phthisis, Scrofula, Rickets, and Tabes. 
 
 4, includes Marasmus, Atrophy, Debility, want of Breast Milk, and Premature Birth. 
 
 5, includes Hydrocephalus, Infantile Meningitis, Convulsions, and Teething. 
 
 (12) Proportional Distribution of Deaths. 
 
 In many instances it is impossible to locate the deaths which 
 occur in Avorkhouses and similar institutions, no exact address 
 being discoverable, and in these cases in getting out the death- 
 
 c 2 
 
20 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 the deaths 
 
 rates of sub-districts it is necessary to distribute 
 according to the population. As this necessitates each time much 
 calculation, it is more convenient to draw out once for all a table, the 
 first line of which gives a factor obtained by dividing the popula- 
 tion of the sub-district by the total population, in the second line 
 this factor is multiplied by 2, m the third line by 3, and so on, up 
 to 9. An example of this kind of table will make the system clear. 
 In the author's district there are the following population 
 groups : — 
 
 All Souls . 
 
 Cavendish Square 
 
 Rectorj' 
 
 St. Mary . . 
 
 Christ Church 
 
 St. John . 
 
 Total 
 
 Population 
 in 1887. 
 26,759 
 14,891 
 24,809 
 21,518 
 34,680 
 33,633 
 
 156,290 
 
 and the proportional table has been constructed by dividing each 
 sub-district by the total population to give the first factor ; e.g., by 
 dividing the population of All Souls by the total population, 
 
 ^^''^^^ =0-17, which, multiplied by 1, 2, 3, &c., gives the numbers 
 156,290 
 
 in the first column of the table ; in the second a similar process 
 
 has been adopted for Cavendish Square, thus the population 
 
 of Cavendish Square, divided by the total population of the district 
 
 gives the factor '09, and the same principle has been adopted with 
 
 the other columns. 
 
 Table VI. 
 
 To Facilitate the Dlstiubution of Deaths of Persons whose Exact 
 Address is not known. 
 
 1 
 
 All Souls. 
 
 Cavendish 
 Square. 
 
 Rectory. 
 
 St. Mary. 
 
 Christ 
 Church. 
 
 St. John. 
 
 ■17 
 
 •Q9 
 
 •17 
 
 •14 
 
 •22 
 
 •21 
 
 2 
 
 •34 
 
 ■18 
 
 •34 
 
 •28 
 
 •44 
 
 •42 
 
 3 
 
 •51 
 
 •27 
 
 •51 
 
 •42 
 
 •66 
 
 •63 
 
 4 
 
 •68 
 
 •36 
 
 •68 
 
 •56 
 
 •88 
 
 •84 
 
 6 
 
 •85 
 
 •45 
 
 85 
 
 •70 
 
 1-10 
 
 1^05 
 
 6 
 
 1-02 
 
 •54 
 
 1^02 
 
 •84 
 
 1-32 
 
 1^26 
 
 7 
 
 1-19 
 
 •63 
 
 1-19 
 
 ■98 
 
 1^54 
 
 1^47 
 
 8 
 
 1-36 
 
 •72 
 
 1^36 
 
 VV2 
 
 1^76 
 
 1-68 
 
 9 
 
 1^53 
 
 •81 
 
 1^53 
 
 1^26 
 
 1^98 
 
 1^89 
 
I.] STATISTICS. 21 
 
 The table is used in the following manner. Supposing there are 
 124 deaths to be distributed between the six sub-districts in pro- 
 portion to their population; the number for All Souls for 
 100 deaths will of course be 17 (obtained from the first 
 column by removing the decimal point), 20 will be 3"4, and for 4 
 the number will be 068. 
 
 100 = 17 
 20 = 3-4 
 4 = 0-68 
 
 21 ■08 
 
 For Cavendish Square the numbers will be 9 + 1-8 -I- 0'36 = 11-16 ; 
 for the Rectory the numbers will be 17 + 3-4 + 0-68 = 21-08 ; for St. 
 Mary the numbers will be 14 + 2-8 + 50 = 17-36 ; the numbers for 
 Christ Church will be 22 + 4-4 + 88 = 27 28 ; the numbers for St. 
 John will be 21 + 4-2 +0-84 = 26-04 ; and adding these numbers 
 together they will be found to exactly make 124. 
 
 E.g., All Souls . . . 21-08 
 
 Cavendish Square . 11 '16 
 
 Rectory .... 21-08 
 
 St. Mary . . 17-36 
 
 Christ Church . . . . . . 27-28 
 
 St. John .... ... . 26-04 
 
 124-00 
 
 and by adding the numbers to the deaths of the sub-districts, 124 
 ■will have been divided up proportional to the population. 
 
CHAPTER II. 
 
 MEAN AGE AT DEATH— MEAN DURATION OF LIFE — PROBABLE 
 DURATION OF LIFE— CONSTRUCTION OF LIFE TABLES. 
 
 (13) Mean Age oi Death. 
 
 The mean age at death of a population is obtained by summing 
 up the ages at which people have died and dividing the number 
 of years by the number of deaths. It is merely an expression of 
 the average at death of a population, and gives no evidence of the 
 health or sanitary condition of the population. When a population 
 is rapidly increasing by excess of births over deaths, the mean age 
 at death is low, because the population is largely composed of 
 young persons. When a population is stationary or nearly so, the 
 proportion of old people to the total population is large, and the 
 mean age at death is high. The mean age at death therefore 
 gives information as to the ages of the dying, and per contra of the 
 living, in different communities, but nothing more. 
 
 The mean duration of life (niean after-lifetime or expectation of 
 life at MrtK) differs widely from the mean age at death, when the 
 population is increasing ; although when the population is 
 stationary, they coincide. Thus the mean duration of life in 
 England from 1871 to 1880 for males was 41-35 years; if the 
 population had been stationary, the mean age of males who died 
 would also have been 41-35 years, and one in 41-35 would have 
 died annually. Whereas the mean age at death was 29 years, 
 whilst one in 44-2 died annually. One in 44-2 died annually and 
 not one in 41-35, because the increase of population has been so 
 long continued by excess of births over deaths, that an excess of 
 persons between the ages of 5 and 55 has accumulated, whose 
 
CHAP. II.] STATISTICS. 2.3 
 
 mortality is low, and this excess, together with proportional diminu- 
 tion of persons over 55, has served to reduce the death-rate and 
 the mean age of the dying. The mean duration of life is found 
 from life tables, which show how many of a given number born 
 live through each year of subsequent life, and what is the sum of 
 the number of years they live. The sum of these years divided by 
 the lives is the mean duration of life.^ '' It is the mean lifetime 
 of a generation of persons traced by the life-table method from 
 birth to death." — Noel M%imphreys. 
 
 There is no accurate method known to calculate mean duration 
 of life, save from life tables, although the following methods are 
 sometimes used : — 
 
 (14) Calculation of Mean Duration of Life. 
 
 The mean duration of life may be approximately calculated from 
 the birth-rate and death-rate by the following formula : — Mean 
 
 duration of life= (^x t) + (s ^ T.]' where & = birth-rate per unit 
 
 of population ; and d = death-rate per unit of population. 
 
 For example, given a birth-rate of 35'35, a death-rate of 2127 
 per thousand ; required the mean duration of life. 
 
 { 1 ^^7 } + { -3 x^Osk } -'''''' °^ ''■'' ^'^ ''''■ 
 What is known as Bristowe's formula is also sometimes used.^ 
 
 (15) The Probable Duration of Life. 
 
 The probable duration of life is the age at which a given number 
 of children born at the same time are reduced one-half, it is there- 
 fore not the same as the " mean duration of life." 
 
 ^ Dr. Louis Parkes, "Some Aspects of Mortality Statistics," Public Sealfh, 
 No. 4, 1888. 
 
 ^ Bristowe's formula is as follows : — 
 
 X = mean duration of life. 
 J = birth-rate of one unit of the population. 
 d — death-rate of one unit of the population. 
 r =■ i - d = increase of one unit in one year. 
 Then— 
 
 a; = log l-\o^d 
 log (1 + r) ■ 
 
24 
 
 A MANUAL Of PUBLIC HEALTH. 
 
 [chap. 
 
 (16) Construction of Life Tables. 
 
 Life tables are calculated on a hypothetical generation of a 
 million persons, consisting of the same proportion of males and 
 females at birth and at subsequent ages which is found to exist in 
 the general population, and on the numbers of each sex dying each 
 succeeding year, until the whole generation becomes extinct. 
 
 The expectation of life or mean after-lifetime of various ages, 
 represents the portion of future life which an individual at any 
 age may reasonably expect to enjoy ; and this, like the mean age at 
 death or mean duration of life, is given in life tables. The follow- 
 ing is Mr. Noel Humphrey's short table showing clearly how the 
 recent decline in the English death-rate has affected the mean 
 after-lifetime at various ages : — 
 
 Table VII. 
 
 Showing Mean After-Lifetime (Expectation of Life) at Vakiotts Ages, from 
 Life Tables based upon English Moetality in 1838 — 54 (N. Humphreys). 
 
 
 Persons. 
 
 Males. 
 
 Females. 
 
 Ages. 
 
 1838—64. 
 
 1876—80. 
 
 1888—34. 
 
 1876-60. 
 
 1838—54. 
 
 1876-80. 
 
 
 
 5 
 10 
 15 
 20 
 25 
 35 
 45 
 55 
 65 
 
 75 
 
 85 and upwards . 
 
 40-86 
 
 50-02 
 
 47-36 
 
 43-54 
 
 39-88 
 
 36-57 
 
 29-99 
 
 . 23-41 
 
 16-94 
 
 11-17 
 
 6-72 
 
 3-87 
 
 43 -.56 
 52-56 
 49-24 
 45-05 
 40-98 
 37-21 
 30-01 
 23-29 
 16-75 
 11-19 
 6-81 
 4-00 
 
 39-91 
 49-71 
 47-05 
 43-18 
 39-48 
 36-12 
 29-40 
 22-76 
 16-45 
 10-82 
 6-49 
 3-73 
 
 41-92 
 51-47 
 48-16 
 43-94 
 39-86 
 36-05 
 28-88 
 22-34 
 16-09 
 10-79 
 6-52 
 3-78 
 
 41-85 
 50-33 
 47-67 
 43-90 
 40-29 
 37-04 
 30-59 
 24-06 
 17-43 
 11-51 
 6 93 
 3-98 
 
 45-25 
 53-65 
 50-32 
 46-15 
 42-10 
 38-36 
 31-12 
 24-21 
 17-37 
 11-55 
 7-04 
 4-15 
 
 The life table is an instrument of investigation ; it may be called 
 a biometer, for it gives the exact measure of the duration of life 
 under given circumstances. Such a table has to be constructed for 
 each district and for each profession to determine their degrees of 
 salubrity, which while they involve a minimum amount of arith- 
 metical labour will yield results as correct as can be obtained in 
 the pre^sent state of our observations. 
 
II.] STATISTICS. 25 
 
 A life table represents a generation of men passing through 
 time ; and time under this aspect, dating from birth, is called age. 
 In the first column of a life table, age is expressed in years, com- 
 mencing at (birth) and proceeding to 100 or 110 years, the 
 extreme limit of observed lifetime. 
 
 If we could trace a given number of children, say 100,000, from 
 the date of birth, and write the numbers down that die in the first 
 year, living therefore less than one year, against in the table, and 
 on succeeding lines the numbers that die in the second, third, and 
 every subsequent year of age until the whole generation had 
 passed away, these numbers would form a table of mortality, 
 showing at what ages 100,000 lives become extinct. 
 
 Again if the 100,000 children were followed,and the numbers living 
 on the first, on the second, and on every subsequent birthday until 
 none were left, the column of numbers would constitute a table of 
 survivorship. So if of 100,000 children bom at a given point of 
 time, the numbers dying {d^, see Life Table, p. 33) in each, sub- 
 sequent year were written in one column, and the numbers 
 surviving {l^ at the end of each year in another column, the two 
 primary columns of the life table would be formed. 
 
 It is evident that if one of these columns is known the other may 
 be immediately deduced from it ; for if, of 100,000 children, 10,295 
 die in the first year of age, 3,005 in the second year of age, it follows 
 that the numbers living at the end of one year must be 89,705, at 
 the end of two years 86,700. Upon adding the column {d^ from 
 the bottom up to the number against any age (x) the sum will 
 represent the whole of the numbers dying after that age; and 
 consequently the numbers living at that age, as shown in the 
 collateral column (Z^). 
 
 The 100,000 children born at the same moment, and counted 
 annually to determine the numbers living at the end of every year, 
 would by our table completely pass away in less than 107 years. 
 If another generation of 100,000 born a year afterwards were 
 followed, the numbers dying in various years of age would not be 
 very different, the circumstances remaining the same ; and the 
 number of those entering each year of age would vary inconsider- 
 ably from those of the first series. If 100,000 children again were 
 bom at annual intervals, and were subject to an invariable law of 
 mortality, they would form a community of which the numbers 
 
20 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 livino- at each age would be represented by the successive numbers 
 (/ ) in the life table. The sum of these numbers, by Dr. Farr's 
 life table No. 3, for healthy districts, would be 4,951,908. The 
 births are here assumed to take place simultaneously at annual 
 intervals; immediately before the births, therefore, in such a 
 community its population would be 4,851,908, to which it would 
 fall progressively from 4,951,908 by 100,000 successive deaths in 
 the year. The average number constantly living would be some 
 number between 4,951,908 and 4,851,908; and it would be very 
 nearly the mean of these limiting numbers. 
 
 In the ordinary course of nature, the births take place in 
 remittent succession ; and if it is assumed that the 100,000 births 
 occur at equal intervals over every year, it is evident that at any 
 given date a certain number will be found living at all the inter- 
 mediate points of age between to 1 year, 1 to 2, 2 to 3, and all 
 the remaining years of age ; the population in the above instance 
 would be found by enumeration to be nearly 4,899,665. 
 
 The annual births would be 100,000 in such a community. The 
 annual deaths would also be 100,000, and by taking out the deaths 
 at each year of age, from the parish registers of a single year, the 
 second column (d^ of the life table would be found. By adding 
 this column of deaths up, and entering the sum of the numbers ■ 
 year by year against each year of age (x), the third column (4) of 
 the life table would be obtained, for it has been already shown that 
 the numbers attaining any age (x) are equal to the numbers dying at 
 that age and all subsequent ages. From the registers of the deaths, a 
 table of the numbers of the population living, in a parish so consti- 
 tuted, could be immediately determined without any enumeration. 
 Its deviations from the truth would be accidental, and they would 
 be set right by taking the mean of many years. So also from a 
 simultaneous enumeration of the numbers living in each year of 
 age, the two columns d^ and I, of the hfe table could be constructed 
 without reference to any registry of the deaths at different ages. 
 
 The mean age at death in such a community would express the 
 mean lifetime, or the expectation of life at birth ; and the product 
 of the number expressing the annual births into the mean age at 
 death would give the numbers of the population. The deaths in 
 each year of age are called the decrement of life. The decrement 
 in the first year is large ; in the first five years the decrements of 
 
II.] STATISTICS. 27 
 
 life are considerable ; at the age of 10-15 they fall to their 
 minimum ; slowly increase to the age of 56 ; increase more rapidly 
 until the maximum is attained at the age of 75 ; then decline 
 gradually to 85, and after that more rapidly until every life is 
 extinct at the age of 107 by this table.^ 
 
 (17) Construction of Short Life Tables. 
 
 According to De Moivre's hypothesis the numbers living decrease 
 in an arithmetical progression down to nothing at the age of 86 ; 
 it has since been assumed that the number living in any year 
 of their age is an arithmetical mean proportional between the 
 numbers that annually enter upon and that annually complete that 
 year. If d deaths occur in a year, they are assumed to take place 
 at cl equal intervals ; and it is by the same hypothesis that, in 
 calculating the expectation of life, it is assumed that the number of 
 living of the age of n years and upwards is less than the sum of 
 those that annually complete that and all the greater ages by half 
 the number that annually complete that year of their age. The 
 errors involved in the hypothesis of an equal decrement are 
 greatest in the first year of life ; but by making the births the basis 
 of the table (if the births are all registered), the decrement in the 
 first year wiU be correctly represented — in other words, the hypo- 
 thesis is not to be applied to the first year ; e.g. if the deaths in the 
 second year of life were 6 '503 out of a hundred constantly living, 
 by the hypothesis 1 '03252 would be alive at the beginning, and 
 
 96 748 
 0"96748 at the end, of the second year ; the fraction . ' would 
 
 therefore express the chance of living the second year. If 43,104 
 were alive at the beginning, 40,388 would be alive at the end, of the 
 
 second year. For 103,252 : 96,748 :: 43,104 : 40,388; or '' 'Vl° x 
 •' , , > > , i03,2o2 
 
 43,104 = 40,388. In this manner the series down to 5 years may 
 
 be calculated (Farr). 
 
 By the above method, in the construction of Dr. Farr's short 
 
 Surrey life table,^ it was found that out of 50,521 boys born in 
 
 - ' Dr. Farr, "On the Construction of Life Tables, illustrated by a new Life Table 
 /-'uie Healthy Districts of England," TTans. of Boy. Soc, 1859, pp. 832-841. 
 
 " Dr. Farr, Fifth Annual Report, "Vital Statistics," by Wm. Farr, ed. by Noel 
 A. Humphreys, p. 467. 
 
28 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 Surrey, 43,637 live a year, 41,857 two years, 40,704 three years, 
 40,031 four years, 39,650 five years. 
 
 The next point was to determine how many of the 39,550 attain 
 the age of ten years. The hving enumerated at the age of 5-10 
 were 13,588, the deaths 145 ; and after the proper correction the 
 
 mortahty, m, was ascertained to be 0-01050 ; so -^ =0-00525, and 
 
 1 _ ijTj, -99475 
 
 .. , ^ = T-T^^r^TT^ = -98955, the probability of hvmg one year 
 
 1 + -km I-IUIFIWK 
 
 1-00525 
 at the middle of the period, or at 7| years of age. But it may be 
 
 assumed that ( ^ ) = P5.5 = the probability of living five 
 
 years from the age of 5 tolO,and (0-98955)^ = 094885, which x 39,550 
 gives 37,527 = the numbers surviving at the age of 10. 
 
 If the calculation be continued down to 15, 20, 25, and every fifth 
 year to the end, the following table will be obtained : — 
 
 
 Table VIII. 
 
 
 SuEKEY Life Table : Males (1841). 
 
 Age. 
 
 Living. Quinqneimial Periods + J ]. 
 
 . 
 
 . 50,521 476,444 
 
 1 
 
 . . 43,637 
 
 2 . 
 
 . 41,857 
 
 3. 
 
 . . . 40,704 
 
 4 . 
 
 . 40,031 
 
 5 . 
 
 • 39,550 . . 425,923 
 
 10 
 
 . . 37,527 386,373 
 
 15 . 
 
 • ■ . 36,469 348,846 
 
 20 
 
 35,338 . . . . 312,377 
 
 25 . 
 
 ■ 34,061 . ... 277,039 
 
 30 . 
 
 ■ 32,742 . . . 242,978 
 
 35 . 
 
 . . 31,189 . . . 210,236 
 
 40 . 
 
 . 29,822 . . 179,047 
 
 45 . 
 
 ■ 28,069 .... . 149,225 
 
 60 
 
 . 25,973 . . . 121,156 
 
 55 . 
 
 • 23,892 95,183 
 
 60 . 
 
 . . 21,459 
 
 65 . 
 
 . 18,235 
 
 70 . 
 
 . 13,976 
 
 75 
 
 9,836 
 
 80 
 
 5,393 
 
 85 
 
 2,031 
 
 90 
 
 290 
 
 95 
 
 58 
 
 100 . 
 
 11 
 
 105 
 
 2 
 
IL] STATISTICS. 29 
 
 Add up the column headed (living) to the number 39,550 
 
 (against the age of 5 years) and the sum will be the number 
 
 of 5 years — of lustres — which the 39,550 persons will live 
 
 39 550 
 + — ^ — = 19,775. Subtract, therefore, 19,775 from the sum 
 
 425,923, and 406,148 will remain, which, divided by 39,550, gives 
 for quotient 102691 lustres as the expectation of life at that age. 
 A lustre is five years, consequently the expectation of life is five 
 times 10-209 or 51-3 years. If 425,923 be divided by 39,550 the 
 quotient will be 10-769, and 10-769 -05 = 10269, the same result 
 as before. The expectation of life will be found to be 34-5 at the 
 age of thirty. 
 
 The number of living at every five years, except the first deduced 
 by this method, may be considered nearly correct ; the expectation 
 of life is slightly overstated by the assumption that the living at 
 ages 5, 6, 7, 8, 9, 10, and 10, 11, &c., are series in arithmetical 
 progression. The error does rot exceed one-tenth part of a year 
 from 5 to 60 years of age. At birth and after 70 it does not 
 exceed half a year, which may be subtracted as a correction. But 
 by calculating the numbers surviving every year up to the age of 
 5, a sufficiently close approximation to the expectation of life 
 at birth will be obtained. The years of life under 5 are 
 
 I X 256,800 = 213,583 ; and the years of life, after the age of 
 5 = 5 X (425,923-19,775) = 2,030,740, and 2,^^0 + 213^3^ 
 
 44-4, a boy's expectation of life in Surrey. 
 
 A life table still shorter may be constructed by taking intervals 
 
 of ten years, and using I — |— j . The errors in the calculation 
 
 of the expectation of life from the living at every tenth year 
 can be corrected. They are always of the same nature. If we 
 take the numbers " living " against every tenth year from the 
 English table, it will be found that the excess of the expectation 
 of life ranges at the ages 10-50 from 0-1 to 0-2 or 0-3 of a year. At 
 birth the true expectation will be obtained very nearly by sub- 
 tracting one year from the expectation derived from the decennial 
 table. 
 
 By adding up the column headed " living " in the subjoined 
 
A MANUAL OF PUBLIC HEALTH. 
 
 [chap-. 
 
 30 
 
 table, dividing by the first number 100,000, multiplying by 10, 
 and subtracting 5, we obtain 42-05 years as the expectation ot Ute, 
 which is too much by '9 of a year. 
 
 Age ^^^^ X 10 = 47-05 ; and 47-05 - 5 = 42-05 years. 
 ^ • 100,000 True exnectation of life _4ri6 
 
 Error 0-89 
 
 Ace 10 ^IME X 10 = 52-47 ; and 52-47-5 = 47-47 years. 
 70,612 True expectation of life 47-44 
 
 Error 0-03 
 
 Table IX. 
 
 Decennial Life Table {from the English Tabic). 
 
 Tears. 
 
 Living. 
 
 Expectation of Life. 
 
 
 
 By the By tlie 
 
 
 
 decennial Error. annual 
 
 
 
 table. table. 
 
 
 
 100,000 
 
 42-05 . . -89 = 41-16 
 
 10 
 
 70,612 
 
 47-47 . . . -03 = 47-44 
 
 20 
 
 66,059 
 
 40-40 ... -06 = 40-34 
 
 30 
 
 60,382 
 
 33-76 . -08 = 33-68 
 
 40 
 
 53,825 
 
 27-23 . . . -09 = 27-14 
 
 50 
 
 46,621 
 
 20-67 . . . -12 = 20-55 
 
 60 
 
 37,996 
 
 14-23 . -23 = 14-00 
 
 70 
 
 24,531 
 
 9-29 . -51 = 8-78 
 
 80 
 
 9,398 
 
 
 90 
 
 1,140 
 
 
 100 
 
 16 
 
 
 (18) The Gonstructio7i of an Extended Life Table. 
 
 An excellent and practical description of the construction of an 
 extended life table was published in the Journal of the Statistical 
 Society, vol. xlvi. pp. 189-213, by Mr. Noel A. Humphreys, for the 
 avowed purpose of enabling those who had no very profound 
 knowledge of mathematics to construct similar tables, as well 
 as to show the influence of the decrease in mortality on the 
 expectation of life. As it is impossible to state the substance of 
 the paper in more concise or clearer language, the description is 
 here quoted verbatim, and illustrated by printing a portion of the 
 life table for males : — 
 
 " To start with, there is a hypothetical million of persons ; 509,208 
 are assumed to be males, and 490,792 females. 
 
II.] 
 
 STATISTICS. 
 
 31 
 
 " The first process was to ascertain the mean annual death-rate 
 in the seventeen years 1838-54, and in the five years 1876-80, at 
 each of the twelve groups of ages dealt with by the Registrar- 
 General in his annual reports ; then to calculate the rate of increase 
 or decrease between the relative rates prevailing in these two 
 periods at each group of ages. These results are shown in 
 Table X. 
 
 Table X. 
 
 Mean Annual Moktamty of Males and Females in England and "Wales 
 IN Seventeen Years 1838 — 5i, and in Five Yeaes 1876 — 80. 
 
 Groups of Ages. 
 
 Males. 
 
 Females. 
 
 Moan Annual Death- 
 
 
 Mean Annual Death- 
 
 
 rate per 1,000 living. 
 
 Increase or 
 
 rate per 1 
 
 000 living. 
 
 Increase or 
 
 
 
 
 Decrease 
 
 
 
 Decrease 
 
 
 
 
 per cent. 
 
 
 
 per cent. 
 
 
 1838—64. 
 
 1876—80. 
 
 
 1838—64. 
 
 1876—80. 
 
 
 All ages 
 
 23-25 
 
 22-16 
 
 - 4-676 
 
 21-64 
 
 19-54 
 
 - 9-685 
 
 0— 5 
 
 72-25 
 
 67-20 
 
 - 6-986 
 
 6213 
 
 57-02 
 
 - 8-224 
 
 5—10 
 
 9-19 
 
 6-44 
 
 - 29-955 
 
 8-93 
 
 5-98 
 
 - 33-030 
 
 10—15 
 
 5-16 
 
 3-60 
 
 - 32-155 
 
 5-49 
 
 3-56 
 
 - 35-203 
 
 15—20 
 
 7-11 
 
 4-96 
 
 - 30-199 
 
 7-95 
 
 5-14 
 
 - 35-322 
 
 20—25 
 
 9-46 
 
 6-84 
 
 - 27-732 
 
 9-05 
 
 6-30 
 
 - 30-364 
 
 25—35 
 
 12-86 
 
 8-70 
 
 - 12-949 
 
 10-49 
 
 7-94 
 
 - 24-296 
 
 35-45 
 
 9-99 
 
 13-48 
 
 + 4-783 
 
 12-79 
 
 11-22 
 
 - 12-303 
 
 45—55 
 
 18-29 
 
 18-96 
 
 + 3-640 
 
 15-96 
 
 14-94 
 
 - 6-384 
 
 55—65 
 
 31-74 
 
 34-64 
 
 + 9-133 
 
 28-16 
 
 28-26 
 
 + 2-469 
 
 65—75 
 
 66-80 
 
 67-60 
 
 + 1-198 
 
 59-82 
 
 60-16 
 
 -1- 0-562 
 
 75—85 
 
 147-36 
 
 146-72 
 
 - 0-434 
 
 134-46 
 
 132-26 
 
 - 1-635 
 
 85 and upwards 
 
 308-21 
 
 304-08 
 
 - 1-339 
 
 288-16 
 
 273-98 
 
 - 4-922 
 
 "Then, starting with the annual mortality of males in each 
 year of age, according to Dr. Farr's English life table No. 3, these 
 rates [see col. 1 of T. XI.] are reduced or raised in accordance with 
 the relation between the mean mortality that prevailed in the several 
 groups of ages in 1838-54, and in 1876-80 respectively. For 
 instance, it is shown in Table X. that at the first group of ages 
 (0-5), the mean annual death-rate of males declined from 72-25 per 
 cent, in 1838-54 to 67-20 in 1876-80, equal to a decrease of 6-986 
 per cent. It has been assumed that the rate of mortality in each of 
 the first five years of age, as shown in Dr. Farr's Table, had 
 declined in the same proportion as the rate for the entire group of 
 
32 
 
 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 five years. Each of the first five rates in col. 1 was therefore multi- 
 plied by •93014, reducing each of them by 6-986 per cent., and 
 thus constituting the ' corrected rate of mortality ' for each of the 
 first five years of age appearing in col. 2 of Table XI. The 
 yearly rates in each group of ages were dealt with in a similar 
 manner, the rates for the five years 5-10 being reduced 29-955 per 
 cent.; those for the five years 10-15, 32-155 per cent. ; and so on 
 through each of the twelve groups of ages. These corrected rates 
 of mortality at each year of age constitute the rrix of the new life 
 table. There is an obvious defect in this series of corrected annual 
 rates of mortality, viz. the irregularities due to the assumption that 
 the changes in the proportions of decrease in the mean rates of 
 succeeding age-periods, took place suddenly at the commencement 
 of each period, instead of coming gradually into operation, as was 
 certainly the case. The series would undoubtedly look better, and 
 would probably be more technically correct, if these irregularities 
 had been graduated and smoothed away, but having regard to the 
 intended purpose of the table, this process has been omitted. 
 " From this mortality (jn^ column the probability of living at each 
 
 2 — m^. 
 year of age {p^ has been obtained by the formula p^ = a~T — 
 
 2 --17046 
 Thus g.-iynAfi = '84293, which represents the corrected proba- 
 bility of a male living one year from birth. 
 
 " By this process, the probability of living one year is obtained 
 for each age in the series. 
 
 " The next column required is one showing the numbers born and 
 living at each age (4). We start for reasons that have already been 
 described, with 509,208 males at birth, and having ascertained 
 the probabiUty at birth of living one year to be -84293, the sur- 
 vivors attaining one year of age or (^ may be obtained by multi- 
 plying 509,208 by -84293. Carrying on this process of multiplying 
 the numbers surviving to each year of age by the probability at 
 that age of living one year, the survivors to the next age are 
 successively obtained, until the generation becomes extinct. 
 
 " Thus the formula used for obtaining the 4 column is : — {l^, xp^ = 
 L + 1)- This process, laborious by common arithmetic, is shortened 
 by the use of logarithms. By adding the logarithm of ^^ to the 
 logarithm of l^, the logarithm of l^, or the number calculated to 
 
11.] 
 
 STATISTICS. 
 
 33 
 
 complete the first year of life, is obtained. The addition of the 
 logarithm of p^ to the logarithm of l^ in like manner gives the 
 logarithm of l.^, and so on to the end of the series. 
 
 Table XI. 
 
 A Portion of Mr. Noel Humphrey's Engllsh Life Table, based on Mor- 
 tality IN Five Years 1876—80 : Males. 
 
 Cols. 
 
 1 
 
 1 ! 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 
 Annual Mortality at 
 
 ^ = 
 
 (^ _ 
 
 P 
 
 X — 
 
 9 
 
 X 
 
 a; 
 
 each year of life. Pro 
 
 baWlity of 
 ^ing one 
 
 from each 
 
 age. 
 
 Numbers liom 
 
 and living at 
 
 each age. 
 
 Mean numbers 
 
 living in each 
 
 year of age. 
 
 Years which the 
 
 males at each age 
 
 will live. 
 
 Englisi Life 
 Table. 
 
 Corrected year 
 for years 
 1876—80. 
 
 
 
 •18326 
 
 •17046 • 
 
 84293 
 
 509,208 
 
 469,218 
 
 21,347,889 
 
 1 
 
 ■06680 
 
 •06213 
 
 93974 
 
 429,227 
 
 416,294 
 
 20,878,671 
 
 2 
 
 •03624 
 
 •03371 
 
 96685 
 
 403,361 
 
 396,675 
 
 20,462,377 
 
 3 
 
 •02416 
 
 •02247 
 
 97778 
 
 389,990 
 
 385,657 
 
 20,065,702 
 
 4 
 
 •01799 
 
 ■01673 
 
 98341 
 
 381,324 
 
 378,161 
 
 19,680,045 
 
 5 
 
 •01369 
 
 ■00959 
 
 99046 
 
 374,998 
 
 373,210 
 
 19,301,884 
 
 6 
 
 ■01088 
 
 •00762 
 
 99241 
 
 371,421 
 
 370,011 
 
 18,928,674 
 
 7 
 
 •00920 
 
 •00644 
 
 99358 
 
 368,602 
 
 367,419 
 
 18,558,663 
 
 8 
 
 •00767 
 
 •00537 
 
 99464 
 
 366,235 
 
 365,253 
 
 18,191,244 
 
 9 
 
 •00649 
 
 ■00455 
 
 99546 
 
 364,272 
 
 3&3,445 
 
 17,825,991 
 
 10 
 
 •00563 
 
 ■00382 
 
 99619 
 
 362,618 
 
 361,928 
 
 ]7,462,.'>46 
 
 11 
 
 •00507 
 
 ■00344 
 
 99657 
 
 361,237 
 
 3'60,617 
 
 17,100,618 
 
 12 
 
 •00478 
 
 •00324 
 
 99677 
 
 359,998 
 
 359,417 
 
 16,740,001 
 
 13 
 
 •00472 
 
 •00320 
 
 99681 
 
 358,835 
 
 358,262 
 
 16,380,584 
 
 14 
 
 •00486 
 
 •00330 
 
 99671 
 
 357,690 
 
 357,102 
 
 16,022,322 
 
 15 
 
 •00519 
 
 ■00362 
 
 99639 
 
 356,513 
 
 355,869 
 
 15,665,220 
 
 16 
 
 •00564 
 
 ■00394 
 
 99607 
 
 355,226 
 
 354,528 
 
 16,309,351 
 
 17 
 
 •00622 
 
 •00434 
 
 99567 
 
 353,830 
 
 353,064 
 
 14,954,823 
 
 18 
 
 •00688 
 
 •00480 
 
 99521 
 
 352,298 
 
 351,455 
 
 14,601,759 
 
 19 
 
 •00759 
 
 ■00530 
 
 99471 
 
 350,611 
 
 349,683 
 
 14,250,304 
 
 20 
 
 •00832 
 
 •00601 
 
 99401 
 
 - 348,756 
 
 347,712 
 
 13,900,621 
 
 21 
 
 •00850 
 
 •00614 
 
 99388 
 
 346,667 
 
 345,606 
 
 13,552,909 
 
 22 
 
 •00868 
 
 •00627 
 
 99375 
 
 344,546 
 
 343,469 
 
 13,807,303 
 
 23 
 
 ■00886 
 
 •0064O 
 
 99362 
 
 342,392 
 
 341,300 
 
 12,863,834 
 
 24 
 
 •00903 
 
 •00653 
 
 99349 
 
 340i206 
 
 '339,101 
 
 12,522,534 
 
 25 
 
 ■00920 
 
 •00801 
 
 99202 
 
 337,993 
 
 336,644 
 
 12,183,433 
 
 96 
 
 •44444 
 
 ■43849 
 
 64036" 
 
 565 
 
 403 
 
 
 97 
 
 •47312 
 
 ■46678 
 
 62156 
 
 362 
 
 294 
 
 718 
 
 98 
 
 •50000. 
 
 •49331 
 
 60429 
 
 225 
 
 180 
 
 424 
 
 99 
 
 •53398 
 
 ■52689 
 
 58301 
 
 136 
 
 108 
 
 244 
 
 100 
 
 ■55000' 
 
 •54264 
 
 57317 
 
 79 
 
 62 
 
 136> 
 
 1 This number shows how many years the 79 males who attain the age of 100 
 years will live, calculated by the English Life Table No. 3. 
 
 D 
 
34 
 
 A MANUAL OF PUBLIC HEALTH. [chap. ji. 
 
 " The next necessary column for our purpose is one showing the 
 mean numbers living in each year of age, which is obviously less 
 than the number surviving to, or living at the commencement of each 
 year. This column is described in a life table as P„ meaning the 
 mean population living during the year following each age in the 
 series. It is assumed that the number living in each year of age 
 is the arithmetical mean of the numbers living at the beginning 
 
 and at the end of the year. P^ is therefore equal to — 1 
 
 This also indicates the number of years of life lived in the year, 
 from age x to age x -\- \. 
 
 " The last column given in the table is what is technically called 
 the q^ column. The number against any age in this column 
 is the sum of all the numbers in the V^ from that, age to the 
 end of the table. It therefore shows the aggregate number 
 of years which the males at each age in the' table will live, until 
 their extinction by death. Thus q^ is equal to 21,347,889, show- 
 ing that according to this life table the generation of 509,208 
 male infants at birth, which was assumed as the radix of the male 
 table, would live this aggregate number of years before final 
 
 extinction by death ; and f^ gives the mean future lifetime of all 
 
 ''X 
 
 the persons living at age x in the table, and as — '- '- = 41'92, 
 
 ^ ° " 509,208 
 
 the mean duration of life of a generation of males subject to the 
 
 mean rates of mortality that prevailed at twelve groups of ages 
 
 during the five years 1876-80 would be 41-92 years." 
 
CHAPTER III. 
 
 AIDS TO CALCULATION. 
 
 (19) Tables. 
 
 FlEST in order are suitable tables, e.g., logarithms to four or 
 five figures ; of these Mr. Hy. Law's and Dr. C. J. Woodward's 
 will be found most convenient. Hoiiel's reprint of Lalande is 
 also to be commended. Crelles' multiplication tables, by the aid of 
 wliich three figures may be dealt with at once, and reciprocals 
 such as Lieut.-Col. Oakes's tables (footnote, p. 15) which reduce 
 division to the short multiplication of decimals and render easy 
 the addition of fractions are all useful. 
 
 The greatest saving in labour and avoidance of monotony is 
 however obtained from the use of mechanical aids such as Pro- 
 fessor Fuller's Spiral Rule and the Arithmometer 
 
 (20) Professor Fuller's Spiral Rule} 
 
 The rule (Figs. 1 and 2) consists of a cylinder jacket {d) that can 
 be moved up and down upon, and turned round, an axis (/), which 
 is held by a handle (e). Upon this cylinder is wound in a spiral 
 a single logarithmic scale. Fixed to the handle is an index (b) 
 which for distinction may be called " the indicator," for the answer 
 to a sum is always read from it. Two other indices (c) and 
 (a), whose distance apart is the axial length of the complete 
 spiral, are fixed to the cylinder {g). This cylinder slides in (/) 
 like a telescope tube, and thus enables the operator to place 
 these indices on any part of the scale. Two stops (o) and {p) 
 
 ^ MessJ-s. Stanley, Great Turnstile, are the agents. The price is Zl. 
 
 D 2 
 
36 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 .1-U-J_i~_u_lj 
 
 -LU-iCLi-iiA. 
 " ' I ■ 1 1 1 1 1 II 
 
 I rn II 
 
 III '' 'I I II 1 1 
 
 / 
 
 ■7 
 
 [a o\ 
 
 Fig. 1. 
 
 Fig. 2. 
 
 are so fixed that when they are brought ia contact, the index 
 (h) points to the commencement of the scale, (n) and (to) are 
 
III.] STATISTICS. 37 
 
 two scales, the one on the piece carrying the movable indices, the 
 other on the cylinder (d). 
 
 The scale commences with 100 and ends with 999, the hundred 
 is read either as one, or ten or a hundred, or a thousand, as may 
 be required ; all the others are read in a similar manner thus : 827 
 is 8-27, or 82-7, or 827000. 
 
 (21) Multiplication by the Spiral Rule. 
 
 The- two main arithmetical operations, multiplication and 
 division, will be readily understood by reference to the diagram 
 which gives a portion of the scale and the indices. The indices 
 it will be noticed are of a different shape to that of the previous 
 figure, the reason being that Fig. 1 represents Professor Fuller's 
 original idea, and the diagram (Fig. 2) the latest form of index, the 
 brass, slip carrying the indices a and c and the logarithmic scale n, 
 having the advantage that if it happens that the edge of the 
 index cannot be seen from being under the indicator instead of the 
 left edge being used for reading the right edge can be used. 
 
 Supposing we multiply by the aid of the instrument 230 by 
 167, place the indicator h as shown by the dotted line at 230, 
 the upper index c in the position shown in the diagram dotted 
 line at 100 that is zero, now turn the cylinder (not the iTidices) 
 until 167 is as shown by the blackened figure at 167, then the 
 indicator b points to 3841. The rule for the number of figures 
 in the product is the algebraic sum of the number of figures in 
 the factors, minus one for each factor brought to the upper index 
 c, the number of figures in the factors 230 and 167 is six, but 
 167 has been brought to the upper index, and therefore 1 must 
 be subtracted ; hence the answer is 5 figures, and the product of 
 multiplying 230 by 167 is 38,410. 
 
 (22) Division by the Spiral Rule. 
 The same diagram may be used for the purpose of explaining 
 division. Supposing we wish to prove the above multiplication 
 to be correct, if it is so, then dividing 38410 by 167 should give 
 230. Place the indicator h as shown black, pointing to 3841, 
 place the upper index c as shown blach at 167, then turn the 
 cylinder round until the index c is at zero, the indicator will now 
 point to 230 thus giving the answer. To know the number 
 of figures in a quotient, the rule is to take the algebraic difference 
 
38 A MANUAL OB" PUBLIC HEALTH. [chap. 
 
 between the number of figures in the divisor and dividend and add 
 one each time the upper index c is used. In this case the algebraic 
 difference between the factors 3-5 = 2 the upper, not the lower, 
 index has been used ; we must therefore add 1, the quotient must 
 therefore consist of three figures only, hence we know the answer 
 is not 2-3 or 2,300, or any other figure but 230. 
 
 The following examples are taken from Professor Fuller's paper 
 of instructions. 
 
 EXAMPLES. 
 
 Multiplication. — 48'42 x -06434 = 3-1153. In this case 6434 is brought to a, 
 so that the number of figures in the product is the sum 2 + ( - 1) = 1. 
 
 13-28 X 142-7 = 1894-9. In this case 142 is brought to c, so that the miraher of 
 •figures iu the product is the sum -1 = 5-1 = 4. 
 
 "What is the weight of a bar of iron 14 ft. x 3" x 2" ; weight of a cubic inch of 
 iron -277 lbs. ? 
 
 14 X 12 X 3 X 2 X -277 = 279-21 lbs. In this case three of the factors have to 
 be brought to c, so that the number of iigures in the product = 6 — 3 = 3. 
 
 Division.— 486-34-4- -0723=6726-6. In this case a is set to 723, so that the 
 number of figures in the quotient is 
 Difference + l-l = 3-(-l) + l-l = 4. 
 
 •01368-^12-64= -001082. In this case c is set to 1264, so that the number of 
 figures in the quotient is 
 Difference -I- 1 =- 1 - 2 -(- 1 =- 2. 
 
 How many gallons will a cistern 4-75' x 3-5'x 2-75' hold ; a gallon is -16037 cub. ft. ? 
 
 4-75 x S-5 X S'T'S 
 
 .^gpgy !-=285-08. The Difference -)- 1 = 4, but c is set to 275, so that the 
 
 number of figures in the quotient = 4 - 1=3. 
 A stone 21-75"x 15-25"x 8J" weighs 268Jlbs. How many cubic feet are there in 
 
 238 tons ? 
 
 21-76x15-25x8-333x238x2240 „,_ „ ^.„ „„,.... „„„„k 
 ogg.75 X 1728 = 31/2-8. Difference 4- 2= 7, but a is set to 26875 
 
 and 1728, and 224 is brought to c, so thenumber of figures in the qiiotient=7-3 = 4. 
 If 48 men working 8 hours a day for 7 days can dig a trench 235' x 40' x 28' ; in 
 how many days can 12 men working 10 hours a day dig 156,060 cub. yds. ? 
 Here 12-48 :: 1:x 
 
 10 - 8 
 235x40x28 
 
 : 156, 060 
 
 27 
 7 X 48 X 8 X 156060 x 27 
 
 12x10x235x40x28 
 Difference + 5 = 12-lH-5 = 6. 
 
 But 15CG6 is brought to c, and a is set to 40 and 28, so the number of figures in 
 the quotient = 6-3 = 3. ^ 
 
 These examples show that the rule gives very great facility for obtaining numerical 
 results ; also that the results are a sufficient approximation for most practical 
 purposes. ^ 
 
 llATIO. 
 
 When either of the movable indices is at one number and the indicator at another, 
 "■"ii I /-^ 7 IS turned into any other position, though the numbers at the indices 
 will be ditterent, their ratio will remain constant. 
 
 Example.— To convert francs and centimes into sterling money, supnosine ex- 
 change 25f. 45c. for 11. The ratio between centimes and penSe is 2545 toTo. Place 
 
III.] STATISTICS. 39 
 
 the cylinder so that the indicator is at 2545, and make one of the movable indices 
 point to 240. Then on moving the cylinder to read off different numbers of centimes 
 at the indicator, the corresponding value in pence will be read at the movable index. 
 Wages Table. — To find the wages for different times at 35s. per week of 57 hours. 
 Place the cylinder so that the indicator is at 57, and make one of the movable 
 indices point to 420, the number of pence in 35s. Then on moving the cylinder to 
 read off different numbers of hours at the, indicator, the corresponding wages in pence 
 will be read at the movable index. 
 
 LOGARITHMS, POWERS AND ROOTS. 
 
 To obtain powers not higher than the seventh, the quickest way is by direct 
 multiplication. 
 
 For higher powers and roots. Place the upper movable index (c) to the number, 
 and read the scales (n and m). (See Pig. 2. ) These together give the mantissa of the 
 logarithm of the number. To this the index has to be added. The index of the 
 logarithm of a number greater than unity is one less than the number of figures in 
 the integral part of that number. Thus the index of 5432 is 3, of 543 '2 is 2, of 
 54-32 is 1, and of 5-432 is 0. 
 
 Multiply or divide the resulting number by the power or root, as shown above. 
 Then place the cylinder so that it reads on the scales (» and ro) tbe decimal part of 
 the quotient. The power or root is then at the index (c). In the result the number 
 of figures before the decimal point is one more than the nimiber in the integral part 
 of the above quotient. 
 
 The scale \n) is read from the lowest line of the top spiral and (m) from the vertical 
 edge of the scale (n). Thus in the diagram, page 36, (n) reads '22, (m) reads -0027. 
 These must be added together making -2227, which is the mantissa of the logarithm 
 of 167 to which (c) points. 
 
 Examples. — 5^^, on placing (c) to 500, scale (n) reads -68 and scale {m) -01897, 
 which gives the logarithm of 5 - -69897, the index being 0. Then -69897 x 13 = 9 -08661. 
 Now;placing the cylinder so that it reads -08661 on scales (n and m) the index (c) 
 reads 12207, and the required power is 1220700000, having 10 figures, as the integral 
 part o f the above quotient is 9. 
 
 741 on placing (c) to 741, scale (m) reads -86 and scale (m) -00982 which gives 
 
 the logarithm of 741 - 2-86982, the index being 2. Then 2-86982-^5 = -57396. Now 
 placing the cylinder so that it reads -57396 on scales {n and m) the index (c) reads 
 37495, and the required root is 3-7495, having one figure before the decimal point, as 
 the integi-al part of the above quotient is 0. 
 
 ROOTS OF DECIMAL FRACTIONS. 
 Write them as vulgar fractions, and multiply numerator and denominator by ten or 
 a power of ten, so that the denominator may have a complete root. Then take the 
 required root of the numerator by the method given above, and of the denominator 
 
 by inspection : 
 
 ~ "^40' _ V40 
 
 10 
 
 y 
 
 ■""■V '- yr«= yTP=^ 
 
 3/40 _ 
 
 .^ 
 
 40 
 
 a' 
 
 10 
 
 / 58600 _ 
 
 58600 
 
 105 10 
 
 Tile facility of obtaining and working with the logarithms of numbers gives the 
 rule a great additional value. 
 
40 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 TABLES. 
 
 There are tables printed on the rule which have been made and selected as those 
 considered most useful. Owing to our want of a decimal system, it has been deemed 
 most important to have a series of tables which give for our measures of weight, 
 length, time, &c., the ec^uivalent decimal fraction of the larger for successive num- 
 bers of the smaller unit. This enables results to be obtained without the necessity 
 of reduction. Thus to find the area of a rectangle whose sides are 24' 6i" and 43'5i". 
 The table gives by inspection -5208 and -4583 opposite 6i" and 5i" respectively, so 
 that the area is obtained by multiplying 24-521 by 43-458. The result, as shown by 
 the rule, is 1065-6. If the parts of a square foot are required in twelfths, the table 
 shows that -6 of afoot is equivalents to 7i twelfths, and the result reads 1065 -7i. 
 
 ADJUSTMENTS OF INSTRUMENT. 
 
 1. When the top movable index points exactly to 100 the bottom movable 
 index must point exactly to the end of the scale. 
 
 2. When the top index points exactly to the end of the scale, the beginning of 
 the scale must be just covered by the edge of the brass scale. 
 
 There are two pairs of movable indices. When the use of one pair would 
 cause the stem of the indices to interfere with the fixed index, the other pair are to 
 be used. 
 
 The adjustment of the index is made by means of one of the screws fastening it 
 ■ to the wood disc. 
 
 (23) The Arithmometer. 
 
 There are at present in the market two species of calculating 
 machines, one a straight instrument, the other a semi-circular. Both 
 are on the same principles, and nearly the same price. It is claimed 
 for the circular kno-wn under the name of Edmonson's circular 
 machine, that. 
 
 The Driving-handle is in the easiest possible position for the hand 
 and -wrist. 
 
 The use of a circular instead of a straight slide brings the 
 " product holes " close under the eye of the operator ; and, being 
 placed in shallo-w a.pertures, all the figures are easily visible. 
 
 The Circular form admits of any product disc being brought 
 opposite any digit on the face-plate, and permits the -working of 
 very extended products and quotients. A product of twenty figures 
 can be worked without special management. 
 
 Two sets of factors can be worked on to the circle (and without 
 intermediate record), the two results can then be worked together 
 as addends, subtrahend and minuend, multiplicand and multiplier, 
 or dividend and divisor. 
 
 Quotients appear in the same line of apertures as products, but 
 on a different part of the circle, clearly marked off, and (without 
 transferring) are in a position to be further operated on as addends, 
 minuends, multipliers or dividends ; or they can be transferred to 
 
III.] 
 
 STATISTICS. 
 
 41 
 
 the face-plate, to be worked as subtrahends, multiplicands, or 
 divisors. 
 
 The Eraser will bring to zero either the whole or a part of the 
 figures on the circle. 
 
 Click-springs to the number discs (a source of constant annoy- 
 ance) are dispensed with. All the discs are locked (when the 
 circle is in its working position), except when the mechanism 
 requires them to move. Thus great certainty of action is insured. 
 
 INDEX SLIDE 
 
 DRIVING HANDLE 
 REGULATOR HANDLE 
 
 Fig. 3. 
 
 The " Markers " on the face-plate have flat thumb-pieces, and 
 can be set as often as desired without hurting the fingers. 
 
 Its principle is extremely simple. Beneath each Number Slide 
 are two radial axes, one above the other. The lower one makes 
 one revolution for each revolution of the motive handle, and has 
 upon it a cylinder. That half of the cylinder which is farthest 
 from the centre of the machine is devoted to reckoning; and the 
 other half to stopping and locking the axis above it, until the 
 moment when the reckoning half, or " reckoner," begins to operate. 
 The "reckoner" is again divided into 10 sections, on which there 
 
42 A MANUAL OF PUBLIC HEALTH, [chap. 
 
 are respectively 0, 1, 2, 3, 4, 5,6, 7, 8 and 9 teeth, and a considerable 
 blank space ; the section with 9 teeth being the farthest from the 
 centre of the machine. The 8 teeth of the next section are a 
 /prolongation of an equal number of the teeth of the preceding ; 
 and so on for each section. So that to the eye the reckoner 
 presents a series of successively decreasing teeth, and from its 
 stepped appearance it may be termed a " stepped reckoner." The 
 stopping or locking half of the cylinder is also stepped to correspond 
 with the stepped reckoner. On the upper axis is a tube, free to 
 slide longitudinally, and having a key fitting into a groove in the 
 axis. The tube carries at its outer end a pinion of 10 teeth gearing 
 with the stepped reckoner, and at its other end a star wheel of 10 
 rays fitting the stepped stop. A fork projecting below the number 
 slide, fits into a groove round the tube, so that the motion of the 
 number slide is communicated to the tube, whose pinion is thus 
 placed in position to gear with that section of the reckoner, the 
 teeth of which correspond in number with the figure in front of the 
 curved rule. The pinion and star wheel are at such a distance 
 apart, that the latter is always upon the section of the stepped stop, 
 corresponding to the section of the reckoner, with which the 
 former is placed to gear. 
 
 On the lower axis, and nearer to the centre of the machine, is a 
 piece movable longitudinally, but carried round with the axis by a 
 pin fitting into a hole at the end of the stepped stop. It is composed 
 of the " secondary carrying tooth," and its corresponding stop, there 
 being an incline on the inner edge of the latter, the use of which 
 will be presently explained. Just above this movable piece, there 
 are, fixed on the upper axis, a second pinion of 10 teeth and a star 
 wheel. The pinion is so set, that when the piece below it is close 
 up to the stepped stop, the secondary carrying tooth passes it by ; 
 but when the piece is moved inwards, this carrying tooth gears 
 with the pinion and when revolving, moves it one tooth forward. 
 As soon as this has taken place, the incline comes in contact with 
 a pin in the frame of the machine, which pushes the piece into its 
 former position. 
 
 Under the discs on the circle, the before-mentioned upper axis 
 carries two revei'sed bevil wheels of 10 teeth each, on a tube free to 
 move longitudinally, but carried round by a key fitting into a 
 groove on the axis. These wheels are moved longitudinally by the 
 
Ill] STATISTICS. 43 
 
 regulator, as may be seen by taking off the circle. Between them 
 (and in gear with one or other of them, according to the position of 
 the regulator) is a similar bevil wheel on the spindle of the corre- 
 sponding number disc, and above the wheel is the " primary carrying 
 tooth." As the pinions and the bevil wheels have each 10 teeth, 
 and the number disc has 10 figures, every tooth when the pinions 
 are moved counts one, either forward or backward on the disc. 
 "When the figure in the aperture over the disc passes from 9 to 
 in addition, or from to 9 in subtraction, ^he primary carrying 
 tooth passes the wedge-shaped end of the upper arm of the carrying 
 lever, which it pushes back. This carrying lever moves on a 
 perpendicular axis. Its lower arm clutches a pin in the shaft of a 
 fork under and parallel with the lower axis beneath the next higher 
 number slide. This fork fits into a groove round the movable piece 
 of the secondary carrying tooth, which it shoots inwards into position 
 for adding or carrying 1 as above described. 
 
 Each lower axis is timed to operate on the pinions above it, at 
 least one tooth later than its neighbour to the right, to allow time 
 for the latter to shoot the carrying tooth. This is not the case, 
 however, with the axis under the lowest Number Slide but one, 
 and the Index Slides B and C, which are all timed to act simul- 
 taneously with the lowest Number Slide. 
 
 It will be seen that each revolution of the motive-handle and 
 consequently of the reckoners, causes the latter to move the pinions 
 above them as many teeth as there are on the sections of the 
 reckoners over which the pinions arerespectively set by the number 
 slides. This motion of the pinions is communicated to the number 
 discs, and therefore adds or subtracts accordingly. 
 
 Thomas de Colmar's straight machine is very similar in mechanism 
 and is a little cheaper than the circular. I have tried both and per- 
 sonally prefer the straight machine ; my reason is mainly because it is 
 lighter and more portable, the straight arithmometer is contained 
 in a box 33 x 7 x 3'5 inches, whereas Edmonson's circular is very 
 much larger and heavier. 
 
 Either of these machines will add, subtract, multiply, divide and 
 extract the Square Root. 
 
 As a sample of the speed of operation, it may be stated that the 
 following multiple is worked in less than half a minute : 
 93,857,926 x 987,416,381,792=92,676,853,693,421,283,392. 
 
44 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. III. 
 
 one 
 
 It multiplies and adds, or multiplies and subtracts, in 
 operation, which takes no more time than multiplying alone. 
 
 It will multiply 12 figures by 12 figures (giving a product of 24 
 figures) ; or, with a multiplicand of 8 figures it will work a 
 multiplier of any number of figures, however great. It will divide 
 a dividend of any number of figures by a divisor of 8 figures, and 
 will carry a quotient to any number of places of decimals. 
 
 The method of working either machine is learnt in a very short 
 time, and will be foi^nd invaluable to those who desire to get out 
 
 A, 
 
 Fig. i. — The Stbaight Aeithmometee. 
 
 Small brass studs gliding in slits. B, Button by means of wliich the machine is 
 adjusted for subtraction (or division) and multiplication (or addition), c, Holes 
 at the bottom of which are seen the results of the operations. D, Holes in which 
 are seen figures indicating the multiplier and the quotient. M,M,M,M is a 
 movable plate. N, The handle which is to work the machine, o. Right button, 
 by means of which all the figures in D. D. can be adjusted to zero. P, Left 
 button, by means of which all the figures c, c, 0, can be placed at zero. 
 
 elaborate life tables, or other tabular matter involving the close 
 application of the mind for many hours to figures. 
 
 In the Journal of the Institute of Actuaries will be found papers 
 by General Hannyngton (vol. xvi.), and by Mr. Peter Gray, giving 
 directions in considerable detail for performing the most elaborate 
 calculations in the formation of life contingency tables by aid of the 
 Arithmometer ; to these papers the reader is referred for farther 
 information. 
 
 ^ Messrs. Stanley, Great Turnstile, Holborn, are the agents for Edmonson's 
 circular machine, 251. Mr. Redfern is the agent for Dc Colmar's Arithmometre 
 price 201. 
 
SECTION II. 
 AIR, VENTILATION, WARMING. 
 
CHAPTER IV. 
 
 AIR. 
 
 (24) General Nature of Air. 
 
 Air collected near the surface of the earth is a mechanical 
 mixture of oxygen and nitrogen, with a constant and a small pro- 
 portion of carbonic acid, together with variable minute traces of 
 other gases, odours; essences, particles of mineral substances, of 
 dead and living organized matter. The air is, owing to the force 
 of gravity, much denser near the earth, and gets attenuated layer 
 by layer as you ascend. A coloured diagrammatic representation 
 of the air envelope to the globe would show accurately the density 
 if the colour was made darkest at the surface and faded gradually 
 into space ; it is now believed there is no definite limit to the 
 atmosphere, it simply gets rarer and , rarer ; if it were possible to 
 make a flight from the earth's surface through the interplanetary 
 space there would be no single point of the passage which could 
 be selected as absolutely destitute of the constituents of the 
 atmosphere. 
 
 (25) Aimospheric Pressure. 
 
 Pressure of the atmosphere varies with locality ; there are areas 
 on the globe of almost constant high pressure and of almost con- 
 stant low pressure. The equatorial tropical regions have a belt 
 of low pressure towards which the trades blow south of the equator, 
 and parallel to it there is a well-defined belt of high pressure 
 of nearly equal breadth throughout ; north of the equator there 
 is a belt of high pressure, but it is irregular in form, in its breadth, 
 and in its inclination to the equator. At the south and north 
 
48 
 
 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 poles there are also areas of low pressure ; that at the south pole 
 remains pretty constant throughout the year, that at the north 
 pole is divided into two centres, at each of which there is a 
 diminution of pressure greatly lower than the average north polar 
 depression. It follows then that there are three extensive areas 
 of low pressure, viz., the equatorial belt and the regions of the pole. 
 The average weight or pressure of the atmosphere in the latitude 
 of London is balanced by a column of mercury 29-905 inches at 
 0° ; this is equal to a pressure of 14.-73 lbs. on the square inch. 
 The standard atmosphere to which, in measuring gases or calcula- 
 tions generally, mixtures are reduced is 760 mm. of mercury at 0° 
 (29-922 inches); this is equivalent to lOS'S kilos on a square 
 decimetre. 
 
 (26) The Weight of a Volume of Air. 
 
 The weight of a litre of air, or any other volume, varies according 
 to the value of gravity at the place of observation. At the latitude 
 of Paris the weight of a litre of dry carbon, dioxide free air is 
 •12932 grms. 
 
 This is also with but slight difference the weight of a litre 
 of purified dry air in London. The presence of carbon dioxide 
 and moisture in air increases its weight. Supposing the air 
 contain -0004 per cent, of carbon dioxide, then the weight of 
 1 litre would be 12935 grm. at 0° and 76 mm. pressure ; if 
 required to know the weight per cubic foot, it only has to be re- 
 membered that 28 litres are equal to 1 cubic foot, therefore the 
 grms. per cubic foot would be 28 times the above or 28 x 1-2935 
 grms. = 37'218 grms. (or 558-9 grains). 
 
 The weight of air in a square milei is no less than 
 59,133,431,808 lbs., and the carbonic acid which it contains weighs 
 31,464,899 lbs., which is equal to 8,490,427 lbs. of carbon, or 3,790 
 tons. 
 
 To be able to reduce volumes of air or gas to standard pressure 
 and temperature and to ascertain their weight, is the basis of the 
 principles of ventilation and air movement generally, and therefore 
 should be carefully mastered. 
 
 To reduce the volume of air at any temperature, pressure, and 
 
 1 (5280)= X 144x14-73 = 59,133,431,808, and 59,133,431,808 xi^5??l=31, 464,899. 
 
IV.] AIR, VENTILATION, WARMING. 49 
 
 moistness to the standard pressure and temperature we require 
 to apply the laws of Boyle and Charles. 
 
 The law of Boyle is : — The volume of a gas is inversely as 
 the pressure per square centimetre, so long as the temperature 
 remains the same, which, translated into simple language, means 
 that if a cubic foot of air is measured at 740 mm. of barometric 
 pressure, to reduce it to the standard pressure it must be multiplied 
 by 740° and divided by 760°. 
 
 The law of Charles is that, assuming no variation of pressure, 
 all gases expand -^^ of their bulk at 0° for each degree of varia- 
 tion of temperature ; in other words, 273 volumes at 0° become 
 274 at 1°, 275 at 2°, and so on. For example, 1,000 volumes of air 
 at 10° will become at 20° 1035-3 ; for 273 at 10° becomes 283, and 
 273 at 20° becomes 293°, hence the volume will increase at the 
 
 ratio of ^ that is the volume ~ x 1000 = 1035-3. The 
 Zoo /oo 
 
 following is then the simple rule for temperature correction of 
 volume. As 273 plus the given temperature is to 273 plus 
 required temperature, so is the given volume to the required 
 volume. 
 
 In practice the two calculations are always required simul- 
 taneously — that is, con-ection both for temperature and pressure ; 
 for instance, supposing it is required to reduce a volume of air 
 at 761 mm. pressure and 20° temperature to the standard pressure 
 of 760 and temperature 0°, the equations are combined as follows : — - 
 761 X 273 
 
 760 X 293 
 
 = -933 
 
 3p 
 To find the weight of moist air -f- must be subtracted from the 
 
 o 
 
 height of the barometer before correcting, p being the tension 
 
 or pressure of aqueous vapour as ascertained from the dew 
 
 point ; thus the litre of air at 0° and 760 mm. pressure (its weight 
 
 when dry being 1-2935 grms.) would, when moist, weigh 1-2909 
 
 grms., or 1 cubic foot = 36-1452 grms. (556-79 grains), because 
 
 it is now really at a less pressure than 760 mm., for the tension 
 
 at 0° being 4-6, and f of 4-6 is equal to 1-7 mm. of mercury, 
 
 which must be subtracted from 760, leaving 758-3 ; then 
 
 -^^^ X. 12,935 = 1-2909 grm. A litre of air with -0004 per 
 
50 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 cent, of carbon dioxide at 15° and 760 mm. pressure will weigh 
 nearly a gramme (■9417), or a cubic foot will weigh 399'4 
 grains. 
 
 (27) Percentage Composition of the Atmosphere. 
 
 Cavendish, who had hot all the refined processes of volumetric 
 analysis at command which we now possess, could find no ap- 
 preciable difference between the percentage of oxygen in the 
 large number of 500 analyses. He found 100 volumes of purified 
 air to contain 20'833 per cent, of oxygen, the rest nitrogen. The 
 most numerous and accurate volumetric analyses of air which 
 have been made since Cavendish, have been those of Angus 
 Smith, Bunsen, and Regnault. Bunsen found in 15 analyses of 
 air, extreme differences of from 20'970 to 20'840. Regnault 
 found air from different parts of the world to vary from 20"940 
 to 20'850; country air occasionally attained 21'0 per cent.; the 
 air of Paris also in one instance approached this number nearly, 
 for he records 20'999. Angus Smith found in the most crowded 
 parts of Perth the mean of 22 analyses to give 20"938 per 
 cent, oxygen, while the air of the sea-shore and the heath gave 
 20-999. 
 
 The analysis of the air by the method of Dumas, by which the 
 air is drawn slowly over ignited copper, is, on the whole, capable 
 of greater accuracy than eudiometric methods, and there have 
 been numerous analyses made by this method : the oxygen unites 
 with the copper, forming copper oxide, and the difference in weight 
 between the bright and the oxidized metal gives at once the 
 oxygen, while the nitrogen can be collected in an exhausted flask, 
 and also weighed. In this process the air is carefully dried and 
 freed from carbon dioxide before it enters the tube. 
 
 The following are some analyses by weight, but in the second 
 column the weights are translated into volume by dividing by 
 the specific gravity of oxygen (1'10561). 
 
 Nitrogen by 
 weight.* 
 
 77.00 Dumas. 
 76-94 Stas. 
 77-02 Marignae. 
 
 1 The percentage volume of nitrogen from this table can be found by subtracting 
 the percentage volume of oxygen from 100, or by dividing the weight percentages of 
 nitrogen by its specific gravity -97135. 
 
 
 Oxygen by 
 
 Oxygen by 
 
 
 weight. 
 
 volume. 
 
 Paris . . 
 
 . 23-00 
 
 . 20-80 . 
 
 Brussels 
 
 . 23-06 . 
 
 20-85 . 
 
 Geneva . 
 
 . 22-98 . 
 
 . 20-78 . 
 
IV.] 
 
 AIR, VENTILATION, WABMING. 
 
 51 
 
 
 Oxygen by 
 
 Oxygen by 
 
 Nitrogen by 
 
 
 weight. 
 
 volume. 
 
 weight. 
 
 Berne . . 
 
 . 22-95 . 
 
 . 20-76 . 
 
 77-05 Brunner 
 
 Faulhom . 
 
 . 22-97 
 
 . 20-78 . 
 
 . 77-03 Dumas. 
 
 Grbningen 
 
 22-99 
 
 . 20-79 
 
 77-01 Verver. 
 
 Copenhagen . 
 
 . 23-01 . 
 
 . 20-81 . . 
 
 76-89 Lewy. 
 
 North Sea 
 
 . 22-60 . 
 
 20-44 . 
 
 77-40 „ 
 
 jj 
 
 . 23-12 . 
 
 20-91 
 
 76-88 „ 
 
 Elsinore . 
 
 . 23-04 . 
 
 . 20-84 . 
 
 76-96 „ 
 
 Guadeloupe . 
 
 . 22-68 
 
 . 20-51 . . 
 
 77-32 „ 
 
 >» 
 
 . 23-14 . 
 
 . 20-93 
 
 76-86 „ 
 
 From all of -which it appears that the two chief gases, oxygen and 
 nitrogen, vary in percentage within small limits from local and 
 seasonal conditions ; the extremes in percentage volume of oxygen 
 heing from 20-5 to 21-0.i 
 
 The gases are not in chemical combination, but simply mixed 
 together — this is proved by three facts. (1) The relative amounts 
 of the gases cannot be expressed by any chemical formula, for the 
 proportions are neither those of their combining -weights, nor of any 
 simple multiple of those -weights. When the proper proportions 
 of the two gases are mixed together to form artificial air, there is 
 no manifestation either of heat, electricity, or change of volume ; 
 which are the usual signs of chemical combination. (2) Air is 
 slightly soluble in water, but the oxygen of the air being more 
 soluble than nitrogen, the air expelled from water by boiling is 
 oxygenized and contains nearly 35 percent, of oxygen ; this could 
 not take place if oxygen formed a compound with nitrogen, water 
 in that case would dissolve the same proportions of the two gases 
 which exist in the air, and the gas collected from water by boiling 
 after the carbon dioxide was absorbed, would have the same com- 
 position as the atmosphere. (3) The refraction of the air is 
 precisely the mean of the refraction of oxygen and nitrogen ; if 
 air was a compound gas, the refraction would either be less or 
 greater than the mean refraction of its constituents. 
 
 Carbon Dioxide (COj), known more commonly under the name 
 of carbonic acid gas, is constantly to be found in all air, and must 
 be considered as a natural constituent. The chief sources of 
 atmospheric carbonic acid are — 
 
 1. Subterranean sources and from the soil. Poggendorf has 
 calculated that the amount from subterranean sources is ten times 
 
 1 That is, in the open air ; — the percentage of oxygen found in mines by Angus 
 Smith occasionally reached very low figures, such, for example, as 18-6 per cent. 
 
 E 2 
 
52 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 greater than all the other sources put together, and that if no 
 causes of diminution existed, the amount of carbon dioxide would 
 be doubled in about 380 years. This carbon dioxide is in part 
 produced by slow processes of combustion continuously going on in 
 the more superficial parts of the earth's crust, and in part from the 
 diffusion of pent-up gas in natural reservoirs, large and small, pro- 
 duced in past ages. 
 
 2. The respiration of man and animals. 
 
 3. Processes of combustion. 
 
 4. Fermentation. 
 
 5. The. burning of limestone, by which carbonate of lime is 
 heated to redness. Under these conditions it parts with its car- 
 bonic acid and becomes caustic lime. 
 
 6. The escape of carbonic acid from natural waters in which it 
 is held in solution. 
 
 Carbon dioxide is a colourless invisible gas ; it is more than half 
 as heavy again as air ; 1 litre at 0° and 760 mm. pressure weighs 
 1-977414 grm. (or 100 cubic inches at 60° F. and 30 inches bar. 
 weighs 47'303 grains) ; its specific gravity compared with air is 1 '5203. 
 On account of its density it can be poured from one vessel to 
 another like water, and hence is liable to collect at the bottom of 
 deep wells, of vats, or similar places. It does not support combus- 
 tion, extinguishing flame immediately ; a candle goes out when 
 the oxygen sinks to ]8'5 per cent, and the carbon dioxide rises to 
 2-5 per cent, but this quantity will not be immediately fatal, for 
 most persons can breathe air containing 5 per cent, for a short 
 period ; anything over .5 per cent, causes insensibility in a longer 
 or shorter time varying with different people ; undiluted carbon 
 dioxide is irrespirable, causing spasm of the glottis. 
 
 Carbon dioxide is quickly absorbed by solutions of caustic 
 alkalies such as soda or potash, or the caustic alkaline earths such 
 as lime or baryta; it is soluble in water, 100 volumes at 0° dis- 
 solving as much as 180 volumes of the gas ; by increasing the 
 pressure, water may be made to take up proportionately larger 
 quantities; when the pressure is reduced the gas escapes, as 
 witnessed every day in the effervescence of aerated waters, 
 champagne, and similar liquids. Water charged with carbonic 
 acid freely dissolves carbonates of lime and magnesia. 
 
 The amount of carbon dioxide varies somewhat according to 
 
IV.] AIR, VENTILATION, WARMING. 53 
 
 locality and season. Risler {Compt. Bend, xciv., 1390-1391) has 
 made monthly estimations for a year of the carbon dioxide of the 
 air at Nyon, Switzerland, sit^iate 420 metres above sea level. His 
 minimum number is "25, his maximum is '35 per 1,000 volumes 
 of air ; the mean of all the estimations being '30 per 1,000. 
 The mean of numerous analyses by Saussure for the air of Geneva 
 and Chambeisoy works out '45 per 1,000. London street air, 
 Angus Smith found to average '36 per 1,000 ; Manchester, •40. 
 In inhabited rooms, ill-ventilated stables, and near middens and 
 other sources of carbonic acid much higher numbers are obtained. 
 The carbonic acid derived from respiration has naturally a relation 
 to the other excretory products of respiration in air, and as it can 
 be very easily estimated its amount is a convenient measure of 
 respiratory impurity : this will, however, be discussed farther on. 
 
 (28) The Fixation of Carbon hy Plants. — Maintenance of the 
 Composition of the Atmosphere. 
 
 It might be supposed that the atmospheric oxygen would 
 continuously decrease and the carbon dioxide increase, but obser- 
 vation, so far, shows that the atmosphere preserves its composition, 
 although in remote periods geologists believe it to have been of an 
 entirely different composition. The great compensating agency at 
 work keeping down the liability of carbon dioxide to increase is 
 the action of the green chlorophyll of plants on carbon dioxide. 
 This green chlorophyll, under the influence of sunlight, has the 
 extraordinary power of splitting the gas up into its two constitu- 
 ents — carbon which it retains, and oxygen which it exhales. This 
 fact was first pointed out by Priestly and Ingenhause ; it is extra- 
 ordinary, because carbon dioxide has hitherto only been decomposed 
 in the laboratory by the action of the most powerful agents, such 
 as potassium brought to a high temperature or metals raised to an 
 intense heat or the electric spark ; yet every little green cell in 
 sunlight quietly fixes carbon and sets free oxygen ; hence there is 
 a continual circle, oxygen being changed into carbon dioxide, 
 carbon dioxide falling again to pieces, the carbon going to build up 
 manifold plant structures, the oxygen to again be changed into 
 carbon dioxide. There is, however, a permanent loss of oxygen 
 ever going on in the oxidation of inorganic matter ; such, for 
 example, as the conversion of the protoxides of iron into the 
 
54 A MANUAL OF PUBLIC HEALTH. [chap 
 
 peroxides, and it is not easy to see how in this last case the oxygen 
 can be returned under the ordinary processes of nature. It can, 
 however, be shown that the reservoir of oxygen is so large that 
 this diminution, even continuing for long periods of time, will not 
 affect appreciably the percentage of oxygen. Professor Thorpe 
 gives a very clear illustration of this. " If," says he, " we suppose 
 the atmosphere to be put in a balloon, and suspended from the 
 end of a balance, it would require 581,000 cubes of copper each 
 having a side of 1 kilometre in length, to restore equilibrium." 
 
 If we also assume that each individual consumes I kilo of 
 oxygen per diem, and that the population of the earth is 
 1,000,000,000, and further, that the oxygen consumed in the 
 respiration of other animals, and in the oxidation of organic 
 matter amounts to four times that required by man, and also that 
 the oxygen disengaged by plants compensates only for the causes 
 of diminution of oxygen not specified, then even in this exag- 
 gerated case, the amount of oxygen abstracted from the air in a 
 century would only amount to fifteen or sixteen of the copper 
 cubes ; or, in other words, the abstraction in a century would be 
 only so^oo ^hi of the total quantity of oxj^gen contained in the air 
 — an amount inappreciable by the most exact eudiometric methods 
 known to us. 
 
 (29) Other Gases more or less constantly present in Air. 
 
 Ozone is an allotropic form of oxygen, its chemical formula being 
 denoted by Og, which signifies that the molecule contains three 
 atoms, whereas ordinary oxygen, O2, contains but two. 22'4 litres 
 at standard temperature and pressure weigh 48 grammes ; it is 1| 
 times the density of oxygen. Ozone is readily changed into 
 ordinary oxygen by heating it to 300°. It has been liquefied by 
 cold and pressure and is then seen to be a blue liquid. Its oxidiz- 
 ing power is very great. It rapidly corrodes caoutchouc, bleaches 
 vegetable colours, and oxidizes metals. It has such an irritating 
 effect on the mucous membranes of the eyes and nose, that it has 
 even been credited as the general cause of catarrh. It may be 
 produced in considerable quantities by the silent electrical dis- 
 charge acting on oxygen. Its occurrence in the atmosphere is 
 referred to electrical agency. From the experiments of Houzeau, 
 country air contains one volume in 700,000. In the air over 
 
IV.] AIR, VENTILATION, WARMING. 55 
 
 marshes, ia the air of crowded dwelling rooms, and in the air 
 generally of cities it is absent. 
 
 The most usual test of its presence is filter paper which has 
 been steeped in a solution of potassic iodide and starch ; moistened 
 paper of this kind becomes blae in the presence of ozone, because 
 ozone decomposes potassic iodide and sets free iodine ; unfor- 
 tunately the test is not conclusive because other oxidizing agencies 
 have the same property. 
 
 Acids. — Nitric acid in very small quantities exists in most air. 
 Sulphurous acid is ever present in the air of towns. A town 
 atmosphere is, from the continuous combustion of coal containing 
 sulphur compounds, sufficiently acid to turn in a few hours 
 moistened blue litmus paper red. 
 
 A. Ladureau (Ann. Ghim. Phys. 5, xxis., 427-432) examined the 
 air of Lille for sulphurous acid gas : he found on an average a cubic 
 metre to contain 1"8 c.c. ; on calm days this was found to increase 
 to 2 c.c, on stormy days it decreased to 1'4 c.c. 
 
 Ammonia. — Traces of ammonia are always present even in the 
 purest air. Mr. Horace T. Brown found a million parts of country 
 air, when the samples were collected two metres from the groimd, 
 to contain from 5'102 to 6'085 parts of ammonium carbonate ; the 
 air of a town contained from 4-059 to 8'732 parts of ammonium 
 carbonate. He considers the normal amount to be about 6 parts 
 per 1,000,000. Heavy rain decreases the amount of ammonia, but 
 only for a time. 
 
 Sulphuretted Sydrogen or its ammonia compound is constantly 
 in the air of large cities like London, as proved by the tarnishing 
 of silver coinage and ornaments. The amount has not been 
 accurately estimated. 
 
 Marsh Gas. — There is always in the air a small quantity of gas 
 which is a compound of carbon, probably marsh gas. A. Muntz 
 and E. Aubin {Comptes Bendus, cxix., 871-874) have found the 
 amount of carbon dioxide which may be obtained by passing air, 
 previously filtered from dust and deprived of its carbon dioxide, 
 over red hot copper oxide, to amount to between 3 and 10 volumes 
 per 1,000,000 volumes of air. It may be stated generally that the 
 amount of the carbon gas or vapour is represented by a volume of 
 carbon dioxide equal to the 100th part of the volume of carbon 
 dioxide existing as such in the atmosphere. 
 
56 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (30) Other Substances floating in Air.— Micro-organisms. 
 
 Common Salt is an invariable constituent of all natural air. It is 
 probably in the minute dust floating in the lower layers of the 
 atmosphere; its presence is proved by a Bunsen flame always giving 
 the line called the sodium line when examined by the spectroscope. 
 All air also contains micro-organisms, the spores of fungi bacteria, 
 micrococci and bacilli. Hesse was one of the first who made 
 quantitative estimations of the micro-organisms in air. A tube was 
 coated on the inside with sterile nutrient gelatine and the air to 
 be examined slowly aspirated through the tube ; in this way the 
 air was made to give up its tiny load of germs, for in passing over 
 the moist sticky gelatine, the minute seeds would adhere. On 
 putting on one side the tube, and keeping it at common room 
 temperatures, the little colonies would grow at all the points which 
 had received a seed or germ, and the points would in a few days 
 be visible to the naked eye. They were afterwards examined by 
 the microscope and their general nature determined. 
 
 Dennis, Miquel, Carnelly and Haldane, Greenleaf Tucker, and 
 others have all made interesting researches as to the contents of 
 the air of different places in micro-organisms. The chief results 
 are summarized in the table on the following page. In the latest 
 research, that of Greenleaf Tucker,^ the micro-organisms were 
 filtered through and arrested by a closely-packed layer of sterilized 
 sugar to which afterwards the nutrient liquid was added. 
 
 (31) The General Difference hetween Town and, Gauntry Air. 
 The following is a representation, of what is constantly found in 
 town and country air, omitting in the enumeration strictly local 
 airs, which may contain any gas almost that is known to science, 
 and also omitting mineral and non-living but organic dust. 
 
 Country Air. 
 Nitrogen 
 Oxygen 
 
 Aqueous vapour 
 Carbon dioxide 
 Ammonia 
 Nitric acid 
 Ozone 
 Marsh gas 
 Common salt 
 Micro-organisms 
 
 Town Air. 
 Nitrogen 
 Oxygen 
 
 Aqueous vapour 
 Carbon dioxide 
 Ammonia 
 Sulphurous acid 
 Nitric acid 
 
 Sulphuretted hydrogen 
 Marsh gas 
 Common salt 
 Micro-organisms 
 
 ^ See Fullic, Eealth, vol. ii. No. 2. 1890. 
 
IV.] 
 
 AIR, VENTILATION, WARMING. 
 
 57 
 
 Table XII. 
 
 Miceo-Okganisms in Aik from Various Sources. 
 
 
 
 Micro-organisms 
 
 
 Place. 
 
 per ID litres of air. 
 
 Authority. 
 
 Season of 
 Year. 
 
 03 
 
 »: 
 
 
 1 
 
 
 p 
 
 o 
 
 s 
 
 3 
 
 
 Sea air (Atlantic Ocean) . 
 
 
 
 
 
 
 
 
 Dennis 
 
 High Mountains .... 
 
 ? 
 
 
 
 0-01 
 
 Miquel 
 
 Moorland .... 
 
 August 
 
 b" 
 
 3-5 
 
 3-5 
 
 CarnoUey & Wilson 
 
 Country ... 
 
 Ann. Average 
 
 
 
 4-6 
 
 Mic^uel 
 
 s, ... . . 
 
 Autumn 
 
 
 
 6-8 
 
 — 
 
 
 August 
 
 
 
 14 
 
 P. Frankland 
 
 Dundee, suburbs . 
 
 Winter 
 
 
 
 1 
 
 1 
 
 Carnelley & Haldane 
 
 ,, town, open places, 
 
 
 
 
 
 
 night . ... 
 
 ,, 
 
 1-5 
 
 
 
 1-5 
 
 ,, ,» 
 
 „ town, close places, 
 
 
 
 
 
 
 day 
 
 j> 
 
 5 
 
 ■5 
 
 5-5 
 
 1 J ,j 
 
 ,, town, open places, 
 
 
 
 
 
 
 day 
 
 5» 
 
 •7 
 
 5 
 
 12 
 
 ,J 5, 
 
 ,, town, open places. 
 
 
 
 
 
 
 day .... 
 
 Spring 
 
 12-8 
 
 
 
 12-8 
 
 Carnelley & Wilson 
 
 Norwich, Cathedral Close 
 
 ? 
 
 
 
 18 
 
 P. Prankland. 
 
 Paris, Eue de Rivoli . 
 
 Ann. Average 
 
 
 
 39 
 
 Miquel 
 
 ,1 ,, jj ... 
 
 August 
 
 
 
 44 
 
 — 
 
 London, open places . . 
 
 i 
 
 
 
 24 
 
 P. Frankland 
 
 ,, roofof ScienceSchools, 
 
 
 
 
 
 
 S. Kensington . . , 
 
 Ann. Average 
 
 
 
 36 
 
 »J 
 
 ,, », »> 
 
 August 
 
 
 
 105 
 
 }f 
 
 ,, St. Paul's Churchyard. 
 
 ? 
 
 
 
 70 
 
 >) 
 
 Sewers (Paris) 
 
 ? 
 
 
 
 9 
 
 Miquel 
 
 „ (Bristol) 
 
 Summer 
 
 
 
 20 
 
 Haldane 
 
 , , (Westminster & Dundee) 
 
 Spring 
 
 79 
 
 io 
 
 89 
 
 Carnelley & Haldane 
 
 Eoyal infirmary, Dundee . . 
 
 Winter 
 
 42 
 
 17 
 
 59 
 
 » }} 
 
 Hospital for Consumption, 
 
 
 
 
 
 
 Brompton . . . 
 
 ? 
 
 
 
 72 
 
 P. Frankland 
 
 H8pital de la Pitie, Paris . 
 
 Ann. Average 
 
 
 
 96 
 
 Miquel 
 
 Bedrooms at Night — 
 
 
 
 
 
 
 3 or more roomed houses. 
 
 
 
 
 
 
 Dundee ... 
 
 Winter 
 
 85 
 
 5 
 
 90 
 
 Carnelley & Haldane 
 
 2 do. . . 
 
 ,j 
 
 434 
 
 26 
 
 460 
 
 J > J) 
 
 1 do 
 
 , J 
 
 585 
 
 15 
 
 600 
 
 
 Mechanically ventilated 
 
 
 
 
 
 
 schools, Dundee 
 
 jj 
 
 160 
 
 6 
 
 166 
 
 ^ ^ 
 
 Naturally ventilated schools. 
 
 
 
 
 
 
 Dundee 
 
 ,, 
 
 1510 
 
 10 
 
 1520 
 
 }} )j 
 
 Jute Mills, Dundee . . 
 
 ,, 
 
 1140 
 
 460 
 
 1600 
 
 ij }i 
 
 Outside Boston Hospital, U.S. 
 
 November 
 
 10 
 
 7 
 
 17 
 
 Greenleaf Tucker 
 
 a ji 
 
 December 
 
 14 
 
 6 
 
 20 
 
 ii i) 
 
 ,» J, 
 
 January 
 
 13 
 
 3 
 
 16 
 
 ji )j 
 
CHAPTER V. 
 
 THE GENERAL PRINCIPLES OF VENTILATION. 
 
 (32) The Mechanism hy which the Air of Booms is made Impure. 
 
 To understand the mechanism of air contamination of dwellings, 
 it is, in the first place, essential to have some knowledge of the 
 laws of gaseous diffusion, and also of the changes which take place 
 in respiration. 
 
 Diffusion of Gases. 
 
 Carbon dioxide is 1| times as heavy as air. If a jar of it 
 be placed in a still atmosphere, and the stopper of the jar removed, 
 the gas will remain for a short period in the jar, but ultimately an 
 analysis of the air in the jar and that of the room will be identical. 
 Similarly, hydrogen is very much lighter than air, and a flask 
 of the gas held mouth downwards will for a short period retain 
 the gas, but not for long. It soon diffuses through the atmo- 
 sphere. 
 
 Diffusion obeys a well-ascertained law, which is, that the 
 diffusibility of two gases varies in the inverse ratio of the square 
 roots of their densities. If we wish to know how rapidly a gas 
 will diffuse in air, we only want to know its specific gravity in 
 relation to air. For instance, the specific gravity of hydrogen is 
 •06926, that of air I'OOO ; but taking hydrogen as 1, the specific 
 gravity of air = 14'44 ; that is, air is 14!"44 times as heavy as 
 hydrogen, and the ratio of the square roots of their densities is 
 v'-i-4'44 to 1, or as 3'8 is to 1. If two equal jars, the one contain- 
 ing hydrogen, and the other air, be placed in a room, and the 
 
CHAP, v.] AIB, VENTILATION, WARMING. 59 
 
 whole of the hydrogen diffuse in 1 hour, the air of the jar will 
 diffuse in 3"8 hours ; so, again, as the inverse square roots of the 
 densities of hydrogen and carbon dioxide are as 3"8 is to '8, which 
 is uearly in the relation of 1 to 5, it will require 5 times the time 
 for an equal quantity of the heavier gas to diffuse — that is, if it 
 takes 1 hour for a litre of hydrogen to diffuse, it will take 
 5 hours for a htre of carbon dioxide to diffuse ; or, if put into 
 an apparatus called a diffusiometer, for every 3"8 c.c. of hydrogen 
 which diffuses, "8 c.c. COj will take its place. 
 
 This diffusion of gases takes place through porous substances, 
 such as plaster, walls, and very thin aniroal membranes; but if 
 the porous material has very fine pores, and is of considerable 
 thickness, the rates of diffusion are different, for under such 
 circumstances the pores act as so many capillary tubes, and the 
 law governing the transit of gases through capillary tubes is 
 different to the above. 
 
 In the respiration of animals, the air on entering the lungs 
 comes in contact with the capillary blood-vessels of the lungs, 
 the walls of which are very thin, and diffusion takes place. If the 
 blood were simply an ordinary organic liquid, the gases of the air 
 would be absorbed according to their solubility at the particular 
 temperature and atmospheric pressure at the time of inspiration ; 
 but the blood has peculiar properties. The venous blood contains 
 in the red corpuscles a substance called haemoglobin, which forms 
 a well-defined, although loosely bound compound with oxygen. 
 The venous blood, on arriving at the lungs with its myriads of 
 hsBmoglobin-containing corpuscles, greedily absorbs oxygen, oxy- 
 hsemoglobin being formed. The blood now becomes bright 
 (arterial) red, and carries the oxygen to all the tissues. The 
 living tissues soon rob the oxyhsemoglobin of its oxygen, reducing 
 it to haemoglobin. Upon this happening, the blood becomes of a 
 dark (venous) colour, nor does it recover its bright hue until the 
 lungs are again entered. The red corpuscles may be likened to 
 legions of little boats, whose office it is to float with the circulatory 
 tides to the lungs, for the purpose of each taking in a tiny cargo 
 of oxygen. After discharging it, they return for more. While the 
 corpuscles are thus busy in collecting and dispensing oxygen, there 
 is at the same time a transpiration of carbon dioxide, for there is 
 so far a true combustion in the tissues — that is, there is develop- 
 
60 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 ment of heat ; oxygen unites with carbon, and carbon dioxide is 
 formed. This absorption of oxygen and expiration of carbon dioxide 
 is quite independent of atmospheric pressure. On the other Jiand, 
 whether less or more nitrogen is absorbed is intimately con- 
 nected with the height of the barometer. If the barometer sinks, 
 nitrogen escapes from the body until equilibrium is restored ; if 
 the barometer rises, then a certain absorption of nitrogen appears 
 to take place. 
 
 There is also a considerable expiration of aqueous vapour. 
 
 (33) Composition of Expired Air. 
 
 Expired air then is deficient in oxygen, is rich in carbon dioxide 
 and in moisture. It also contains very often organic volatile bodies, 
 such as ether and gases derived from food or drink consumed, and 
 it is not unfrequently somewhat ammoniacal. A persons' breath 
 smells of ether after taking alcohol, the expired air will blacken 
 silver after eating eggs, and eructations of marsh gas are known to 
 occur in some forms of indigestion. The healthiest person's breath 
 also contains other forms of organic matter, the exact nature of 
 which is obscure.^ The most recent researches show that the 
 breath is singularly free from micro-organisms, the lungs acting as 
 a very efficient filter. 
 
 The content of carbon dioxide in expired air varies according 
 to body weight, to age, and other circumstances, such as activity or 
 rest. It may be taken generally as 5 per cent, of the volume 
 of the expired air in the case of an average-sized man doing 
 ordinary work. Speck, in 41 experiments made on his own breath 
 under different conditions, found a maximum of 5'43 per cent, and 
 a minimum of 3 33 per cent., while the oxygen also varied from 
 1501 to 17-21 per cent. 
 
 Pettenkofer and Voit made some very elaborate researches on 
 the amount expired of oxygen, moisture, and carbon dioxide, of 
 two healthy persons, during the 24 hours, under very different 
 conditions of food and labour. 
 
 1 E. Wurtz (Oomptes Bend., evi. 213 — 214) drew the air expired from the lungs 
 through a 1 per cent, solution of oxalic acid. He found ammonia to be the chief 
 product ; but besides this, isolated a base the hydrochloride of which had a peculiar 
 odour, and formed crystallizable soluble salts with the chlorides of gold and platinum. 
 
v.] AIB, VENTILATION, WARMING. 61 
 
 The following are mean numbers of some of Voit and Pettenkofer's 
 researches : — 
 
 At rest . 
 At work 
 
 Cai'bon dioxide in Water in the 
 the 24 hours. 24 hours, 
 grms. gims. 
 716 ... . 821 
 .1187 1777- . 
 
 Oxygen consumed 
 
 in the 24 hours. 
 
 grms. 
 
 761 
 
 1072 
 
 At rest . 
 At work . 
 
 Ordinary Diet. 
 928 . . . 931 
 806 . . . 1151 
 
 831 
 . . 650 
 
 At rest . 
 
 Diet Rich in Egg Albumen. 
 . 1020 . 1168 . 
 
 863 
 
 At rest . . 
 
 Nitrogen Free Diet. 
 839 925 . 
 
 808 
 
 The facts given with regard to the respiratory contamination of 
 air may be summarized as follows : — 
 
 An adult man at rest consumes in 24 hours about 816 grms. 
 of oxygen, part of which is retained in the body ; part is expired 
 in the form of COg. The oxygen retained amounts to from 
 120 to 200 grms., or 439 litres. The carbon dioxide will be 
 about 870 grms., or 439 litres. He will also separate nearly a 
 litre of water. At work these quantities will be increased. In 
 ordinary not very laborious occupations, he will consume 861 
 grms. of oxygen, and will exhale 996 grms. (504 litres) of COj 
 and 1,464 grms. of water. 
 
 A man will therefore, under ordinary conditions, in the 24 hours, 
 spoil about 3,000 litres (105-9 cubic feet) of air, and if undergoing 
 any exertion 3,700 litres (130'7 cubic feet) or more. It is not far 
 from the truth, and easy to remember that adults spoil every hour 
 about 5 cubic feet of air (140 litres) — that is, render 5 cubic feet 
 of air absolutely irrespirable. 
 
 (34) The Contamination of Air hy Animals. 
 
 It is of practical importance in a public health point of view 
 to also study changes in the air produced by the respiration of 
 cattle, horses, and domestic animals, the more especially because 
 there are many dwellings in which the atmosphere is common to 
 beast and man ; for instance, in the case of stablemen with rooms 
 over a stable, in which the separation is mei'ely porous lath and 
 plaster and the floor boarding. 
 
 There is one peculiarity with regard to the contamination of 
 
62 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 the atmosphere by sheep, pigs, horses, and cattle generally, and 
 that is the large quantity of marsh gas which escapes from the 
 intestine. A certain quantity is occasionally produced in the 
 human body, and also contaminates the air, but it is entirely 
 insignificant to the regular and normal production of the intestinal 
 gases of the herbivora. 
 
 Regnault and Eeiset have made some excellent determinations 
 of the amount of oxygen consumed, the carbon dioxide and marsh 
 gas exhaled of sheep, pigs, and calves. The following is an abstract 
 of the results of their investigations : — 
 
 Table XIIT. 
 
 
 Weight of 
 
 animal in 
 
 kilos. 
 
 Oxygen 
 consumed, 
 grms. pel- 
 hour. 
 
 Oxygen 
 consumed 
 per kilo 
 of hody 
 weight. 
 
 CO2 
 exhaled. 
 
 Nitrogen. 
 
 Marsh Gas 
 
 (CH4) in 
 
 Hti-es. 
 
 Sheep 
 Calves 
 Pigs 
 
 67-7 
 
 97-3 
 
 1056 
 
 33-51 
 
 45-87 
 49-30 
 
 ■495 
 •480 
 •477 
 
 42-63 
 54-54 
 60-50 
 
 •246 
 •280 
 •025 
 
 1-4 
 
 1-3 
 
 ■1 
 
 Presuming that the ratios found by experiment for calves hold 
 good for cows and horses, an average-sized cow of 230 kilos weight 
 would consume 110'4 grms. of oxygen per hour, and would 
 exhale 1288 grms. of COg, and 307 litres of marsh gas. It 
 would therefore render every hour 37l'4 litres (13"2 cubic feet) of 
 air irrespirable. Horses would give similar numbers. 
 
 Sheep of average size spoil 112'6 litres (3-97 cubic feet) per hour 
 of air; calves 154'2 litres (5'20 cubic feet); pigs of moderate size 
 165'8 litres (5'85 cubic feet) ; rabbits about 10 litres ('37 cubic feet) ; 
 fowls, I'O litre (-037 cubic feet) ; medium-sized dogs, 23^5 litres 
 (•79 cubic feet) ; a cat, 10 lbs. in weight, 17-8 litres ("6 cubic feet). 
 
 If we could only regard respiratory impurity, it would be correct 
 to say that 10 sheep contaminated the air in about the same degree 
 as 8 men ; that calves and pigs were more than equal to a man ; 
 that 14 rabbits or 140 fowls were equal to a man; but in 
 practice such animals contaminate the air very much more than 
 the above, for they are ever associated with their own excreta, 
 and their intestinal gases passing into the air are additional 
 impurities. 
 
v.] AIR, VENTILATION, WARMING. 63 
 
 (35) Quantity of Air required 'per Head per Hour. 
 
 Ventilation is the art of supplying without perceptible draught ^ 
 the requisite quantity of pure air. 
 
 It has been already stated that every hour an adult man renders 
 absolutely irrespirable 5 cubic feet of air ; a man under certain cir- 
 cumstances — such as in an air-tight chamber containing the necessary 
 appliances to remove promptly the carbon dioxide by a continuous 
 spray of strong potash, to absorb the excess of aqueous vapour by 
 means of anhydrous chloride of calcium, and in some way or other 
 to deal with organic matter evolved from the lung — would live for 
 an indefinite time if supplied hourly with about 28 litres or a 
 cubic foot per hour of oxygen, for the nitrogen of the air is used 
 over and over again. In the apparatus invented by Fleuss, this 
 problem is partly accomplished ; with the aid of the apparatus, 
 which essentially consists of an ingenious respirator connected 
 with a reservoir of oxygen and a rubber sponge saturated with 
 caustic potash, a man may cut himself off entirely from the exter- 
 nal air, and in this way descend into the ocean depths or into mines 
 rendered dangerous from choke-damp. Operating under ordinary 
 conditions, however, there are no means at hand to remove the 
 impurities of the breath, and the only way which is found to answer 
 is by enormous dilution. It is generally recognized that to keep 
 the air in the highest degree of practicable purity, no less than 
 3,000 cubic feet per hour of air is required ; this quantity is 600 
 times the amount of air spoilt. Multiplying then by 600 the 
 cubic feet of air which the different animals render irrespirable, 
 we get the following theoretical amounts of air which should be 
 supplied per hour to animals : — 
 
 
 Cubic feet per head 
 
 Cubic feet of space. 
 
 
 per hour. 
 
 
 
 Horses . 
 
 7,920 = under ordinary conditions 
 
 to . 
 
 1,584 
 
 Cows 
 
 7,920 
 
 
 1,584 
 
 Pigs . 
 
 . 3,510 
 
 
 702 
 
 Calves 
 
 ■ 3,120 
 
 
 604 
 
 Dogs 
 
 474 
 
 
 95 
 
 Cats 
 
 360 
 
 
 72 
 
 Rabbits 
 
 222 
 
 
 44 
 
 Fowls 
 
 22 
 
 
 4 
 
 ' The feeling of draught is not always produced by an actual current of air ; if 
 for instance, a person should sit by a cold wall, there is a radiation of heat from the 
 person's skin, causing the same sensation and the same effects as if blown upon by a 
 current of cold air. 
 
64 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 It has been already stated that carbon dioxide, although in small 
 quantities in itself not injurious, nevertheless has such a close 
 relationship with other impurities — the air pollution rising and 
 sinking with the increase or decrease of the carbon dioxide — that 
 its estimation is utilized as a measure of impurity. The standard 
 Dr. Parkes adopted was '6 carbonic acid per 1,000 volumes of air. 
 If this number is adopted, then the ventilation, to be successful, 
 must not allow the carbonic acid to exceed this. Experiments 
 were made both by Dr. de Chaumont and the late Dr. Parkes, in 
 which they found the organic impurity of the air was perceptible 
 when the carbon dioxide rose to '6 per 1,000 volumes (i.e. "0006 in 
 each cubic foot). This standard is a high one, and difficult to attain, 
 but experience has shown the correctness of Dr. Parkes's views, and 
 the standard is now generally accepted. 
 
 For the purposes of air supply the weight of a man may be 
 taken as 140 lbs., which is the mean number of lbs., deduced from 
 British statistics by Dr. W. Stephenson, for males of the labouring 
 classes between the ages of 25 and 30 ; the average weight of the 
 non-labouring classes is rather more, viz. 154 lbs. Using, however, 
 the standard weight of 140 lbs., and taking 3000 cubic feet of air per 
 hour as the proper amouat, the quantity of air to be supplied will 
 for other ages be proportional to the weight of the individuals ; the 
 average weight of children of 5 years of age is about 40 lbs., 
 10 years of age 66 lbs., and 15 years of age 105 lbs. ; hence we 
 shall not be far wrong if the necessary air supply be stated as 
 follows : — 
 
 Air Supply. 
 5 years and under . 855 cubic feet per hour. 
 
 From 5 to 10 years . . . 1,414 ,, ,, 
 
 From 10 to 15 years . 2,250 ,, ,, 
 
 Above 15 years . 3,000 „ ,, 
 
 Parkes and De Chaumont have given simple formulae by which 
 the amount of cubic feet of air to be supplied hourly so as to 
 reduce the COg to any standard can be readily calculated. One of 
 these is as follows : — Let e be the assumed quantity of OOj 
 exhaled by an adult male in an hour, viz. '6 cubic foot, r the 
 ratio per cubic foot of air to which it is desired the CO^ should be 
 reduced, and R the ratio of CO2 naturally in the air, viz. "0004 per 
 
 cubic foot. Then -; — ^ = required delivery of air per hour in 
 
r-] 
 
 AIR, VENTILATION, WARMING. 
 
 65 
 
 then 
 
 cubic feet. For example, let r be '0006, then -rr^r^ rr^r^ - 3000. 
 
 ■UUUb — "0004 
 
 If the standard of purity be taken not as -0006, but as "0009, 
 • OOOq — -0004 ~ 1200 cubic feet to be supplied per hour. 
 
 Or if the carbonic acid (COg) in the air be determined by experi- 
 ment, and the experimental number be substituted for r, the 
 answer will give the amount of air which has entered and been 
 utilized. Thus if in an experiment the COg in the air be ascer- 
 tained to be 3'5 per 1000 volumes (i.e. '0035 in each cubic foot), then 
 
 ■ nns" — -nooA ~ 1935"3 cubic feet of fresh air which have entered 
 
 the room and been utilized. 
 
 The amount of impurity in rooms, as estimated by the organic 
 matter, the carbon dioxide, and the number of micro-organisms, 
 varies inversely as the cubic space, as the following table' well 
 shows : — 
 
 Table XIV. 
 
 Imptjrity of the Air of Slbepino-Rooms in Eblation to Cctbic Space. 
 
 Cubic 
 
 space per Person. 
 
 No. of 
 Houses. 
 
 Excess 
 Temp. 
 
 Carbonic 
 Acid. 
 
 Organic 
 Matter. 
 
 Total 
 Germs. 
 
 100 
 
 180 cb. ft. 
 
 14 
 
 19 
 
 11-5 
 
 2-7 
 
 80 
 
 180 
 
 260 „ 
 
 18 
 
 19 
 
 10-7 
 
 2-7 
 
 49 
 
 260 
 
 340 „ 
 
 6 
 
 19 
 
 10-3 
 
 2-1 
 
 32 
 
 340 
 
 500 „ 
 
 4 
 
 18 
 
 9-2 
 
 1-5 
 
 42 
 
 500 
 
 1,000 „ 
 
 6 
 
 13 
 
 8-6 
 
 1-0 
 
 6 
 
 1,000 
 
 2,500 ,, 
 
 8 
 
 13 
 
 6-7 
 
 0-7 
 
 9-1 
 
 2,500 
 
 4,000 „ 
 
 4 
 
 16 
 
 7-9 
 
 0-9 
 
 13-1 
 
 Cleanliness tends to air purity; dirtiness of rooms to air con- 
 tamination, as the table on the following page shows. 
 
 (36) Atmospheric Impurity from Covibustion. 
 
 In our climate we pass a large portion of time by the aid of 
 artificial hght, and all artificial lights, with the exception of the 
 electric, contaminate the air with carbon dioxide and sometimes 
 other products of combustion ; all these products ought to be led 
 
 ' On the VeTiiilaticm of Schools, by Sir Henry Roscoe. The results of both tables 
 are based apparently on Camelley and Haldane's researches. 
 
 F 
 
66 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap.- 
 
 into the outer air by special shafts, in this -way assisting in- 
 stead of rendering ventilation more difficult, but as this cannot 
 always be done it is necessary to consider to what extent the aia- 
 should be diluted to neutralize the product from gas, candles, 
 petroleum and other sources of illumination. 
 
 Table XV. 
 
 
 
 
 Effect of Cleanliness. 
 
 
 
 
 Space per 
 person. 
 
 Carbonic 
 Acid. 
 
 Organic 
 matter. 
 
 Miero- 
 organlsms. 
 
 I Clean . . 
 One-roomed ) Dirty . . . 
 Houses. 1 Dirtier . 
 ( Very dirty 
 
 295 
 200 
 221 , 
 220 
 
 7-99 
 
 9 87 
 
 10-66 
 
 11-01 
 
 2-34 
 3-23 
 2-42 
 2-69 
 
 18 
 41 
 49 
 93 
 
 Two-roomed \J^^y<^^^^'^ 
 Houses. jg^- ; 
 
 273 
 264 
 233 
 
 12-20 
 9-34 
 9-40 
 
 1-93 
 1-37 
 2-03 
 
 10 
 22 
 69 
 
 Unventilated ( Clean . 
 
 Board < Average 
 
 Schools. ( Dirtier . 
 
 167 
 166 
 191 
 
 19-68 
 14-17 
 22-47 
 
 3-25 
 2-90 
 2-73 
 
 91 
 125 
 198 
 
 Schools. |l,33,i,^„ 
 
 194 
 155 
 152 
 
 12-50 
 12-81 
 10-78 
 
 2 "26 
 
 1-48 
 
 • 1-75 
 
 3 
 16 
 30 
 
 The amount of air-dilution to purify sufficiently the atmosphere 
 polluted by gas or lamps need not be so great in relation to the 
 carbon dioxide as in the case of breath impurity ; it will be ample 
 dilution if we supply 900 cubic feet of air for every cubic foot of 
 carbon dioxide per hour evolved by the light, and as a cubic foot of 
 coal gas properly burnt evolves about 2 cubic feet of COg, for 
 every cubic foot of coal gas allow 1,800 cubic feet of air per hour. 
 
 The following table gives the amount per hour of carbon dioxide 
 which it is stated are evolved when a sufficient quantity of each 
 of the illuminants named is burnt to give a light equal to 20 
 standard candles : — 
 
 Tallow . . 
 Spei-maceti or wax 
 Paraffin wax 
 Coal gas 
 Cannel gas 
 Paraffin oils 
 
 Cubic feet of carbon 
 dioxide evolved. 
 10-1 
 8-3 
 6-7 
 5-0 . 
 4-0 
 . , 3-0 
 
 Cubic feet of air required 
 for sufficient ventilation. 
 
 9,090 
 7,570 
 6,063 
 4,500 
 3,600 
 2,700 
 
v.] AIR, VENTILATION, WARMING. 67 
 
 A common three-light chandelier will burn about 12 feet per 
 hour, and hence requires 21,600 cubic feet of air to properly dilute the 
 combustion products. It must also be remembered, that coal gas 
 always contains some sulphur compounds which are burnt up to 
 sulphuric acid, and that gas fittings are seldom perfect ; hence a gas 
 supply is pretty certain to more or less continuously add its quota 
 of impurity even when not burning. The other means by which 
 apartments are made impure are the presence of any kinds of 
 organic decomposable matter, the oxidation of fresh paint, the 
 drying of size on the walls, and dust either produced in the house 
 itself or driven in from outside. In hospitals, infirmaries and wher- 
 ever there are sick people, the air is liable to be dangerously con- 
 taminated with emanations from the discharges from wounds, or 
 expectoration from diseased lungs ; in such cases the greater 
 amount of air dilution and the. larger in reason the cubic space the 
 better. 
 
 (37) Velocity of Air which can he home vnthout Discomfort. 
 
 Having fixed the amount of air to be supplied, the next question 
 is the manner in which this is to be effected, and this again depends 
 upon the velocity with which the air can be supplied (if we adopt 
 natural ventilation) through the ventilators. If it were possible to 
 place a person without discomfort in a cube of 100 feet and drive 
 the outside air through this cube at a high velocity, the amount of 
 cubic space per head would not be of such great importance. It 
 has however been shown by Parkes and others that air at a 
 temperature of between 55° to 60° F. can stream through an 
 opening at a rate of 2 miles per hour (8 feet per second) without 
 causing any discomfort, but at a speed greater than this it becomes 
 perceptible, that is, a " draught " is experienced ; warm air of 90° 
 may be brought in at a higher speed than cool, but even in this 
 case there are limits. A cubic space of 500 cubic feet with an inlet 
 opening of 12 square inches could be supplied with 3,000 cubic feet 
 of air hourly, but the velocity would be 7 miles an hour or 10 feet 
 per second. This would of course be so uncomfortable in cold 
 weather, that the tenant of such a room would block up the 
 ventilators. A change of four times in the hour is about the limit 
 which in practice can be borne, hence the minimum cubic space 
 should be 750 cubic feet. 
 
 F 2 
 
68 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (38) Principles Governing Air Movement. 
 
 Previous to entering on details of the methods by which ventila- 
 tion can be accomplished, it is necessary to explain fully the 
 principles which govern air movement. 
 
 All simple ventilation depends for its motive power on a differ- 
 ence of temperature between two columns of air, the heated air 
 ascends, the cold aii- descends. Investigating the reason of this 
 more closely, the cause of an air current is, that under the influence 
 of heat, the specific gravity of a body of air is made lighter than 
 that of the air in its immediate neighbourhood, and just as in the case 
 of liquids of two different specific gravities, the heavier forces the 
 lighter upwards. If, for example, there be two columns of air in a U 
 tube each 10 feet high so long as there is no change of temperature 
 or aspirating force the two colurans will exactly balance, and no 
 movement will take place, but if the temperature of the one limb 
 is raised say 20°, then the heated air will expand 10 X 20 x '002 
 and became 10'4 feet in height and movement must ensue. The 
 velocity of this movement is calculated by Montgolfier's rule which 
 is constructed on the following data. The velocity in feet per 
 second of falling bodies is nearly equal to eight times the square root 
 of the height through which they have fallen, and fluids pass through 
 an orifice in a partition with a velocity equal to that which a body 
 would attain in falling through a height equal to the difference in 
 depth of the fluid on the two sides of the partition. The air 
 pressure at the surface of the earth is ever varying, but it is taken to 
 average 14 lbs. to the square inch, and this is the weight of a 
 column of air of equal density 5 miles in height. Air therefore 
 rushes into a vacuum at the same speed as that which a heavy body 
 would acquire in falling a height of 5 miles, 1,339 feet per second, 
 or if it rush instead of into a vacuum into a room in which the 
 pressure is less than outside, the velocity with which it rushes in is 
 due (if we disregard friction) to the falling of a body through a 
 height which represents the difference of pressure outside and 
 inside. This velocity can in ordinary cases be theoretically obtained 
 by multiplying the height from the aperture at which air enters to 
 that from which it escapes by the difference of temperature between 
 the outside and inside, and multiplying this by the coefficient ^ of 
 ' The exact coefficient is .002039°, 
 
v.] AIR, VENTILATION, WARMING. 69 
 
 the expansion of air for 1° F. "002 ; thus a column 40 feet high, and 
 a difference of temperatnre between the external air and the 
 internal of 20° would give 1-6 for 40 x 20 x -002 = 1-6, and 1-6 
 feet is the height in feet which will produce the velocity of the 
 inflowing current. To calculate the velocity from this the square root 
 of 1"6 must he multiplied by 8 which wiU give the velocity in one 
 second of time, 8 x ^ 1"6 = 10"12 and this again multiplied by 60 
 gives the velocity per minute. Or if the cubic delivery be required 
 the velocity per second must be multiplied by the area of the 
 opening and this by 60. 
 
 In practice a large allowance must be made for friction ; in the 
 case of a Tobin's tube, the tube being short and wide, the allowance 
 of one fourth of the velocity to be deducted would be sufficient, but 
 where the length of the tube is great and its diameter small, one 
 haK or more of theoretical velocity will have to be deducted. If one 
 fourth be deducted from the above example the velocity per minute 
 is 455 feet; if one half, then the velocity is 304 feet per minute; if 
 the shaft be a chimney having a cross sectional area of 1 foot by 5 
 feet, then the efflux in cubic feet per minute will be 304 x '5 =172'0 
 cubic feet per minute. 
 
 Quite as important as friction in hindering the action of ventila- 
 tion is the alteration of specific gravity of contaminated air. In most 
 cases of air contamination the specific gravity of the air is increased 
 and therefore more difficult to move, e.g., the specific gravity of air 
 being I'OOO, that of carbon dioxide is 1"529, of sulphuretted hydrogen 
 1'177, and generally the stinking organic vapours are heavier than 
 air and tend on that account, if the air is stiU, to hang about the 
 localities from which they emanate, or if there are air currents, the 
 stenches are apt to flow down towards the basements of houses 
 from the upper stories ; those for instance who have laboratories on 
 top floors know how readily sulphuretted hydrogen seems to flow 
 down the staircase, and the same is true of ether vapour. It is 
 scarcely necessary to say that in such cases calculations based upon 
 the movements of pure aii' give erroneous results. 
 
 (39) Inlets and Outlets. 
 
 The great variation in temperature in this country renders it 
 difficult to arrange the inlets and outlets so that they will deal with 
 
70 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 the proper quantity of air in all seasons, it has therefore been found 
 best in practice to take some definite standard per head. The size 
 usually accepted is 24 square inches for inlet, and the same for 
 outlet ; these are safe figures. The outlets should admit of being 
 closed or regulated in size so as to adapt themselves to the contin- 
 gencies of very cold weather. The student should nevertheless know 
 how to calculate the deUvery of air by any opening if the size of the 
 opening, the height of the heated column of air, and the difference 
 of temperature be known. This may be done from the formula 
 already given. For instance, in the above example, a chimney for 
 that particular difference of temperature has passing through it 
 172 X 60 = 10,320 cubic feet per hour; it is required to reduce the 
 size so that 3,000 cubic feet only pass up the chimney when there is 
 a temperature difference of 40°. The size of the opening is at 
 present '5 square feet, or 72 square inches, and it must be reduced 
 
 in the proportion of 3,000 to 10,320, ^'^"^ ^^^ = 20-93, so 
 
 that the openings would have to be reduced to 20'93 square 
 inches. 
 
 De Chaumont has given a generally applicable and useful 
 formula based on Montgolfier's rules, and giving the discharge per 
 hour in square inches. No correction is made for friction, and 
 therefore in the case of long tubes, the sizes must be increased in 
 the proportion of 3 : 4. 
 
 Another kind of formula is given by Mr. Morrison in a valuable 
 paper on the ventilation of tunnels {Proc. of the Institution of Civil 
 Engineers, 1876), which will be found useful in calculating the 
 pressure necessary to force air through shafts. Mr. Morrison's 
 remarks are worthy of quotation. He says : — 
 
 " The friction of air varies as the square of the velocity multiplied 
 by the pressure against the sides of the passage. This pressure 
 being uniform, its total amount depends upon the total surface, 
 that is, the length multiplied by the perimeter of the cross section. 
 The force required to propel air through any passage is therefore 
 equal to the square of the velocity into the total surface multiplied 
 by the coefficient of friction. It is more convenient to state the 
 force in lbs. per square inch or per square foot, or as so many inches 
 of water pressure ; the above result should therefore be divided by 
 the area of the cross section. 
 
v.] AIR, VENTILATION, WARMING. 71 
 
 " The best form of tlie formula for practical purposes of veutilation 
 
 seems to be : H. = r where 
 
 A 
 
 H = head of pressure in feet of air of same density as the flowing 
 air. 
 
 L = length of the pipe or passage in feet. 
 
 P = perimeter of cross section in feet. 
 
 A = area of pipe or passage in square feet. 
 
 Y ^'velocity in thousands of feet per minute. 
 
 K = co-efficient of friction = 0'03. 
 
 " This formula is perfectly general, and may be used for any fluid ; 
 H will always be the head stated in feet of the flowing fluid. 
 
 "The pressure of 1 foot of air, at 60° F. is 00765 lb. per 
 square foot. The pressure of 1 inch of water is o'2 lbs. per square 
 foot. Therefore if it be desired to reduce any result in feet of 
 air to its equivalent in inches of water, the process is simply to 
 
 divide it by — _ = 68 ; e.g. the head required for a current of 
 
 10 miles per hour through a tunnel 7 miles long, the perimeter 
 
 oo r . ■ TT KV2PL 003 X 0-880' X 83 X 36960 ,.„. ^ 
 
 83 feet is: H = r = 7=^^ ,= 150 feet 
 
 A 473 
 
 of air = 2J inches of water. 
 
 " For circular passages, taking D for the diameter, the formiila 
 
 4L 
 becomes H = K V^ x -^ • 
 
 " These formulae are only applicable to passages whose diameter is 
 small in proportion to their length. For short passages the length 
 should be increased by about 50 diameters of the passage : thus the 
 
 formula for circular passages becomes H = KV^ X — ^^ — pj 
 
 and that for irregular-shaped passages, H = K V^ x j 
 
 " The value 0'03 is reduced from a formula explained by Mr. 
 Hawksley, Past-President, in a discussion on the Ventilation of 
 Coal Mines.^ 
 
 " In a Paper on the Ventilation of Coal Mines, read before the 
 Geological Society of Manchester in 1862, Mr. Atkinson adopts the 
 same formula as the Author, but gives a constant nearly ten 
 1 Vide Minutes of Proceedings Inst. O.E., vol. vi., p. 192. 
 
V2 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 times that of most authorities. ^ Mr. Atkinson gives a table of 
 coefficients depending on the material of which the passage is 
 composed : — 
 
 Material. Observer. Coefficient. 
 
 Burnt earth Peclet ... . 0-268 
 
 Galleries of coal mines . . . Greenwell 0'254 
 
 Sheet iron (clean) .... Peclet ... . 0-067 to 0-105 
 
 Cast iron (old and tarred) . . Giraud . . . 0-048 
 
 Gas in pipes Hawksley . . 0-030 
 
 Water m pipes Etelweiu . . . O'OSO 
 
 Sheet iron (old and rusty) Girard . . . 0-027 
 
 Tinned iron . . D'Aubuisson . . 0-025 
 
 " In a discussion on Fans, Mr. Greenwell stated that the coefficient 
 of friction varied according to the nature of the sides of the passage, 
 as shown by Giraud, D'Aubuisson, &c.^ To this Mr. Hawksley 
 replied that these discrepancies arose from badly-conducted experi- 
 ments ; he had had good opportunities of making experiments in 
 mines with long uniform airways, as well as in pipes, and there were 
 not in reality any such differences of coefficients. On another occa- 
 sion^ Mr. Hawksley said that, when the density of any elastic fluid 
 did not materially vary throughout the length of the pipe, the same 
 rule as for inelastic fluids applied, and that the general formula 
 
 V = 48 . / -T- V being the velocity in feet per second ; this 
 
 formula, reduced to the form adopted by Mr. Morrison, gives 
 a constant of 0-031. From Eytelwein's formula according to 
 Beardmore Mr. Morrison deduces ■0'028 as the constant. In a 
 Paper by Mr. Lowe the constant is given as 0-030, and in an old 
 formula, the constant is given as 0'028. From experiments on the 
 pneumatic tube from Euston to Holborn,* taking the velocity of 
 the air to be that of the carriage, allowing nothing for the work 
 done in moving the carriage, a maximum value is obtained of 
 0036, and making allowance for the weight of the carriage, the 
 results give a probable value for the constant of 027. The ex- 
 periments in Lime Street tunnel Liverpool are not well suited for 
 deducing a constant,^ the length, 1,200 yards, being hardly as great 
 
 ' Quoted also by C. Cope Pearce in the Transacticms of the South Wales Institute 
 of Mining Engineers, vol. v. The figures, howeyer, are taken from the original. 
 
 * Vide Minutes of Proceedings Inst. G.E., vol. xxx., p. 304. 
 
 * Ihid., vol. xxxiii., p. 53. 
 
 * Engineering, 23rd Aug., 1872. 
 
 * Vide Inst. Meeh. Eng. Proceedings, 1871, p. 22 et seq. 
 
 was 
 
v.] AIE, VENTILATION, WARMING. 73 
 
 in proportion to widtli as is desirable. From the data given, making 
 use of the formula for short passages, the constant comes out 0"049; 
 but the velocity of the air may have been higher than taken : a 
 difference of 20 per cent, would bring the constant to the same 
 figure as the others. From experiments made at Crewe, shortly 
 before the ventilation of this tunnel was carried out, the following 
 formula was deduced : — 
 
 Discharge in cubic feet per hour, 1,314 /sj -y-; d = diameter of 
 
 pipe in inches, h = head in inches of water, I = length in yards. 
 This gives a constant for the formula adopted by Mr. Morrison, of 
 0029, and he believes that the authorities quoted are sufficient to 
 justify 0"03 as the value of the constant K." 
 
 METHODS OF VENTILATION. 
 (40) Simple Openings. 
 
 In fine summer weather, people open their windows and doors, 
 and ventilation is easy ; it only becomes in this climate a matter 
 for skill and study during the cooler months of the year, hence, in 
 speakiag of systems of ventilation, it must always be presumed 
 that the house contains warmer air than that which is external ; in 
 such a case the air within will be of less specific gravity than the 
 air without, and the latter will tend to press in at any opening. 
 
 If, for instance, there is an opening at the bottom of the room, 
 another at the top, in the absence of wind there will be a steady 
 stream of air from below upwards, but if there should be wind, or 
 if the openings for the admission of air be blocked or too small in 
 area, the draught may be reverse — such reverse draughts often 
 occur when windows are open at the top, the air streaming in 
 like a douche of cold water. It has often been pointed out that 
 under such circumstances, although large volumes of air seem to 
 be coming in, the effect on the atmosphere of the room is not 
 commensurate with the draught, the reason being that the vitiated 
 air, having its specific gravity increased by its contaminations, and 
 becoming cooled by the rush of cold air, descends with it to be 
 partly breathed over again. 
 
74 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (41) Accepted Principles to he applied to simple Natural Ventilation. 
 
 There are certain principles with regard to simple ventilation 
 generally accepted ; these are as follows : — 
 
 (1) In natural ventilation, no opening for the admission of fresh 
 air to be near the ceiling, but preferably a few feet above the 
 floor. 
 
 (2) The inlets for fresh air should always direct the current of 
 air upwards. 
 
 (3) The openings for the admission of air should in their 
 aggregate area be larger than those for the efflux of air. Flues 
 or shafts for extracting air should all be of the same height, 
 otherwise (however paradoxical it may seem) one either counteracts 
 the other, or renders the effect less considerable. 
 
 In certain cases, however, it is necessary to have ample openings 
 on a level with the boards. For instance, in asylums in which 
 there are wards for imbeciles and idiots, the flooring is so often 
 fouled with excreta, that unless such openings exist, through which 
 the air, rendered heavy and moist by offensive organic vapours, can 
 flow, the wards cannot be kept sweet. So again, the very best 
 method of ventilating a water-closet is to have an opening on a 
 level with the floor into the external air, and a flue near the upper 
 part of the closet. These will sometimes act in one way and 
 sometimes in another, but in either case the oflfensive air is rapidly 
 diluted and swept away.^ 
 
 Methods of ventilation which are not dependent on mechanical 
 aids or on artificially warming the air, may be classified for 
 practical purposes as follows : — Appliances connected with win- 
 dows ; appliances connected with walls or chimneys; appliances 
 connected with doors ; special flues or shafts. 
 
 (42) Appliances connected with Windows. 
 
 The simplest plan of all is that suggested by Dr. Hinckes Bird, 
 the original model of which is to be seen in the Parkes Museum. 
 A board of wood is placed under the lower sash of the window 
 so as to completely block it up. The effect of this is that a 
 
 ^ The same remarks apply to stables and cowhouses ; in such places cold currents 
 near the surface of the floor will not incommode the animals, for their sensitive parts 
 are not the feet but the loins, and in both cases there is constant floor polllition. 
 
v.] AIE, VENTILATION, WARMING. 75 
 
 rectangular staft is made between the upper and lower sashes, 
 up which the external air presses, and being directed upwards, 
 curves gently into the room without perceptible draught. The 
 board is sometimes made with a hinge in the middle, for greater 
 convenience in either placing or removing it. Instead of being 
 placed underneath the lower sash, it may be placed in front of it, 
 and then the window may be opened at the bottom for a little 
 distance, but not so far as to be lifted beyond the upper edge of 
 the board. In this way two rectangular ventilating shafts are 
 formed, the one having its sides formed by the board and a portion 
 of the window and window-frame, the other formed by the upper 
 and lower sashes of the window. In each case the current of air 
 is directed upwards. A modification of this system is the use of 
 a short glass blind, adapted to the lower part of the window. 
 It is, on the whole, preferable to the board, because there is then 
 no interception of light. 
 
 Perforated Sashes. — Holes are bored in the lower bar of the 
 upper sash; the air enters vertically, but being divided up into 
 small streams, no draught is perceptible. The objection to this is, 
 that the window-frame is considerably weakened. 
 
 Currall's Window Ventilator. — An opening is made in the lower 
 sash-bar, and then a metal plate is fixed inside in a direction 
 parallel to the window-frame, so as to direct the cuiTent of air 
 upwards. The vertical section of such a system is, therefore, 
 pretty well that of a right angle. It is in principle the same idea 
 as that of Hinckes Bird, the only difference being that Currall's 
 ventilator is permanently fixed. 
 
 Louvres. — ^Any one who has a Venetian blind has an appliance 
 that can be utilized very effectually as a louvred opening ; for the 
 window can be opened, and the sashes placed at any angle, so as to 
 allow the air to come in either upwards or horizontally. But the 
 most common form of louvre is constructed by removing a pane 
 and fixing glass louvres in a metal framework. The louvres are 
 connected together by a simple mechanical arrangement, and can 
 be opened or shut at pleasure. Glass is of course not the only 
 ma,terial which may be used as louvres, but most decidedly the 
 best, being most easily cleaned, and not intercepting the light. 
 The proper place for these appliances is not the upper part of the 
 highest panes, but the lowest pane of the ;ipper sash. 
 
76 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Swinging Windows. — These are much used in hospitals and 
 board schools. Sometimes the window swings on a centre pivot, 
 and in this way a very large opening is obtained. Sometimes the 
 upper part of the window opens inwards Hke a valve, and thus 
 directs the current up towards the ceiling. 
 
 Double Windows. — These are very useful in cold weather, as the 
 layer of air between the two windows gets to a certain extent 
 warmed. By opening the outer one at the bottom, the inner one 
 at the top, a very efficient air-shaft is formed, as in Hinckes Bird's 
 plan. 
 
 Cooper's Ventilator. — Cooper's ventilator consists of a circular 
 disc of glass, perforated with five or more holes, attached by means 
 of a pivot to a pane of glass similarly perforated. On turning the 
 disc, the holes in the pane and disc can be made to correspond, or 
 not, just as required. 
 
 (43) Appliances connected with Walls and Chimneys. 
 
 Perforated Bricks. — Ellison's conical ventilator consists of cone- 
 shaped perforations in bricks. It may be experimentally proved 
 that if the air is blown in from the narrow to the wide end of the 
 cone, the stream of air widens and spreads, so that draught is not 
 easily felt. Such bricks are very useful placed just behind, and 
 concealed by, the skirting-board. 
 
 Direct Openings in the Wall. — One of the best known of these 
 is Sherringham's valve, which consists of a metal box fitting in a 
 hole in the wall, with a heavy flap exactly balanced by a weight at 
 the end of a string passing over a pulley. By pulling at the 
 weight the valve can be shut, or by lifting the weight the valve 
 may be opened. 
 
 Stevens' Draiver Ventilator is like a drawer, with the end most 
 remote from the handle wanting. The drawer fits into the whole 
 length of the wall. When it is shut there is no current; when 
 pulled open, the air enters freely, and, striking against the front 
 bearing the handle, is given an upward direction. 
 
 Jennings' Inlet is an opening in the wall, through which the air 
 is first led into a small chamber, where the dust can deposit. From 
 this " dust trap " it passes through louvres into the room. 
 
 There are many other ways which have been proposed, and are 
 
v.] AIR, VENTILATION, WARMING. 77 
 
 more or less effectual. Pictures, skirting-boards, cornices, mirrors 
 may all be utilised, both to conceal openings in walls and to give 
 the air a proper direction. 
 
 Arnott's Valve is a valve which is used as an exit ventilator. 
 It consists of a Kght metal flap, swinging inside a metal frame- 
 work in such a way that it only opens towards the chimney flue ; 
 back pressure from the flue causes it instantly to shut. 
 
 Boyle's Exit Ventilator is on the same principle, but instead of 
 metal there are a number of light talc flaps. 
 
 Openings in Dom-s. — These are not much made use of; but 
 sometimes a panel is made to open, either pivoted or otherwise. 
 
 Currall's ventilator for doors is precisely the same as the one for 
 windows just described. 
 
 (44) Special Shafts or Tiobes. 
 
 Tohin's Tubes. — One of the best known and most efficient forms 
 of ventilation is by means of what is called a Tobin's tube. It is a 
 right-angled tube, the one limb leading in a horizontal direction 
 into the outer air ; the other, vertical, being in the room. The 
 vertical pipe should not much exceed six feet. Some Tobin's 
 tubes are provided with valves, in order to throw them out of use 
 when not required. The air streams in, and is directed up towards 
 the ceiling, and then falls like water from a fountain, in fine 
 streams, becoming partly warmed during the descent. These 
 tubes may be placed in the corners of the room. They are sus- 
 ceptible of ornamentation, and are nearly always efficient. If a 
 tray of water, or a piece of canvas kept constantly moist, be placed 
 in the horizontal limb, and the air deflected upon the wet surface 
 by metal plates, most of the dust and soot, which otherwise in 
 smoky towns eflects an entrance, is deposited. 
 
 With the exception of Tobin's tubes, most of the shafts or tubes 
 act in extracting and not in delivering air. 
 
 MacKinnel's tube does however combine the two systems and 
 acts both as a delivery and an exit tube. It consists of two 
 cylinders, one inside the other, passing from the ceiling into the 
 outer air. The inner tube is longer than the outer one and 
 projects above it outside, while at its lower end it also projects 
 into the room and carries a circular rim, the rim being parallel 
 
78 A MANUAL OF PUBLIC HEALTH. [chap, v, 
 
 ■with the ceiling. A gas burner may be placed in the inner tube 
 to cause a greater extraction ; the vitiated air passes up the inner 
 tube and escapes, the colder external air flows down through the 
 annular space between the outer and inner tube, but is prevented 
 from spraying Jike a douche on the heads of the inmates by the 
 circular rim which compels the air to pass downwards in curved 
 streams, this system has answered well in the case of square or 
 round one storied buildings such as stables. 
 
 (45) Cowls and Extraction Shafts Generally. 
 
 A chimney is of course an excellent extraction shaft when a fire 
 is burning ; the amount of air which passes up is enormous, and if 
 the mean temperature of the shaft is known can be calculated 
 from the formula given at page 69. The efficacy of cowls has 
 probably been overrated. In the numerous experiments carried out 
 by the cowl committee, consisting of Mr. Eogers Field, Mr. Peggs, 
 and Mr. Eassie, the result was, speaking generally, that the much 
 advertised cowls had little advantage over a simple tube or shaft. 
 The motive power in the absence of wind is the difference of 
 temperature between the external and internal air, but when wind 
 is present the wind passing over the top of a shaft will aspirate 
 the air and cause movement independent of temperature. 
 
 Cowls are under certain circumstances advantageous, for 
 instance, the common way of ventilating ships and steamers is by 
 means of a cowl turned towards the wind, the air is in this way 
 forced into the lower and enclosed parts of the vessel, a windsail 
 again acts in the same way and may be considered a canvas cowl. 
 Cowls whether aspirating or the reverse, fixed or revolving, owe 
 any efficacy they possess to wind, and they are of course of no more 
 use than ordinary tubes in foggy still conditions of the atmosphere 
 just when ventilation is most urgently needed. 
 
 If more than one extraction tube is applied for the purpose 
 of ventilating a room, the principle already enunciated that the 
 separate shafts must be of equal height should be borne in 
 mind. 
 
CHAPTER VI. 
 
 SYSTEMS OF VENTILATION COMBINED WITH WARMING OR 
 DEPENDENT ON MECHANICAL AGENCIES. 
 
 (46) Gas as an Aspirating Agent. 
 
 Gas and lights generally may be made to purify the air of a 
 room, instead of contaminating it, by placing some simple tube 
 arrangement with a trumpet mouth over each light, and leading 
 the tube out into the open air. The aspirating force of gas may 
 be utilized for the purpose of ventilating small spaces placed in 
 difficult positions. For example, a water closet in the centre of a 
 building may be kept fairly sweet by carrying a tube direct from 
 the outer air in a horizontal position to the floor of the closet, and 
 a shaft led vertically upwards to the roof, and placing in the shaft 
 a tiny jet of gas ; in this way the dkection of the air is controlled, 
 and the shaft at all times will be warmer than the external air. 
 Special lightsfor rooms, such as the Wenham, have, when properly 
 fitted up, arrangements by which the products of combustion are 
 carried away by a flue, while the gas itself is supplied with the 
 upper layer of air near the ceiling already somewhat impure. 
 
 (47) Pritchett's Miniature Hot Water Apparatus. 
 
 This is a combined system, by means of which a room is at once 
 warmed and ventilated. It consists of a small boiler, which can 
 be heated by a spirit lamp, or placed on a fire. Attached to the 
 boiler are two cylinders, each made double ; the water circulates in 
 the double casing of the cylinders, the effect being to make two 
 shafts, one for the admission of air, the other for its extraction. 
 The cylinders are placed vertically, the outer cylinders being the 
 
80 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 hottest and used for the extraction of foul air, the inner cylinders 
 are cooler, but are yet sufficiently hot to warm the entering air. 
 
 (48) Ventilation Depending on Water Power, 
 
 There are several systems which owe their efficacy to the 
 mechanical force of water, for instance, the Eolus water spray 
 ventilator consists essentially of a fly-wheel fitted with fans. A 
 jet of water directed against this causes it to revolve. Such a 
 system can of course be made either to propel air in or to extract 
 air from a room. This simple form of mechanical ventilation has 
 much to recommend it. By regulating the water supply the rate 
 at which the fans revolve can be adjusted to a nicety. 
 
 (49) The Ventilation of Underground Passages such as Mines. 
 
 This section of the subject may be illustrated by an abstract of 
 Mr. Morrison's short account of the ventilation of underground 
 passages, such as mines and tunnels by mechanical means. 
 
 The Furnace. — The simplest plan is the furnace, which at one 
 time was the only system employed, and it is still used in many 
 collieries. There is a good deal to be said in favour of its 
 simplicity, but it is only in the case of very great depths that this 
 system can compete for economy with mechanical methods, and 
 even then there are various drawbacks. The useful effect rarely 
 exceeds 5 per cent, of the actual energy given out by the coals, 
 and although, at a colliery, this is often, but wrongly, considered a 
 matter of minor importance, in tunnel ventilation it is of the first 
 consequence. 
 
 Air Pumps. — One of the first mechanical ventilators was 
 invented by Mr. Struv^, of Swansea.^ It consists of a piston, 
 somewhat resembling a gasometer, working in a brick chamber, in 
 an annular space filled with water. The air is admitted by, and 
 expelled through, flap-valves. It is well suited for extracting 
 large quantities of air from collieries at pressures of 5 inches or 6 
 inches of water; but the large amount of clearance renders it 
 unsuitable where the pressure is sufficient to cause a practical 
 difference in the density of the air. The effective duty is stated 
 
 1 Tide Inst. Mech. Eng. Proceedings, 1869, p. 133 ; and Trans. Inst, of Eng. in 
 SeotlaTid, vol. xiv. p. 72. 
 
 ^ Vide Minutes of Proceedings Inst. C.E., vol. x. p. 38. 
 
VI.] AIB, VENTILATION, WARMING. 81 
 
 to vary from 40 per cent, of the actual power put into the pump 
 to 40 per cent, of the gross boiler power. 
 
 There is a pair of ventilators of this description at Cwm Avon.^ 
 with pistons 18 feet in diameter and of 7 feet stroke, working 8 
 strokes per minute. This machine exhausts from 40,000 to 
 56,000 cubic feet per minute, with a water gauge of 3 inches. A 
 slightly smaller ventilator at Risca Colliery^ exhausts 43,800 cubic 
 feet per minute, with a water gauge of 2 3 inches. 
 
 Exhausters on a somewhat similar principle have been erected 
 at the St. Gothard Tunnel works.^ These are cylinders hung one 
 at each end of a rocking beam, which alternately dip into annular 
 tanks of water. The space to be ventilated is connected with 
 these air-cylinders by pipes with inlet valves, and the tops of the 
 air-cyHnders are furnished with outlet valves. Each time the 
 cylinder rises it fills with air from the pit or tunnel, which in 
 falling it expels through the valves on the top. These exhausters 
 are therefore single-action pumps, while Struv^'s are double action. 
 They are intended to work with a water gauge of 6 inches, and 
 their general design renders them suitable for much higher water 
 gauges than Struv^'s. 
 
 Lemielle's Ventilator. — Lemielle's ventilator consists of a vertical 
 drum, with movable leaves or vanes,^ placed eccentrically in a 
 casing, so that the leaves lie close against the drum on one side 
 of the casing, but expand as they pass the other, and thus sweep 
 out a certain amount of air at each revolution. There is a venti- 
 lator of this description at Page Bank Colliery,* Durham, 23 feet 
 in diameter and 32 feet high. It usually works up to about 
 60,000 cubic feet per minute with a 2'6 inch water gauge, and 
 but occasionally to 97,000 cubic feet per minute with a •6'6 inch 
 water gauge. The useful effect is 36 per cent, of the gross boiler 
 power. 
 
 The Steam Jet. — In some collieries the steam jet has been 
 tried with success, as at Lower Moor Colliery,^ Oldham. The 
 
 ^ Vide Scmth Wales Inst, of Engineers, vols. v. and vi., passim. Paper by C. 
 Cope Pearoe. 
 
 ^ Engineering, 7th May, 1875. 
 
 ' Vide North of England Institute of Mining Eng. Trani., vols, xviii. p. 63 ei 
 seq., and xix., p. 2. Steavenson on Mechanical Ventilation. Inst. Mcch. Eng. 
 Proceedings, 1858, p. 63. 
 
 * Vide Inst. Meek. Eng. Proceedings, 1869, p. 147. 
 
 ' Engineer, 19th Jan., 1872. 
 
 G 
 
82 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 apparatus consists of seventy-two vertical pipes 5 feet long and 
 7 inches in diameter, fitted to an iron frame on the top of the 
 upcast shaft: into each is inserted a steam pipe having a nozzle 
 1^^ inch in diameter, supplied with steam at 38 lbs. pressure. 
 This rough apparatus exhausts 16,000 cubic feet per minute. 
 
 In the working of pneumatic tubes, between telegraph offices 
 in London, the steam jet has been tested against a first-rate steam- 
 engine;^ at 40 lbs. pressure the engine does most work, but 
 at 70 lbs. pressure the steam jet is superior. The nozzle, in 
 this instance, is constructed in the most approved manner, and the 
 vacuum produced is equal to 23 inches of mercury ; but Mr. 
 Morrison does not know of any instance where, with a water 
 gauge of a few inches, such good results have been obtained by a 
 steam jet as by other means. The jet is probably ill suited for 
 exhausting large quantities of air at low pressures. 
 
 The Fan. — The best means of ventilation for tunnels seems to 
 be the fan. It is used in collieries and mines throughout the 
 world, and is the only machine that has ever been applied to tunnel 
 ventilation. 
 
 The fan erected at Lime Street tunneP is 29 feet 4 inches in 
 diameter, 7 feet 6 inches wide, and runs at forty-five revolutions 
 per minute, is by no means of the most approved construction, 
 but the circumstances of the case are peculiar ; at times the 
 tunnel ventilates itself through the fan, which is constructed to 
 allow of this, the heat of the boiler-fires assisting the natural 
 ventilation. When the fan is at work the vacuum in the tunnel 
 near the bottom of the shaft is only equal to 0'14! inch of water, 
 but near the fan it is equal to 0*54 inch. When the air leaves 
 the fan the pressure is equivalent to 0'19 inch of water above 
 the atmosphere, this being the pressure required to drive the air 
 through the chimney into the open air. The fan therefore seems 
 to exhaust 431,000 cubic feet per minute, against a pressure of 
 0-54 -f- 0-19 = 073 inch of water, which represents 50 HP. The 
 actual indicated HP. of the engine is 134. When running at 
 forty-four revolutions, but doing no work, the indicated HP. ex- 
 pended in the friction of the engine and machinery is 34. The 
 effective duty of the fan is therefore only 37 per cent, of the gross 
 
 1 Vide Minutes of Proceedings InsL C.E., vol. xxxiii-.p. 16. 
 ^ Vide J?is<. Mech. Eng. Proceedings, 1871, p. 24. 
 
VI.] AIK, VENTILATION, WARMING. 83 
 
 power, or 50 per cent, of the net power. The effective duty of 
 many other fans is, however, much higher. 
 
 The pneumatic tube from Euston to the General Post Office is 
 worked by a fan in Holborn,^ 3,080 yards from Euston. This fan 
 is 22 feet in diameter, and is driven at the rate of one hundred 
 and sixty revolutions per minute. The tube is tunnel-shaped, 
 4 feet wide and 4 feet 6 inches high. The usual speed of the 
 carriage is about fifteen miles an hour. As the tube has an area 
 of 16'3 square feet, the discharge is 20,000 cubic feet of air per 
 minute. The fan is arranged to work either for exhausting the air 
 or for compressing it. At the speed mentioned the water gauge is 
 about 10 inches,^ and this shows a useful power of thirty-two horses. 
 
 The Metropolitan Railway Company once made use of this 
 tube for the purpose of ventilating their tunnel.^ The tube 
 crosses the tunnel between Gower Street and Portland Road ; and 
 valves were arranged so that, on each journey of the carriage from 
 Euston to Holbom, as soon as the carriage passed the Metropoli- 
 tan tunnel, the valves opened, and the air was drawn from the 
 Metropolitan railway instead of from Euston. But the tube could 
 only be used when the fan was exhausting, and when the carriage 
 was between the Metropolitan railway and Holborn ; that is about 
 once an hour for five or six minutes. 
 
 Of late years a great many fans have been introduced. One 
 called the Guibal fan seems to give satisfaction.* The effective 
 duty of some of them has been stated to be 83 per cent, of the 
 actual power put into the fan shaft ; ^ but generally it is not 
 so high. In these fans the casing is concentric with the fan, and 
 quite close to it, with only one opening, the size of which is regu- 
 lated by a shutter. The chimney is funnel-shaped, to allow the 
 velocity of air to be reduced before entering the atmosphere. The 
 fact that so mxich of the circumference of the fan is useless for 
 discharge would lead to the supposition that the quantity of air 
 must be less than that discharged from other fans of equal size.^ 
 
 ^ Engineering, 23rd Aug., 1872. Engineer, 10th Nov., 1865. 
 ^ Vide Min. of Proceedings Itist. C. E. , vol", xxxiii. p. 4. 
 ' Engineer uni Engineering, 31st July, 1874. 
 
 * Vide Inst. Mech. Eng. Proceedings, 1869, p. 78. North of England Institute of 
 Mining Eng., Trans., vol. xiv., p. 73. Engineering, 9th April, 1875. 
 
 = Vide Inst. Mech. Eng. Proceedings, 1869, p. 152. 
 
 * Mr. Cowper seems to hold the same opinion. Vide Minutes of Proceedings Inst. 
 C.E., vol. XXX., p. 258, 
 
 G 2 
 
84 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 It seems, however, that the useful effect of these fans is high, 
 and that, for any given discharge and water gauge, the Guibal 
 fan will work with less coal than many others, and with as little 
 as any. 
 
 There is a fan of this description working at Thirslington 
 Colliery. It is 36 feet in diameter and 12 feet wide, and at eighty 
 revolutions it will discharge 80,000 cubic feet per minute, under a 
 water gauge of 6'2 inches. A somewhat smaller fan, at Gethin 
 Colliery, discharges 153,600 cubic feet per minute, under a water 
 gauge of 26 inches. It is stated by Mr. Wilkinson that he ob- 
 tained 63,000 cubic feet of air per minute from a Guibal fan, with 
 a similar amount of steam required for 40,000 cubic feet per 
 minute with Struv^'s ventilator. 
 
 On their first introduction fans were supposed to be applicable 
 only to low water gauges ; but it has been found that they will 
 work economically up to high gauges for ventilating purposes. 
 There are some at Grand Busson, near Mons, in Belgium, 30 feet 
 diameter, working at one hundred revolutions per minute with 
 7 inches water gauge. 
 
 To produce a current of air of 10 miles an hour through a 
 tunnel 20 miles long, a water gauge of less than 7 inches is 
 required, or, including an allowance of 1 inch for friction in the 
 air-passages, &c., 8 inches altogether ; it is therefore evident that 
 fans are suitable for the pressures required in all practical cases; 
 and as they are better adapted for passing large quantities of air 
 than any other ventilating apparatus, they should be employed in 
 all cases where tunnels are to be ventilated artificially. The best 
 fans appear to utilize more than 70 per cent, of the actual power 
 applied to the fan shaft, or 15 to 20 per cent, less than the 
 indicated power of the engine. 
 
 The Blackman Air Propeller. — The Blackman air propeller is a 
 fan. .One 4 feet in diameter driven at a speed of 330 revolutions 
 a minute, with an expenditure of one horse power, discharges 
 15,000 feet per minute. 
 
 Engineers have lately preferred to deliver air by pumps rather 
 than by fans, the amount of air being known in this system with 
 certainty. In schools and colleges in Dundee for example venti- 
 lating pumps are driven very economically by water motors ; the 
 pumps are rectangular wooden boxes, stiffened by iron ribs, and 
 
VI.] 
 
 AIR, VENTILATION, "WARMING. 
 
 85 
 
 provided at top and bottom with inlet valves consisting of a 
 number of short waterproof cloth flaps working against a vertical 
 wooden grid. A wooden piston with a vertical travel is held in 
 place and worked by wire ropes above and below, which lead over 
 pulleys to the water motor ; the piston is balanced by a counter- 
 weight on the descending branch of the upper rope. A piston 5 
 feet square, with a stroke of 5 feet, works at 20 strokes per minute 
 and delivers 150,000 feet per hour. These pumps have been 
 designed by Mr. Cunningham, and when a greater volume of air is 
 required he uses revolving pumps of the Roots blower type. These 
 latter pumps are usually driven by a gas engine. The inlets are 
 vertical. The air thus supplied may be warmed before entering 
 the rooms by steam coils. 
 
 Cost of Mechanical as compared with Natural Ventilation. — 
 Mechanical ventilation is the only kind of ventilation which can 
 be relied upon for large public buildings such as churches, schools, 
 assembly rooms, theatres, and the like. In the valuable report of 
 Professor Camelley for the use of the school board of Dundee 
 (1889) he compares the cost and efficacy of the systems of natural 
 and mechanical ventilation, his chief conclusions being as follows : 
 
 In schools badly ventilated on the natural system, the micro- 
 organisms increase up to a certain point with increase of wall and 
 floor space, whereas in mechanically ventilated schools where the 
 air is quickly renewed, the micro-organisms decrease with increase 
 of cubic space. This is shown in the following table : — 
 
 Table XVI. 
 
 Cubic Space per Person. 
 
 Naturally Ventilated. . 
 
 Mechanically Ventilated, 
 
 OS 
 II 
 
 
 ■5^ 
 II 
 
 ill 
 
 ■5 cS 
 
 o % 
 
 1^ 
 
 .2 t-' 
 
 3e| 
 
 
 
 
 
 
 
 
 
 P 
 
 Cubic feet — 
 
 
 
 
 
 
 
 
 
 50—100 . . 
 
 6 
 
 21-5 
 
 16-2 
 
 119 
 
 
 
 
 
 100—150 
 
 14 
 
 15-5 
 
 19-6 
 
 128 
 
 7 
 
 14 
 
 7-8 
 
 23 
 
 150—200 .... 
 
 5 
 
 18-9 
 
 12-3 
 
 150 
 
 8 
 
 11-4 
 
 9-6 
 
 14 
 
 200—250 . . . 
 
 9 
 
 21-1 
 
 16-8 
 
 188 
 
 5 
 
 11-8 
 
 12-3 
 
 10 
 
 250—300 .... 
 
 4 
 
 17-1 
 
 9-5 
 
 187 
 
 
 
 
 
 300 and upwards . 
 
 4 
 
 15-1 
 
 11-8 
 
 12 
 
 6 
 
 13-0 
 
 3-7 
 
 2 
 
86 A MANUAL OF PUBLIC HEALTH. [cHAr. vi. 
 
 The cost per head to naturally ventilate a school built to accom- 
 modate 1,000 children, as well as to heat, may be put at 2^d. per 
 head ; the mechanical system will cost 7id., the difference being 
 thus 19^. 15s. per annum. The figures refer to Dundee, hence the 
 cost will be greater in towns where coal is dearer, less where coal 
 is cheaper than in Dundee. But in any case 201. or 251. per year 
 per 1,000 children extra should be considered well spent if it 
 conduce to greater purity of air. Carnelley investigated several 
 systems both of heating and ventilating schools, and recommends 
 a fan or fans driven by a gas-engine ; also that the fressh air should 
 be blown in not sucked out ; that incoming air should be filtered 
 through coarse jute cloth placed diagonally across the large inlet- 
 flue or across the air chamber ; that there should be but one main 
 inlet air shaft, freely open at the top, and not fitted with Louvre 
 boards, and lastly that the fresh air inlet shafts in the various 
 rooms ventilated on the mechanical principle should be much 
 wider and shallower than is usually the case, so as to distribute 
 the air in a thin stream. 
 
CHAPTER VII. 
 
 WARMING. 
 
 (50) General Principles of Warming Booms. 
 
 The nervous system is benumbed by great heat or cold. 
 
 Humboldt long ago drew attention to the analogy between the 
 torpor of the larger reptiles during tropical heat and the hyber- 
 nation of certain animals during winter. 
 
 Cold lessens the vitality generally, its stress being most felt 
 by the aged and young ; the heat in this country is seldom exces- 
 sive for a sufficiently long period to cause disturbance to the public 
 health, save indirectly. 
 
 The best temperature for intellectual activity is from 62° to 65°, 
 therefore these are the temperatures for living rooms ; on the other 
 hand sleeping rooms are best kept much cooler ; sleep is generally 
 soundest when the air of the room is a few degrees above freezing 
 point, always provided that the body itself is kept warm by suffi- 
 cient wraps ; it is a great mistake to heat in any way sleeping 
 rooms, that is provided the sleepers are in good health. 
 
 The difficulty of maintenance of temperature to any particular 
 degree can hardly be exaggerated. Our houses are as it were 
 little cellular boxes, at the bottom of a vast aerial ocean, which is 
 often more than 20° in excess or below the temperature desired. 
 Nor does it make the practical solution of the problem easier 
 when we have to build the same house for extremes of heat and 
 cold. 
 
 (51) Warming ly Open Fireplaces. 
 
 The " pleasant pokeable fire," as an open fire has been called, 
 is peculiarly English ; countries like Sweden, Norway, Russia, and 
 
88 A MANUAL OF PUBLIO HEALTH. [chap. 
 
 the Northern States, with their extreme winters, have preferred the 
 more economical stoves. 
 
 The open fire is of course wasteful : a pound of coal, if all its 
 heat were utilized, would warm a room 20 feet square and 
 12 feet high 10° above the surrounding air, but quite eight 
 times that quantity has to be used in open grates even of the best 
 construction. On the other hand they have two great merits, 
 they are cheerful and powerful ventilators : most chimneys of ordi- 
 nary houses extract from 30,000 to 40,000 cubic feet of air hourly. 
 
 The best modem grates are of the warm air type, that is cold 
 pure air is conveyed from without by a special flue to the back 
 of the grate, it is then warmed by contact with the heated surfaces 
 and streams into the room^ 
 
 The following are the principles to be observed in the construc- 
 tion of warm air grates. The bars in front should be as thin as 
 possible, and fitted not horizontally but vertically, the sides of fire- 
 brick, and splayed to an angle of 135°. The back and sides of the 
 grate should be " gilled," the gills projecting into the chamber at 
 the back. The flue leading to the back of the grate must draw 
 its air supply from an unexceptionable source. The warm air 
 must be delivered at the lowest practicable point, the usual t)lace 
 being just below the mantel-board. The grate itself should be 
 raised a few inches above the floor, and if slow combustion is 
 required, the bottom of the grate may be formed of a solid hit 
 of terra-cotta or fire-clay. In places where instead of coal,. wood 
 is burnt, the fuel may be on the hearth itself; in that case the air 
 chamber should not alone be at the back of the fire-place, but 
 should communicate also with a space under the hearth ; by means 
 of this "hollow hearth," the heat which otherwise would be expended 
 on the stove and ground is in great part conveyed into the room. 
 
 (52) Stoves. 
 
 The old fashioned stove, which may be defined as a sheet-iron 
 box in which the fuel was burnt, and connected with a pipe to 
 lead away the smoke and gases, was an efficient but unhealthy 
 method of heating a room. When in full action a length of the 
 pipe, and no small portion of the stove itself would be heated to 
 redness, the thin iron in that state became of a spongy texture, 
 and carbon monoxide and dioxide freely streamed through, poisoning 
 
VII.] AIE, VENTILATION, WARMING. 89 
 
 the atmosphere. The little floating particles of organic matter in 
 the air would be borne by currents against the red-hot iron and 
 be consumed. The effect of these miniature cremations, small 
 at any given point or moment, was considerable when the process 
 went on for hours and caused the air to feel " burnt and dry," 
 and to have a peculiar smell.' The Pensylvanian stove invented 
 by Franklin, was one of the earliest built on correct principles ; 
 the modern ones are little more than improvements of this type of 
 stove. 
 
 The first principle of a modern stove is that it shall be con- 
 structed of materials which will not permit the transmission of 
 gases through the walls; this is attained by the use of fire-clay 
 linings. The stove should be composed of a judicious combination 
 of iron, fire-clay, fire-brick or porcelain. The forms of stoves are 
 so varied that only types of the chief can be described. 
 
 Slow-comhustion Stoves. — The Meidingen stove is much used in 
 Germany, it is composed of an inner cylinder made up of a series 
 of thick externally fluted rings ; the rings are enclosed with a double 
 casing, which casing can be connected with the outer air by means 
 of a pipe. A door fixed in the grate regulates the draught, and 
 when the stove is fully charged the fuel may be made to burn 
 quickly in from three to four hours, or slowly in twenty-four hours, 
 according to necessity. 
 
 A slow combustion stove to which was awarded a gold medal at 
 the International Health Exhibition is constructed as follows : The 
 fire-place is lined with fire-clay, there is a door for the reception 
 of the fuel, and there is another door at the lower part of the stove 
 serving the double purpose of admitting air and removing the 
 ashes. The gases of combustion and the smoke, instead of escaping 
 direct into the chimney, are first ignited and then made to pass 
 through two chambers, and they finally escape through the 
 flue ; between the divided chamber and the fuel box is another 
 chamber, the office of which is to warm the air supplied to, the 
 room. To this chamber a special flue carried underneath the 
 boards conveys the outside atmosphere and it enters the room as 
 warm air. The stove is essentially a slow combustion stove, and is 
 an improvement upon those which are directly supplied with air 
 from outside, for these of course do not ventilate the rooms, because 
 most of them are entirely closed. 
 
90 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Saxon Snell's Thermohydric Grate.— This is more a stove than 
 a grate, combining however the advantages of both. A small 
 boiler is placed behind the grate and communicates with a series 
 of iron pipes alongside of it. These are also filled with water and 
 air is admitted to the room between these hot water pipes. The 
 products of combustion are carried off by a flue, which as may be 
 seen in the St. Marylebone and Netting Hill Infirmary, may be 
 placed underneath the floor, and the grate occupy the centre of 
 the room. 
 
 (53) Systems applicable for Schools and Public Buildings. 
 
 In the warming of schools and public buildings generally a 
 combined system of warm air grates and of hot water or steam 
 pipes is best. The air of school rooms and corridors may be 
 warmed up to 50° by coils or radiators, and wherever more heat 
 is required that ^.dditional degree may be obtained by open 
 fireplaces. 
 
 Air that has been artificially heated, although heated in such a 
 way that it is not contaminated by the gases of combustion, has 
 nevertheless been changed and deteriorated in quality. Direct 
 observation on the electric state of the air of close ill-ventilated 
 rooms has shown that the electric condition of the air is reversed, 
 and instead of being positive it is that which is called negative or 
 resinous electricity. This change in the electrical state is probably 
 accompanied by other chapges such as a diminution of ozone, but 
 direct observations on this point are wanting. The greater the 
 degree the air is heated, the greater the change the air undergoes ; 
 hence any form of air heating in which the pipes are brought to a 
 heat beyond boiling water, is to be deprecated. 
 
 (54) The High Pressure System. 
 
 In this system iron pipes of wrought iron are used, they are 
 filled with water ; at the highest point, there is a short bit of empty 
 pipe called the " expansion pipe ; " there is no boiler, the pipe pass- 
 ing direct through the furnace fire. In this closed system, there is 
 necessarily great pressure, and the temperature and the pressure 
 have a direct relationship. A modem and good improvement 
 consists in the addition of a safety valve. The faults of the system 
 
VII.] AIR, VENTILATION, WARMING. 91 
 
 are the great irregularity in the temperature of different parts of 
 the same coil, and the rapidity with which any slackening of the 
 fire diminishes the heat. The danger from explosion is not great ; 
 if a pipe should burst it merely splits and there is a sudden rush 
 of water and steam, but no fragments of metal fly about. Although 
 from the defects mentioned and especially from the liability by the 
 use of high pressure pipes to overheat the air, the writer considers 
 the system objectionable for the purpose of warming houses; on 
 the other hand it is useful for the purpose of heating drying closets 
 and for disinfecting chambers ; wherever in short a small space has 
 to be brought to a high temperature. 
 
 (55) Steam Heating. 
 
 This is only suitable for buildings large enough to support the 
 expense of constant and skilled supervision. The advantages 
 of a steam apparatus over a hot water apparatus consist chiefly in 
 the greater ease of application of the heating surfaces, where great 
 inequalities of level occur, especially when the boiler has to be 
 placed above the places to be heated as well as in the smaller 
 heating surface required. The disadvantages are the constant 
 skilled attention already mentioned, the want of permanence of 
 temperature unless supervised with great care ; added to this, more 
 fuel is required and the wear and tear is greater than in the case of 
 a hot water apparatus. 
 
 (56) Hot Water Systems. 
 
 The ordinary hot water apparatus consists of a service cistern, 
 a cistern at the highest point — a boiler and pipes extending from 
 the boiler to the highest cistern and from the highest cistern back 
 to the boiler; at any part of the course the pipes can be curled in 
 coils or otherwise arranged to increase the heating surface. The 
 water in the system is continually circulating, the hot water rising 
 from its lower specific gravity in the one pipe and descending when 
 cooled by its higher specific gravity in the other pipe. 
 
 The pipes can be usually maintained to 200°, a temperature 
 that does not seem to deteriorate perceptibly the air passing over 
 them. 
 
 It may be useful to know how to calculate the length of pipe 
 
92 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 required to maintain a room at a temperature of say 50°. If the 
 question is considered apart from the element of time 1 cubic 
 foot of water raised 1° will raise 2,990 cubic feet of air to a 
 like temperature ; the element of time can only be determined by 
 experiment. Mr. C. Hood^ found that an iron pipe 4 inches 
 external diameter, loses 851 of a degree of heat per minute (i.e. 1° 
 in 70 seconds) when the excess of its temperature is 125° above that 
 of the sunounding air. 
 
 Therefore 1 foot in length of pipe 4 inches in diameter will 
 heat 222 cubic feet of air, 1° per minute, when the difference 
 of temperature of pipe and temperature of air is 125°. Before 
 this calculation is applied to the practical heating of buildings, 
 many corrections must be made, especially if there is much 
 window surface, for the loss of heat from glass is consider- 
 able. Hood found that 1 square foot of glass in still air will 
 cool 1'279 cubic foot of air as many degrees per minute as the 
 internal temperature of the room exceeds the external temperature 
 of the air. Thus if the difference between the internal and ex- 
 ternal temperature of a room be 30°, then 1'279 cubic foot of 
 air will be cooled 30° by each square foot of glass. Wind of 
 course increases the cooling power very much. 
 
 Neglecting losses from doors and crevices, and only considering 
 the windows and the amount of air to be warmed. Hood reckons 
 the quantity of air to be warmed as at least 3'5 to 5 cubic feet for 
 each square foot of air per minute for each person the room 
 contains, and 1'25 cubic foot for each square foot of glass. 
 
 The following table saves the necessity of calculation (see 
 Table XVII.) 
 
 An example will show how it is used, supposing the temperature 
 in the winter is likely to be 10° outside and the number of feet of 
 pipe is required to be known to supply 40 persons with 12 cubic 
 feet per minute of air at 50°. 
 
 J Let p be the temperature of the pipe and t the temperature that the room is 
 125 
 required to be kept at, then -—„=x which will represent the number of feet of pipe 
 
 that will warm 222 cubic feet of air 1° per minute, when j)— 2 is different from 
 the proportions given above. U d represent the difference between the internal 
 and external temperatures of the room and c the number of cubic feet of air which are 
 
 d c 
 to be warmed per minute, then a; — = p, that is, p wUl be the number of feet of 
 
 pipe 4 inches in diameter which will warm any quantity of air per minute. 
 
VII.] 
 
 AIR, VENTILATION, WARMING. 
 
 93 
 
 The amount of air required at 50° is therefore 480 cubic feet. 
 Now looking down the first column of the table, find the external 
 temperature, which is 10°, next the temperature 50°, at which 
 the air is required in the horizontal column, the figure under 
 this i.e. at the intersection of the two lines is 150, which is the 
 number of feet of pipe of 4 inches diameter, the temperature 
 of the pipe being 200° which will heat 1,000 cubic feet per. minute, 
 and as 480 cubic feet are alone required the simple rule of three 
 
 calculation 
 
 150x480 = 72 
 1,000 
 
 gives the length of pipe. 
 
 Or instead of so many feet per head, a rule may be drawn from 
 experience that in rooms for every 1,000 cubic feet 12 feet of 4-inch 
 pipe is required to maintain in cold weather the temperature to 
 50° a room measuring 20 x 40 x 15 requiring 144 feet. 
 
 Table XVII. 
 
 Table showing the Quantity of Pipe, 4-inoh Diametek, which will Heat 
 1,000 Cubic Feet of Aik per Minute any eequieed numbek of Deseees. 
 Tempeeature of the Pipe being 200° F. 
 
 Temperature 
 
 
 Extenial 
 
 Temperature at which the room is rec[uired to be kept. 
 
 Air. 
 
 
 - 
 
 50 
 
 5°5 
 
 60 
 
 6°5 
 
 70 
 
 
 Feet. 
 
 Feet. 
 
 Feet. 
 
 Feel. 
 
 Feet. 
 
 10 
 
 150 
 
 174 
 
 200 
 
 229 
 
 259 
 
 12 
 
 142 
 
 166 
 
 192 
 
 220 
 
 251 
 
 14 
 
 135 
 
 159 
 
 184 
 
 212 
 
 242 
 
 16 
 
 127 
 
 151 
 
 176 
 
 204 
 
 233 
 
 18 
 
 120 
 
 143 
 
 168 
 
 195 
 
 225 
 
 20 
 
 112 
 
 135 
 
 160 
 
 187 
 
 216 
 
 22 
 
 105 
 
 128 
 
 152 
 
 179 
 
 207 
 
 24 
 
 97 
 
 120 
 
 144 
 
 170 
 
 199 
 
 26 
 
 90 
 
 112 
 
 136 
 
 162 
 
 190 
 
 28 
 
 82 
 
 104 
 
 128 
 
 154 
 
 181 
 
 30 
 
 75 
 
 97 
 
 120 
 
 145 
 
 173 
 
 32 
 
 67 
 
 89 
 
 112 
 
 137 
 
 164 
 
 34 
 
 60 
 
 81 
 
 104 
 
 129 
 
 155 
 
 36 
 
 52 
 
 73 
 
 96 
 
 120 
 
 147 
 
 38 
 
 45 
 
 66 
 
 88 
 
 112 
 
 138 
 
 40 
 
 37 
 
 68 
 
 80 
 
 104 
 
 129 
 
 42 
 
 30 
 
 50 
 
 72 
 
 95 
 
 121 
 
 44 
 
 22 
 
 42 
 
 64 
 
 87 
 
 112 
 
 46 
 
 15 
 
 34 
 
 56 
 
 79 
 
 103 
 
 48 
 
 7 
 
 27 
 
 48 
 
 70 
 
 95 
 
 50 
 
 — 
 
 19 
 
 40 
 
 62 
 
 86 
 
94 A MANUAL OF PUBLIC HEALTH. [chap. vii. 
 
 Although as a rule it is much better to trust to radiators and 
 hot water pipes only for corridors and waiting rooms, warming the 
 room itself by open warm air grates, it cannot be denied that a 
 general system which supplies warm air from a distance has 
 certain advantages, the more particularly in those cases where 
 expense is of secondary importance. For instance, in the ventila- 
 tion of the House of Commons, the foul air is extracted from the 
 ceilings by furnaces connected with powerful upcast shafts ; the 
 fresh air is cooled in summer by ice, and is heated in winter by 
 a steam battery ; it is brought through a cast iron perforated floor 
 covered with a peculiar open coating of whipcord ; this air is partly 
 forced in as required by steam bellows, the air is also washed by 
 passing it through canvas wetted with spray. 
 
 The warming and ventilation of a school- at Bigelow, U.S., 
 deserves mention, and is thus described by Dr. Hunter.^ " The 
 ventilation is effected by a plan recently introduced. There is a 
 common central shaft of wood lined with tin carrying the hot air 
 pipes for supplying the rooms. The air enters near the ceiling at 
 a temperature of 100° by an opening 20 X 35 inches, and is ex- 
 hausted near the floor, passing to the shaft mentioned. The result 
 is good." In this case no motive power is used, the lower cold air 
 falls by its own weight through the lower openings while the warm 
 air streams in through the upper apertures. 
 
 In all these general systems of warming, the success greatly 
 depends on a sufficient quantity of warm air being delivered and 
 also on the care taken in keeping all other channels closed save 
 those which are intended to convey the air to the rooms or to 
 extract it ; air rushing in by other channels of course deranges the 
 whole system. 
 
 ^ Sixth Annual Report State Board of Health. Massachiisetts. 
 
CHAPTER VIII. 
 
 PRACTICAL EXAMINATION OF AIE. 
 
 (57) Examination hy the Senses. 
 
 Examination by the sense of smell, is in a practical point of view 
 of first importance, minute quantities of organic matter, traces of 
 sulphuretted hydrogen, of coal gas, of ether, of carbon bisulphide, 
 of scents of various kinds, empyreumatic matters and many other 
 substances are detected by the sense of smell in such infinitesimal 
 (juantity as to rival and in some cases exceed the most delicate 
 chemical and physical methods known to science ; on the other 
 hand the senses will not detect considerable quantities of carbon 
 dioxide, carbon oxide, marsh gas, and several other vapours. 
 
 The nature of the organic more or less volatile matter which is 
 given off by the skin and breath and makes the air feel so " stuffy " 
 requires farther elucidation and to some extent varies in different 
 individuals. It consists in part of volatile fatty acids and their 
 ethers, and it may be hazarded as a conjecture that the faculty of 
 dogs in scenting out their masters is dependent mainly on the kind 
 and combination of the fatty acid which the particular man evolves 
 in his perspiration. 
 
 (58) Dust — Bacteria. 
 
 In ordinary living rooms the amount of dust will require no 
 estimation, but in the case of factories and work rooms, the 
 amount of dust per cubic foot may be desirable to be estimated. 
 To make some sort of estimation is easy, but to get good accu- 
 rate results is difficult for the reason that the dust is always 
 imperfectly distributed. The best method is to fix up a large 
 aspirator and pull two or three gallons through a tube- at least one 
 
96 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 inch in diameter which tube contains for a couple of inches of its 
 length crystals of sugar or sodic sulphate packed sufficiently tight 
 to allow the air to penetrate, the layer farthest from the aspirator 
 being packed loosely and then increasing in density towards the 
 aspirator ; at the conclusion of the experiment the soluble filter is 
 removed, dissolved in water, and the solution filtered through a 
 small weighed filter, the filter washed, dried, weighed, and the 
 weight returned as so much per cubic foot; of course the dust 
 collected should also be submitted to microscopical examination. 
 
 It is scarcely necessary to say that the crystals must be pure and 
 free from any kind of dirt ; to collect the dust in this way is far 
 better than by pulling it through liquids or by the use of small 
 tubes. For quantitative estimations it is essential that there be no 
 draught of any account through the tube, and the only way to 
 avoid this is to use a tube of large diameter and to aspirate slowly. 
 
 For the mere qualitative examination of dust, air may be drawn 
 through glycerin or through boiled distilled water. In some 
 researches it will be advisable to surround a tube with ice and salt 
 and draw the air through this tube, thus condensing moisture and 
 any condensable volatile matters. 
 
 The bacteriological examination of air is also best performed by 
 drawing the air through closely packed sugar or sodic sulphate or 
 other soluble filter previously sterilized, and then dissolving the 
 filter in water sterilized by boiling and cultivating in the manner 
 detailed at page 160. 
 
 (59) Chemical Method of Estimating Organic Matter in the Air. 
 
 The best chemical method of estimating organic matter in the air 
 is its approximate estimation by means of permanganate of potash. 
 
 A known bulk of air is drawn through a little distilled water 
 and the amount of oxygen consumed determined by the Forchammer 
 process.'' 
 
 (60) Estimation of Carhonic Acid in the Air. 
 
 The simplest process of all, and one which might be used without 
 
 the smallest knowledge of chemistry, is the phenol-pthalein method. 
 
 ' 10 CO. of the solution of permanganate [p. 164] and lOc.c. of sulphuric acid 
 1 : 3 are added to a known bulk of water, say a litre ; the whole is then heated for 
 four hours to 26-6° C. (80° F.). At the end of that time the water is titrated with 
 the hyposulphite solution [p. 165], using KI and starch as an indicator. The value 
 is obtained by running a control with distilled water. 
 
VIII.] 
 
 PRACTICAL EXAMINATION OB" AIR. 
 
 97 
 
 Phenol-phthalein gives to alkaline solutions an intense crimson 
 colour, but it is very sensitive to COg and this property can be taken 
 advantage of to make approximative determinations of carbonic 
 acid in the air. The latest development of the method is that of 
 Lunge and A. Zeckendorf.i It requires simply a solution of well 
 ignited sodic carbonate Nag CO3, 53 grms to the litre, coloured 
 crimson by "02 grm. of phenol-phthalein and a suitable flask and an 
 india-rubber pump delivering about 70 c.c. of air; the india-rubber 
 pump must be provided with valves so as to admit the air in one 
 direction and expel it in another. The 
 pump B is connected with the flask A as 
 in the figure (Fig. 5), so that the air passes 
 through the solution. To make a deter- 
 mination of COg in the air, the pump is 
 worked several times so as to fill the flask 
 with the air to be examined, then 10 c.c. 
 of the sodic carbonate solution are added 
 and the pump slowly worked until the 
 sodic carbonate solution is decolourized 
 and the number of times noted. Very 
 impure air will be decolourized by two 
 complete emptyings of the india-rubber 
 pump ('SO per cent.) ; for moderately im- 
 pure air 9—10 ('09— "10 per cent.) volumes 
 wiU be required. The ordinary air of 
 towns will take twenty-five volumes ('052 
 per cent.) and the best country air forty 
 volumes ('038 per cent.). G. Lunge and 
 Zeckendorf standardize their apparatus by 
 actual experiment as against the Petten- 
 kofer process and with a pump of 70 c.c. 
 found the following percentages of COg corresponded to 
 number of fillings of the pump. The air in the flask is not 
 taken into account, for it is a constant quantity. If therefore the 
 operator uses a rubber pump delivering 70 c.c. the table will be 
 sufficiently exact, but with any other size, he must standardize 
 it by actual experiment. 
 
 Fie. 5. 
 
 the 
 
 ZeiUchr. f. angew Chemie, No, 14, 1888. 
 
 H 
 
98 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 Table XVIIT. 
 
 Showino the Pbeoentagb of Carbonic Acid (Pettenkofee) Corkesponding 
 with eveey filling of the ball op the minimetric. apparatus. 
 
 No. of Fillings. CO2 
 
 per cent. 
 
 No. of Fillings. CO2 
 
 per cent.- 
 
 2 
 
 30 
 
 16 
 
 071 
 
 3 . 
 
 25 
 
 17 
 
 069 
 
 4 . 
 
 21 
 
 18 
 
 066 
 
 5 . 
 
 18 
 
 19 
 
 064 
 
 6 
 
 155 
 
 20 
 
 062 
 
 7 . 
 
 135 
 
 22 
 
 058 
 
 8 
 
 115 
 
 24 
 
 054 
 
 9 . . . . 
 
 100 
 
 26 
 
 051 
 
 10 ... 
 
 09 
 
 28 ... 
 
 049 
 
 11 
 
 087 
 
 30 . . 
 
 048 
 
 12 
 
 083 
 
 35 ... 
 
 042 
 
 13 
 
 08 
 
 40 . .. 
 
 •038 
 
 14 
 
 077 
 
 48 . 
 
 030 
 
 15 
 
 074 
 
 
 
 (61) Nephalometric methods. 
 
 Mr. Wanklyn suggested imitating the cloud or turbidity which 
 carbon dioxide produces in clear baryta water, by adding to another 
 portion of baryta water, known quantities of COj in the form of 
 sodic carbonate. This is a simple method, which takes but little 
 skill or practice. 
 
 The following apparatus is required : — 
 
 Large clean stoppered bottles, such for instance as Winchester 
 quarts, the capacity of which has been carefully determined by 
 filling them with water and then measuring the water (16'3862 
 c.c.=l cubic inch), a pair of bellows, several glass cylinders such as 
 are in use for " nesslerising," a graduated burette with glass stopcock 
 the graduations being in lOths of ac.c. ; a solution of carbonate 
 4-47 grams to the Htre, 1 c.c. of this is equal to 1 c.c. of COj or 
 by weight to 1'97 milligram ; baryta water strength about '1 per 
 cent. The air of the place to be tested having been blown in for a 
 little while by the bellows, to replace the original air in the bottle 
 the stopper may be inserted and the bottle conveyed to the labora- 
 tory or testing place, for it is seldom convenient to perform the 
 testing in the room. To perform the. actual estimation 100 c.c. 
 
vm.] PRACTICAL EXAMINATION OF AIR. 99 
 
 of the baryta water is poured into the bottle, the stopper inserted 
 and the bottle shaken some minutes, the baryta now absorbs all CO^ 
 which unites with the baryta forming an insoluble carbonate, and 
 produces a greater or less turbidity according to the amount of 
 GO2 present ; the baryta water thus made turbid is poured into a 
 glass cylinder, and placed side by side with another cylinder con- 
 taining 100 c.c. of clear baryta water; into this clear baryta water is 
 dropped from a burette the solution of sodic carbonate until the 
 two cylinders of liquid are equal in turbidity. 
 
 If the bottle contain 2,000 c.c. of air and the turbidity is imitated 
 by using 2 c.c. of the sodic carbonate, this of course means that 
 2,000 volumes of air contain 2 c.c. of CO^ — that is '1 per cent. If 
 greater accuracy is required the air acted upon must be reduced to 
 the standard pressure and temperature by calculation. 
 
 A similar method has been used by Dupr^ and Hake, the 
 carbonic acid being absorbed by pure basic lead acetate solution, and 
 the turbidity produced being imitated by running into a similar 
 bulk of basic acetate solution a solution containing known 
 quantities of CO,. 
 
 The Author's method. — The author prefers to absorb COg by a 
 strong solution of caustic soda and then to estimate the COg 
 absorbed either by weight or as a gas. Caustic soda is dissolved in 
 water to something like 25 or 30 per cent. If the caustic soda is 
 not quite pure, that is free from carbonate, most of the carbonate 
 settles to the bottom, sodic carbonate being imperfectly soluble in 
 strong soda lye, hence the soda must be allowed to settle before 
 being used. 20 c.c. of this strong soda is then placed in the bottle 
 containing the air to be tested, and having been allowed 
 to act for some ten minutes or more, the 20 c.c. are 
 transferred to a Schrotter's COj apparatus (see Fig. 6) 
 and the last traces of soda are washed out by means 
 of some recently boiled distilled water. The flask is 
 charged with strong sulphuric acid in a, to dry the 
 issuing gas, and also by weaker acid in h, the whole 
 is carefully weighed, and then the acid is allowed to 
 fall drop by drop on to the alkali ; when the reaction j.^^ g 
 is finished the last traces of COj are expelled by gently 
 boiling the contents for about a minute. On cooling, the flask 
 is reweighed — the loss represents the weight of COg in the volume 
 
 H 2 
 
100 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 of air. Weight is translated into volume or vice versa by the aid 
 of the following short table : — 
 
 Table XIX. 
 
 Showing the Relation between Weight and Volitmb of COj in 
 Milligrammes and Cubic Centimethes. 
 
 Milligrammes. 
 
 Cubic Centimetres. 
 
 Cubic Centimetres, 
 
 Mllligraiiimes, 
 
 1 
 
 •5057 
 
 1 
 
 1-97 
 
 2 
 
 . . 1-0114 
 
 2 . . 
 
 3-94 
 
 3 
 
 1-5171 
 
 3 
 
 5-91 
 
 4 
 
 2-0228 
 
 4 
 
 7-68 
 
 5 
 
 2-5285 
 
 5 
 
 9-85 
 
 6 
 
 3-0342 
 
 6 
 
 11-82 
 
 7 . 
 
 3-5899 
 
 7 
 
 13-39 
 
 8 
 
 4-0456 
 
 8 
 
 15-76 
 
 9 
 
 4-5513 
 
 9 
 
 17-73 
 
 It is necessary to observe that a determination is made once for 
 all in the same manner of the amount of COg in the soda solution 
 and the number obtained is a constant correction; an example 
 will make all clear. 
 
 20 grms. of the soda solution put into the Schrotter were found 
 after the addition of the acid and boiling up to have lost 12 
 milligrammes. 
 
 20 c.c. of the soda after acting on 2,500 c.c. of air were found to 
 have lost 32 milligrammes, which subtracted from 12 gives 20 
 milligrammes derived from the air ; 20 milligrammes are by the 
 table equal to 1011 c.c. of carbonic acid, that is 2,500 volumes 
 contain 10-11 of COg or "4 per cent. 
 
 If it is preferred to measure the COj as a gas, this may be done 
 simply by putting a short test-tube charged with more than 
 sufficient acid to neutralize the alkali, in the flask containing 
 the soda ; to the flask must be adapted by means of a perforated 
 caoutchouc cork, a piece of glass tubing which in its turn is 
 connected with a piece of rubber tubing some 15 or 16 inches long 
 and has a short angled bit of glass tubing terminating in an almost 
 capillary orifice. All air is to be expelled from the apparatus by 
 boiling the liquid until the steam rushes out with considerable 
 force, the delivery tube is then inserted under mercury in a 
 eudiometer tube also mercury-filled, the value of the divisions of 
 
VIII.] PRACTICAL EXAMINATION OF AIR. 101 
 
 which are known in c.c. and the acid carefully spilt little by little 
 into the soda by inclining the flask ; the gas displaces the mercury 
 in the tube, and the last traces are collected by boiling. The whole 
 is allowed to cool and the gas measured after the usual corrections. 
 In this case also a control experiment must be made on a known 
 bulk of soda solution, and the amount of COg subtracted. This 
 method is not really so accurate as that by weight, as determined 
 in a Schrotter's apparatus, because of the solubility of COg in the 
 water condensed from the steam and floating on the top of the 
 mercury in the eudiometer tube. 
 
 (62) Petterikofer' s Volumetric Method. 
 
 The method which is known as Pettenkofer's consists in ascer- 
 taining precisely the alkalinity of clear baryta water then absorbing 
 the carbonic acid by the baryta water, allowing the insoluble 
 carbonate to settle and again taking the alkalinity, which is of 
 course proportionately less. 
 
 The best strength for the baryta water is 7 grms. of the 
 crystallized hydrate to the litre ; it may be stored in a bottle, 
 stoppered by a doubly perforated cork, the one carrying a short 
 tube loosely filled with pumice-stone moistened with potash ; into 
 the other perforation is fitted a long tube bent syphon wise, 
 the one limb of the syphon reaching nearly to the bottom, the 
 longer limb extending outside a few inches below the bottom and 
 being fitted with a short piece of caoutchouc tube and clip, the bottle 
 itself standing on a suitable shelf, and the syphon once filled and kept 
 full the baryta can always be syphoned off clear, and since the air 
 drawn in to replace the liquid drawn out is freed by the potash 
 from CO2, the alkalinity of the liquid will not alter. The baryta is 
 first standardized by a solution of oxalic acid 28736 grms. to the 
 htre (each c.c. = 1 milligramme CO2), the indicator may be either 
 phenol-phthalein or methyl orange. The solution of oxalic acid is 
 run from a burette into say 25 c.c. of the baryta water coloured by 
 the indicator until by the change of colour it is seen that the exact 
 point of neutralization is reached. 
 
 This number is to be taken as the standard, supposing for instance 
 that 25 c.c. of clear baryta water took 30 c.c. of the acid solution 
 and another 25 after acting on a given bulk of air and being 
 
102 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 allowed to deposit took 25 c.c. of the acid solution, then a quantity 
 of baryta water equal to 5 c.c. of the standard baryta water has 
 disappeared, it has been converted to an insoluble form. Since the 
 oxalic acid solution is made of such a strength that each c.c. is 
 equal to 1 c.c. of CO^ it follows that there are 5 c.c. of CO2 in 
 the air under examination. In this as in the other cases it will 
 be convenient to use for the testing or collecting the air large 
 dry bottles with accurately fitting stoppers. After the air has been 
 pumped in, then 50 c.c. of the clear baryta water are added, the 
 stopper inserted and the liquid well distributed in the bottle, by 
 shaking ; after a quarter of an hour or longer the contents are trans- 
 ferred to a stoppered cylinder, allowed to stand excluded from the 
 air until the carbonate is completely settled, and then 25 c.c. of the 
 clear liquid removed by a pipette and the alkalinity determined. 
 
 Lime water may be used instead of baryta water ; a modification 
 of the method also consists in filtering, with special precautions to 
 prevent the farther absorption of COj, the barium carbonate off, 
 converting it into sulphate by adding a sufficient quantity of 
 sulphuric acid, igniting and weighing ; one part of barium sulphate 
 is equivalent to 'ISQl of COj. 
 
 (63) Ustimation of Carton Monoxide, CO. 
 
 It is much to be regretted there is no easy or household test for 
 the presence of this dangerous gas. The best qualitative test is 
 probably that of Vogel : a drop of blood is diluted with water, and 
 the reddish liquid shaken up in a bottle with the air to be ex- 
 amined ; the liquid is then examined by the spectroscope, and the 
 position of the bands on the scale noted ; a little ammonium 
 sulphide is now added ; if carbon monoxide is present, the spec- 
 trum will undergo no change. The test is said to detect 'OS per 
 cent. 
 
 If a greater quantity of the gas in the air is present than a mere 
 trace, the air, shaken up with a solution of the double chloride of 
 palladium and sodium will produce a black precipitate in the 
 solution, and the quantity present may be approximately estimated 
 by acting on a similar bulk of the solution with air containing 
 known quantities of CO, on similar principles to those detailed at 
 page 98, under the head of " Nephalometric Methods." Before 
 
VIII.] PRACTICAL EXAMINATION OF AIR. 103 
 
 raakiBg the test, sulphuretted hydrogen should be absorbed by 
 passing the air through a solution of lead acetate. Larger quanti- 
 ties of CO are detected and estimated by absorption by cuprous 
 chloride. A solution of cuprous chloride in strong hydrochloric 
 acid absorbs readily CO, forming Berthelot's compound, in which 
 one molecule of CO is united with one molecule of cuprous chloride ; 
 on dilution of the cuprous chloride solution, which has absorbed 
 CO with water, and addition of the double salt of palladium and 
 sodium, there is a black precipitate of palladium. 
 
 (64) Sulphuretted Hydrogen. 
 
 Hydric sulphide is detected in very small quantities in air by 
 either exposing strips of paper moistened by lead acetate to the 
 air or by drawing the air through a solution of the same salt. If 
 there is only a dark colour, but no precipitate, the amount may be 
 estimated on colorimetric principles — that is, the colour may be 
 imitated by acting on a similar bulk of lead acetate solution by- 
 water containing known quantities of hydric sulphide. 
 
CHAPTER IX. 
 
 HOW TO MEASUEE CUBIC SPACE AND TO REPORT ON 
 VENTILATION. 
 
 (65) GioMc space allowed hy law or hy local regulations. 
 Table XX. 
 
 
 Cubic Space 
 
 
 
 per head.l 
 
 Authority. 
 
 
 Cubic feet. 
 
 
 Board Schools (minimum allowed, new code) 
 
 100 
 
 Educational Dept. 
 
 General Schoolrooms ,, ,, 
 
 130 
 
 London School Board. 
 
 Graded Schools „ „ 
 
 117 
 
 }} > t a 
 
 Dundee Board School, average 
 
 152 
 
 
 Common Lodging House (sleeping rooms) 
 
 300 
 
 Local Govt. Board. 
 
 Kegistered Houses let in Tenements — 
 
 
 
 {a) Rooms used both for sleeping and | 
 living j 
 
 400 
 
 j" Various regulations 
 -j compiled by Local 
 [ Govt. Board. 
 
 
 (J) Rooms used for sleeping only- 
 
 300 
 
 »» jr 
 
 British Army Barracks miuimam 
 
 600 
 
 Army Regulations. 
 
 Prisons, seldom under . 
 
 750-800 
 
 
 Non-textile Workrooms . . 
 
 250 
 
 Factory Act. 
 
 Army Horses (minimum) . . . 
 
 1,600 
 
 Army Regulations. 
 
 „ „ (in Infirmary) 
 
 1,900 
 
 j> )) 
 
 (66) The Ciibe of Rectangular and Triangular Spaces. 
 
 Every sanitary officer should know how to measure cubic 
 space, 
 
 (a) Cubic space of a square or rectangular room. 
 
 This is by far the most common case, the rule being simply to 
 
 ' To obtain roughly the cubic feet per hour it is usual to multiply by five. Thus 
 the Board Schools will give to the scholars only 500 cubic feet per hour, which is an 
 insufficient quantity. 
 
CHAP. IX.] 
 
 MEASUEEMENT OF CUBIC SPACE. 
 
 105 
 
 multiply the three dimensions together — that is, height, length, 
 and breadth. 
 
 For example : a room 10 feet high, 15 long, and 12 broad, has 
 a cubic space of 1,800 cubic feet, for 10 x 12 x 15 = 1,800. 
 
 (b) Cubic space of a room, the upper part of which has a 
 triangular section. 
 
 X 
 
 f 
 
 Fig. 8. 
 
 This may either be a lean-to roof, such as Fig. 7, or any other 
 kind of roof, such as Fig. 8. 
 
 The first process is to obtain the cube of the rectangular space, 
 dhd, next the area of the triangular space, ahe, ■which, when 
 multiplied by the length, gives the cube of that portion of the 
 room, and the two added together make the total cube. 
 
 The area of a triangle, the perpendicular height of which is 
 known (and in rooms the height can always be known), is found 
 by multiplying the base by half the perpendicular height. Thus, in 
 the triangle, ahc. Fig. 7, the base, ah, being 10 feet, and cd being 
 6 feet, the area is 30 feet, for 10 X 3 = 30 ; or, it may be put in 
 another way : multiply base by perpendicular height and divide 
 the product by two. 
 
 Applying this principle to the measurement of a room of which 
 Fig. 8 is a section. Supposing the length is 30 feet, the extreme 
 height, e/, 15 feet, the breadth, cci, 14 feet, and the height of wall, 
 hd, 10 feet, required the cubic space. 
 
 First cube, ahcd, 10 X 30 x 14 = 4,200 ; then get area of 
 triangular space, ahe, which by our rule is half the perpendicular 
 OT, that is, 5 or 2"5, and multiply this by the base, 14 feet, and the 
 product by the length, that is, 30 fee1>— 2-5 x 14 x 30 = 1,050, 
 which, added to 4,200, = 5,250. 
 
 A shorter method of doing this pi-oblem is to consider the 
 sectional area, that of a trapezoid, obtain its area, and then 
 multiply by the length. 
 
106 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 The rule for obtaining the area of a trapezoid is : multiply the sum 
 of the parallel sides by the perpendicular distance between them, and 
 half the product will be the area. The parallel sides in this instance 
 are ac,.ef\ the distance between them is half the breadth, 7 feet; 
 then 10 + 15 X 7 = 175, and 175 X SO = 5,250, the same as before. 
 
 So, again, if a room has either a sectional area, like ahcd. 
 Fig. 9, in which the side ah is parallel to 
 the side dc, measure off a perpendicular 
 de, add the lengths of dc and db together, 
 multiply by the length of the perpendicular 
 de, halve the product and multiply by the 
 length of the room or the height, accord- 
 ing as the trapezoid figure belongs to a Fig. 9. 
 section or' a ground plan. 
 
 Equilateral Triangiilar Spaces. — It is useful to remember' that, 
 although the area of an equilateral triangle can be found by the 
 general rule, in this special case the area can be calculated without 
 measuring off any perpendicular, if one side only is known ; the 
 rule being that the area is equal to half the side squared, and 
 multiplied by the square root of three. 
 
 Since the square root of three is 1"732, another way of putting 
 it is : halve the side, square it, and multiply it by 1'732. An 
 equilateral triangular space, one side of which was 8 feet, would 
 have an area equal to 27"712 square feet. A cupboard in a room 
 having this area, and 10 feet high, would of course cube out as 
 277-12 cubic feet. 
 
 (67) Cubic Space of Booms, the Ground Plan of which is of an 
 irregular Figure. 
 
 In this instance the room may be divided 
 up into triangles, the area of the triangles 
 found and multiplied by the height, or it 
 may be more convenient to consider the 
 area that of a trapezium. The area of a 
 trapezium is found by multiplying the 
 diagonal by the sum of the perpendicu- 
 lars let fall upon it from the opposite 
 angles, and halving the product. Sup- 
 posing, 'for instance, Fig. 10 is the ground plan of a room 12 feet 
 
IX.] MEASUREMENT OF CUBIC SPACE. 107 
 
 high. First of all a diagonal is carefully measured along ac and 
 found to be 30 feet ; perpendiculars are next measured from e and 
 / to the opposite angles, and these are found to be 5 and 7 feet ; 
 required the cubic capacity. 
 
 Here the sum of the perpendiculars is 7 + 5 = 12 ; the area is 
 
 ^ = 180 ; and the cube is 180 x 12 = 2,160. Or, by the 
 
 method of triangles, the base of the triangle acd multiplied by 
 the perpendicular df gives twice area of triangle adc, and the 
 base ac of the triangle ahc multiplied by perpendicular he gives 
 twice triangle area of abc, or 
 
 30 X 7 = 210 
 30 X 5 = 150 
 
 2) 360 
 
 180 
 12 
 
 2160, 
 
 and generally the area of any irregular room may be obtained by 
 dividing it into triangles, and then the cube obtained by multiplying 
 the sum of these areas by the height. 
 
 (68) The Cube of Cylinders, such as pillars. 
 
 It may occasionally happen that in cubing a room the cube of 
 pillars supporting the ceiling will have to be subtracted ; the cubic 
 contents, also, of water mains, of wells and cylindrical cisterns are 
 all calculated on the same principles. 
 
 To cube cylindrical bodies it is necessary to remember a few 
 elementary properties of a circle, and to know how to get the areas 
 of circles. 
 
 The relation of the circumference to the diameter is as 1 is to 
 3"1416, a number which may be perhaps committed to memory 
 better by making the nonsense word tofos — the t standing for the 
 three, the o for the one, the / four, and so on. 
 
 It hence follows that the diameter may be known if the circum- 
 ference is given, and vice versa; for the diameter multiplied by 
 3'1416 gives the circumference, and the circumference divided by 
 3"1416 equals the diameter. 
 
108 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 To obtain the area of a circle the usual way is to square the 
 diameter, and multiply by -7854 ; this number can always be 
 remembered if 3-1416 is remembered, for "7854 is one-fourth of 
 3'1416 ; another method is to divide both circumference and dia- 
 meter by 2, multiply them together, and the result is the area. 
 The cube of a cylinder is of course the area multiplied by its 
 height. 
 
 For instance, take the case of a pillar of two feet diameter and 
 15 feet high. d^x-78o4!xh=cube of pillar, or taking the figures 
 4 X -7854x15 = 47124 cubic feet. Supposing the circumference 
 only of the pillar be given and its height, the process is as in the 
 following example. A pillar is 5-2 feet in circumference, and 
 15 feet high ; required its cube : — 
 
 = diameter that is 1-655 
 
 o'-LtpID 
 
 l-655^x -7854x15 = 32-27, which is the cubic content in feet. 
 
 The area of a sector of a circle is found by getting the area of 
 the whole circle, multiplying it by the number of degrees in the 
 arc, and dividing by 360 ; this will not often be required, save as a 
 preliminary step to obtain area of segment. On the other hand the 
 areas of segments are frequently found ; many bow windows, for 
 instance, are segments of circles, and in order to obtain the cube of 
 the space occupied by a bow window, the ground plan of whicb is 
 less or greater than a semicircle, the first step 
 is to get the area, and then to multiply by the 
 height. 
 
 The area of the sector ahce is first obtained, 
 next the area of the triangle abe, the two areas 
 are then subtracted one from the other, if the 
 segment is less than a semicircle ; or added if 
 greater than a semicircle, this area multiplied 
 by the height gives the cube. Should only the 
 chord (Fig. 11) ah and the height or length cd 
 be given the diameter and the number of degrees must be cal- 
 culated out as follows : — 
 
 Diameter = — '- -f cd 
 cd 
 
 Having got the diameter we know from trigonometry that the sine 
 
IX] 
 
 MEASUREMENT OP CUBIC SPACE. 
 
 109 
 
 asc = — and from a table of sines the angle aec, and therefore 
 ae ^ 
 
 aeb is obtained from this number, the sum of the two angles 
 
 equalling the number of degrees in the arc. For instance,, given 
 
 the chord a& = 8 and cd = 2, ad is | of 8 = 4, and - +2=10, 
 
 therefore the diameter is 10 and radius ae equals 5. The sine of 
 
 4 . 
 
 aec, - = '8, which on reference to a table of sines is equal to 53° 8', 
 o 
 
 and the whole angle in the sector is therefore twice that or 
 
 106° 16', or the area may be found by the following rule : — to | of 
 
 product of chord and height, add the cube of the height divided by 
 
 twice the chord (a6x^/xf) + -5 — t,- -^PP^ji^o these principles to 
 
 practice. In the room of which Fig. 12 is a ground plan the length 
 from a to ^ is 36 feet, the breadth de is 21 
 feet, the distance from /to g is 1"4 feet, and a 
 the height of the room is 12 feet, required 
 the cubic capacity of the whole. First of 
 all the room is cubed, neglecting the bow 
 36 X 21 X 12 = 9,072, the next step is to ob- 
 tain the number of degrees in the sector agh, 
 to get which we want to know the diameter 
 of the circle of which it is an arc, J the chord 
 
 10"5^ 
 ah = lOo, and therefore -^^77 -t- 1'4 = 
 
 1-4 
 
 : 80-15. 
 
 The diameter is then 80'15, and hence the 
 
 radius is 40"075, the sine acq = — that is 
 
 ^ ac 
 
 10'6 
 /•r^.ntj- = 15° 11' nearly. The number of degrees in the arc is there- 
 fore 2 X 15° 11', or 30° 22'. The area of the sector can now be 
 80-152 X -7854 X 30° 22' 
 
 obtained 
 
 360 
 
 425-6, from this area subtract 
 
 the area of the triangle ahc which is | c/ x ah, or 18 X 21 = 378, and 
 425-6 — 378 gives 47-6 as the area of the sector agh, this number 
 multiplied by the height gives the cube 47'6 x 12 = 57l"2, and 
 571-2 + 9,072 gives the total cube of the room as 9,643 cubic 
 feet. 
 
110 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (69) Area of Ellipses. 
 
 The bow windows in some rooms may be in the form of an 
 elliptical curve, and the rule to find the area of an ellipse is, 
 multiply the product of the two diameters by "7854!. If, for instance, 
 in Fig. 12, the bow window is to be considered as half an ellipse, then 
 the major diameter is 21 feet, the minor 1'4 x 2, or 2-8 and 2'8 X 
 21 = 68-8; 58-8 x -7854 = 46-18 this must be halved = 23-09, and 
 the cube of the elliptical bow window is 12 X 23'09, or 277-08. 
 The area of hexagons may be obtained by the general rule, mul- 
 tiply the sum of the sides of the polygon by the perpendicular let 
 fall from its centre upon one of the sides and half the product will 
 be the area. 
 
 For example, in Fig. 13 let ah = 7S feet and op. = 6*5 feet, the' 
 sum of the sides is then 6x73= 44-1, and the area equals 
 44-1 X 6-5 ^^^g.g^ j^ ^^^ ^^^^ ^^ ^ p^j^_ 
 
 gonal pillar or other solid be required, it is 
 of course obtained by multiplying the area 
 by the height. Should the side of a 
 polygon and the number of its sides only be 
 
 fi b given, its area may be obtained by the trig- 
 onometrical formula, area = 7 Xa;^X cot 
 
 4 n 
 
 when n equals the number of sides, and x = the length of one 
 side. For instance, supposing the area of a regular hexagon be 
 required the side of which is 3. The number of sides is of 
 course 6, therefore w = 6 
 
 -; xS^xcot-— r° or - X 3' X cot 30° = 23-38 
 4 6 4 
 
 In this case a still easier way may be adopted, for a hexagon with 
 angles of 30° may be considered as composed of 6 equilateral 
 triangles, the area of one of which may be calculated by the rule 
 already given (page 106), I'S^x^/S, and area of the pol3'gon= 6 X 
 1-52 X V3 = 23-38. 
 
 The solidity of a cone or pyramid is found as follows : -^Mul- 
 
IX.] MEASUREMENT OF CUBIC SPACE. Ill 
 
 tiply the area of the base by the perpendicular height, and 
 J of the product will be the solidity or cubic 
 content. By the aid of this rule the cubic 
 contents of some peculiar shaped roofs 
 may be solved. For instance, let Fig. 
 abcde represent a roof, required the cubic 
 content ; — ab = 80 feet breadtb, ae = 20 feet, 
 dc = 50 feet, and perpendicular height = 10 
 feet, let dgs be a plane section parallel to the end cbp, then dpgs 
 will be a prism, asdg will be a pyramid. Cube of prism 
 ^x 50x20x10 =5,000, cube of pyramid 1x30x20x10 =■ 2,000, 
 total 7,000 cubic feet. 
 
 (70) The Cuie of Bedangular Prismoids aiid Frustums of Cones 
 
 or Pyramids. 
 
 A frustum is a cone or pyramid with its top cut off. In 
 modern built houses there are not infrequently rooms in orna- 
 mental towers, which may be treated as frustums. The rule is 
 to the sum of the areas of the two ends, add four times the 
 area of the middle or mean section parallel to the ends, mul- 
 tiply this sum by the height, and one-sixth will be the solidity. 
 For example, let the figure abche represent a 
 small room the length of the floor along ah /\Z3\. 
 
 is 12 feet, the breadth ae or Ip is 7, and the ///TA 
 
 height is 7 feet, the length of the ceiling is dc /^ I \! \ 
 or fh is 8, and the breadth is .4. Here the area \ / ^ \ \ 
 
 of the floor is 7 X 12 = 84, the area of the ceiling \/ \^ 
 
 is 8 X 4 = 32, the mean section is the half of the "-c^ 
 
 two extreme lengths added together | (12-1-8) 
 
 = 10, multiplied by the half of the top and bottom breadths 
 
 i (7-1-4) =5'5, then by the rule the cube is 
 
 (84+32-1-4 X 10 X 5-5) X 7x^ = 392. 
 
 CuMc Capacity of a Borne. — This may be found by multiplying 
 two-thirds of the product of the area of the base by' the height 
 (area of base x A x |). 
 
112 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 (71) To Find the Cubic Content of Irregular Spaces. 
 
 The cubic content of irregular solids is most conveniently ob- 
 tained by applying Thomas Simpson's formula for finding the area 
 of an irregular curvilinear space. To the sum of the extreme 
 sections add four times the sum of the middle or mean sections, and 
 twice the sum of the given intermediate sections : this sum mul- 
 tiplied by one-third the common 
 distance between any section and 
 the next middle section equals the 
 cubic content. This will be found a 
 useful rule for finding the capacity 
 of old-fashioned drains and similar 
 channels. Thus to borrow an example 
 from Tate's geometry. Eequired the 
 content of a drain, see Fig. 16, whose 
 cross sections taken at 30 feet apart are as follows : the top breadths 
 ah are 4, 3, and 6 feet, the corresponding depths are 3, 2, and 4 
 feet, and the breadth dc at the bottom 2 feet, being the same for 
 every section of the drain. Here the sections are all trapezoids ; 
 hence we have area of 1st section ^ (4 -(- 2) x 3 = 9 ; area of 2nd 
 
 area of 3rd section, ^ (5 -(- 2) x 4 = 14 ; 
 
 section, 4 (3 -H 2) X 2 = 5 
 
 area 1st middle section 
 /3-I-5 
 
 + 2 X ^5- = 6|: area 2nd middle 
 
 section 
 
 ^e 
 
 + 2 X 
 
 2 + 4 
 
 = 9, hence, by the general for- 
 
 2 ' ~ y " 2 
 
 mula, observing 2(^ = 30 .■. d = \o. 
 
 15 r 1 
 
 J |9 +14 + 4(6f+9) + 2x5 I = 482-5 cubic feet. 
 
 Content = 
 
 (72) Example of Reports on Ventilation. 
 
 A report! by ^^g i^te Professor de Chaumont on the ventilation 
 of a barrack room, will serve as an example of the kind of report 
 which should be made by a sanitary officer if in any case he should 
 be called upon to make a detailed and scientific examination of 
 ventilation. 
 
 Ar'/Mj Medical Department Statistical and Sanitary Report, vol. vi., 1864. 
 
IX.] EXAMPLES OF REPORTS ON VENTILATION. 113 
 
 Nov.l5th, 1865, 1a.m., Room 2, G battery, over the stable, intended for 25 men, 
 21 men actually occupying it. Length, 40 feet; breadth, 28 feet; height, 10 '5 
 feet. 
 
 Cubic Feet. 
 Gross cubic space . . . . 11,760 
 
 Deductions . 417 
 
 117343 
 
 which gives for 25 men (11,327 cubic feet), per man, 453 cubic feet; for 21 men 
 (actual number) 540 cubic feet. 
 
 Ventilalion — InUt Acting. ' 
 
 One stove louvre, 130 sijuare inches ; l'-25 X 2'-16 (J taken). Rate of movement 
 not measurable ; no fire. 
 
 Otitlets. 
 Two shafts (10" X 10"), opening obstructed by a board, 4 only taken in conse- 
 quence, rate not measurable . . . . . 50 square inches. 
 One chimney .... 60 ,, ,, 
 Total outlet . . . 110 „ „ 
 
 Inlet . 130 ,, „ 
 
 Total inlet and outlet . . 240 ,, ,, 
 
 This gives for 25 men 9 '6 sq. inches per man ; for 21 men 11 '4 sq. inches ; 
 actual discharge by chimney, 10,433 cubic feet per hour. Very strong smell of 
 stables. 
 
 Area (room space) per man (25 men) ....... 45 square feet. 
 
 (21 men) . 53 
 Total inlet and outlet per man (25 men) 9'6 ,, inches. 
 
 „ „ (21 men) .... 11-4 „ 
 
 Delivery not Measurable. 
 Discharge for 25 men, per man, per hour . . . 417 cubic feel. 
 
 For 21 men, per man, per hour . . . 500 ,, ,, 
 
 Discharge for 25 men, per man, per hour 417 „ ,, 
 
 For 21 men, per man, per hour 500 ,, ,, 
 
 Carbonic Acid. 
 
 First determination , . 1'028 in 1,000 volumes. 
 
 Second „ . . 1-127 
 
 2 )2-155 
 
 Mean ... 1-077 
 
 Dry bulb, 60° -5 ; wet bulb, 59°-5 ; Dew point, 58°-15. Elastic force of vapoui-, 
 •493. "Weight of vapour in a cubic foot of air, 6 -5 grains. Additional weight of 
 vapour required to saturate the air, '4 grain. Humidity (saturation 100) 94. 
 
 At 3-50 a.m. ; Dry bulb, 58°; wet bulb, 56°. Dew point, 54° -2 ; Elastic force 
 of vapour, -421 ; Weight of vapour in a cubic foot of air, 4 -7 grains ; Additional 
 quantity required to saturate the air -7 grain ; Humidity, 87. 
 
 Carbonic Acid. 
 First determination . . . 1227 in 1,000 volumes. 
 
 Second „ . 1-200 
 
 2 )"2"i27 
 Mean . . . . 1-214 
 
 On the 16th November, 11p.m. ; — Smell Close. Carbonic acid 804 in 1,000 
 volumes. Dry bulb, 60° ; wet bulb, 57°. Dew point, 54°-4. Elastic force of vapour, 
 •423. Weight of vapour in a cubic foot of air, 4-77 grains. Additional quantity 
 required to saturate the air, 1 -0 grain. Humidity, 82. 
 
 I 
 
114 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 To briefly indicate how each of the observations are obtained — 
 oubic space and measurement of areas generally by actual measure- 
 ment on principles detailed on pages 104 — 111. 
 
 Movement of air, by an anemometer. The anemometer used 
 for the purpose of ascertaining the velocity of currents of air, 
 essentially consists of small very light mica sails set in a metal 
 frame; these turn on an axis, furnished with an endless screw, 
 which again turns a clock-work train, moving needles, which travel 
 round properly divided circles and register the velocity. Of these 
 anemometers there are various forms, one of the best is made by 
 Mr. Casella, and contains improvements suggested by the late Dr. 
 Parkes. The graduations for each instrument are obtained by 
 actual experiment by means of machinery made for that purpose, 
 so that the indications of all are as comparable with each other as 
 the weight or measure of ordinary substances. 
 
 The indications are shown by means of the large dial and hand 
 and five smaller ones as shown in the annexed plate. The whole 
 
 Fig. 17. 
 
 circumference of the large dial is divided into 100 parts, and re- 
 presents the number of feet up to 100 traversed by the current of 
 air. The five smaller dials are each divided into 10 parts only, 
 one revolution of each being equal to ten of the preceding dial, and 
 represents 1,000, 10,000, 100,000, 1,000,000, and 10,000,000, re- 
 spectively. By means of the large dial, the low velocity of 50 
 
IX.] EXAMPLES OF EEPOETS ON VENTILATION. 115 
 
 feet per minute may be measured, and by the smaller ones con- 
 tinuous registration is extended up to 10,000,000 feet, or equal to 
 1,893 miles, being practically beyond what the most extended ob- 
 servations can require, whilst jewelling in the most sensitive parts 
 insures the utaiost delicacy of action. By moving the small catch 
 a backwards or forwards, the work is put in or out of gear, without 
 affecting the action of the fans ; this prevents the injurious effect 
 of stopping them suddenly, and enables the observer to begin or 
 end his observations to a second. A small handle with universal 
 joint accompanies the instrument, and may be screwed in at the 
 base ; by putting a stick through this, it may be raised or lowered 
 to any required height, and used in any position. A table accom- 
 panies each instrument by means of which allowance may be made 
 for the difference caused by inertia at high and low velocities. 
 
 Carbonic acid, by the method detailed on page 97. 
 
 The dew point, calculated from the difference between the 
 wet and dry thermometers, or obtained directly from Dynes' 
 hygrometer. 
 
 Elastic force of vapour, the number is found, as described at 
 p. 129, opposite the number for the dew point. 
 
 Weight of vapour in a cubic foot of air, is obtained from Table 
 XXIII. p. 133, opposite the dew-point temperature. 
 
 Additional weight required for complete saturation by taking 
 out the number indicating the weight in grains of moisture to 
 completely saturate the air at the temperature of the dry bulb, and 
 then subtracting the weight of vapour already found from the table 
 actually in the air, as shown by the dew-point. 
 
 Humidity from tables or by dividing the weight of vapour 
 actually found by the weight of vapour, which, if the air was 
 saturated, it would have contained, saturation being considered 100", 
 Thus, in the example on page 113 — 
 
 Weight of vapour in cubic foot of air ^-^y x 100 
 
 „ cubic foot of air =-826 
 
 when saturated '^ ' ' 
 
 I 2 
 
SECTION III. 
 METEOROLOGY. 
 
CHAPTER X. 
 
 THE BAROMETER. 
 
 (73) Principle of the Barometer. 
 
 The fundamental principle underlying all barometers in which 
 fluids are used is that the heights of two columns of two 
 fluids are inversely as their specific gravities; air is 10,784 times 
 lighter than mercury, therefore a column of thirty inches of mercury 
 would support an atmosphere five miles high if it were all equally 
 dense. 
 
 A barometer is made by filling a tube of sufficient length closed 
 at one end, with the fluid and inverting it into a cistern of the 
 same fluid. The liquid sinks a certain distance until it is balanced 
 by the atmospheric pressure. Its level then remains within certain 
 limits stationary. If the atmosphere from any cause gets lighter 
 the barometric fluid in the tube falls, in the cistern rises, if the 
 atmospheric pressure increases the barometric fluid rises, that in 
 the cistern falls. The longer the column, the more obvious will 
 be the oscillations. With the knowledge experimentally acquired 
 that mercury of 13 "59 sp. gravity will have when used as a baro- 
 metric fluid a column of about thirty inches, it is easy to calculate 
 the length of the column of any other fluid provided the specific 
 gravity of the fluid is known ; for instance glycerin has a specific 
 gravity of 1'26 required, the length of a barometric column of 
 glycerin. 
 
 As 126 the specific gravity of glycerin: 30 inches :; ]3'59 the 
 specific gravity of mercury = 323 ' 5 inches or 27 feet. 
 
 Water would have a still longer column, alcohol longer still, 
 ether longer than alcohol, for the lighter the liquid the longer the 
 column. 
 
120 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Since a long column is far more sensitive than a short column. 
 Physicists early turned their attention to constructing barometers 
 with water. But water barometers are no longer made, the few 
 which were constructed gave untrustworthy results, mainly from 
 the effect of temperature on the aqueous vapour in the top of the 
 tube and from other causes. 
 
 (74) The Glycerin Barometer. 
 
 The barometer of the future seems decidedly to be the glycerin 
 barometer invented by Mr. Jordan, which has been now for several 
 years in use at Kew. 
 
 The body of the instrument is formed of an ordinary metal gas 
 tube five-eighths of an inch internal diameter, and furnished at 
 the top with a gun metal socket iu which is cemented a glass tube 
 four feet long, inside diameter one inch ; the upper end is formed 
 in the shape of an open cup, and it has fitted into its neck a stout 
 india-rubber stopper. The height of the fluid is observed in this 
 tube, and read by means of brass scales placed on either side of 
 the tube and fitted with indices and verniers, which are moved by 
 means of milled heads placed at the bottom of the scales. 
 
 The cistern is a cylindrical vessel of copper tinned inside, five 
 inches deep and ten inches diameter. It is fitted with a cover screwed 
 on, and air has access through a pinhole in the cap attached to 
 the cover ; the cap has a recess packed with cotton wool, so that 
 the air filters in dust-free. There is an arrangement by which the 
 lower end of the tube can be for temporary purposes closed by a 
 plug. To fill the tube with glycerin, the glycerin, warmed to 100° F., 
 and tinted with aniline, is poured into the cistern, and air sucked 
 out at the top by an air-pump to the full extent to which the 
 glycerin will rise ; the lower end is then stopped with the plug 
 and the rest of the tube filled absolutely full with glycerin. The 
 india-rubber stopper is now inserted and the lower plug withdrawn ; 
 the glycerin now sinks to about 323 inches, and bubbles of air 
 in the course of a day or two find their way up into the vacuum. 
 These are most conveniently removed by applying an air pressure 
 pump to the surface of the fluid in the cistern by making a con- 
 nection with the cap, the upper india-rubber stopper beino- of 
 course temporarily removed. This operation may have to be 
 
X.] 
 
 THE BAROMETER. 
 
 121 
 
 repeated ; lastly, to prevent absorption of water, petroleum speci- 
 ally purified is poured in a layer of about an inch on the top of 
 the glycerin in the cistern. 
 
 Glycerin has a very small coefficient of expansion, according to 
 Reinold -000303 for 1° F. between 32° and 212°; readings have 
 to be corrected for temperature and reduced to sea-level. It may 
 also be desirable to express the readings in terms of the mercurial 
 barometer ; if done by calculation it must be remembered that 
 323 '571 inches equals 30 '3 inches Kew standard; a convenient 
 plan is to have mercury equivalents attached to the scale of the 
 instrument. 
 
 The following is one of the well-known diagrams which appear 
 
 
 
 A.M 
 
 . 
 
 
 
 
 P..M 
 
 
 
 
 M ? 
 
 /ncties 
 
 
 6 
 
 e 
 
 1 
 
 3 ^ 
 
 : 
 
 ' 
 
 £ 
 
 6 
 
 t 
 
 3 IV 
 
 1 £ 
 
 % 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 , 
 
 
 ' 
 
 
 825- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ' 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ' 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ( 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 i 
 
 • 1 
 
 
 
 
 
 
 — 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 — 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 — 
 
 Sun 
 
 
 
 
 
 Su 
 
 shin 
 
 e 
 
 1 
 
 1 
 
 1 
 
 
 
 [Sun 
 Sets 
 
 P.iS€S 
 
 \ 
 
 1 1 
 
 1 1 1 
 
 1 
 
 A.M. 
 
 8 10 M 2 
 A.M. 
 
 P.M. 
 
 Fig. 18. 
 
 daily in the Times, the glycerin values on one side, the mercurial 
 on the other. 
 
 (75) Mercurial Barometers. 
 
 The advantage of the mercurial over the glycerin barometer 
 is its portability and moderate size. It is not every one who cares 
 to have a tube over twenty-seven feet long carried through his 
 rooms, while the length of the mercurial barometer is under three 
 feet. 
 
 The simplest of mercurial barometers is the syphon form. A 
 glass tube is bent in the form of a syphon, the longer limb being 
 
122 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 
 n 
 
 Fig. 19. 
 
 about thirty-two inches in length, the shorter 
 eight or nine inches; to both upper and lower 
 limbs scales are fixed, and the difference of 
 level in the two gives the height of the 
 barometer. 
 
 The best and most accurate form of mercurial 
 barometer is that known as Fortia's; in this 
 what is called the cistern- error is got rid of. 
 When mercury falls in the tube the mercury 
 in the cistern in which the tube is immersed 
 necessarily rises, and if the mercury rises in 
 the tube of course the mercury in the cistern 
 falls: hence there is a constant source of error 
 from the height of the mercury in the cistern 
 varying. In Fortin's there is an inner cistern 
 containing the mercury, the bottom of the cistern 
 is of a flexible material (leather) and by means 
 of a small screw the cistern capacity is either 
 contracted or enlarged, and in this way the' 
 level adjusted before each observation. 
 
 The one figured (Fig. 19) was made by Mr. 
 Casella. The mercury in the cistern is ad- 
 justed at each observation to a fixed ivory point 
 which thus forms the zero of the scale. 
 
 The cistern is made partly of glass, to admit 
 of the zero of the scale being visible, and the 
 mercury is adjustable to the zero or ivory 
 point by means of a thumb-screw acting upon 
 the flexible base. The vernier reads to ■ 002 
 of an inch, or, by estimation, to O'OOl inch, 
 and is adjusted by a rack and pinion motion. 
 In front of the barometer a thermometer is 
 attached, in contact with the tube, with divi- 
 sions etched on the stem. For facility of 
 reading, a slab of white porcelain is placed be- 
 hind the scale. The barometer is mounted in 
 a brass frame, and suspended from a bracket 
 at the top of a mahogany board, so as to insure 
 perpendicularity. At the bottom of the board 
 
X.] 
 
 THE BAROMETER. 
 
 123 
 
 is a socket, with clamping screws for steadying the barometer in a 
 vertical position, when an observation is made. The instrument 
 is so mounted that it can be turned at pleasure to any source 
 of light. 
 
 (76) Reading a Mercurial Barometer. 
 
 The attached thermometer must first be read. Next the cistern 
 error must be got rid of; this is done by the bottom screw, the mer- 
 cury is raised or depressed until it barely touches the ivory point 
 which, with its reflection, will then appear as a double cone. The 
 height of the column is then taken by adjusting the lower edge of 
 the vernier, so that it shall exactly form a tangent to the convex 
 surface of the mercury in the tube just excluding the light from 
 the apex when the eye is in the same plane with 
 the back and front lower edges of the vernier. 
 In adjusting the level in the cistern, the mer- 
 cury should always be screwed up to the cone, 
 and if the point of the cone is submerged the 
 screw must be turned down until it is quite clear 
 of the surface before the final adjustment is 
 made. This precaution is necessary in order to 
 preserve the same form of surface of mercury in 
 the tube at different readings. 
 
 How to Read the, Vernier.- — By means of the 
 annexed diagram, the use of the vernier in 
 insuring accurate measurement is readily un- 
 derstood. C D represents part of the fixed scale 
 of the barometer, and A B is the sliding scale 
 or vernier. The scale C D is divided into inches, 
 tenths, and half-tenths of an inch, so that each 
 division of the scale is "05 ; A B is made equal 
 to 24 divisions of the scale, and is divided into 
 25 equal parts. It follows, therefore, that each 
 division of the vernier is smaller than each 
 division of the scale by the 25th part of 05 ; 
 which is '002 inch. The lower edge of the 
 vernier A, is set to the top of the barometrical 
 column, and hence we have to find the height 
 of A. First we read on the scale, say 2915 ; next we look along 
 the vernier until we find one of its lines which lies evenly with 
 
 
 B 
 
 — 
 
 
 30 
 
 -3- 
 
 
 — 
 
 
 — 
 
 
 — 
 
 
 - 
 
 — 
 
 
 - 
 
 — 
 
 
 
 - 
 
 — 
 
 
 — 
 
 
 — 
 
 
 
 - 
 
 — 
 
 
 — 
 
 
 — 
 
 
 — 
 
 
 % 
 
 — 
 
 
 
 — 
 
 
 29 • 
 
 
 — 
 
 
 
 — 
 
 
 c 
 
 — 
 
 
 c 
 
 Fig. 20. 
 
124 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 a line of the scale. As shown in the figure, this line is the second 
 above 3. Now each of the figures engraved on the vernier counts 
 as hundredths, and each intermediate division counts as two 
 thousandths (-002) ; hence the vernier shows 034, and this added 
 to the scale reading 2915, gives the reading sought, 29184. 
 
 In the Kew pattern barometers the inches on the scale are not 
 really inches, but are so contracted as to thoroughly correct for the 
 variation of the level of the mercury in the cistern. 
 
 In the old barometers this was effected by calculating the so- 
 called " capacity correction ; " in the Fortin barometers it is done 
 by raising or lowering the mercury to the fiducial ivory point, and 
 in the Observatory standard by moving the scales to the mercury. 
 
 The instructions given above for using the Fortin barometer 
 apply equally to the Kew pattern, except that the cistern adjust- 
 ment is unnecessary. 
 
 (77) Correction of Barometer Readings. 
 
 In order to ascertain the true pressure of the atmosphere, and to 
 render comparable observations made in different localities, it is 
 usual to reduce all barometric observations to what they would 
 have been had the instrument been at the temperature of melting 
 ice, and the barometer itself at the mean level of the sea. These 
 corrections are fully explained, and all necessary tables are given in 
 Marriott's Hints to Meteorologieal Observers, and in Scott's Instruc- 
 tions/or the Use of Meteorological Instruments, and in many other 
 meteorological books, but some formulae are given below which 
 may be useful to those who may happen to be without a set of 
 tables or text-book when they wish to reduce their observations. 
 
 A special correction for temperature must be made in the case 
 of barometers of the Kew pattern, a full account of which appears 
 in the Philosophical Magazine for 1861. 
 
 These fortnulse assume that the scale is brass, and also that the 
 expansion of mercury is uniform for the range of temperature em- 
 ployed, whiih latter assumption, though not absolutely true, will 
 give no appreciable error. 
 
 Barometric readings must be reduced to sea-level, and to 32 
 degrees of the Fahrenheit thermometer (0°C.) These are most 
 conveniently obtained from tables, but the principle should be 
 thoroughly understood. 
 
X.] THE BAROMETER. 125 
 
 There is also a correction for capillarity, and one for differences 
 of gravity,^ the latter depending on the latitude, that is the 
 different distances from the centre of the earth. The two latter 
 are neglected save in very refined observations. These correc- 
 tions are simplest when the French system of millimetres is in 
 use. For moderate elevations the following formulae for both the 
 English and metrical barometer are sufficiently accurate. 
 
 (a.) Formula for the reduction of the English barometer to 
 the freezing point and sea-level. 
 
 H = Ah — 
 
 9<-256\ E 
 
 '") 
 
 + , 
 
 100000 7^812'86-l-945i! 
 Where H is the corrected reading in inches. 
 h is the observed reading in inches. 
 t is the temperature in degrees Fahrenheit. 
 E is the elevation of the station above the sea-level 
 in feet. 
 (&.) Formula for the reduction of the metrical barometer to the 
 freezing point and sea-level. 
 
 1,6196/' "•■ 10-54! + 0-41 * 
 Where H is the corrected reading in millimetres. 
 h is the observed reading in millimetres. 
 t is temperature iu degrees centigrade. 
 jE is the elevation of the station above the sea-level in 
 metres. 
 
 (78) The Aneroid Barometer. 
 
 The aneroid barometer is of special value to medical officers of 
 health in country districts, for from its portability it may be used 
 for the determination of heights and contours, matters which are 
 often necessary to know, whether for the purposes of passing 
 judgment on a drainage scheme ; the initiation of a water supply 
 
 ^ The force of gravity is usually symbolised by the letters', at Paris gi = 980 '94 cm, 
 at Greenwich it equals 981 '17. 30 inches or 76 cm. of mercury at Paris represent 
 therefore a little less pressure than at Greenwich. If h equals the height of the 
 mercurial column, d the specific gravity of mercury, the measure of the pressure of 
 air is ghd in absolute units of force ; taking the barometer to be for instance at 
 Greenwich as 76 cm, then 981-17 x 76 x 1.3-596 = 1013800 grms. per square 
 centimetre. The value of g for any latitude I and any height h in centimetres 
 above sea-level may be found from the following formula : — 
 
 g = 980-6056 (1 - -00257 cos 2 2-1-96^ x 10'). 
 
126 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 or for studying the general configuration of the district. Aneroid 
 barometers are now made of very great accuracy, but they must 
 be compared with the standard mercury or glycerin barometer 
 occasionally, otherwise mistakes may occur. 
 
 An aneroid barometer is a thin metallic air-tight box, deeply 
 corrugated to increase its elasticity, from which the air has been en- 
 tirely removed : the upper and lower surfaces of the box are held 
 in a state of tension or separation from each other by means of 
 a strong spring ; the atmosphere pressing with varying intensity 
 on the box, the two walls respond being driven in or relaxed ; 
 this action communicates motion to smaller springs which are 
 connected with a needle on the dial. 
 
 The diminution of pressure in measuring heights with this or 
 any other form of barometer is not 
 equal for equal differences of altitude, 
 but it follows known laws, and altitude 
 scales have been computed, taking the 
 varying ratio between pressure and alti- 
 tude into account, besides this the tem- 
 perature of the air is another cause of 
 variation, for as temperature affects air- 
 density it also affects the ratio of pres- 
 FioTil! sure to altitude. Mr. Rogers Field has, 
 
 however, invented an " Engineering 
 Aneroid " (see Fig. 21) in which there is an adjustable scale for 
 temperature. 
 
 The altitude scale adopted in this aneroid is that of the late 
 Astronomer-Royal (which has been compared with the formulae of 
 Laplace, Guyot, Baily, Plantamour and other authorities, and 
 found to give results lying between them), and as the instru- 
 ment is intended for the accurate measurement of moderate 
 altitudes, the range is purposely limited so as to give au open 
 graduation. The adjustment for the temperature of the air is 
 applied by shifting the scale in accordance with the fic^ures en- 
 graved on the outside of the instrument. The rim which holds the 
 glass should be slightly raised, so as to be free from the locking- 
 pin, and then turned until the figures corresponding to the air 
 temperature are opposite to the pin, when the glass should be 
 depressed so as to re-lock it. 
 
X.] HYGROMETERS. 127 
 
 The process of observation is extremely simple. The first thing 
 is to determine, eitlier by observation or estimation, the air temper- 
 ature likely to prevail during the series of observations : if this is 
 done within 5° it will be sufficiently accurate (within about 1 per 
 cent.). The scale must then be set to this temperature in the 
 manner above explained. Subsequently the readings must be 
 taken from the outer scale of feet, and the difference will give the 
 difference of elevation. The following example, given by the 
 maker, Mr. Casella, of actual observations taken between Hamp- 
 stead and London will explain the proceeding : — 
 
 Temperature of 40° arud scale set accordingly. 
 
 JoiriiNBT TO London : — Feet. 
 
 Reading at Jack Straw's Castle, Hampstead . 1640 
 
 „ ,, Horse Guards, London . 1200 
 
 Difference . 440 
 
 JOUKNEY FROM LONDON : — 
 
 Heading at Horse Guards, London . . 1215 
 
 ,, ,, Jack Straw's Castle, Hampstead . 1640 
 
 Difference . , . 425 
 
 2)865 
 
 432 feet 
 
 The true difference of altitude, according to the Ordnance levels, 
 is 428 feet, showing an error of only four feet. The accuracy of 
 the result will be further increased if the observations are repeated 
 more than once, and the average of the results taken. 
 
 It should be mentioned that the above principle of adjustment 
 can only be correctly applied to aneroids in which the graduation 
 is nearly uniform, and therefore extreme care is taken in the selec- 
 tion of suitable instruments for this purpose. 
 
 (79) Hygrometers. 
 
 An hygrometer is an instrument for ascertaining the amount of 
 vapour in the air. Hygrometers are either constructed on the 
 principle of absorption, of condensation, or evaporation. 
 
 The hair hygrometer of Saussure is an example of absorption ; 
 when the air is damp the hair absorbs moisture and shrinks in 
 size, returning to its original length when dry. 
 
 One of the most accurate and modem of hygrometers is that of 
 Dynes, which acts on the principle of condensation (see Fig. 22). 
 Its indications are obtained with unusual facility by means of a 
 
A MANUAL OF PUBLIO HEALTH. 
 
 [OHAP. 
 
 128 
 
 little water and ice, or cold water only. This is put into the cup 
 A, and allowed to flow gently through the small chamber D, 
 whence it rises through a perforated diaphragm into the space 
 above. In this space rests the bulb of a sensitive thermometer,' 
 the space being covered water-tight by a thin smooth piece of 
 silver or black glass. By turning the tap B the water will flow 
 
 :-3b [i 
 
 -& 
 
 Fro. 22. 
 
 Fig. 23. 
 
 gently from the spout, as shown, thus cooling the cover ; when 
 the temperature reaches the dew-point, a strong film of vapour or 
 dew will be visible, the temperature being shown on the graduated 
 stem of the thermometer (Figs. 22 and 23), either horizontal or 
 vertical form. 
 
 In the vertical form of this hygrometer (Fig. 23) ether may be 
 employed, and a constant supply of it kept in the instrument for 
 use whenever required. 
 
CHAPTER XT. 
 
 THE DEW-POINT — RAINFALL — SUNSHINE — WIND. 
 
 (80) Determination of the Dew-point. 
 
 The dew-point is ascertained indirectly by evaporation by means 
 of two ordinary mercurial thermometers placed under precisely the 
 same conditions, save that in the one " the wet bulb " has its bulb 
 constantly kept moist by being covered with a thin piece of muslin, 
 a thread from which dips into pure distilled water. As the water 
 from the muslin is ever evaporating, the wet bulb always, save 
 when the air is already saturated, gives a lower reading than the 
 dry ; and from the difference between the two readings the dew- 
 point can be ascertained by means of tables or by calculation. 
 
 From these observations the following may be ascertained : — 
 (1) The dew-point ; (2) the elastic force of vapour, or the amount 
 of the barometric pressure due to the vapour present in the atmo- 
 sphere ; (3) the quantity of vapour in a cubic foot of air ; (4) the 
 additional vapour required to saturate a cubic foot of air; (5) the 
 relative humidity ; and (6) the weight of a cubic foot of air at the 
 pressure prevailing when the observation is made. 
 
 The formula for reduction, when the reading of the wet bulb is 
 above 32°, is 
 
 ■^ 88 ^ 30' 
 when the wet bulb is below 32° the formxxla is 
 
 -^ 96 30' 
 
 /is obtained from Regnault's determinations tabulated in Table 
 XXI. 
 
 K 
 
130 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 The dew-point is found from F by using Table XXI. reversely, >nd 
 
 finding the temperature opposite the elastic force calculated. To 
 
 borrow an example from Buchan's Meteorology. Suppose the dry 
 
 bulb to read 50°, and the wet 45°, barom. 29 inches, then/= '299 
 
 inch (from Table XXL); «^ = 50° - 4-5° = 5° ; and A = 29 inches. 
 
 Hence, 
 
 5^ 29 
 
 88 ^ 30 
 
 F =-- -299 
 
 = •244 
 
 from Table XXI., the temperature opposite "244 is seen to be 39-7°, 
 which is therefore the dew-point. A more convenient method of 
 calculation is to use Glaisher's factors, in which, by simple multi- 
 plication of the difference between the dry and wet bulbs, and 
 subtracting the product from temperature of the dry bulb, the 
 dew-point is found (see Table XXII.). For instance, in the above 
 example the dew-point would be found as follows : — 
 
 The factor opposite the dry-bulb (temperature 50°) is 2'06, the 
 difference between the two thermometers is 5°; 2'06 x 5 = 10'3, 
 and 10-3 - 50° = 397°. 
 
 The relative humidity of the air is calculated on the assumption 
 
 that dry air = 0, and absolutely saturated air = 100. It is found 
 
 % dividing the elastic force corresponding to the temperature of 
 
 the dew-point by the elastic force corresponding to the temperature 
 
 of the air, and multiplying the quotient by 100. For example, 
 
 •244 is the elastic force at 39-7° ; at 50° it is -361. Then 
 
 •244 
 77-KT X 100 = 676, or in round numbers 68 ; 68 is therefore the 
 
 00 -L 
 
 relative humidity. 
 
 Table XXI. 
 
 Showing the Elastic Force of Aqueous Vapour in Inches of Mercury 
 FROM 0° TO 80". Calculated from Regnault's Data. 
 
 Temp. 
 
 Force of vax:tour. 
 
 Temp, 
 
 Force of vapour 
 
 Temp. 
 
 Force of vapour. 
 
 
 
 ineli. 
 
 
 
 inch. 
 
 
 
 inch. 
 
 
 
 ■044 
 
 5 
 
 ■054 
 
 10 
 
 •068 
 
 1 
 
 •046 
 
 6 
 
 •057 
 
 11 
 
 •071'' 
 
 2 
 
 •048 
 
 7 
 
 •060 
 
 12 
 
 •074 
 
 3 
 
 •050 
 
 8 
 
 •062 
 
 13 
 
 •078 
 
 4 
 
 ■052 
 
 9 
 
 •065 
 
 14 
 
 •082 
 
XI.] 
 
 THE DEW-POINT. 
 
 131 
 
 
 Table XXI. 
 
 {continued) 
 
 
 
 Temp. 
 
 Force of vapour. 
 
 Temp. 
 
 Force of vapoui-. 
 
 Temp. 
 
 Force of vapour. 
 
 
 
 inch. 
 
 
 
 inch. 
 
 
 
 inch. 
 
 15 
 
 •086 
 
 39^7 
 
 •244 
 
 51 ■O 
 
 •374 
 
 16 
 
 •090 
 
 40^0 
 
 ■247 
 
 51 ^3 
 
 ■378 
 
 17 
 
 •094 
 
 40^3 
 
 ■250 
 
 51-5 
 
 ■381 
 
 18 
 
 •098 
 
 40^5 
 
 ■252 
 
 61^7 
 
 •384 
 
 19 
 
 •103 
 
 40^7 
 
 •254 
 
 52-0 
 
 •388 
 
 20 
 
 •108 
 
 41^0 
 
 •257 
 
 52^3 
 
 •393 
 
 21 
 
 •113 
 
 41^3 
 
 •260 
 
 52^5 
 
 •396 
 
 22 
 
 •118 
 
 41^5 
 
 •262 
 
 52^7 
 
 •399 
 
 23 
 
 •123 
 
 41-7 
 
 •264 
 
 53-0 
 
 •403 
 
 24 
 
 •129 
 
 42^0 
 
 •267 
 
 53 3 . 
 
 •407 
 
 25 
 
 •135 
 
 42^3 
 
 •270 
 
 63^5 
 
 •410 
 
 26 
 
 •141 
 
 42^5 
 
 •272 
 
 53^7 
 
 •413 
 
 27 
 
 •147 
 
 42^7 
 
 •274 
 
 54-0 
 
 •418 
 
 28 
 
 •l.-iS 
 
 43^0 
 
 •277 
 
 54 ■S 
 
 •422 
 
 29 
 
 •160 
 
 43^3 
 
 •280 
 
 54^5 
 
 •425 
 
 29-5 
 
 •163 
 
 43 ■S 
 
 •283 
 
 54^7 
 
 ■428 
 
 30-0 
 
 •167 
 
 43^7 
 
 •285 
 
 55^0 
 
 ■433 
 
 30-5 
 
 •170 
 
 44-0 
 
 ■288 
 
 55^5 
 
 ■441 
 
 31-0 
 
 •174 
 
 44^3 
 
 •292 
 
 56^0 
 
 •449 
 
 31-5 
 
 •177 
 
 44^5 
 
 •294 
 
 56^5 
 
 •457 
 
 32-0 
 
 •181 
 
 44^7 
 
 •296 
 
 57^0 
 
 ■465 
 
 32-5 
 
 •184 
 
 45-0 
 
 •299 
 
 57^5 
 
 •473 
 
 33-0 
 
 •188 
 
 45^3 
 
 •303 
 
 58-0 
 
 •482 
 
 33-5 
 
 •192 
 
 45^5 
 
 •305 
 
 59^0 
 
 •500 
 
 34-0 
 
 •196 
 
 45^7 
 
 •307 
 
 60-0 
 
 •518 
 
 34-5 
 
 •199 
 
 46 
 
 •311 
 
 61 ■O 
 
 •537 
 
 35-0 
 
 ■204 
 
 46^3 
 
 •315 
 
 62-0 
 
 •556 
 
 35-3 
 
 •206 
 
 46 ■S 
 
 •317 
 
 63^0 
 
 ■576 
 
 35-5 
 
 ■208 
 
 46^7 
 
 •319 
 
 64-0 
 
 ■596 
 
 35-7 
 
 •209 
 
 47^0 
 
 •323 
 
 65^0 
 
 ■617 
 
 36-0 
 
 •212 
 
 47^3 
 
 ■327 
 
 (i6^0 
 
 ■639 
 
 36-3 
 
 •214 
 
 47^5 
 
 •329 
 
 67^0 
 
 ■661 
 
 36-5 
 
 •216 
 
 47^7 
 
 •331 
 
 68-0 
 
 ■684 
 
 36-7 
 
 •218 
 
 48 
 
 •335 
 
 69^0 
 
 ■708 
 
 37-0 
 
 •220 
 
 48-3 
 
 •339 
 
 70^0 
 
 ■733 
 
 37-3 
 
 •223 
 
 48^5 
 
 •342 
 
 71 ■O 
 
 ■759 
 
 37-5 
 
 •225 
 
 48^7 
 
 •344 
 
 72^0 
 
 •785 
 
 37-7 
 
 •226 
 
 49^0 
 
 •3i8 
 
 73 ■O 
 
 ■812 
 
 38-0 
 
 •229 
 
 49^3 
 
 •352 
 
 74^0 
 
 ■840 
 
 38-3 
 
 •231 
 
 495 
 
 ■355 
 
 75-0 
 
 ■868 
 
 38-5 
 
 •233 
 
 49^7 
 
 •357 
 
 76^0 
 
 ■897 
 
 38-7 
 
 •235 
 
 50^0 
 
 •361 
 
 77^0 
 
 ■927 
 
 39-0 
 
 •238 
 
 50^3 
 
 ■365 
 
 78^0 
 
 ■958 
 
 39-3 
 
 •240 
 
 60-5 
 
 ■367 
 
 79^0 
 
 ■990 
 
 39-5 
 
 ■242 
 
 50-7 
 
 ■370 
 
 80^0 
 
 1^023 
 
 K 2 
 
132 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 Table XXII. 
 
 Faotoes foe Multix'lying the Excess of the Dry Bulb Thermometer over 
 THAT of the Wet Bulb, to pinjd the Exce.ss of the Temperature of 
 THE Air above that op the Dew-Point. 
 
 Dry bulb 
 thefmometer. 
 
 Factor. 
 
 Dry bulb 
 thermometer. 
 
 Factor. 
 
 Dry bulb 
 thermometer. 
 
 Factor. 
 
 10 
 
 8 
 
 78 
 
 40 
 
 2-29 
 
 7°0 
 
 
 77 
 
 11 
 
 8 
 
 78 
 
 41 
 
 2-26 
 
 71 
 
 
 76 
 
 12 
 
 8 
 
 78 
 
 42 
 
 2-23 
 
 72 
 
 
 75 
 
 13 
 
 8 
 
 77 
 
 43 
 
 2-20 
 
 73 
 
 
 74 
 
 14 
 
 8 
 
 76 
 
 44 
 
 2-18 
 
 74 
 
 
 73 
 
 15 
 
 8 
 
 75 
 
 45 
 
 2-16 
 
 75 
 
 
 72 
 
 16 
 
 8 
 
 70 
 
 46 
 
 2-14 
 
 76 
 
 
 71 
 
 17 
 
 8 
 
 62 
 
 47 
 
 2-12 
 
 77 
 
 
 70 
 
 18 
 
 8 
 
 50 
 
 48 
 
 2-10 
 
 78 
 
 
 69 
 
 19 
 
 8 
 
 34 
 
 49 
 
 2-08 
 
 79 
 
 
 69 
 
 20 
 
 8 
 
 14 
 
 60 
 
 2-06 
 
 80 
 
 
 68 
 
 21 
 
 7 
 
 88 
 
 51 
 
 2-04 
 
 81 
 
 
 68 
 
 22 
 
 7 
 
 60 
 
 52 
 
 2-02 
 
 82 
 
 
 67 
 
 23 
 
 7 
 
 28 
 
 63 
 
 2-00 
 
 83 
 
 
 67 
 
 24 
 
 6 
 
 92 
 
 54 
 
 1-98 
 
 84 
 
 
 66 
 
 25 
 
 6 
 
 53 
 
 65 
 
 1-96 
 
 85 
 
 
 65 
 
 26 
 
 6 
 
 08 
 
 56 
 
 1-94 
 
 86 
 
 
 65 
 
 27 
 
 5 
 
 61 
 
 67 
 
 1-92 
 
 87 
 
 
 64 
 
 28 
 
 5 
 
 12 
 
 68 
 
 1-90 
 
 88 
 
 
 64 
 
 29 
 
 4 
 
 63 
 
 69 
 
 1-89 
 
 89 
 
 
 63 
 
 30 
 
 4 
 
 15 
 
 60 
 
 1-88 
 
 90 
 
 
 63 
 
 31 
 
 3 
 
 70 
 
 61 
 
 1-87 
 
 91 
 
 
 62 
 
 32 
 
 3 
 
 32 
 
 62 
 
 1-86 
 
 92 
 
 
 62 
 
 33 
 
 3 
 
 01 
 
 63 
 
 1-85 
 
 93 
 
 
 61 
 
 34 
 
 2 
 
 77 
 
 64 
 
 1-83 
 
 94 
 
 
 60 
 
 35 
 
 2 
 
 60 
 
 66 
 
 1-82 
 
 95 
 
 
 60 
 
 36 
 
 2 
 
 50 
 
 66 
 
 1-81 
 
 96 
 
 
 59 
 
 37 
 
 2- 
 
 42 
 
 67 
 
 1-80 
 
 97 
 
 
 59 
 
 38 
 
 2 
 
 36 
 
 68 
 
 1-79 
 
 98 
 
 
 68 
 
 39 
 
 2-32 
 
 69 
 
 1-78 
 
 99 
 100 
 
 
 68 
 57 
 
XL] 
 
 RAINFALL. 
 
 133 
 
 Table XXIII. 
 
 Weight in Gkains of a Cnsio Foot op Vapour, tindeii the Phesstjbe of 
 30 Inches of Meeouky fob evbby Degree of Temperature from 0° to 
 100°. The TempekAture is the Dew-Point, and the "Weight of Vapour 
 IS THE Weight which can be Sustained at that Temperature without 
 BECOMING Visible. 
 
 
 Weight in 
 
 
 Weight in 
 
 
 Weight in 
 
 Temp. F. 
 
 grains of a 
 cubic foot 
 
 _Iemp. F. 
 
 grains of a 
 cubic foot 
 
 Temp. F. 
 
 grains of a 
 cubic foot 
 
 
 of vapour. 
 
 ^ 
 
 of vapour. 
 
 
 of vapour. 
 
 32 
 
 2-13 
 
 55 
 
 4-87 
 
 7°8 
 
 10-31 
 
 33 
 
 2-21 
 
 56 
 
 5-04 
 
 79 
 
 10-64 1 
 
 34 
 
 2-30 
 
 57 
 
 5-21 
 
 80 
 
 10-98 
 
 35 
 
 2-48 
 
 58 
 
 5-39 
 
 81 
 
 11-32 
 
 36 
 
 2-48 
 
 59 
 
 6-58 
 
 82 
 
 11-67 
 
 37 
 
 2 -.57 
 
 60 
 
 577 
 
 .83 
 
 12-03 
 
 38 
 
 2-66 
 
 61 
 
 5-97 
 
 84 
 
 12-40 
 
 39 
 
 276 
 
 62 
 
 6-17 
 
 85 
 
 1278 
 
 40 
 
 2-86 
 
 63 
 
 6-38 
 
 86 
 
 13-17 
 
 41 
 
 2-97 
 
 64 
 
 6-59 
 
 87 
 
 13-57 
 
 42 
 
 3-08 
 
 65 
 
 6-81 
 
 88 
 
 13-98 
 
 43 
 
 3-20 
 
 66 
 
 7-04 
 
 89 
 
 14-41 
 
 44 
 
 8-32 
 
 67 
 
 7-27 
 
 90 
 
 14-85 
 
 45 
 
 3-44 
 
 68 
 
 7-51 
 
 91 
 
 15-29 
 
 46 
 
 3-56 
 
 69 
 
 776 
 
 92 
 
 1574 
 
 47 
 
 3-69 
 
 70 
 
 8-01 
 
 93 
 
 16-21 
 
 48 
 
 3-82 
 
 71 
 
 8-27 
 
 94 
 
 16-69 
 
 49 
 
 3-96 
 
 72 
 
 8-54 
 
 95 
 
 17-18 
 
 50 
 
 4-10 
 
 73 
 
 8-82 
 
 96 
 
 17-68 
 
 51 
 
 4-24 
 
 74 
 
 9-10 
 
 97 
 
 18-20 
 
 52 
 
 4-39 
 
 75 
 
 9-39 
 
 98 
 
 1873 
 
 63 
 
 4-55 
 
 76 
 
 9-69 
 
 99 
 
 19-28 
 
 54 
 
 471 
 
 77 
 
 9-99 
 
 100 
 
 19-84 
 
 (81) Measurement of Rain — Bain Gauges. 
 
 A rain gauge may be constructed of any open vessel of known 
 area, the rain collected being afterwards measured in a common 
 ounce measure. A fluid ounce contains 1-733 cubic inch of water. 
 An easy calculation will then sho-w how much this is per square 
 inch of surface. 
 
 Accurate observations can however only be made by having 
 a proper rain gauge, as represented in the diagram (see Fig. 24), 
 which is what is known as the " Meteorological OfEce Rain Gauge." 
 It has a high rim to secure the more correct measurement of snow 
 
134 
 
 A MANUAL OP PUBLIC HEALTH. 
 
 [chap. 
 
 In this is a funnel directing the rain into a graduated glass vessel, 
 (Fig. 25), by the aid of which the rainfall is estimated directly. 
 
 Mainly through the efforts of Mr. G. J. Symons, F.R.S., the 
 great practical importance of an accurate knowledge of the amount 
 of rain falling in different localities has been increasingly recog- 
 nized during the last twenty-five years. The general result of 
 experiments has been to show that the size of the gauge is not 
 very important, but that practically from 3 to 8 inches in diameter 
 is the most expedient. In exposed positions 5-inch gauges collect 
 i-ather too little ; for such stations 8-inch gauges are therefore 
 
 Fig. 24. 
 
 Fig. 25. 
 
 preferable. If the orifice of a gauge be nearly level with the 
 ground it will collect an undue amount, as the water will splash in 
 off surrounding grass, leaves, or soil ; on the other hand, if the 
 gauge be raised above the ground, it will collect less the higher it 
 is raised. It has therefore been decided that the orifice should in 
 all cases be 1 foot above the surface of the ground. 
 
 Mr. Symons' rules as to placing rain gauges are as follows : — 
 Rules for Observers. — A rain gauge should not be set on a slope 
 or terrace, but on a level piece of ground, at a distance from shrubs, 
 trees, walls, and buildings— at the very least as many feet from 
 their base as they are in height. Tall-growing flowers, vegetables, 
 and bushes must be kept away from the gauge. If a thoroughly 
 clear site cannot be obtained, shelter is most endurable from N.W. 
 
XI.] RAINFALL. 135 
 
 N., and E., less so from S., S.E., and W., and not at all from S.W. 
 or N.E. 
 
 The funnel of a rain gauge must be set quite level, 1 foot 
 above ground, and so fixed by three or four pegs that it will 
 remain firm in spite of any gale of wind. 
 
 The gauge should be emptied regularly each day, at 9 a.m., and 
 the amount then measured entered to the day before that of 
 measurement. 
 
 The measurement simply consists in emptying the contents of 
 the bottle into the glass measure, which must be held upright, and 
 noting the number of the division to which the water rises. Each 
 division equals one hundredth of an inch; the fifty divisions, there- 
 fore, equal half an inch — that is to say, one division should be 
 entered as '01; 25 as "25; and 50, or half an inch, as ■50; of 
 course, if there is more than that, it must be measured separately ; 
 for instance, twice full up to the 50 and once to the 6 would be 
 
 •50 
 
 •50 
 
 1"06 or one inch and six hundredths. 
 
 The amount should always be written down before the water is 
 thrown away. 
 
 All columns should be cast up twice. When there is no rain, a 
 line should be drawn rather than cyphers inserted. 
 
 When very heavy rains occur, it is desirable to measure on their 
 termination, and enter the particulars as remarks, and it will be 
 found a safe plan after measuring to return the water to the gauge, 
 so that the morning registration will not be interfered with. Of 
 course, if there is the slightest doubt as to the gauge holding 
 all that falls, it must be emptied, the amount being previously 
 written down. 
 
 In snow, melt what is caught in the funnel and measure that as 
 rain, and select a place where the snow has not drifted, measure 
 with a rule the average depth, and enter it in the remarks. 
 
 A fall of rain measuring the tenth of an inch in depth, corre- 
 sponds to the deposit of 2,262 gallons, or about 40 hogsheads, or 
 10 tons weight of water per acre. 
 
136 
 
 A MANUAL OF PUBLIC HEALTH 
 
 [chap. 
 
 Bainy days. — In recording meteorological observations it is of 
 value to know the number of rainy days in any particular place, 
 the accepted definition of a rainy day is a day on which falls at 
 least '01 inch of rain. 
 
 (82) Registration of Stmlight. 
 
 In the interests of health the number of hours direct sunshine 
 that falls on any particular locality is perhaps more important 
 than any other single factor. 
 
 Fig. 26. 
 
 The registration of sunlight of late years has been simplified by 
 the invention of several ingenious appliances. One of the best of 
 these is the Whipple-Cassella universal sunshine recorder (see 
 Fig. 26). 
 
XI.] WIND ANEMOMETERS. 137 
 
 A strip of cardboard is arranged so that the sun's rays, concen- 
 trated to a focus by a large spherical lens, shall trace a charred line 
 on it when they are unobscured by cloud or mist. The instrument 
 is universal, having divided latitude and diurnal circles, and thus 
 can be easily set for any locality and for any day in the year. 
 
 The sunshine is best expressed in percentages of the possible 
 sunshine, if for instance the sun is above the horizon for ten hours 
 and the record is but one hour, then the sunshine received is 
 obviously 10 per cent. 
 
 (83) Wind Anemometers. 
 
 An Anemometer for the purpose of estimating currents of air 
 has been already noticed in speaking of ventilation ; such a delicate 
 instrument as there described would not be suitable for registering 
 the force or velocity of the wind. The public observatories use for 
 the most part Robinson's and Osier's anemometers, the one 
 registering the swiftness of the air current, the other the pressure. 
 
 Robinson's anemometer consists of four metallic cups screwed on 
 to the ends of two horizontal iron rods crossing each other at right 
 angles and supported on a vertical axis which turns freely. A train 
 of clock work is connected with the revolving axis by means of an 
 endless screw, and the number of revolutions is recorded on the 
 dial. 
 
 Osier's anemometer essentially consists of a plate a foot square 
 kept perpendicular to the wind by means of a vane ; the board has 
 attached to it a spiral spring to which an index showing the degree 
 of pressure is attached ; by a mechanical arrangement this pressure 
 is recorded by a pencil. 
 
 The velocity of the wind can be approximately calculated from 
 the pressure and conversely by the following formula : — 
 
 Pressure = V^ x 'OOo and velocity = ^y 200 >' P. 
 
SECTION IV. 
 WATER SUPPLY. 
 
CHAPTEE XII. 
 
 SOUKCES OF WATER SUPPLY. 
 
 In a few cases a water supply is obtained by distilling sea water, 
 such as for instance in the small towns in some parts of Peru where 
 rain never falls and where there are no other sources of supply, 
 but leaving this quite exceptional instance, the sources of supply 
 for the main part fall under the three following heads: — I. Rivers; 
 II. Lakes; and III. Wells. 
 
 (84)) I. Rivers. 
 
 The word naturally includes all running water, whether from 
 springs or streams. The ordinary flow of rivers depends upon 
 springs or other underground drainage, it is only in times of flood 
 that surface waters find their way into the channel. In but very 
 few instances is a stream pure enough to be used directly; it 
 generally has to be stored and filtered. In the majority of instances 
 a water supply from a river can be led into a storage reservoir 
 without pumping, that is by gravitation alone, provided the intake 
 is placed far enough up the river. In other instances pumping 
 must be resorted to. 
 
 (85) II. Wells. 
 
 Wells are either surface, or deep wells or artesian wells. 
 
 A surface well may yield water which comes from a considerable 
 depth, but it is generally merely rain and subsoil water mixed with 
 more or less of the soluble matters of the soil dissolved ; occasion- 
 ally surface wells are very pure. In some parts of Devonshire, for 
 example, surface wells yield water containing but two or three 
 grains of mineral and an unweighable quantity of organic matter. 
 
142 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Deep wells are derived from springs. A spring is a How of water 
 which essentially depends upon the following conditions. A per- 
 meable stratum crops up on the surface of the ground, resting upon 
 an impermeable stratum ; rain falling upon the permeable stratum 
 percolates through until it is stopped by the impermeable stratum. 
 If the stratum again crops up at a lower level the spring there 
 bursts forth, if this does not happen, the water is stored up as in 
 a reservoir, and can be reached by sinking a well. 
 
 Wells are therefore sunk through impervious strata into pervious 
 strata, the water in the latter being confined bj^ impervious strata 
 below. Imagine a sheet of india-rubber, and on the sheet a thick 
 layer of sand, and above a layer of putty or some other doughy 
 material, if water is now made to pass into the sand it is confined 
 between the two layers, the under one preventing the water 
 running away, the upper preventing evaporation ; this is an illus- 
 tration of most of the water-bearing stratum into which wells are 
 sunk. 
 
 (86) Artesian Wells. ^ 
 
 These are tube wells often sunk to a very great depth. The 
 most common and successful artesian wells have been sunk into 
 the chalk. 
 
 From many of the artesian wells the water rises above the 
 mouth in a stream, and pumping machinery is unnecessary. Thus 
 the new La Chapelle well sunk in the Paris basin has a depth of 
 720 metres and the water rises 35 metres above the mouth. This 
 well furnishes 6,000 cubic metres in 24 hours. It is even proposed 
 to utilize this force to drive a dynamo for the production of 
 electricity. At Ponce de Leon, Florida, the water from an artesian 
 well drives a turbine wheel and dynamo, and by means of this 
 motive force the hotel is lit by electricity. In other cases the- 
 water has to be pumped to the surface. 
 
 (87) III. Lakes. 
 
 When lakes are used as reservoirs for the supply of large towns, 
 
 the enormous quantity of water drawn off might lower the water 
 
 in the lake and so injure various vested rights ; to obviate this, the 
 
 water-level in the lake has to be raised by heightening the barrier 
 
 1 The word "Artesian " is deriYed from " Artois '' a place where the first Artesian 
 well is said to have been sunk. 
 
XII.] 
 
 WATEK-SUPPLY. 
 
 143 
 
 at its outlet, the height to which this barrier has to be raised 
 depends -wholly upon the area of the lake and the quantity likely to 
 be drained from it. Loch Katrine, 3;000 acres in area, only required 
 the barrier to be raised 4 feet, in order that with a maximum 
 lowering of 7 feet, it might provide a storage of 5,687 million 
 gallons for a supply of 50 million of gallons per day. Thirlmere, 
 which is to supply Manchester, has an area of 350 acres, and the 
 barrier has to be raised 50 feet in order to furnish a storage of 8,100 
 million gallons for a similar daily supply. 
 
 (88) Quantity of Water per Head. 
 
 The actual quantity per head supplied to towns varies within 
 very wide limits. The following interesting table is given by the 
 late Major Bolton, based upon Sir J, W. Bazalgette's figures : — 
 
 Table XXIV. 
 
 Showing Consumption Pee Head or the Population. 
 
 
 Galls, per head. 
 
 
 Galls, per head. 
 
 Alexandria 
 
 18—20 
 
 Madrid . . . 
 
 3-3 
 
 Amsterdam 
 
 11—15 
 
 Marseilles . 
 
 158-4 
 
 Adelaide . . 
 
 50 
 
 Montreal 
 
 60 
 
 Athens 
 
 21—56 
 
 Munich . . 
 
 33 
 
 Baltimore . . . 
 
 54 
 
 Naples . . . 
 
 15-4 
 
 Barcelona . . 
 
 7—14 
 
 New York . . 
 
 60-9 
 
 Berlin ... 
 
 13-3 
 
 Ottawa 
 
 102-5 
 
 Bombay . . . 
 
 20 
 
 Paris .... 
 
 . . 36 
 
 Boston 
 
 73-3 
 
 Pernambuco . 
 
 7-3 
 
 Brisbane 
 
 . . 33-5 
 
 Pesth . . 
 
 33 
 
 Buenos Ayres 
 
 20 
 
 Philadelphia . 
 
 54-15 
 
 Buda . . 
 
 12-5 
 
 Pietermaritzburg 
 
 44 
 
 Cairo . 
 
 . . 11 
 
 Riga . . . 
 
 31 1 
 
 Calcutta . . 
 
 2-2 
 
 Rio . . 
 
 30 
 
 Chicago . . . 
 
 102-5 
 
 Rome . ... 
 
 160-38 
 
 Christiana 
 
 39-7 
 
 Rotterdam . . 
 
 22-45 
 
 Copenhagen . 
 
 . . . 13-9 
 
 Rouen 
 
 30-8 
 
 Delhi . . 
 
 16 
 
 San Francisco . 
 
 64-5 
 
 Dresden . 
 
 14-96 
 
 St. Petersbm-g 
 
 21-3 
 
 Durban . 
 
 2 
 
 St. Jago . 
 
 5-6 
 
 Frankfort . . . 
 
 24 
 
 Seville .... 
 
 7-26 
 
 Genoa . . 
 
 . 24-5-94-76 
 
 Stockholm 
 
 ;3-5 
 
 Hague . 
 
 17-6 
 
 Stuttgart 
 
 26-4 
 
 Hamburg . . . 
 
 45-5 
 
 Sydney . . 
 
 . . 25 
 
 Hanover . . 
 
 15-09 
 
 Toronto . . . 
 
 82 
 
 Hongkong . . 
 
 5-18 
 
 Trieste . . . 
 
 . . -4-4 
 
 Kurrach§e . 
 
 . . 25 
 
 Valparaiso . 
 
 20 
 
 Lahore . . 
 
 10 
 
 Venice . 
 
 8 
 
 Lu Lausanne 
 
 . . . 126 
 
 Vienna 
 
 13-2—19-8 
 
 Liege 
 
 . 16-5—30 
 
 Washington 
 
 143 
 
 London . . 
 
 31-25 
 
 
 
144 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 The quantity required for a town supply is stated usually as 
 
 follows : — 
 
 Table XXV. 
 
 
 Gallons per day per Inhabitant. 
 
 Least. 
 
 Average. 
 
 Greatest. 
 
 Water req^uired for domestic purposes . 
 Public purposes, i.e. for washing streets, 
 
 extinguishing fires, flushing sewers, &c. 
 Trade and manufacturers ... 
 
 Waste about . 
 
 Total 
 
 7 
 
 3 
 
 7 
 
 10 
 
 3 
 
 7 
 
 15 
 
 3 
 
 7 
 
 2 
 
 2 
 
 2 
 
 19 
 
 22 
 
 27 
 
 It is impossible to give a large daily supply of water to any place 
 which has not suitable channels, such as good sewers for its re- 
 moval, but provided a town is properly supplied with drains, there 
 should be no limit to the water supply ; in the middle and upper 
 classes of houses, the general employment of baths ^ much increases 
 the demand for water. It is the writer's opinion that no town in 
 this climate can be considered adequately supplied unless the 
 quantity per head amounts to at least 30 gallons, and if there are 
 manufactories which draw upon this supply, then it must be pro- 
 portionately increased. 
 
 (89) Catchment Areas, Contour Lines, Ridge Lines. 
 
 In taking a survey of a catchment area for the purpose of sup- 
 plying a town with water, a plan is necessary showing by means of 
 " contour lines " the undulations and general slopes of the ground, 
 and here will be a convenient place to insert a brief account of 
 what is meant by the terms " contour lines" " datum," " ridge lines." 
 In the ordnance map there are seen a number of dots usually 
 following the course of the main roads, with figures upon them ; 
 these figures express in feet and decimals of a foot, the heights of 
 the ground at the various places mentioned, thus B.M. 355"2 means 
 that the particular spot is 355"2 feet above the ordnance datum, 
 and the ordnance datum level for Great Britain, is the level of 
 mean tide at Liverpool as ascertained by a series of observa- 
 
 ^ An ordinary full length bath will take from forty to sixty gallons of water. 
 
XII.] RAINFALL IN RELATION TO WATER SUPPLY. 145 
 
 tioBs taken by the ordnance survey in 1844 ; it is 8 inches below 
 the general mean level of the ocean around our coasts. If the place 
 indicated by any of these figures be visited there will be found a 
 broad arrow marked on some permanent object such as a mile-stone, 
 or a church, or a rock. 
 
 Contour lines are "lines of equal altitude," and are "what would 
 represent the water's edge, supposing water to stand at the various 
 levels" marked out by the figures. The contour lines marked out 
 in the 6-inch ordnance map are drawn at every 25 feet (vertical) 
 of elevation apart and these lines may be taken as the basis. But 
 for the purpose of water-supply or drainage, contour lines require to 
 be drawn closer than this ; they are usually drawn for local pur- 
 poses every 8 or 10 feet of elevation apart. Ridge lines are also 
 called water-shed lines. As the name indicates, ridge lines along 
 tbe wbole of their course are higher than the ground immediatel}' 
 adjacent on each side, hence the ground slopes downwards from 
 them at both sides. 
 
 Since all water supply comes either directly or indirectly from 
 the rain, the amount of rain which can be utilized for the supply 
 of a town depends upon the depth of rainfall and the catchment area. 
 
 A catchment area is also called " caichment lasin," "drainage area" 
 or gathering ground. It is in almost every case a district enclosed 
 by a ridge line, which line is continuous, save where the water 
 finds exit. The ridge line may, and commonly does, give off 
 branches, and thus there are produced subsidiary or secondary 
 catchment areas. All the details of such an area are obtained 
 from a series of levels, and the drawing of contour lines as above 
 described. 
 
 (90) Rainfall in relation to Water Supply. 
 
 The most important data respecting the depth of rainfall, are 
 as foUov/s : — 
 
 (1) The least annual rainfall. 
 
 (2) The mean annual rainfall. 
 
 (3) The greatest annual rainfall. 
 
 (4) The distribution of the rainfall at different seasons and 
 especially the longest continuous drought. 
 
 (5) The greatest flood rainfall, or continuous fall of rain in a 
 short period. 
 
146 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 For the purposes of water supply, the most important of these are 
 the least annual rainfall and the longest period of drought, but for 
 drainage works, the greatest annual rainfall and the greatest flood 
 rainfall. 
 
 The amount of water from a gathering ground may be approxi- 
 mated from the formula Q = 6215 A (| E-E) where Q is the 
 supply in gallons daily, A the catchment area in acres, R the 
 average annual rainfall, and E the loss from evaporation both in 
 inches. 
 
 In constructing reservoirs, the storage capacity is calculated from 
 the number of rainless consecutive days, likely to be experienced in 
 any given locahty. In our climate this is seldom more than a 
 month. 
 
 (91) General Principles of a Tovjn Water Supply. 
 
 A supply of water to a town should properly be at such a height 
 that by gravitation alone the water may be cast in a jet 20 feet 
 above the highest houses. Such a system in its most perfect 
 character, does away with the necessity for fire engines of the 
 ordinary type ; for by the multiplication of hydrants, facilities are 
 given to deal promptly with fires. The growing height of modern 
 buildings, enables this system only to be adopted partially. In 
 towns of great extent and irregular levels, care has to be taken 
 that certain portions of the mains and branches are not exposed to 
 excessive pressure, this is obviated by causing " loss of head" either 
 by passing the water through small inilets or by the use of 
 loaded valves. 
 
 The points to be considered in water mains for streets are that 
 they should be made of a material that will not contaminate the 
 water, that they be of sufficient size and strength, and that the joints 
 be absolutely water-tight. The usual material is cast-iron, and 
 the empirical rule as regards strength is " that the thickness of a 
 cast iron pipe is never to be less than a mean proportional 
 between its internal diameter and one forty-eighth of an inch." 
 
 A more accurate formula is as follows, the limit of safety being 
 six times the working pressure 
 
 thickness _ greatest working pressure on feet of water 
 diameter 12,000 
 
XII.] CONSTANT AND INTERMITTENT WATER SUPPLY. 147 
 
 The capacity of the pipes must be adapted to the greatest 
 hourly demand for water. The length required is said to be 
 about one mile to every 2,000 or 3,000 inhabitants. 
 
 The usual material for the service pipes is lead ; it is therefore 
 of much importance in initiating a water supply to first 
 ascertain whether the water will act on lead. 
 
 (92) Water Meters. 
 
 There are two kinds of water meters, the positive and the in- 
 ferential. Kennedy's and Frost's piston meters are examples of the 
 positive kind. A piston works in a cylinder and is successively filled 
 from the top and the bottom, and the number of strokes auto- 
 matically recorded. The capacity and the piston being known the 
 result is so many measures of water. 
 
 The inferential meter is a turbine an example of which is that 
 known as Siemens' ; the flowing water causes a turbine to revolve, 
 and from the velocity of current as measured by the revolutions 
 of the turbine the quantity of the water is " inferred." 
 
 (93) Constant and Intermittent Water Supply. 
 
 A constant water supply is a continual connection of the stored 
 water supply of the company with the consumer's house, so that he 
 is never destitute of water. An intermittent water supply is a 
 supply only given at intervals ; the water is turned off from the 
 branch-pipes during most of the day, being only allowed to flow for 
 a sufficient time to fill the cisterns. 
 
 A constant water supply demands special fittings, but only small 
 cisterns or none at all. An intermittent water supply requires 
 that each house shall have storage room for at least 24 hours 
 supply. 
 
 Each system has its dangers, but there is less danger of local 
 pollution in the case of constant than intermittent. In the 
 intermittent system there is the danger of cistern pollution, be- 
 sides, which, when the water at the main is turned off there 
 must necessarily be left a vacuum in the branch- pipes and also 
 in the mains, and foul gases may be drawn in. Two cases 
 occurred in the writer's district, in which coal-gas was in this 
 way sucked in in quantity and whenever the water was turned 
 
 L 2 
 
148 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 on, a very large delivery of coal-gas preceded the burst of water. 
 In these cases there were defects in the gas service pipe and the 
 water service pipe, both were near together in the ground. Each 
 time that the service pipe became empty coal-gas and air were 
 drawn in. 
 
 With the constant service occasionally pipes will have to be 
 repaired ; in that case the water must be turned off from mains or 
 branches, and suction will then result just the same as with the 
 intermittent. In both cases defective mains or service 'pipes, although 
 running hare full, may draw in polluting matters. It has been 
 proved experimentally that a fluid flowing through a tube with 
 defective joints although the tube may be bore full and at some 
 pressure yet a vacuum may occur at the joints and any gas or liquid 
 in contact with the joints sucked in ; for instance, Mr. John Spear 
 traced an epidemic of typhoid at Mountain Ash to the contamination 
 of the water-main in the manner indicated. 
 
 A curious pollution of a water-main is described by Dr. Tripe in 
 his annual report for 1887. The water from the dead end of a 
 particular main had an offensive odour. This on investigation was 
 proved to be caused by a large growth of weed in this portion. 
 
 (94) Fittings for Constant Water Supply. 
 
 In effecting the change from constant to intermittent the 
 following are the rules with regard to fittings in force in the 
 Metropolis : — 
 
 (1). Communication Pipes, — Point of entry must be first approved by the 
 company. Pipe to boundary fence should be new, or where the company allow the 
 existing lead pipes to remain, the strength and soundness will be entirely at the risk 
 of the consumer. Weight of pipes to be as specified in regulation. (2). Iron pipes 
 not allowed if they are to be in contact with the ground. 
 
 Every house must have but one communication pipe. 
 
 Every house at present branched, must have its own separate "communication- 
 pipe," except in the case of a group or block of houses or those supplied by stand 
 pipes, the water rates of which are paid by one owner ; such owner may at his option 
 have one sufficient communication pipe for such group or block. 
 
 The connection must be made by means of sound and suitable brass screwed 
 ferrule or stop-cock, with union, and half-inch water way. 
 
 The joints cf the stop-cock and ferrule must be wiped by the consumer's plumber. 
 
 All joints must be of lead and ' ' wiped " or plumber's joints. 
 
 No pipe is to be laid in or through drains or near gas pipes. 
 
 (2). Stop-valve. — A sound and suitable screw-down stop-valve, not less than 
 half an inch, and not greater than the pipe must be fixed in the communication pipe 
 at or near the entrance, and properly covered. 
 
 (3). CiBTBENs AND BALL VALVES. — AU cistems must be above ground, properly 
 covered, accessible for inspection and cleaning, and fitted with efficient ball valves. 
 
XII.] CONSTANT WATEE SUPPLY. 149 
 
 Wherever there is a wash-out pipe with ground plug, or any other kind of attachment, 
 it must be connected to a warning- pipe. 
 
 (4). Stand Pipes. — Stand pipes or small cisterns properly fitted should be sub- 
 stituted for butt and underground cisterns. 
 
 Owners of small tenement houses are recommended, where practicable, to fix the 
 stand pipes in the kitchens or washhouses, whereby they will be more protected from 
 injury by frost or mischief, and future expense will be saved in repairs. 
 
 Stand pipes must not be fixed over drain.«;. 
 
 (5) Wabning Pipes. — All waste pipes must be removed or converted into warning 
 pipes, and so placed that the discharge of water may be readily seen by the officers 
 of the company. Such pipes to be of lead and of the minimum weights specified 
 in regulation 29.^ 
 
 (6). Dkaw Taps. — All draw taps must be sound and suitable, and of the screw- 
 down kind. 
 
 Draw taps of the " screw-down " kind may be fixed on the rising main to supply 
 water for drinking purposes. 
 
 Taps over sinks ought to be of the waste-preventer kind. 
 
 (7). Stand Pipes in Couets. — All stand pipes or cocks fixed outside in courts 
 or public places to supply groups or blocks of houses, must be of the waste-preventer 
 kind, and protected from injury by frost, theft, or mischief. 
 
 (8). Water- Closets. — Water-closets, boilers, and urinals must be served through 
 cisterns or service-boxes, each water-closet, cistern, or service-box to have an efficient 
 waste preventing apparatus, limiting the Bush or discharge to two gallons of water, 
 and urinals to one gallon. 
 
 (9.) Water Closet Down Pipes. — Every " down pipe " hereafter fixed for the 
 discharge of water into the pan or basin of a water-closet is to have an internal 
 diameter of not less than one inch and a quarter, and if of lead, is to weigh not less 
 than 9 lbs. to every lineal yard. 
 
 (10). Baths. — No bath to have any overflow pipe other than a warning pipe. 
 In every bath the outlet and inlet must be distinct and unconnected, the inlet to be 
 above the high water level, the outlet to have a water-tight plug, valve, or cock. 
 
 ^ Beg. 29. All lead warning pipes and other lead pipes of which the ends are 
 open, so that such pipes cannot remain charged with water, may be of the following 
 minimum weights, that is to say : — 
 
 J inch (internal diameter) 3 lbs. per yard. 
 
 4 ,, „ ... ... ... ... ... J ,, ,, 
 
CHAPTER XIII, 
 
 THE WATER SUPPLY OF THE METKOPOLIS. 
 
 (95) The LoTbdon Water Companies. 
 
 Aix students of sanitary science should be acquainted with the 
 general features of the water supply of London.^ 
 
 London is supplied by eight companies, and the supply is con- 
 trolled in common by certain general enactments, viz. : — 
 
 The Metropolis Water Acts of 1852 and 1871. 
 
 The Fire Brigade Act of 1865. 
 
 The Water Works Clauses Act of 1847. 
 
 Each company has also its special Act. The eight companies 
 are as follows : — 
 
 (96) 1. Kent Waterworks Company. 
 This company supply : — 
 
 Deptford, Greenwich, "Woolwich, Charlton, Lee, Plumstead, Eltham, Bromley, 
 Dartford, Bexley, Erith, Chiselhurst, Mottingham, Kidhrooke, and parts of the 
 parishes of Le-wisham, Camberwell and Eotherhithe. 
 
 The water supply of the Kent Company is derived from deep chalk 
 wells between Crayford and Deptford. 
 
 The water when viewed through a two-foot tube is of a pale blue 
 colour ; it contains less than one-tenth of a grain of organic matter per 
 gallon, from 1"2 to 3 '7 grains of common salt, from 16 to 18 grains of 
 calcic carbonate, some salts of magnesia, potash and soda, and a small 
 quantity of silica, the solid residue, according to Dr. Bernay's analyses, 
 varying in different wells from 22-6 to 33-9 grains per gallon, the total 
 hardness from 16 '2° to 20 '3° per gallon, and the permanent hardness 
 from 2-8° to 7-7° per gallon. 
 
 The Company has six pumping stations and eleven covered reservoirs. 
 
 ^ For further details see Colonel Sir Francis Bolton's London Water Supply, from 
 whence the account in this book has been mainly followed. 
 
CHAP. XIII.] THE WATEE SUPPLY OP THE METEOPOLIS. 151 
 
 (97) 2. The New Biver Company. 
 
 This company supply : — 
 
 St. Martin-in-the-Fields ; St. Paul, Covent Garden ; St. Mary-le-Strand ; St. 
 Clement Dane ; Savoy Precinct ; St. John the Baptist, Savoy, Strand; St. James, 
 "Westminster ; St. Anne, Soho ; Rolls Liberty ; St. Andrew, Holborn-above-Bars ; 
 St. George-the-Martyr ; Saffron Hill ; Hatton Garden ; Ely Rents ; Ely Place ; 
 St. Sepulchre Without ; St. Giles-in-the-Pields ; St. James and St. John, Clerkenwell ; 
 St. Luke, Middlesex ; St. Mary, Islington ; St. Pancras ; Holy Trinity, Minories ; 
 St. Katharine Precincts (Docks) ; The City of London ; St. Mary, Whitechapel ; 
 Christchurch, Spitalfields ; Norton Folgate ; St. Leonard, Shoreditch ; St. John, 
 Hackney, St. Mary, Hornsey ; St. Mary, Stoke Newington ; Highgate Hamlet ; 
 St. Botolph, Aldgate Without ; Inner and Middle Temple ; Thavies, Staple, 
 Barnard, Lincoln and Gray's Inns ; Great and Little Amwell ; St. Margaret ; 
 Hoddesdon ; Wormley ; Broxboume ; Cheshunt ; Enfield, Edmonton ; Tottenham. 
 
 And in conjunction with other companies, the New River Company 
 supply :— 
 
 St. Martin-in-the-Fields ; St. James, Westminster ; St. Pancras ; St. Katharine 
 Precinct ; St. Mary, Whitechapel ; Christchurch, Spitalfields ; Norton Folgate ; 
 St. Leonard, Shoreditch ; St. John, Hackney ; St. Mary, Stoke Newington ; St. 
 John, Hampstead ; Enfield ; Tottenham. 
 
 The New River Company took its origin in the enterprise of Sir 
 Hugh Myddelton who, partly at his own cost, conveyed after five years 
 hard work water in an artificial channel from the springs in the 
 county of Hertford into the City of London. 
 
 The New River takes its rise at Chadwell Spring, about one mile 
 beyond Ware, in Hertfordshire. It is joined at a short distance from 
 its source by a branch cut bringing water from the river Lee. The 
 original length of the river was forty miles, but this has been reduced 
 to twenty-eight miles. Along its course it also receives the water 
 pumped up by powerful machinery from at least thirteen deep chalk 
 wells. Besides which there are a number of service and storage 
 reservoirs. 
 
 The company supply a population of over a million living in about 
 147,000 houses. 
 
 The average composition of the New River water is in grains per 
 gallon: — chlorine, I'O; total oxidised nitrogen, -33; carbon, "07 j 
 hardness, 14°-3 ; total solids, 19-9. 
 
 (98) 3. The Hast London Water Company supply in the County 
 
 of Middlesex : — 
 
 Whitechapel, Old and New Towns ; Spitalfields ; Part of Bishopsgate ; ArtUlery 
 Ground ; Part of St. Botolph, Aldgate ; St. George-in-the-East ; Shad well ; Limehouse ; 
 Wapping ; Ratcliffe ; Bow ; Bromley ; Poplar ; Bethnal Green ; Part of Shoreditch ; 
 IJackney ; Part of Tottenham in the county of Essex ; East and West Ham ; Low 
 Leyton ; Walthamstow ; Wanstead ; Woodford ; Chigwell ; Loughton. 
 
 The company have three distinct sources of supply from the river 
 Lee, intake being at Chingford ; from deep wells in the chalk at 
 
152 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Walthamstow and Chingford, and from the ri^er Thames at Sunbury. 
 The latter is used only occasionally, when the other supplies are low. 
 The company have nine stations, a large number of reservoirs with 
 filtering beds, <fec. 
 
 The general composition of the water is very similar to that supplied 
 by the New River Company. 
 
 (99) 4. Tlie Southwarh and Vauxhall Comjpany. 
 This company supply water to the following : — 
 
 Barnes ; Battersea ; Bermondsey ; Clapham ; East Sheen ; Ham ; Kew ; Mortlake"; 
 Putney ; Petersham ; Part of Kichmond ; Roehampton ; Sheen ; Wandsworth ; 
 Part of "Wimbledon ; St. Giles, Camberwell ; St. Mary, Newington ; St. Mary, 
 Wimbledon ; St. Mary, Lambeth ; St. Mary, Rotherhithe ; St. Saviour's, South wark ; 
 St. Olave's, Southwark ; St. Thomas, Southwark. 
 
 The company also, in aanjunction with the Lambeth company, supply 
 parts of the parishes of Lambeth, Newington, Camberwell, St. George, 
 Christchurch, Bermondsey, and Clapham. 
 
 The water is derived from the Thames, from which river the 
 company is authorized to take twenty million gallons per day. 
 
 There are two sets of Wrks drawing supply from the Thames into 
 subsiding reservoirs. 
 
 The upper works send water into the Battersea works, where 
 the same is there filtered, and pumped into the London district. 
 At-nthe lower works the water is filtered at Hampton, and from 
 the two sets of works the district is supplied by the company. 
 
 The total length of the mains and service pipes is about 711 
 miles. 
 
 The average composition of the water delivered by this company is, 
 in grains per gallon :— chlorine, 1-0; total nitrogen, -16; organic 
 carbon, -12; hardness, 14-0; total solids, 19-7. 
 
 (100) 5. The West Middlesex Com;pany. 
 
 The West Middlesex Company supply the following places and 
 parishes : — 
 
 Hampstead, conjointly with the New River Company; St. Pancras, ditto; 
 St. Ann's, Soho, ditto ; St. James, Westminster, ditto ; St. Marylebone, conjointly 
 with the Grand Junction Company ; Paddington, ditto ; Chiswick, ditto ; Hammer- 
 smith, ditto ; Kensington, ditto and Chelsea Company ; Chelsea, conjointly with the 
 Chelsea Company ; St. Margaret's, Westminster, ditto ; Fulham, ditto ; also the 
 suburban parishes of Willesden and Hendon. 
 
 The water supplied by the company is wholly derived from the 
 Thames, the intake being from the Thames, above that of the South- 
 wark and Vauxhall and Grand Junction "Waterworks. The water 
 flows direct from the river, through fine screens into the engine wells. 
 The water thus taken in at Hampton goes to subsiding reservoirs at 
 
XIII.] THE WATER SUPPLY OF THE METEOPOLIS. 153 
 
 Barnes, is filtered through eight filter beds having a joint area of 
 twelve acres and from thence passes to the chief distributing station 
 at Hammersmith. There are also large reservoirs at Kensington, 
 Barrow Hill, and Kidderpore. 
 
 The general composition of the water is the same as that of the 
 Vauxhall Company. 
 
 (101) 6. The Grand Junction Company. 
 
 This company supply water to the following places : — 
 
 Part of St. James, 'Westminster ; part of St. George, Hanover Square ; a small 
 part of St. Maryleboue ; Paddington ; north part of Kensington ; part of Hammer- 
 smith. ; Chiswick ; Acton ; Ealing ; New Brentford ; Heston ; Hounslow ; Isleworth ; 
 Hanwell ; Twickenham ; Hampton ; Hampton Wick ; Teddington ; Hampton Court ; 
 Bushey Park ; Whilton ; Hanworth. 
 
 The water is derived wholly from the Thames, the intake being at 
 Hampton. The company have five stations for filtering, storing and 
 pumping purposes at Hampton, Kew Bridge, Campden Hill, Kensington, 
 at Kilburn, and at Ealing, 
 
 Of the 48,000 houses supplied by the companj' at least 30,000 are 
 supplied by the constant water system. 
 
 (102) 7. The Lamheth Waterworks. 
 The Lambeth Waterworks supply the following places : — 
 
 Thames Ditton ; Esher ; Long Ditton ; Kingston-npon-Thames ; Maldon ; 
 Morden ; Wimbledon ; Merton ; Mitoham ; Tooting Graveney ; Clapham ; Wands- 
 worth ; Battersea ; Streatham ; Croydon ; St. Mary, Newington ; Camberwell ; 
 Bermondsey ; St. Mary, Lambeth ; St. Saviour ; St. George the Martyr ; Christ- 
 church. 
 
 The intake is from the Thames three miles above Hampton Court 
 Bridge ; from this intake an underground conduit over four miles in 
 length Conveys the water through East and "West Molesey and Thames 
 Ditton to the existing works at Ditton. There is also an intake at 
 Ditton. There are eight pumping, filtering, and storing stations, viz., 
 at Molesey, Ditton, Kingston Hill, Brixton, Streatham, Norwood, and 
 Rockhill. 
 
 (103) 8. The Chelsea Company. 
 
 The places and parishes in which the Chelsea Water Company 
 
 supply water are as follows : — 
 
 St. Luke, Chelsea ; part of All Saints, Fulham ; part of St. Mary Abbotts, 
 Kensington ; Kensington Palace and Precincts ; part of St. George, Hanover Square ; 
 part of St. James, Westminster ; part of St. Martin in the Fields ; St. Margaret, 
 Westminster ; St. John the Evangelist, Westminster. 
 
 The water is derived from the Thames, the intake being at Walton, 
 on the south bank of the Thames. There are also stations at Walton 
 and West Molesey, Surbiton, and Putney Heath. 
 
154 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (104) Summary of the London Water Supply. 
 
 The relative proportion from the various sources of supply was for 
 the year 1884 as follows : — 
 
 From the Thames and certain chalk springs in 
 
 the Thames valley about . . . .50 parts of the whole. 
 From the Lee and certain chalk springs in the 
 
 Lee Valley 38 „ ,, „ 
 
 From eighteen chalk wells (about |^ ■, q 
 
 eight in the north and ten in the south) } " " " 
 
 (105) Purification of London Water Supply. Filter Beds} 
 
 The water supplied from the Thames to London is all submitted 
 to the purification processes of subsidence and filtration, the filter 
 beds of the different companies vary in detail, but are all con- 
 structed upon the same plan ; for example the four filter beds of 
 the West Middlesex Company (6 acres in total area) at Barnes 
 have a total thickness of filtering medium of 5 feet 6 inches, con- 
 sisting of 2 feet 8 inches of Thames sand, 1 foot of Barnes sand, and 
 2 feet 3 inches of gravel of various degrees of coarseness ; beneath the 
 filter beds there are collecting drains of 6 inches diameter ; they 
 are pierced and laid 20 feet apart. 
 
 Efficient filtration largely depends on the rate or flow of the 
 water through the filtering medium. It is laid down as an accepted 
 standard that the rate of filtration for the Metropolitan waters 
 should not exceed 540 gallons per square yard of filter bed each 
 24 hours, or 2 gallons per square foot per hour. None of the 
 London Companies at the present time infringe this rule, and the 
 filtration rate in practice is slower than the above. 
 
 ' One of the tnost interesting experiments on the purification of water on a large 
 scale was made at Antwerp in 1881. The water was first passed tlirough a layer of 
 fine sand, and then through a filter of spongy iron mixed with gi'avel. This filter 
 was however found to clog at the top rather rapidly and the iron also required some- 
 what frequent renewal. It was found on further experiment that the water could be 
 purified more economically by scattering cast iron borings in the water as it flowed 
 through horizontal revolving cylinders these cyUnders were furnished with pro- 
 jecting plates fastened at intervals round the inside, as the cylinder revolved the iron 
 was scooped up and discharged on reaching the top. The iron was in this process 
 fii'st converted into ferrous oxide., by the oxygen in the water ; the ferrous oxide was 
 next in part dissolved by the carbonic acid gas as bicarbonate, a salt very easily 
 decomposed into ferric oxide, which finally precipitates carrying organic matter down 
 with it, the precipitate being very easily removed by filtration through sand. 
 
XIII.] THE WATER SUPPLY OP THE METROPOLIS. 155 
 
 Even this simple filtration does not act entirely mechanically but 
 in some degree destroys organic matter. The oxygen dissolved in 
 the water and the thin film of air coating the little floating 
 particles tend to oxidize the various debris; added to this, minute 
 micro-organisms are ever at work disintegrating the substances 
 upon which they feed. Hence these filters purify by mechanical 
 means, by the aid of bacteria, by other vital processes, and by a 
 purely chemical process of oxidation. 
 
 The upper layer of the filter beds gets from time to time clogged 
 up, and has to be broken up and renewed. 
 
CHAPTER XrV. 
 
 THE SCIENTIFIC EXAMINATION OF WATER. 
 
 (106) Purity oj Water. 
 
 Absolutely pure water, consisting of a chemical union with 
 condensation of two volumes of hydrogen and one of oxygen, is a 
 chemical curiosity — the purest distilled water always having some 
 slight traces of foreign matters. Pure water is, indeed, only 
 obtained by very refined methods. That which occurs in nature 
 invariably contains some saline and some organic matters with 
 certain gases in solution. Whether a water is pure or impure is 
 entirely relative, for no ordinary water is pure. What, however, 
 the chemist and the hygienist mean by " impure water " is water 
 which there is reasonable ground for believing may injure health. 
 
 Water may be polluted injuriously in various ways. The most 
 direct pollution is that in which excremental matters are passed 
 straight into the water as, for example, occurs in a stream wherever 
 there is a floating population ; it is much the same thing when 
 sewage is conveyed into a stream : there are also the various effluent 
 waters from factories, from mines, the dead bodies of animals, insects, 
 leaves, the droppings from birds, and various forms of personal 
 pollution; all these are matters more or less appreciable to the 
 sight, but there are also those insidious forms of secret under- 
 ground pollution as, for instance, the contamination of a well from 
 a far-off cesspool or midden-heap, or from an imperfect drain. 
 
 It will also be remembered that even when the water has left a 
 reservoir and is being conveyed within the main, chances of pol- 
 lution are not exhausted. (See p. 148.) 
 
CHAP. XIV.] ANALYSIS OF WATER. 157 
 
 (107) Examination and Analysis of Water} 
 
 It need scarcely be remarked that it is not the water 'per se the 
 analyst analyzes, but his researches are directed with the object of 
 discovering what substances are held in solution or suspension in 
 the water. 
 
 The medical officer of health need not be a professed analyst, 
 but he certainly should be able to make a qualitative and 
 quantitative analysis of such a nature as to determine the main 
 constituents, and should also be able to interpret an analysis. 
 
 The examination falls under the following heads : 
 I. Examination by the Senses. — Smell, taste, and general 
 appearance. 
 
 II. Biological. — Embracing microscopical appearances; culti- 
 vation of fungi and dormant germs; experiments on animals; 
 experiments on fish. 
 
 III. Chemical methods. 
 
 (108) I. — Examination hy the Senses. 
 
 Water that is evidently turbid, that possesses an odour and 
 unpleasant taste, requires no analytical process to condemn it ; 
 such a water is unsuitable for drinking purposes; A water pos- 
 sessing even any one of the above bad qualities will, as a rule, on 
 further examination be found considerably polluted. 
 
 Colour. — A 2-foot tube, the ends closed with plate glass is 
 generally used for ascertaining the colour of water. It is only the 
 purest water that examined in this way possesses a faint, blue tint. 
 The great majority of drinking waters are more or less coloured 
 with varipus hues of brown and green. Dr. Tidy uses for the 
 purpose of giving a definite statement of '' colour '' two hollow 
 wedges, the one filled with a blue solution, the other with a brown 
 solution, by sliding the one wedge over the other any combination 
 of brown and blue may be produced : the colour of the water in 
 the 2-foot tube is thus " matched " by the wedges, and the 
 conjoint colour expressed as the combination of so many milli- 
 
 ^ In the author's work on Foods, their Composition and Analysis, Lond. , 1888, 
 will be found in great detail processes for water analysis. 
 
158 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 metres of the colours. It is found that a very close relationship 
 between the amount of organic matter in the water and the depth 
 of brown colour exists. 
 
 Smell. — This is best ascertained in the following manner : — Half 
 a litre or a litre of the water is warmed to blood heat in a flask, 
 the flask being closed with a cork or stopper, a long glass tube 
 three-quarters of an inch in diameter is introduced, and the water 
 sucked up once or twice so as to wet the sides of the tube 
 thoroughly; still keeping the tube in the flask but so that its 
 lower end is out of the water, one nostril is applied to the upper 
 end and a prolonged inspiratory sniff is taken. In this simple 
 way, very faint odours may be appreciated. 
 
 (109) II. — Microscopical and Biological Methods. 
 
 To make a microscopical examination of water it is necessary to 
 examine the sediment which falls in scanty or copious amount 
 according to the quality of the water. To do this, the 
 author's tube will be found very convenient. 
 
 Its capacity is about a litre. It is in principle a big 
 pipette, so arranged that all the sediment collects in a 
 small glass cell or cap. The little glass cell, c (Fig. 27), 
 is adjusted so as to close the end of the tube, and then 
 the water is poured in and allowed to subside. At the 
 end, say of twenty-four hours, the rod, E, is inserted so as 
 to stopper the pipette-tube from the inside, now the 
 cap c with its cubic centimetre of water may be removed 
 without interfering with the main bulk. From this 
 small concentrated bulk, drops are placed under the 
 microscope without any preparation, others are divided 
 up on several slides and treated with (1) dilute iodine 
 solution, (2) drops are dried and examined for bacteria 
 by staining with methyl violet, and (3) other drops 
 are coloured with carmine and glycerin which has the 
 property of staining the nuclei of cells red. 
 
 A litre of water which throws down only a little sand 
 
 and unrecognisable dihris destitute of living forms may be con- 
 sidered, in a microscopical sense, pure. 
 
XIV.] ANALYSIS OF "WATER. 159 
 
 The matters found in a water are — 
 
 1. Lifeless Forms. 
 
 (1). Mineral matters, e. g., sand, clay. 
 
 (2). Vegetable matters. — In all shallow waters, in rivers, and in 
 all water which is exposed to the atmosphere, the microscopist 
 seldom fails to find vegetable dSbris in the shape of dotted ducts, 
 spiral vessels, parencliymatous cells, bits of cuticle with the hair 
 still adhering, the down of seeds, and other similar matters. 
 
 (3). Bead animal matters. — {a) Purely animal, such as hairs from 
 domestic or wild animals, striped muscular tissue, scales of moths 
 or other lepidoptera. 
 
 (6) Human ddhris — human hair, epithelium. 
 
 (c) Manufactured matters — wool, silk, and other matters. 
 
 2. Living Forms. 
 
 (a) Vegetable. — The most common vegetable forms are confervje, 
 oscillatoria, volvocina, desmids, diatoms, and . bacteria. All of 
 these, with the exception of diatoms and bacteria, contain chloro- 
 phyll, and are therefore of a green colour. Water containing 
 these green organisms must of necessity have been exposed to air 
 and light. 
 
 (b) Animal Forms. — Neglecting various water insects and living 
 forms which can be seen by the naked eye, such as water fleas, the 
 most frequent moving organisms seen in water are various forms 
 of infusoria. These are for the most part propelled by the aid of 
 fine motile hairs called " cilise." 
 
 Bacteria. — These are best discovered in a water by the method 
 of cultivation. 
 
 The method of cultivation which the writer has found simplest 
 is as follows : — 
 
 The first step is to obtain a perfectly sterile gelatinous media. 
 This is done as follows — a pound of any lean meat is chopped up 
 as finely as possible, and allowed to soak in about 700 c.c. of cold 
 water for twelve hours. At the end of that time the red, feebly- 
 acid liquid is separated in part by decantation, and in part by 
 filtering through a linen cloth. 100 grms. of commercial gelatin are 
 soaked for several hours in about 300 c.c. of water, and ultimately 
 dissolved by the aid of heat: the gelatin solution is added to 
 
160 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 the meat infusion in a flask, a fractional portion taken and its 
 acidity carefully determined by decinormal soda. Sufficient sodic 
 carbonate is now added to neutralize the whole liquid, as well as 
 about a grm. of common salt and a grm. of glucose. The flask 
 with its contents is now heated by imrnersing it in boiling water 
 for two or three hours. The albuminous portion coagulates, and 
 the coagulum carries various insoluble matters with it. The liquid 
 is now filtered (the filter being kept hot by a steam jacket) into 
 several Lister flasks; the flasks are well plugged with sterile 
 cotton wool, and then submitted for three successive days to the 
 heat of the water bath for a couple of hours. The result is a 
 sterile jelly solid at ordinary temperatures. 
 
 The cultivation takes place on glass plates 4 inches x 4 inches ; on 
 to these plates are cemented glass rings ^ inch broad, ^ inch deep, 
 and 3'8 inches in diameter, thus forming large shallow cells. The 
 rings are cemented on to the plates by means of the jelly itself as 
 follows : — The rings and plates are both heated to a high tempera- 
 ture in a hot air oven ; while still hot a few drops of the liquified 
 jelly are dropped from the flask on to the ground surface of the 
 ring. The ring is then applied to the plate, rotated 
 and put face downwards under a dust-proof shade to 
 cool and set. The water to be examined is weighed in 
 a simple form of drop-bottle (see Fig. 28), a drop or 
 two is placed by means of the pipette stopper on to 
 the plate, and the bottle reweighed so as to obtain by 
 difference the weight of the drops. The nutrient 
 gelatin melted at a gentle heat in the flasks is now 
 poured into the cell so as to form a layer Jts-tli of an 
 inch deep. The glass cell is then put into a special 
 Fig. 28. chamber formed of two shallow glass dishes, the one in- 
 verted over the other ; the air of the chamber is kept 
 moist by saturating a piece of blotting paper at the bottom with a 
 solution of mercuric chloride (1 :100). After from three to five days, 
 little dots or colonies appear in the gelatin ; these are centres of 
 development, each centre being a colony containing many thousands 
 of individual forms. They may easily be divided by examining 
 them under a low power into bacilli, micrococci and fungi, they 
 may also be divided into liquifying and non-liquifying according 
 as to whether the gelatin is liquified by their action or not. The 
 
XIV.] QUALITATIVE EXAMINATION OF WATER. 161 
 
 glass plate is conveniently ruled by a diamond into squares,^ Pro- 
 vided the colonies are not very numerous, they are easily enumer- 
 ated, but such liquids as sewage require to be largely diluted with 
 sterile water before taking droplets for examination. 
 
 A good water seldom contains more than 1,000 colonies per 
 gramme when cultivated within 24 hows after collection. If a long 
 time elapse between the collection of a water and the cultivation, 
 a cultivation gives but little information, for no water is absolutely 
 sterile, and the power for increase in micro-organisms is prodigious. 
 It is probable that a number of different kinds of micro-organisms 
 is more important as indicative of pollution than a large number 
 of one kind. Hitherto the method of cultivation has not been of 
 the high value which it was first confidently anticipated it would be, 
 for the methods employed develop common micro-organisms grown 
 at a low temperature, and pathogenic organisms require a compara- 
 tively high temperature such as 20° to 30° Cent., the liquifying 
 organisms in practice almost invariably prevent cultivation longer 
 than a few days, the whole mass of gelatin becoming liquid and 
 running together ; and lastly the investigation requires much time. 
 
 It is to be hoped that future research may yet make the method 
 practically useful ; there are several researches which point out to 
 a possibility of isolating the pathogenic from the non-pathogenic ; 
 for instance, Chantemesse and Widal have shown that trichloride 
 of iodine in the proportion of 1 to 500 in nutrient gelatin inhibits 
 the growth of all common micro-organisms, but the so-called 
 typhoid bacillus wUl, nevertheless, grow, and by these means they 
 were able to isolate it from other micro-organisms in excreta." 
 
 (110) Qualitative Uxamination of Water. 
 
 The qualitative chemical examination of a water may be re- 
 stricted to — the addition of a little " Nessler's " solution, when, if 
 ammonia is present, there will, be a greater or less yellow, amber, 
 or brown colour — the detection of nitrites, nitrates — the reaction 
 of the water and the presence or absence of metals. 
 
 Nitrites. — The best tests for nitrites are (1) the metaphenylene- 
 diamine test ; (2) Meldola's test ; (3) the napthylamine test. 
 
 ^ There are now glass plates sold divided into squares for the purpose of counting 
 bacteria. 
 
 " In the chapter treating of enteric fever will be found further details as to the 
 possibility of isolating the bacillus of typhoid fever. 
 
 M 
 
162 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (1) The Metaphenylenediamine Test. — The solution is made by- 
 dissolving 5 grms. of metaphenylenediamine in 100 c.c. of water 
 and slightly acidifying with sulphuric acid. A c.c. of the reagent 
 added to 50 c.c. of the water strikes a pale yellow to a deep orange 
 red, according to the quantity of nitrite present. 
 
 (2) Meldola's Test is a solution of para-amido-benzene-azo- 
 dimethy-aniline in water acidified with hydrochloric acid (strength 
 about "02 per cent.). The reagent is added to the water to be 
 tested, the whole acidified with sulphuric acid, warmed for 15 
 minutes on the water bath, and then alkalized with ammonia. If 
 nitrites are present, the liquid becomes salmon-coloured when 
 acid ; and when alkalized with ammonia, green, with small quanti- 
 ties, and blue with large quantities of nitrite. 
 
 (3) The Napthylamine Test. — The water is first treated with 
 sulphuric acid, acidified, and a solution of hydrochloride or sul- 
 phate of napthylamine added. A minute trace of nitrite strikes 
 a pale pink; if much nitrite be present there is a ruby colour 
 produced, and the solution becomes turbid from the separation 
 of colouring matter. 
 
 The above three tests are of great delicacy, detecting one part 
 of nitrite dissolved in several millions of water. 
 
 Detection of Nitrates. — There is no qualitative test for nitrates 
 not shared with nitrites ; in the absence of nitrites, the diphenyl- 
 amine test is very convenient. Diphenylamine is dissolved in 
 a little water by the aid of strong sulphuric acid. A few drops 
 of the solution are added to 10 or 20 c.c. of water and double 
 the volume of sulphuric acid. A purple blue colour denotes pre- 
 sence of nitrates. 
 
 Beaction of Water. — Nearly all waters are alkaline, and- strike 
 therefore a yellow colour with methyl orange, a dark red with 
 cochineal. If acid, the colour with methyl orange is reddish 
 orange, with cochineal a yellow tint. 
 
 Detection of Metals. 
 
 lo'on. — A mixture of ferro and ferridcyanide of potash strikes a 
 blue colour. 
 
 Lead or Co^pper. — A solution of cochineal strikes in a neutral or 
 alkaline solution a feeble red having a faint blue tinge to a deep 
 mauve blue, according to the quantity present, Hydric sulphide 
 
XIV.] QUANTITATIVE CHEMICAL EXAMINATION OF WATER. 163 
 
 gives a brown to black colour. Lead is distinguished from copper 
 by the ferrocyanide test. A solution of potassic ferrocyanide 
 added to a water containing a trace of copper, gives a brown 
 colour, or if more than a trace be present, there will be a precipitate. 
 Zinc. — Potassic ferrocyanide added to a filtered and acidulated 
 water containing zinc, gives a light white cloud or heavy precipitate 
 according to the amount present. 
 
 (Ill) Qioantitative Chemical Examination. 
 
 Merely qualitative examination of water is in the majority of 
 instances insufficient, and it is necessary to know the amounts of 
 certain constituents in water. Here will be described the simplest 
 processes only, and it will be presumed that the reader is un- 
 acquainted with practical details. The first thing is to fit up some 
 small room as a laboratory. To work with comfort it will be 
 necessary to have a good sink in the room to carry away refuse 
 liquids, and to have water and gas laid on. There should be a 
 water-tap over the sink and water and gas laid on with taps 
 with straight nozzles at 3 feet intervals along the working bench. 
 The bench or table should be not more than 20 inches high, 
 for all the apparatus is elevated by means of stands and a high 
 bench is not so convenient for working. 
 
 The chemical apparatus required to determine chlorine, nitro- 
 gen as nitrates, free ammonia, albuminoid ammonia, oxygen 
 consumed, sulphates, hardness, total solid residue, is as follows 
 (the prices given are from Townsen and Mercer's list) : — A 
 balance to carry 100 grms. in each pan and to turn when loaded 
 with half a milligrm. (£6 15s.) ; a box of grm. weights 
 (£1 15s.); 1 platinum dish to contain 100 c.c. of water, (about 
 £2 7s.) ; a copper water bath, with holes cut in it for the recep- 
 tion of the dishes ; a set of glass and porcelain dishes ; a porce- 
 lain slab; graduated flasks, either 100 c.c, 500 c.c, and 1 
 litre, or if preferred, 70 c.c. and 700 c.c These flasks have a 
 circular mark scratched on the neck, and contain the exact 
 quantity when they are filled up to this mark. Two or three 
 retorts, each capacious enough to hold a litre ; the retorts should . 
 be tubulated and stoppered ; a copper air bath, with a Page's 
 regulator and thermometer ; at least two burettes, with stand ; a 
 Liebig's condenser, with adapter and stand ; Nesslerising cylinders ; 
 
 M 2 
 
164 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 retort holder, with universal joint clip; triangular stands; 
 asbestos mill-board ; wire gauze ; triangles made of wire, covered 
 with pieces of tobacco pipe for the support of platinum or porce- 
 lain dishes during ignition ; one or two pairs of crucible tongs ; 
 filter paper ; corks ; cork-borers ; distilled water ; pure sulphuric 
 acid ; pure hydrochloric acid ; pure potash ; potassic permanganate ; 
 silver nitrate; potassic iodide; potassic chromate; sulphate of 
 copper ; zinc foil ; ammonic chloride ; calcic carbonate ; mercuric 
 chloride ; pure sodic chloride ; sodic hyposulphite ; methyl orange. 
 
 (112) Solutions Required for the Analysis. 
 
 With these reagents and apparatus, the first thing to be done 
 is to make up the following solutions which are arranged 
 here in alphabetical order for facility of reference : — 
 
 Ammonium Chloride 'Sl^G grm., pure distilled water 1 litre, each 
 c c. contains "0001 grm. of ammonia, that is one-tenth of a milli- 
 gramme. 
 
 Calcic Chloride Solution. — Pure calcic carbonate, '2 grm. ; dissolve 
 in just sufficient dilute hydrochloric acid, evaporate to dryness in 
 a platinum dish, and dissolve in a litre of water. 
 
 Copper Sulphate. — Copper sulphate, 30 grms. made up to a litre 
 with distilled water. 
 
 Nessler Solution. — 35 grms. of potassic iodide are dissolved in 
 100 c.c. of water, 17 grms. of pure mercuric chloride are boiled in 
 300 c.c. of water and then cooled. The mercuric solution is added 
 little by little to the potassium iodide, until a permanent precipi- 
 tate is formed. The liquid is now made up to a litre, with a 
 solution of sodic hydrate (strength, 20 per cent.). Lastly, the 
 reagent is made more sensitive by the final addition of a little more 
 of the mercuric chloride solution, until a permanent precipitate be- 
 gins to form. The solution is put on one side to deposit, and the 
 clear liquid decanted for use. 
 
 Potassium Iodide Solution. — Potassium iodide, 1 part, dissolved 
 in 10 parts of water. 
 
 Potassium Monochromate. — Potassium monochromate 50 grms. 
 . dissolved in a litre of water. 
 
 Potassium Permanganate. — (a) Alkaline ; potassic permanganate 
 8 grms., potassium hydrate 200 grms., distilled water 1,100 c.c, the 
 solution is boiled down to 1,000 parts, and kept in properly stoppered 
 
XIV.] QUANTITATIVE CHEMICAL EXAMINATION OF WATER. 165 
 
 bottles. (&) Standard volumetric for oxygen process ; •395 grms. of 
 potassic permanganate is dissolved in a litre of water. Each c.c. 
 contains "0001 grm. of available oxygen. 
 
 /Silver Nitrate, Standard Solution of. — 4"7887 grms. of silver 
 nitrate are dissolved in pure distilled water, and the solution made 
 up so as to measure exactly 1 litre. 
 
 Soap, Standard Solution of. — 150 parts of lead plaster are 
 triturated in a mortar with 40 grms. of dry potassic carbonate, and 
 made into a cream with the addition of absolute alcohol ; when 
 dissolved, filter, and by the addition of water reduce the strength 
 to that of proof spirit. The solution of lead soap is then diluted 
 up with proof spirit to the proper strength. The proper strength is 
 when 14'25 c.c. are required to form a permanent lather with 
 50 c.c. of the calcic chloride solution. 
 
 Sodic Hyposulphite. — One part of crystallized sodic hyposulphite 
 is dissolved in water and the solution made up to 1 litre. 
 
 (113) The Operatioti of Weighing. 
 
 One of the first things to be learnt is the operation of weighing 
 on a delicate chemical balance. It is ascertained that the beam 
 swings accurately by allowing the beam to swing without any load 
 in the scales ; if the beam swings to one side more than the other 
 the student wiU find at the top of the beam in the centre, some 
 simple mechanism by turning which the beam is adjusted. 
 
 To Bead the Weights. — The brass weights from 100 grms. to 1 
 grm. create no difficulty for they have the figures marked upon 
 them. It may be found convenient to arrange the other weights 
 on a slip of paper in front of the balance with their values marked 
 clearly on the paper thus — 
 
 •5 -2 1 -1 -0*5 -02 -01 -01 -005 -001 
 the weights are then simply read from the blank spaces, for instance 
 supposing the weights marked with a star are on the balance pan, 
 the small weights taken axe obviously "556 grm. for they add up as 
 follows : — 
 
 •5 
 
 •05 
 
 •005 
 
 •001 
 
 •556 
 
1G6 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 The weights between 1 milligrm. ('OOl) and 5 milligrms. (-005) are 
 most conveniently ascertained by working the rider ; each main 
 division equalling a milligrm. 
 
 The weights must be taken off in strict order and placed upon 
 the scale by the aid of a pair of forceps. For instance, suppose the 
 weight of a platinum dish should be 38-923 grms. this weight would 
 be ascertained as follows: (1) 50 grms. weight, too heavy j (2) 20 
 grms. weight, not enough ; (3) 10 grms. weight added to the 20, still 
 not enough ; (4) 5 grms. weight added to the weights in the pan, 
 not enough ; (6) 2 grms. weight added, not enough ; (7) 1 grm. 
 weight added, not enough; (8) 1 grm. weight, too heavy; (9) 1 
 grm. weight removed ; (10) '5 grm. added, not enough ; (11) "2 grm. 
 added, not enough ; (12) "1 grm. added, not enough; (13) '1 grm., 
 not enough; (14) '05, too heavy; (15) '05 removed and '02 
 grm. substituted, not enough ; (16) '01 grm. added, too heavy, and 
 therefore removed (17) '005 grm. added, too heavy; (20) "005 
 removed and the balance closed, and the rider worked about the 
 beam between the first and fifth division until the exact balance 
 and swing is found with the rider on the third division. 
 
 THE ANALYSIS. 
 (114) Relation between the Litre and the Gallon. 
 
 The analyst can either operate on litres or decimal parts of a 
 litre, or take advantage of the relation that the English grain 
 and the gallon has to cubic centimetres. This relation is such that 
 a milUgrm. of residue from 70 c.c. is equivalent to a grain 
 per gallon. For instance, if 70 c.c. of water on evaporation leaves 
 •076 grm., or, in other words, 76 milligrms., the water has a solid 
 residue of 76 grains per gallon, or if a water contain in 70 c.c. 
 •005 of chlorine, that is 5 grains per gallon. If the analyst wishes 
 to return the analysis in parts per 1,000 or per 10,000, it is then 
 best to take 100 c.c. for the solid residue and half a litre or a litre 
 for distillation. Parts per litre, that is parts per 1,000 are easily 
 turned into grains per gallon by multiplying by 70; thus if a 
 litre of water give -0714, that is 4-99 grains per gallon for 
 •0714 X 70 = 4^99. 
 
 It will be presumed in the following that the analysis is to be 
 expressed in parts per 1,000, 
 
xiT.] QUANTITATIVE CHEMICAL EXAMINATION OF WATER. 167 
 
 (115) Solid Residue. 
 
 100 C.C. of the water are placed in a platinum dish on the water- 
 bath, evaporated to dryness, cooled and weighed ; the weight of the 
 empty dish being subtracted from the combined dish and residue 
 of course gives the weight of the residue. After weighing, the 
 latter may be ignited over a Bunsen burner, and it should be 
 noticed whether there is blackening or scintillation. 
 
 (116) Ammonia, 
 
 Nearly all waters are alkaline and therefore the ammonia 
 present may be simply expelled by boiUng ; the reaction of water is 
 best ascertained by a solution of methyl orange ; if the water is not 
 alkaline it will be necessary to add a very small quantity of recently 
 ignited sodic carbonate, and some chemists always add this and 
 return the ammonia as " expelled by sodic carbonate." Half a 
 litre or a litre of the water is placed in a tubulated retort adjusted 
 to a Liebig's condenser, and 100 c.c. distilled over, a cubic centi- 
 metre of the Nessler solution is added to the distillate ; if no 
 ammonia at all is present, no perceptible yellow or amber tint will 
 be noticed, but in any other case a pale yellow, amber, or dark 
 brown colour or even a precipitate, according to the amount of 
 ammonia present, will be produced. In these cases the maximum 
 of colour requires a certain time, from ten minutes to a quarter of 
 an hour, for its development. The exact tint of colour produced is 
 to be imitated by running into 80 or 90 c.c. of pure distilled water, 
 a carefully measured volume from a burette of the standard 
 ammonic chloride solution, adding 1 c.c. of Nessler, and making 
 up with pure distilled watet, to the same volume of the distillate : 
 this tint is not likely to be hit ofi" at the first trial, either the com- 
 parison liquid is too dark or too light. It is of course open to the 
 analyst to repeat the process by making other comparison fluids 
 with varying quantities of the ammonic chloride solution until 
 the right tint is obtained, but this is tedious and unnecessary. It 
 is easier to reduce the length of the darker liquid, until it balances 
 the lighter, and then to calculate the amount. For instance, 
 supposing the Nesslerised distillate measuring exactly 100 c.c. is 
 darker than the comparison Hquid, which latter contains 2 c.c. of 
 the ammonic chloride solution, but it is found that by pouring away 
 
168 A MANUAL OF PUBLIC HEALTH. [cbap, 
 
 30 c.c. of the darker liquid, the two discs seen by looking down 
 through the two cylinders placed side by side on a white surface 
 such as a porcelain plaque, are exactly matched, then the following 
 proportion sum will give the number of c.c. of ammonic chloride 
 which the distillate is equal to — as 70 : 2 : : 100 = 2-85 c.c. 
 
 Various forms of tubes are to be bought facilitating this method, 
 such as Nessler cylinders with taps half-way down and the tubes 
 graduated into divisions, others have mirrors attached below and 
 are fixed in a stand with proper arrangements for shutting off 
 extraneous light. But for practical purposes glass cylinders of pure 
 white glass, a white porcelain slab, and an upright narrow glass 
 measure graduated into c.c. are quite sufficient for the purpose. 
 Of course the number of c.c. of ammonic chloride to which the 
 distillate is equal to gives at once the value for ammonia ; 
 for example, in the case quoted the ammonia would be equal 
 to 2-85 c.c. X -0001 that is -000285 grm. of ammonia. With 
 water containing so little ammonia as the above, the whole 
 will practically come over in the first 100 c.c. but it is safe to distil 
 a second quantity of 100 c.c, and to test by adding again the 
 Nessler solution ; waters which contain- so large a quantity of 
 ammonia as to give a distillate of a deep amber colour, must be 
 distilled in less quantities than the above, for as Nesslerising is only 
 accurate for the estimation of small quantities of ammonia, a 
 quarter of a litre or less should be taken of waters known to be im- 
 pure ; or any water which by a preliminary testing with Nessler 
 before distillation is shown to be very impure, is better dealt with by 
 distilling a quarter of a litre over, colouring the distillate with a 
 c.c. of methyl orange solution, and dropping into it from a burette 
 deci-normal hydrochloric acid until it just changes colour, every 
 c.c. of d.n. hydrochloric = -0017 NH. 
 
 The free ammonia thus estimated, the next process is to add 50 
 c.c. of alkaline permanganate to the liquid in the retort and to 
 again distil. It is well to boil up the 50 c.c. for some minutes in 
 an open dish before adding it, and the addition of the hot alkaline 
 solution is best poured through a funnel passed through the tubu- 
 lure of the retort. The distillate is collected, about 100 c.c. at a 
 time, and the various fractions Nesslerised until all ammonia 
 is proved to have come over. The result is returned as 
 " albuminoid ammonia." 
 
XIV.] QUANTITATIVE CHEMICAL EXAMINATION OF WATEE. 169 
 
 (117) Chlorine. 
 
 Chlorine is estimated by the volumetric solution of silver nitrate. 
 100 c.c. of the water are either placed in a beaker resting on a 
 white slab, or in a porcelain dish, just coloured with a solution of 
 potassic chromate, and then the silver nitrate solution dropped in 
 from a burette, until a reddish tinge is produced. The explanation 
 of the test is as follows : silver chromate is a red salt, it is not formed 
 until all the chlorides are first used up; upon its appearance, 
 therefore, it is certain that all the chlorine is combined with silver. 
 Each c.c. of the silver solution equals a milligrm. ('001 grm.) 
 of chlorine, so that the number of c.c. used multiplied by "001 
 equals the chlorine in 100 c.c. of water. (The reaction is made 
 •more delicate by observing the tint through a solution of 
 chromate.) 
 
 (118) Nitrates. 
 
 The quickest method of estimating nitrates is by indigo-carmine. 
 It is fairly accurate when the nitrates are in quantities — such for 
 example as over a grain per gallon, but save with special pre- 
 cautions it is not a good method for the estimation of small 
 quantities. 
 
 4 grms. of sublimed indigotin are digested for some hours with 
 five times their weight of Nordhausen sulphuric acid, the liquid is 
 diluted, and made up to two litres. A normal nitre solution is 
 made by dissolving I'Oll grm. of pure potassic nitrate in one litre of 
 water. From this solution, solutions of ^, ^, xV> A) -st normal are 
 prepared. An assay is now made by mixing, say 20 c.c. of the 
 nitre solution with any amount of the indigo solution run from a 
 burette deemed sufficient, in a wide-mouthed flask of 150 c.c. 
 capacity. Oil of vitriol is run into a test-tube, the volume being 
 equal to the united volumes of the indigo solution. The contents 
 of the test-tube are now tipped into the mixture and the flask 
 heated (best by a chloride of calcium bath) to 140°. If the indigo 
 solution is insufficient, the liquid is suddenly decolourized, but in 
 other case the liquid will continue blue. Less or more is therefore 
 taken for the next experiment. As the amounts of the indigo 
 solution are not proportionate exactly to the amount of nitric acid 
 present, it is necessary to standardize by means of different 
 
170 A MANUAL OY PUBLIC HEALTH. [chap. 
 
 strengths of the nitre solution and the results should be all marked 
 on the label of the bottle. To make a nitrate determination in a 
 water, 20 c.c. of the water are taken, some indigo solution run in 
 and an equal bulk of pure sulphuric acid, the water being kept 
 hot the while, and the indigo dropped in from a burette, until 
 there appears a faint blue or blue green colour. The approximate 
 strength of the water being thus known, a second determination is 
 made and the value of the indigo obtained from the nearest 
 number which has been determined previously in standardizing. 
 
 Estimation of Nitrates as Ammonia. — This may be done by either 
 making the water strongly alkaline by dissolving in it little by 
 little metallic sodium, then distilling until free from ammonia. The 
 retort is cooled, a small piece of aluminium foil is dropped in and 
 the retort allowed to stand over-night. The water is again 
 distilled, any ammonia produced is derived from the reduction of 
 nitrates or nitrites. 
 
 Estimation by the Co^er-Zinc Couple is more convenient. — ^Pieces 
 of clean zinc foil, well crumpled, are immersed in a solution of 
 copper sulphate (3 per cent.), when the zinc is coated, the liquid is 
 poured off, the couple washed with a little distilled water, and then 
 any convenient quantity of the water poured on to the couple and 
 the whole allowed to stand in a warm place over-night. The water 
 may be distilled and the ammonia estimated, subtracting what has 
 been previously found as " free " ammonia, but in most cases the 
 ammonia may be estimated directly by taking 10 — 25 c.c. of the 
 water, diluting it up 100 c.c, and then Nesslerising direct. Here 
 again the same correction for ammonia pre-existing will have 
 to be made. 
 
 (119) Hardness. 
 
 (A) Total Hardness. — 100 c.c. of the water to be examined are 
 placed in a suitable bottle which can be either stoppered or corked 
 and the standard solution of soap run in from a burette little by 
 little ; after each addition the water is violently shaken to see 
 whether it "lathers" or not. By a very little practice the stages 
 of the process can be detected by the ear quite as readily as by the 
 sight ; so long as the soap solution is insufficient, the shaking pro- 
 duces a sharp sound, whereas directly the soap has Tised most of 
 the earthy salts up, the sound changes to a soft muffled note. 
 
XIV.] QUANTITATIVE CHEMICAL EXAMINATION OF WATEE. 171 
 
 Sufficient soap solution has been added when a good foam or froth 
 has been produced which remains pretty well the same for five 
 minutes. There is a difference in the time that it takes to soften 
 waters which contain little or no magnesian salts; and those 
 which contain magnesian salts; the latter are decomposed with 
 considerable slowness nor is the end reaction so sharp. Waters 
 which take per 70 c.c. more than 16 c.c. of the soap solution 
 require to be diluted, for the results are found not to be accu- 
 rate when such comparatively strong solutions of earthy salts 
 are treated. In these cases therefore a prehminary trial is made 
 and then the water diluted accordingly, the best dilution being 
 that which uses from 14) to 16 c.c. of the soap solution per 70 c.c. 
 of the diluted water. 
 
 (B) PermaTient Hardness. — By boihng water holding in solution 
 carbonate of lime, the carbon dioxide, that is the gas which dissolves 
 carbonates of lime and magnesia, is expelled, hence these carbonates 
 are thrown down as a precipitate. The boiling should be brisk 
 and continued until at least a third of the water has disappeared, 
 the water is then made up to its original volume by means of 
 distilled water, filtered and treated with soap solution just as 
 before, the result is returned as " permanent hardness," that is 
 hardness due to soluble salts like lime or magnesic sulphates or 
 nitrates. 
 
 By subtracting the number of degrees of " total hardness " from 
 the number of degrees of " permanent hardness," the degrees of 
 " temporary hardness " are obtained. 
 
 (120) Alkalinity. 
 
 It is of great use to measure the alkaUnity of the water. 100 c.c. 
 of the water are placed in a Nessler cylinder, coloured yellow by 
 means of a solution of methyl orange and deci-normal hydrochloric 
 acid run in from a burette until the reddish hue shows that the 
 liquid has become neutral, each c.c. of deci-normal acid is equal to 
 '005 grm., that is 5 mUligrms. of lime carbonate, to which salt the 
 alkalinity of water is usually due. 
 
 (121) Sulphates. 
 
 The quantitative determination of sulphates is very simple : 
 a quarter of a litre or if the water should be soft, a litre of the 
 
172 A MANUAL 0¥ PUBLIC HEALTH. [chap. 
 
 ■water, acidified with hydrochloric acid, is heated to boiUng in a 
 large beaker, and a solution of barium chloride run in until 
 a precipitate ceases to form ; the liquid is allowed to simmer for 
 a few minutes and then put on one side to deposit, which may 
 take some little time ; the clear liquid is decanted off, the deposit 
 boiled up in a little distilled water, collected on a filter, washed, 
 ignited in a platinum crucible and weighed ; one part of barium 
 sulphate is equal to •134 SOg. 
 
 (122) Classification of Natural Waters and the Interpo'etation of a 
 Chemical Analysis. 
 
 Great ingenuity has been displayed in the division and sub- 
 division of waters. The simplest divisions are however the best, 
 and it is quite sufficient to divide waters into : (1) surface waters, 
 (2) spring waters, (3) river waters. 
 
 (1) Surface %oaters are those which are received almost direct from 
 the heavens, that is they fall on what is termed a gathering ground 
 and form streams, superficial wells, or lakes. Such waters are often 
 more or less discoloured by peaty matters but contain only small 
 amounts of dissolved salts. The waters of Dartmoor for instance 
 often have a total residue of 5 or 6 grains per gallon, about 2 
 or 2"5 of which are due to lime carbonate ; similarly the water of 
 Loch Katrine supplying Glasgow only holds in solution 2"3 grains 
 to the gallon. Such waters necessarily have very small amounts of 
 chlorine, nitrates, and sulphates. There is another peculiarity, which 
 is that they are largely influenced by season. 
 
 Occasionally it happens that these soft surface waters have an 
 acid reaction, this acid reaction is said to be commonly caused by 
 the rain washing through the sulphurous acid laden air of a town ; 
 at all events the best known instances of acid waters are derived 
 from the north of England, and occur under conditions which are 
 favourable to such an occurrence. An acid water will attack 
 lead. 
 
 (2) Springs. — These exhibit every variety of composition, according 
 to the geological formation in which they arise. As a rule the 
 waters from all springs are alkaline, and they contain in solution 
 more or less carbonates of lime and magnesia ; those from the chalk 
 are particularly hard, but organically pure. 
 
XIV.] INTERPRETATION OF AN ANALYSIS. 173 
 
 Deep springs are very constant in their composition, and do not 
 exhibit strongly signs of seasonal variation. 
 
 (3) Bivers. — Most river waters partake of a mixed character, for 
 they are derived both from deep springs and from the rainfall 
 flowing off the watershed through which the river runs. The 
 composition of river water exhibits distinct seasonal variations in 
 composition. At times of greatest rainfall, a river is most impure 
 and at times of least rainfall most pure. 
 
 (123) Interpretation of an Analysis. 
 
 There is no difficulty in condemning a water which is very bad 
 or in pronouncing a water very good ; the difi&culty begins when 
 the pollution is small in amount and doubtful in character. 
 
 A water that has an offensive smell, or exhibits many moving 
 organisms or on cultivation shows a number of colonies of diverse 
 species, is absolutely unfit for use. 
 
 A well water sunk near a house, showing a vast difference in 
 composition from a neighbouring well sunk at the same depth in 
 the same soil, must be looked on with suspicion. 
 
 If a number of wells in a village are examined all of which 
 are of nearly the same depth and in the same soil, the purest 
 may be taken as a kind of standard by which to judge the 
 others. 
 
 Soft peaty waters may contain a considerable amount of organic 
 matter and may be coloured rather highly, yet if the chlorides and 
 sulphates be low, and agree well with a sample taken from a portion 
 of the gathering ground which from its uninhabited character 
 must be pronounced unpolluted by sewage, such waters cannot be 
 pronounced injurious. 
 
 In forming judgment upon a doubtful water, reliance must 
 not be placed upon any one factor of the analysis, but the 
 report must be based upon a valuation of all the determinations, 
 and a careful consideration of the general tendency of evidence. 
 It was proposed by the late Mr. Wigner to assign a definite 
 numerical value to each part of the component parts of an 
 analysis. This idea is a good one, the chief difiiculty in its 
 practical adoption, being that the different classes of water cannot 
 all be measured by the same scale. 
 
174 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Mr. Wigner's values are as follows : — 
 
 Appearance in 2 feet tube 
 
 Coloiu" tlue 2 
 
 „ pale yellow 2 
 
 » green 2 
 
 ,, dark yellow 4 
 
 , dark green 4 
 
 Suspended matter to be added to valuation of appearance — 
 
 For traces 1 
 
 „ heavy traces 2 
 
 „ turbidity 4 
 
 Smell when heated to 100° F.— 
 
 Vegetable matter 1 
 
 Strong peaty 2 
 
 Offensive of animal matter 4 
 
 Chlorine as chlorides "5 gr. per gallon = 1 
 
 Phosphoric acid as phosphates — 
 
 Traces 2 
 
 Higher quantities from 4 to 8 
 
 Nitrogen as nitrates •] 00 gr. per gallon = 1 
 
 Ammonia "005 gr. , , =1 
 
 Albuminoid ammonia "OOl gr. ,, =1 
 
 Oxygen absorbed in 15 minutes at 80° F. . . . '002 gr. ,, =1 
 
 4 hours ,, ... -010 gr. „ =1 
 
 Hardness before and after boiling added together 5° = 1 
 
 Total solid matter 5 grs. per gallon = 1 
 
 Heavy metals, slight traces = 6 
 
 ,, more than traces =12 
 
 Microscopical results — 
 
 Vegetable debris in small quantity • 4 
 
 Diatoms and bacteria in small quantity 6 
 
 large , 12 
 
 Hairs and animal debris, 10 to 20 according to the quantity observed. 
 
 Mr. Wigner considered that a water wliicli gave values not 
 exceeding 15 an extremely pure water. The limit of a first-class 
 water would be about 40 ; of a second-class water, 65, and any- 
 thing beyond 65 would be a third-class water. 
 
 Dr. Frankland divides waters into two sections, according to the 
 results of a combustion : — 
 
 Section I. — Upland Sueface Watek. 
 
 Class I. — "Water of great organic purity, containing a portion of organic elements 
 (organic carbon and organic nitrogen), not exceeding '2 part in 100,000 parts of 
 ■water. 
 
 Class II. — Water of medium purity, containing from 0*2 to 0'4 part of organic 
 elements in 100,000. 
 
 Class III. — Water of doubtful purity, containing from 0*4 to 0'6 part of organic 
 elements in 100,000. 
 
 Class IV. — Impure water, containing more than 0"6 part of organic elements in 
 100,000. 
 
XIV.] SOFTENING WATEE. 175 
 
 Section II. — "Water other than Upland Surface. 
 
 Class I. — "Water of great organic purity, containing a proportion of organic 
 elements not exceeding 0"1 part in 100,000. 
 
 Class II. — ^Water of medium purity, containing from O'l to 0"2 part of organic 
 elements in 100,000. 
 
 Class III. — ^Water of doubtful purity, containing from 0'2 to 0'4 part of organic 
 elements in 100,000. 
 
 Class IV. — Impiire water, containing upwards of 0"4 part of organic elements in 
 100,000. 
 
 The above mainly deals with interpretation of the organic 
 elements of a water, but a water may be organically pure, and 
 yet be unfit to drink because of objectionable mineral or saline 
 constituents. 
 
 It may be at once laid down, that with regard to metals, if iron 
 is in sufficient quantity to give a chalybeate taste, such water is 
 not fit for a public supply, A water which contains no carbonates 
 of the earths and has a slight acid reaction^ will assuredly attack 
 lead, and unless specially treated is not suitable for a public supply, 
 A water which contains anything over 5 grains per gallon of 
 magnesian salts, is not a good supply, and if there is choice 
 another supply should be substituted. 
 
 (124) Purification and Softening of Water. 
 
 The most perfect method of purifying water is by distillation, a 
 method which in the rainless districts of Peru and Chili is relied 
 on to supply a considerable population, and one which is used on 
 most of Her Majesty's ships at the present day. The other 
 methods of purifying water are : — I. Subsidence ; II. Filtration ; 
 III. Chemical treatment. 
 
 I. Subsidence. — Waters containing suspended matters are often 
 very effectually cleared and rendered fit for use by being stored 
 in reservoirs; the water being at rest, the suspended matters 
 slowly or quickly according to their specific gravity sink to the 
 bottom. 
 
 II. Filtration. — Filtration on a large scale has been already 
 treated of. The best domestic filters are " the silicated carbon 
 filter," " Spencer's filter," the filtering material of the " Sewage 
 and Water Purification Company," and " Bischoff's spongy iron 
 
 ^ Dr. Tidy lias made experiments which tend to show that a water containing no 
 silica attacks lead ; if subsequent research should confirm this, it will be of great 
 importance to determine the silica in water. 
 
176 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 filter." All these not only act as efficient strainers, but also 
 without doubt have some not quite understood chemical action ; 
 probably in most of them each little particle is a feeble galvanic 
 couple, and by alternate reductions and oxidations induces chemi- 
 cal change. The test of a good filter is that it filters slowly, that 
 when a solution of quinine sulphate, 8 grains to the gallon, is 
 filtered the filtrate should be destitute of bitter taste and that it 
 retains its properties for a year, or longer. 
 
 ' III. Chemical Treatment. — For the purpose of clearing turbid 
 waters, which will not readily deposit suspended matters, the 
 following chemical substances are in use : — The salts of iron, espe- 
 cially ferrous sulphate ; the salts of aluminum, especially alum and 
 aluminate of soda ; and silicate of soda. 
 
 Most turbid waters are improved by a little ferrous sulphate, the 
 salt breaks up, and the hydrated ferrous oxide falls slowly to the 
 bottom entangling with it more or less organic matter ; treatment 
 with alum or sodic silicate acts in a similar manner, hydrated 
 alumina oxide or silica falling down. 
 
 Softening water also purifies it. Clarke's process is the addition 
 of a sufficient quantity of lime to the water to unite with the free 
 carbonic acid, the result being that the lime which has been added 
 falls down as lime carbonate, and also that which is akeady in the 
 water and has been kept in solution by the free carbonic acid. 
 The exact amount of lime to be added can be calculated if the 
 amount of free carbon dioxide is known, or it may be found by 
 adding lime water of known strength from a burette to a measured 
 portion of the water until a sample tested with silver nitrate, gives 
 instead of a white or yellowish precipitate a brown ; as soon as this 
 brown precipitate is produced, the addition of the lime water is 
 stopped, and then the reverse process is followed, that is the hard 
 water is added little by little to the same water already limed 
 until the brown colouration ceases to be produced. Clarke's pro- 
 cess of course only deals with " temporary hardness," any hardness 
 due to sulphates or nitrates of lime and magnesia remains, but by 
 the addition of a sufficient quantity of caustic soda to decompose 
 the earthy sulphates, the permanent hardness is also removed. 
 
 In Clarke's process the carbonates thrown down are in a state of 
 very fine division, and take some time to subside. There are, how- 
 ever, various forms of apparatus invented which quicken the process 
 
XIV.] SOFTENING WATER. 177 
 
 by rapidly removing the sediment ; this is accomphshed by running 
 the water, milky from the chemical reaction, over shelves, trays, or 
 cloths, which present a large surface to which the precipitate 
 adheres. One of the best of these is that known as " Howatson's 
 water softener." In this machine the precipitated carbonate adheres 
 to a sort of webbing, the process is continuous, the milky water 
 running in by one set of pipes, and the softened clear water 
 running off at the top. 
 
SECTION V. 
 DRA mS—SE WERS—SE WA GE DISPOSAL. 
 
 N 2 
 
CHAPTER XV. 
 
 DRAINS. 
 
 (125) Legal distinption between Drains and Seivers. 
 
 The legal definition and distinction between "drains" and 
 " sewers " is thus laid down by the Public Health Act, 1875 : — 
 
 " ' Drain ' means any drain used for the drainage of one building 
 only, or premises within the same curtilage, and made merely for 
 the purpose of communicating therefrom with a cesspool or other 
 like receptacle for drainage, or with a sewer into which the drain- 
 age of two or more buildings or premises occupied by different 
 persons is conveyed. 
 
 " ' Sewer ' includes sewers and drains of every description, except 
 drains to which the word ' drain ' interpreted as aforesaid applies, 
 and except drains vested in or under the control of any authority 
 having the management of roads, and not being a local authority 
 under this Act." 
 
 The definition under the Metropolis Local Management Acts, 18 
 and 19 Vict., c. 120, sect. 250, and 25 and 26 Vict., c. 102, sect. 
 112, is almost the same, but with regard to " drain " the definition 
 is extended to " and shall also include any drain for draining any 
 group or block of houses by a combined operation under the order 
 of any Vestry or district Board, or pursuant to the order, or with 
 the sanction or approval of the Metropolitan Commissioners of 
 Sewers." 
 
 It is of practical importance to thoroughly grasp these two 
 definitions, for a drain will be commonly maintained by a private 
 individual, whereas public sewers are vested, maintained, and re- 
 paired by the local authority. It will be seen it is neither size nor 
 
182 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 function that makes a channel for carrying sewage a sewer or a 
 drain, but whether it drains more than one house, if it does, and 
 the houses so drained belong to, or are tenanted by different 
 persons, although the drain may be only a 6-inch pipe, it is a 
 sewer under the Act, save under the Metropolis Local Management 
 Act, it may be the combined drainage of a block of buildings 
 sanctioned or ordered by the authority. As may easily be con- 
 jectured from this somewhat loose definition, there are many cases 
 in which it is doubtful whether the channel for the conveyance of 
 sewage is a " drain" or a " sewer." 
 
 It is in some cases advantageous for a main sewer not to be 
 absolutely water tight, but drains for houses should in all cases 
 have sound joints; a proper drain for the carrying off of sewage is a 
 water tight tube ; on the other hand an agricultural drain, or what 
 is called a " weeping " drain, which is sometimes put in the base- 
 ments of damp houses, is a channel for the reception of the water 
 in the soil, the subsoil water, and the joints are open and unce- 
 mented. 
 
 (126) Brick Brains and their Defects. 
 
 House drains are now invariably made of glazed socket pipes, or 
 in some cases of iron pipes ; the evil of square brick, or of barrel 
 drains, the common construction of forty years ago, is well set out in 
 the following passage from the report of the Metropolitan 
 Sanitary Commission, 1848 : — 
 
 " It is a first principle that where matter is conveyed by several 
 small currents, if these small currents are united into another 
 channel, of a proper form and inclination, the quicker will be the 
 flow of the united currents, and the more powerful the sweep of 
 any matter in suspension. From the practical observations of 
 sewers kept free from deposit, it is manifest that very small 
 currents suffice for the purpose, if the inclination be good, and the 
 flow be concentrated and kept regular, for which additions of small 
 quantities of water, at particular intervals and seasons, it is con- 
 sidered would be sufficient. 
 
 " The reverse of these principles generally obtains in practice in 
 the majority of the districts of sewers. In the first place the house 
 drains are so constructed as to spread and impede the streams, and 
 are often kept running separately for unnecessary distances from 
 
XV.] 
 
 BRICK DRAINS. 
 
 183 
 
 tlie sinks and house gutters. The house drains, too, receiving the 
 water from the small 1-inch leaden pipes of kitchen sinks, are 
 sometimes of sixty times the capacity of these pipes in the smaller 
 houses, they are generally made of bricks in the following form 
 (Fig. 30) :- 
 
 -•^ 
 
 Fig. 29. 
 
 Fig, 30. 
 
 " The architects and builders generally put in barrel drains to the 
 larger houses in the foUowing form (Fig. 31), made of brick, with 
 porous mortar in the upper portions : — 
 
 "T" -r — »— — - 
 
 li=S5^^J:^i=fcJ:^;^^fe*:fe^^^^55&s.. 
 
 i^^-l 
 
 ■ ■ 3 
 
 ^^_ 
 
 
 - — - 
 
 — >-— — — "-^aa:^ ■■■J) 
 
 n^ — 
 
 .A^V^^ . ^':% 
 
 Fig. 31. 
 
 " These and the flat brick house drains are generally put in " dry " 
 at the bottom, or without mortar, to let in the water of the land 
 drainage, but they commonly let out at their bottoms or sides, 
 instead of the ends, much sewer water, which permeates the 
 foundation and site of the house, leaving the solid refuse de- 
 posited on the surface of the drain to decompose and ultimately 
 choke it up. It is rare to find any house drain of this description 
 without deposit. They are indeed made upon the hypothesis that 
 they will accumulate deposit, and the construction of brick is pre- 
 ferred that the drains may be the more readily opened, and the 
 
184 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 deposit from time to time removed. One of the surveyors of the 
 Surrey and Kent sewers, Mr. Joseph Gwilt, the author of an 
 encyclopsedia of architecture, prescribes a size of drain of 5 feet 
 square for a moderate sized mansion to enable a man to get at it 
 to cleanse it from time to time. The MetropoKtan Building Act 
 prescribes that the least size of house drains shall be nine inches ; 
 the hypothesis being that, inasmuch as even these drains accumu- 
 late deposit, drains still larger are desirable. 
 
 " Now it is proved that whilst house drains of such size and 
 construction as have been enforced by the Commissioners of 
 Sewers accumulate deposit, drains of a smaller size keep perfectly 
 clear. Thus, whilst a 12-inch drain, which is required by the Kent 
 and Surrey, and the Tower Hamlets and the City Commissioners, 
 accumulates deposit and generates noxious gases, a tubular drain, 
 of nine times less capacity, or of 4 inches in diameter, or 
 proportional to the house of from 3 to 6 inches keeps perfectly 
 clear. Even 3-inch drains convey away the refuse from middle 
 sized houses and keep perfectly clear, whilst the larger permeable 
 brick drains are choked up." 
 
 Mr. Roe, the (then) surveyor of the Holborn and Finsbury 
 division of sewers, who led the way in systematic improvements in 
 the form of construction of main lines of sewers in the metropolis, 
 made for the Commission experiments on the rate of flow of water 
 through the common brick drains for houses, as compared with the 
 rate of discharge through earthenware drains of the same capacity, 
 and with the same run of water. The general results given are 
 that through earthenware tubes the rates of discharge are increased 
 to an important extent, in the smaller and more frequent forms to 
 the extent of more than one-third. In other words, an economy 
 of one-third the quantity of water to obtain the same result is 
 effected by them, and the general efficiency of the drainage in 
 ordinary runs proportionately augmented. Examples are given 
 on the following page (Table XXVI.). 
 
 Besides the general disadvantages pointed out in the above 
 extract from the Metropolitan Commission's report, there are 
 certain other special evils attendant on the use of brick drains in 
 towns supplied with a sewer system; these are the comparative 
 ease with which rats are able to work through the brick-work and 
 make runs, and the general tendency of brick drains to enhance 
 
XV.] 
 
 VARIETIES OP DRAIN PIPES. 
 
 18& 
 
 the cost of maintenance of the sewers. A brick drain in connection 
 •with a brick sewer, if at all defective at the junction between 
 sewer and drain, soon damages the sewer, by allowing the house 
 sewage to trickle between the sewer wall and the earth, and thus 
 loosen the brick-work. 
 
 To summarize the above points, the chief defects of house drains 
 when constructed of brick, are : — 
 
 (1) A tendency to deposit. 
 
 (2) The velocity of sewage in brick drains is less than in pipe 
 drains, hence they have to be laid at a greater fall. 
 
 (3) Brick drains are almost impossible to be made tight, and 
 except they be laid in concrete nearly always leak. 
 
 (4) Brick drains are not so easily trapped as pipe drains. 
 
 (5) They have a tendency to damage any sewer with which they 
 are connected, and hence to make the cost of the sewer maintenance 
 greater. 
 
 Table XXYI. 
 
 COMPAEATIVE TiME OF ElTN OF WATEB. THEOTJGH BEICK DeAINS AND 
 
 Glazed Pipes. 
 
 Inclination. 
 
 Depth of "water. 
 
 Time througli 
 glazed pipes. 
 
 Time through 
 brick drains. 
 
 Level 
 
 5 inclies 
 44 „ 
 54 „ 
 
 3 ,, 
 34 „ 
 i „ 
 
 6 „ 
 
 38 
 
 164 
 
 19 
 
 18 
 
 25 
 
 15 
 
 134 
 
 50 
 25 
 27 
 26 
 36 
 22 
 214 
 
 2 inches iu 50 feet . . . 
 11 
 
 n „ „ 
 
 H „ „ . . . 
 
 2| „ 
 
 (127) Varieties of Drain Pipes. 
 
 The pipes at present in use for drains or sewers, are from 4 
 inches up to 18 inches, and are made of pipe clay or a mixture of 
 fire and pipe clay ; they are salt or glass glazed. They are provided 
 with collars or sockets at the one end, which receives the spigot 
 end of the next pipe, the joints being filled in with Portland cement ; 
 clay is often used instead of cement but the practice is to be dis- 
 countenanced, for the clay is liable to wash out. There are certain 
 patent joints, such as Stanford's, that do not require cementing, a 
 sort of ball joint is made, and a little grease renders all tight ; this 
 
186 A MANUAL OF PUBLIC HEALTH, [chap. 
 
 kind of joint also has the advantage that a little play is permitted 
 without damaging the union. 
 
 It is advisable in laying drains to have at certain points and 
 intervals pipes so constructed that the drain can be cleared or 
 inspected. Otherwise if anything should be the matter, such as a 
 stoppage, a pipe has to be broken. There are a multitude of 
 ingenious devices for this purpose. 
 
 Jennings, for example, supplies a pipe in which the ordinary 
 socket is replaced by a divided ring, the one half can at any time 
 be removed and the pipe lifted out. Messrs Doulton make a 
 "lidded" pipe, in which a third of the pipe can be taken off the 
 whole length. There are also " capped " pipes to be had ; in these 
 elliptical holes are cat in the upper portion, and the openings are 
 closed by well cemented covers. It is however not so easy to push 
 long lengths of clearing rods through an elliptical hole of this kind, 
 so that in the author's opinion, access pipes of the Jennings' or the 
 " lidded " type, will be found more generally useful. 
 
 The following axioms with regard to house drains are 
 accepted : — 
 
 All joints must be watertight. 
 
 The larger pipes receive the smaller ones, and not vice mrsa, 
 thus 12 inch may go into 15 inch, 9 inch into 12 inch, 
 6 inch into 9 inch, 4 inch into 6 inch, and 2 inch into 
 4 inch pipes. 
 
 Never lay drain pipes underneath a house if it can be avoided. 
 
 "Where one drain joins another, the line of junction should be 
 that of a curve, or an obtuse angle. T and ]_ shaped junctions 
 are wrong. 
 
 "When a drain changes its direction, there should be some means 
 of inspection. 
 
 (128) Fall of Souse Brains. 
 
 The " fall " of a drain is the angle it makes with a horizontal 
 plane, and is ascertained on the same principles as that of any 
 sloping surface. The least fall should be one in forty-eight, that 
 is I inch to a foot ; a greater fall is preferable, but as in the case of 
 sewers, a drain may have too great a fall; for instance, a per- 
 pendicular soil-pipe entering a sewer, as in the diagram Fig. 29 is 
 apt to produce a deposit. 
 
XV.] GENERAL METHOD OF HOUSE DRAINAGE. 187 
 
 ^ze of House Brains. — For ordinary ten-roomed houses, 4 inch 
 pipes are usually ample, larger houses require 5 and 6 inch pipes, 
 and large mansions may require for the main drain 9 inch pipes. 
 
 (129) General method of House Drainage. 
 
 The simplest case is that of a country house, provided with 
 water-closets and having facilities for disposing the sewage upon 
 the land. 
 
 In such a case the drain may be laid at the proper gradient 
 mentioned above, and terminate so as to deliver into a Field's flush 
 tank ; it will in this case be unnecessary to ventilate specially the 
 drain, but there should be syphon traps to all sink wastes, and the 
 end of the drain should be provided with a flap-trap. 
 
 Field's flush tank is a tank with a syphon arrangement ; when 
 the liquid rises above the syphon bend the syphon comes into play, 
 and the liquid is discharged with a rush ; the reason why it is 
 advisable even in small country houses to have an automatic flush 
 tank to deliver the sewage upon land, is because it is found that 
 in most cases in which the sewage is carried direct on to the 
 channels on the land without the intervention of a tank a more or 
 less foul deposit is formed at the outlet of the pipe. 
 
 Where dry earth closets are in use in country places, there is 
 only the slop water to be got rid of, and it is sometimes recom- 
 mended to discharge this direct into agricultural pipes laid at a 
 suitable depth in the garden or other ground, the slop water thus 
 escapes at various points and fertilizes the crops, but this soil 
 pollution is only admissible in cases where it will not pollute 
 drinking water, and even here it is preferable to use a tank, and 
 discharge the sewage intermittently and with a rush, because it is 
 found that the earth about the first few agricultural pipes, gets far 
 more than its due share of sewage and there is liability to deposit. 
 
 A flap-trap should be placed on the sewer end of a drain, to 
 prevent flow of .sewage up the drain pipes when the sewer is 
 surcharged. 
 
 No house drain should be a continuous channel for gas to flow 
 from the sewer into the house, a syphon or disconnecting chamber 
 being always interposed. 
 
 If a drain has to be diminished in size, it is best to use the 
 tapering pipes made for the purpose. 
 
188 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 The system most in vogue now in the better class of houses, is 
 to disconnect the drain from the sewer by means of a disconnecting 
 chamber and syphon. The disconnecting chamber is a sort of 
 man-hole, the sides of brick, and on the floor are open earthenware 
 channels in connection with the house drains, while on the sewer 
 side of the chamber is a syphon ; in this way, whatever odours or 
 evil properties there may be in the house sewage, no gas from the 
 sewer system is allowed to enter. The grating over the manhole 
 makes a good air inlet, and if the drains of the house are also 
 ventilated, the air should more or less continuously sweep through 
 the system. The ventilation of the house drain should be by a 
 pipe 4 inches in diameter, carried from the highest point of the 
 drain above the eaves of the house, away from bedroom windows. 
 
 (130) Traps. 
 
 Traps are contrivances to confine sewer gas; they are either 
 mechanical or " water seals." The simplest form of trap is what is 
 called a flap-trap ; as applied to the end of a drain the flap-trap is 
 simply a small door, hanging from its hinge, it allows fluids to pass 
 freely one way, but prevents more or less perfectly the passage of 
 fluids or gases the reverse way. Provided the flap accurately fits 
 and the hinge is in good working order, a flap-trap at the end of a 
 drain prevents sewer gas coming into the house with any force. 
 But as the junction of the flap cannot be made absolutely perfect, 
 it does not prevent some small leakage of gas by diffusion ; on the 
 other hand such a trap affords a good barrier against rats, and also 
 against the ponding back of the sewage from the sewer if the 
 sewer should be running bore full. Other defects of the valve-trap 
 are oxidation of the various parts, especially the hinges ; the fact 
 that when water is rushing through the drain the trap is necessarily 
 open, and sewer gas can then pass freely. 
 
 In the Metropolis there is no systematic inspection of the traps 
 to the mouths of the house drains ; they belong to the house owner, 
 but he has no means of personally inspecting them nor of keeping 
 them in order. Without a doubt they should in all cases belong 
 to the local authority, and form part of the sewer system. 
 
 Another form of mechanical trap is the " Bower b trap." The 
 pipe to be trapped dips into a vessel containing a ball of india- 
 rubber, which by its buoyancy seals the bottom of the pipe that 
 
XV.] , TKAPS. 189 
 
 dips into the vessel of water which forms the water trap. There 
 can be no doubt of the efficiency of the principle of this kind of 
 trap, a familiar illustration of which is exemplified in the modern 
 form of glass marbles closing the necks of aerated water bottles. 
 The marble presses against a ring of india-rubber, and the greater 
 the pressure of gas the firmer the seal. It is also exemplified in 
 some of the best forms of mercurial pumps ; for example, in the 
 mercury pump 'described and figured in the author's work on 
 foods.^ A glass float rises on the surface of the mercury, its conical 
 end plugs the tube, and thus there is a very effectual valve. 
 
 (131) The Water Seal. 
 
 The commonest form of trap is, however, the water seal, which 
 is an application of the water lute of the chemist. 
 
 The water seal may be destroyed in different ways : — (a) it may 
 be forced, as for instance when there are two traps on the same 
 line of drain and no opening between them and hot water is 
 poured down the drain, the air will suddenly expand, and one 
 or both traps wiU be forced, the air bubbling through ; (&) by the 
 water in the trap evaporating, this very often happens with the 
 beU-trap, the shallow water ring becomes dry, and then gas 
 escapes; (c) "syphoning," this may happen when from any cause 
 the pipe running fuU bore creates a vacuum behind the column 
 of water, and sucks the seal out of the trap. A good example 
 is given by Baldwin Latham in his work on sanitary engineer- 
 ing (see Fig. 32). S is the soil pipe open at its head ; D a pipe 
 running from the wash-hand basin B ; U is ■ a urinal. Every 
 time the basin was used it unsealed the urinal trap, and water 
 put down the urinal untrapped B. This mutual untrapping was 
 cured by the insertion of the ventilating pipe. The column 
 of water acts in these cases as if it, were a solid piston ; 
 as it passes a branch it sucks the water from the syphon ; the 
 general cure for this is, as in the case cited, the ventilation of the 
 branches ; (d) the seal of a water trap may also be broken by the 
 capillary action of a thread or a piece of cloth having by accident 
 got into the syphon and hanging over the lip of the trap ; the 
 water may in this way be slowly extracted, dripping away from the 
 end of the cloth or thread and the trap left dry. If the water in a 
 1 Foods, their Composition and, Analysis, 
 
190 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 trap becomes saturated with foul gas, it may deliver up tlie gas 
 from the house side of the trap ; but this only occasionally happens. 
 
 Fig. 32. 
 
 Water seal traps of approved form, and those in which the above- 
 cited conditions of unsealing are not present, may be considered as 
 perfect barriers to -sewer gas. 
 
 (132) Examples of Traps. 
 
 One of the most common, and at the same time the worst traps, 
 is what is known as the " bell trap " (see Fig. 33). It consists of 
 two parts, a fixed iron box with a pipe connected 
 with the drain, and a movable bell-shaped cover; 
 the rim of the bell dips into the water around 
 the vertical pipe. The following are the ob- 
 jections to the bell trap : the cover is so easily 
 removed that as a fact it is more often off than 
 on; when once removed sewer gas has free 
 channel, the thin film of water forming the seal affords no adequate 
 
 Fig. 33. 
 
XV.] 
 
 TRAPS. 
 
 191 
 
 resistance to sewer gas ; slight pressure forces the seal ; the circular 
 channel for the water is a natural receptacle for dirt and dust ; it 
 rapidly gets filled up, and then of course the trap is useless ; lastly, 
 from its constniction, in dry weather the water rapidly evaporates, 
 thus abolishing the seal. 
 
 An old form of trap, still used in the country, is the " dip-stone 
 trap." It may often be seen in brick drains, placed so as to inter- 
 pose a baiTier between the house drain and the sewer. The drain 
 is deepened at the spot, a piece of slate or stone placed tight 
 across the drain but leaving a space of about 3 inches beneath. 
 Water remains in the deepened part, forming a fairly good seal. 
 It is also sometimes interposed in the course of a pipe drain, and 
 in that case forms a bricked rectangular cavity. The objection to 
 this form of trap is the liability to accumulation, and such traps 
 are often little better than small cesspools. Dr. Corfield considers 
 that these forms of traps may be much improved by making the 
 ends nearest the house nearly vertical, giving the opposite one a 
 gentle slope, and fixing the dip-stone so as to slant in the direction 
 of the stream, and rounding off the inside with concrete, rendered 
 in cement so that there are no angles or corners. 
 
 Stoneware syphon traps are superseding the forms mentioned. 
 It is now a common practice to insert a stoneware gully trap 
 between the house and the sewer, as 
 well as to have all the yard and sur- 
 face traps stoneware syphons. Ex- 
 perience has, however, amply proved 
 that a syphon connected with a sewer 
 through which all the house drainage 
 passes gets very frequently choked up ; 
 it is therefore necessary to provide 
 some facility for opening or cleansing 
 the syphon. For this purpose an up- 
 right piece is made from the lowest 
 piece of the syphon, which may be 
 continued up to the surface of the 
 ground. It is better still to make an 
 opening for inspection at the house 
 end of the syphon, so that instead of being closed with a tight lid, 
 a grating may be placed over it and it may be used as an air inlet. 
 
 
 Fig. 34. 
 
192 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 The best system of all is of course to have a manhole built of 
 brickwork, with grooved channels at the bottom entering a syphon. 
 In this way it is impossible for gas from the sewer to flow along 
 the house drain into the house, and obstructions in the syphon, 
 should they occur, are readily removed. This system was to a 
 great extent introduced by Buchan, of Glasgow. Buchan's dis- 
 connecting chamber and trap is represented in Fig. 34. 
 
 (133) Grease Traps. 
 
 In sculleries of the middle class and the larger houses generally, 
 quantities of hot liquefied fat are thrown into the drains ; the fat 
 directly it is cooled by the cold water inside the drain sets, and 
 entangling various debris, is a potent factor in stopping a drain ; 
 
 hence it has been found necessary 
 ^8 ' to deposit this fat in what is 
 
 ^B^ 1. ^0\ called a grease box or grease 
 
 ~^^r ||y^J trap. A grease box is simply a 
 
 "•S'.'sl .^^^^"^^^^^ rectangular small catchpit, con- 
 
 'j^^y'j'i ^^^^^^^j p^fp— I nected on the one side with the 
 
 p == =^=J 'fe i^ scullery sink and continued on 
 
 ^^ ^^^^ ^y the other into the drain. Fig. 35 
 
 PiQ 35 is a good form of grease trap ; 
 
 the fat floats so that by bending 
 
 the exit pipe downwards, so long as the water retains its level, 
 
 the escape of the grease into the drain is prevented. The grating 
 
 is movable and can be taken off for the purpose of removing the 
 
 accumulation of fat. Grease traps are necessary evils, but they 
 
 are often productive, through inattention, of nuisance. 
 
 (134) Inspection of Drainage. 
 
 If a drain of a house enter a sewer large enough for a man to 
 creep up, a small portion of the drain can be inspected from the 
 sewer, by the aid of a bull's-eye lantern ; at all events, it can in 
 this way be readily ascertained whether the drain is brick or pipe, 
 and whether it is damaging the sewer, and also whether it has a 
 flap-trap or not. 
 
 Proceeding inside the house, all visible parts must be examined 
 in great detail — sinks, waste-pipes, soil-pipes, and rain-water pipes. 
 
XV.] SPECIAL DRAIN TESTS. 193 
 
 all being methodically inspected, and notes taken of their position, 
 apparent course, and delivery ; the size and material should always 
 be noted. In bad escapes of sewer-gas, the gas may blow up a 
 defective pipe so strong that the hand alone will feel the current, 
 or, if the current is not evident, the flame of a candle held above 
 it will give signs of up or down draught. It is not enough to 
 examine drainage in a quiescent state, it must also be examined 
 at the time closets or waste-pipes are discharging ; an escape of gas 
 may often be made visible by sharp pulling up the closet-valve, 
 and also by pouring a large volume of hot water down the drain. 
 There are besides special tests — these are what are known as " the 
 peppermint test," " the smoke test," and " the water test." 
 
 (135) Special Drain Tests. 
 
 The peppermint test requires two persons, one of whom takes a 
 bottle of peppermint oil and pours about two ounces at the highest 
 or other suitable point, and then follows it up with several buckets 
 of boiling water, taking special precautions by shutting doors and 
 other openings that the odour is not allowed to escape into the 
 house, save through defects in the drain itself. The operator must 
 of course, remain at the spot where he has applied the test, other- 
 wise the odour remaining iu his clothes will obscure allindications. 
 His companion now examines all along the course of the drain, 
 and if there is any smell of peppermint, it is a proof of defect. 
 The addition of some strong ammonia to the peppermint oil is 
 said to render the test more certain. As the principle of this test 
 is the volatility of a strong-smelling substance, it is obvious that 
 any volatile substance can be substituted for oil of peppermint — 
 for instance, bisulphide of carbon, powdered iron sulphide followed 
 by a strong acid so as to disengage sulphuretted hydrogen, light 
 petroleum, ether, and other substances. 
 
 The smoke test is best applied at the lowest practical portion of 
 a drain, if a special opening cannot be conveniently made, then a 
 trap can be taken out and the sewer end of the drain blocked up 
 by a plug. " Smoke rockets " are sold for the purpose of applying 
 the smoke test ; the rocket is lit, pushed into the drain, and the 
 opening Well covered with sacks or anything else which will keep 
 the smoke in, a dense volume of smoke fills the drain, and bursts 
 
 
 
194 A MANUAL OF PUBLIC HEALTH. [chap. xv. 
 
 through defective joints and places. There are also some very good 
 machines in the market by which large volumes of smoke can be 
 pumped into the drains. The water or hydraulic test is more 
 applicable to new drains not covered in than to covered or old 
 drains. A plug^ is put in the lowest portion of the drain, and it is 
 then filled with water ; if the joints are not cemented an escape 
 takes place, and the level of the water sinks to a corresponding 
 degree. 
 
 ^ Plugs are in commerce ; one of the best is an iron disc, with a deep flange 
 in which is a thick ring of rubber. They are made of different sizes. 
 
CHAPTER XVI. 
 
 SEWERS. 
 
 (136) Drain- Sewers. 
 
 Where the separate system is in use, as in Ely, Gloucester, 
 Dover, and many other towns — that is where there are two sets of 
 pipes and channels, the one for the sewage, the other for the 
 storm and subsoil water, then the main sewers should be absolutely 
 water-tight ; and preferably constructed of socket-pipes. On the 
 other hand, where there is no separate system, it seems best to 
 take in the subsoil water, and therefore the mains should be con- 
 structed of brick. These latter kind of sewers Dr. Gorfield calls 
 " drain-sewers," because they fulfil a double function- — they act like 
 ordinary agricultural drain-pipes and drain away the subsoil water, 
 and also as channels for the sewage. The chief points to be 
 noticed in drain-sewers are the following : — 
 
 (1) They must be placed at sufficient depth to drain the 
 cellars. 
 
 (2) They should have a fall of from 1 in 20 to 1 in 250 ; the 
 latter is not always possible ; the least fall by which it is known 
 that a good sewer can be kept free from deposit is 1 in 1,000. 
 
 (3) They should be egg-shaped in section, for it is capable of 
 proof, that an egg-shaped sewer is cheaper to construct, is stronger, 
 gives a greater "hydraulic depth," and therefore an increased 
 velocity^ than any other form. 
 
 (4) The flow in any sewer should not be under 2 feet per 
 second nor over 4| feet per second ; the former will just keep a 
 properly constructed sewer free from deposit ; the latter will 
 unnecessarily increase the maintenance expense. 
 
 o 2 
 
196 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Sewers should be laid in as straight lines as possible, aud placed 
 in a bed which will not be likely to sink. Concrete as a bed is often 
 used. The gradients must be true throughout. If curves are 
 necessary, the radius of the curve should not be less than ten 
 times the cross-sectional diameter of the sewer. 
 
 No sewers or drains should join at right angles or directly opposite 
 the entrance of others : two sewers joining together should always 
 do so in the direction of the flow of the sewage ; at such junction 
 it is often advisable to form what is called a bell mouth with a 
 ventilating shaft. 
 
 Provision must be made for easy access to sewers for flushing 
 and clearing them, without breaking up the roadway ; this is 
 effected by side entrances, manholes, flushing chambers, and the 
 like. The position of these manholes is of great importance, they 
 should certainly be never placed opposite to the entrance of a 
 public school ; it is from time to time necessary for the manhole 
 door to be opened during several hours, and during this time sewer 
 gas freely streams through the opening. In the writer's district 
 there have been several just complaints from this cause; these 
 complaints have been dealt with in some instances by removing 
 the manhole or side entrance to a more suitable spot, in others by 
 making stringent regulations that the manhole is only to be used 
 in certain hours. 
 
 (137) The Flushing of Seioers. 
 
 Sewers should be flushed periodically, whether there is any 
 deposit or not. The simplest flushing apparatus is any kind of 
 dam which ponds up the water, and is capable of being suddenly 
 removed. The power of water used in this way is surprising. In 
 an experiment with a flushing gate, 4 feet high, the quantity of 
 water ponded back up for one flush was 26,665 feet ; three flushes 
 carried brickbats 1,300 feet ; the reason for this flushing power is 
 not alone the simple mechanical force, but also the loss of weight 
 of solids by immersion in water, a brickbat weighing several 
 pounds in air weighs much less in water, and hence the mechanical 
 force added to the buoyancy force of the water moves it. Formerly 
 the deposits in the sewers were removed by hand lubour, now such 
 deposits are only removed by hand labour when flushing fails. 
 Hand labour is expensive ; it was stated in the evidence before the 
 
ivi.] SEWERS, 197 
 
 Metropolitan Sanitary Commission, that where 6,688 yards of foul 
 deposit had been removed by flushing it was calculated that as the 
 whole cost of removing it by hand labour would have been £2,387, 
 while the cost of putting up the inside apparatus and flushing gate 
 was £1,203, and the cost of men's time £644 12s. Id., there was 
 thus a saving of £539. 
 
 Pipe sewers are sometimes mechanically cleansed by dragging a 
 chain through them and afterwards well flushing. 
 
 (138) Dead Ends of Seivers. 
 
 No sewer should terminate in a dead end, that is to say in a cul- 
 de-sac, without ventilation, it is in the dead ends that the worst 
 forms of gas and deposits of a foul kind are apt to collect. Dead ends 
 where possible, should be done entirely away with by connecting 
 them with the general sewer system. In the writer's district, where 
 the dead ends of two sewers have been some 50 feet apart, the dead 
 ends have been connected by means of a 12 inch pipe with good 
 results, the 12 inch pipe not carrying sewage but simply allowing 
 the air to circulate. It is a good plan to place an automatic flush 
 tank at dead ends, so that every 24 hours or oftener the sewer will 
 be properly flushed out. In some instances the writer has recom- 
 mended a ventilating shaft run up the nearest house, the upper 
 end well above the eaves, and this has answered. The combination 
 of ventilation and automatic flushing ought in all cases to keep a 
 dead end free from danger. 
 
 (139) The Size of Sewers. The Separate System. 
 
 When we come to the " separate system " — that is where the 
 sewers only carry diluted sewage, and the storm water is so far as 
 practicable kept out of the sewers — in this case the main sewers may 
 be of pipes properly jointed and of very moderate size. It will give 
 a good illustration of the large area a comparatively small pipe 
 will drain if reference be made to an old experiment of importance 
 in the early history of drainage. The Metropolitan Commission 
 of Sewers initiated experiments by placing pipes within the large 
 sewers of the metropolis. Mr. Hale laid in tbe sewer running 
 through Upper George Street from the Edgware Eoad to 
 Manchester Street where it falls into the Scholars' Pond sew er, a 
 12 inch pipe drain, 560 feet long, and by proper appliances com- 
 
198 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 pelled the sewage that would otherwise have flowed into the Upper 
 George Street sewer, a sewer 5 feet 6 inches by 3 feet 6 -inches, to flow 
 through this pipe ; the area thus drained was equal to nearly 44 
 acres of houses. During ninety-six hours of rain the pipe sewer 
 was never more than half full, and it ran bore full on only one 
 occasion for a brief period during an exceptional storm. It was 
 also shown in the same series of experiments that the water flow- 
 ing through a pipe of the kind possessed great mechanical power. 
 
 " On one occasion," said Mr. Hale, " I had the sewer in Upper 
 George Street cleaned out immediately below the pipe, and then 
 caused a quantity of deposit, consisting of sand, pieces of bricks, 
 stones, mud, &c., to be put in the head of the pipe ; the consequence 
 was the whole of the matter passed clear through the pipe (560 
 feet long), and much of it deposited some distance from the end, on 
 the bottom of the old sewer. When the pipe was flowing nearly 
 half full, two pieces of brick, one weighing If lb. and the other 
 1 lb. 13 oz., were impelled by the force of the water through the 
 whole length of pipe and struck the legs of the man at one end 
 of the pipe with considerable force. A live rat was also washed 
 out with great violence through the pipe and struck the legs of a 
 man with such force as proved the rat had no control over its own 
 motion." ' 
 
 One of the first towns that used the separate system was Slough ; 
 a system of pipe drains was laid slightly above the level of the old 
 deep sewers. About 8^ miles of pipe sewers, varying from 9 
 inches to 15 in diameter, were laid, 1,200 yards of the outfall 
 sewer being cast iron, 15 inches in diameter, jointed with lead 
 and gasket. The subsoil water is kept out of the pipes as much as 
 possible and goes with rain water along the old channels. Besides 
 Slough, Reading, Oxford, Halstead and a few other places in this 
 country have adopted the separate system ; in America, Memphis on 
 the Mississippi, and Pullman near Chicago, are notable examples of 
 separate sewerage. 
 
 (140) The Shape and Construction of Seivers. 
 
 Small sewers made of glazed pipe from 6 inches to 18 inches in 
 diameter are circular, and there is little or no benefit in making 
 
 ^ Report of tlm Germral Board of Health on the Water Supply of the Metropolie, 
 p. 186. 
 
xvr.] 
 
 SEWERS. 
 
 199 
 
 these sizes any other form ; the pipes are made in short lengths and 
 are usually jointed by passing the end or spigot into the socket or 
 faucet of the next, the spigot end of course is laid in direction of the 
 flow, that is down hill. In certain patent joints such as Stanford's 
 no cement is necessary ; in the ordinary pipes, a ring of gasket or 
 tarred hemp is often forced in the space filled with cement. Larger 
 sewers are built in the eggshaped section shown in the diagrams — 
 
 FiQ. 36. 
 
 Fig. 37. 
 
 Fig. 36 is the old form, Fig. 37 is the new form ; the latter has a 
 sharper invert. The advantage of this form is that in dry weather 
 a naiTower channel is left for the small stream of sewage, and hence 
 deposit is less likely to occur. 
 
 Fig. 38. 
 
 In Fig. 38 is shown a section of a sewer made of bricks mouided 
 so as to suit the curved structure ; the section shows two coui;ses 
 
200 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 of brick with an invert of glazed earthenware, the whole imbedded 
 in a concrete setting. 
 
 Sewers are sometimes made wholly of concrete, the composition 
 of the concrete being five to seven of sand and gravel or broken 
 stone to one of Portland cement. A mould is first formed, the con- 
 crete run round, and when the concrete has set the mould is removed. 
 
 (141) Capacity of Sewers. 
 
 It has been already described that the capacity of the London 
 sewers which convey the sewage to the outfall is calculated on the 
 assumption that the sewage averages 31 J gallons per head, and that 
 they will also dispose of \ inch of rainfall. In sewering the town of 
 Dantzic, in which the geological formation is chiefly sand, and the 
 district flat, Mr. Baldwin Latham provided for a ^ inch of rainfall 
 every twenty-four hours, and 6 cubic feet of diluted sewage. No 
 fixed rule can be given, because the water supply of various towns 
 is so different in quantity and the geological formation is 
 different. In places having a very impervious soil, sewers will 
 have to be larger than in the more pervious strata. The average 
 sewage of Birmingham is 50 gallons a head, of Cardiff 66, of 
 Croydon 76, of Plymouth 66. All these are water-closet towns. 
 On the other hand, Preston with a small number of water- 
 closets only produces liquid sewage at the average rate of 24 
 gallons per head. It is however accepted that speaking generally 
 a main drain-sewer should be constructed on the assumption that 
 there will be 5 cubic feet (31J gallons) of sewage per head to 
 be dealt with in the twenty-four hours, and a certain proportion of 
 rain, depending on locality and area. The careful observations 
 carried on at various meteorological stations and tabulated by Mr. 
 Symons, F.R.S., give valuable rainfall data for every district in the 
 British Islands, and it will be useful to remember that 1 inch of 
 rain is equal- to 3,630 cubic feet, or 22,622 gallons per acre. 
 
 The size of sewers vary so much that it is evident engineers have 
 in practice applied no general principle ; a drain-sewer will take 
 sewage, subsoil water, and storm water : the amount of the subsoil 
 water will vary in different localities ; the sewage is mainly dependent 
 in its volume on the water supply used or wasted, and the storm 
 water of course varies very much ; it is however generally admitted 
 that a main drain-sewer intended to receive all the sewaare of a 
 
XVI.] SEWEBS. 201 
 
 thickly populated square quarter of a mile, witli a water supply of 
 20 gallons a head, if the average rainfall be equally distributed 
 throughout the year, need have no larger area than 4 square 
 feet, but that since storms must be considered, then double that 
 quantity, namely 8 sqxiare feet of sectional area will be sufficient. 
 
 (142) Steep Gradients. 
 
 Special arrangements have often to be made where, from the con- 
 formation of the ground, steep gradients are a necessity ; the usual 
 way is to make a tumbling bay, the sewer delivering from above 
 having a flap valve, the lower sewer being disconnected from the 
 upper by means of a manhole ; in this way there can be no pressure 
 of gas, and the flap will keep any sudden rush of wind back ; this 
 is called " ramping " a sewer. 
 
 Difficulties are often met with in laying sewers from the kind of 
 soil in which they are laid ; for instance, in loose sandy soil the 
 subsoil water often gets into the pipes before the cement is set, and 
 the cement is in this manner washed away ; the remedies proposed 
 are either the use of cast iron pipes, or the use of a subsoil drain 
 and pipe rest (manufactured by Messrs. Brooke and Sons, Hudders- 
 field), this drain is in the form of the letter Q ; it is laid and 
 jointed at the bottom of the trench like an ordinary pipe sewer 
 This has the effect of draining away and therefore lowering the 
 subsoil water, upon this subsoil drain the true sewer is laid, 
 and it rests on a good foundation undisturbed by water or sand. 
 
 (143) Inverted Syphons. 
 
 Sewage has sometimes to be conveyed along the bed of the river ; 
 in such cases it is usually carried by an inverted syphon, con- 
 structed of iron pipes. The town of Dantzic, intersected bv 
 navigable channels and surrounded with fortification ditches over 
 which no permanent work can be carried, necessitated the use of 
 syphons there as an integral part of the sewer system, which was 
 designed by Mr. Baldwin Latham ; and in Mr. Latham's work on 
 sanitary engineering these syphons and the various modifications 
 of them are very clearly described. 
 
 It is not improbable that the sewage of the south side of the 
 metropolis, now discharging at Crossness will have to be brought 
 over to the north side, if so, this will be effected by a syphon 
 carried on or beneath the Thames bed. 
 
202 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 (144) Storage Sevjage Reservoirs. 
 
 In those towns which discharge their sewage into the sea it is 
 necessary to provide either a sufficient storage reservoir, to pond 
 xip the sewage during the time in which otherwise it would be 
 tide locked, or to construct a tank sewer, which is practically a 
 longitudinal reservoir ; many engineers prefer to make a tank 
 sewer — that is a very capacious sewer at the lowest practical level 
 — rather than a covered reservoir, and it certainly seems that the tank 
 sewer can be flushed and cleansed easier than a storage tank. In all 
 these cases there must be special ventilating arrangements and 
 efficient traps to prevent the sewer gases becoming a nuisance. 
 
 (145) Boad Gullies. 
 
 Road gullies connected with the sewers, are of two kinds, viz., 
 
 those which are intended to pass every- 
 thing into the sewers, and those in- 
 tended to intercept mud, sand, and the 
 detritus of the roads generally. The 
 former are to be found only in towns 
 where the sewers have abundant fall 
 and flushing water ; in most towns the 
 mud must be intercepted. This is ac- 
 complished by making a catch-pit 
 below the point of overflow into the 
 sewers of considerable depth and size, and removing the deposit 
 from time to time ; Fig. 39 is a diagram of an ordinary road gully. 
 
 (146) Ventilation of Seivers. 
 
 In the metropolis this is almost entirely effected by direct 
 openings into the sewer at frequent intervals along the centre of 
 the roadway : these openings are never offensive along the great 
 main arteries of sewage where there is an ample air current in 
 the sewers themselves, but on the other hand, in certain positions 
 where the sewers a.re somewhat flat, in the proximity of dead ends 
 and under other local conditions, the sewer openings are a cause of 
 danger and offence. 
 
 Charcoal boxes have been tried, various ingeniously arranged 
 trays of charcoal being placed in sewer ventilators and the sewer 
 
 Fi&. 39. 
 
VENTILATION OP SEWERS. 
 
 203 
 
 gas passing through the boxes has to some extent been deodor- 
 ized, but on the other hand a serious mechanical impediment to 
 the diffusion of the sewer gas into the open air is in this method 
 introduced, besides which the charcoal soon gets useless and fre- 
 quent renewal is necessary. For these reasons charcoal boxes are 
 condemned. 
 
 The Metropolitan Board of Works, a year or two ago, recom- 
 mended a strip of flannel to be hung in the sewer ventilating 
 shaft and a jar containing a concentrated solution of sulphurous 
 acid gas (SOj) hung over the flannel; 
 by carefully adjusting the stopcock 
 of the jar, the solution dropped upon 
 the flannel keeping it always moist 
 and filling the shaft with sulphurous 
 acid gas. The writer has seen this 
 tried, and with attention it may be 
 made to act fairly well. 
 
 A better plan is disinfection of the 
 sewer air by Reeves' apparatus. In 
 this ingenious invention an apparatus 
 in shape and appearance like a filter 
 is placed over the ventilating hole ; 
 this has two chambers, the upper one 
 is filled with strong sulphuric acid, 
 the lower with dry potassic perman- 
 ganate or sodic permanganate ; 
 the sodic permanganate cham- 
 ber is connected with a water 
 supply and the cock is so regu- 
 lated that a small stream of 
 water washes through the per- 
 manganate, the solution escap- 
 ing on to a splash plate below 
 the apparatus ; on to this same 
 splash plate is delivered the 
 
 sulphuric acid, the result of the 1 ig 40 
 
 reaction being permanganic 
 
 acid, free oxygen, and sulphur dioxide. The sewer air passes 
 through this atmosphere and a strongly disinfecting liquid enters 
 
204 A MANUAL OF PUBLIC HEALTH. [chap. xvi. 
 
 the sewer. The writer has investigated carefully this apparatus, 
 and it is certainly effectual when in perfect working order, but 
 requires attention. 
 
 Another method which is on its trial is Reeling's patent sewer 
 gas exhauster and destructor ; as shown in the diagram (Fig. 40), 
 a large burner is placed within the shaft, and the arrangement is 
 such that the sewer gas either passes through flame or other sur- 
 faces brought to a high state of heat. The claim of the inventors 
 is that it carbonises any organic matters which the sewer gas may 
 contain. 
 
 (147) The Outfall of Sewers. 
 
 The outfall of an inland sewer should be protected by a flap- 
 valve, otherwise winds are liable, should they blow in the right 
 direction, to sweep any sewer gas back towards the town ; the 
 position of the outfall should of course be such as not to create 
 a nuisance. An outfall should never deliver direct below the 
 surface of a river, save in cases where there is ample fall, otherwise 
 the sewage is more or less locked up in the sewers. The position of 
 an outfall delivering sewage into the sea requires to be placed so 
 that it is under water at all periods of the tide, that it does not 
 impede navigation, that it does not deliver the sewage so that 
 the ebb tide carries it in front of" the town, and lastly, that it is not 
 placed in such a position that the sewage is ultimately deposited 
 on the shore of the town. All this requires often prolonged and 
 special study, by means of floats and other appliances on the spot, 
 of the various tides, currents, eddies and the effects of particular 
 winds. Sea outfalls are almost always constructed with proper 
 valves or sluices to prevent back currents — the inflowing of the 
 sea up the sewers. 
 
CHAPTER XVII. 
 
 THE SEWERAGE OF THE METROPOLIS. 
 
 (148) Interception. 
 
 Every student of practical hygiene should make himself ac- 
 quainted with the main features of the drainage of the metropolis, 
 not simply on account of the magnitude of the work, nor the 
 interests involved, but because it is at the present time the finest 
 example of the important principle of " interception.'' 
 
 The principle of interception is this, that where there is a small 
 longitudinal fall, and comparatively great lateral falls, and moreover 
 the town to be drained is of considerable size, it is more advan- 
 tageous to intercept the sewage of the higher zones by a special 
 channel, called " an intercepting sewer." In this way a town is 
 divided up into small and manageable areas. 
 
 In sea-side places interception is specially advantageous, for the 
 lower levels are tide-locked for many hours of the day, while if an 
 intercepting sewer carry the sewage from the higher levels to some 
 distant point, there is no interruption of the flow from the portion 
 of the town thus drained. 
 
 Nevertheless it cannot be said that these considerations had as 
 much weight with the designers of the metropolitan system as the 
 stinking state of the river Thames, the whole drainage at one time 
 emptying at different points close along the shores of the great city 
 itself, until huge intercepting sewers carried it elsewhere at a safer 
 distance into the same river. 
 
 (149) Size of the main London Sewers. 
 
 The general history of the various commissions, schemes, and 
 legislation on metropolitan sewerage will be found in the First 
 
206 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Beport on Metropolitan Sewage Discharge of the Boyal Commission, 
 London, 1884, to which the reader may be i-eferred. 
 
 The designers of the London main drainage, although recognizing 
 the many advantages of a separate system for sewage and for 
 rainfall, were compelled to undertake the problem of removing 
 rainfall and sewage in one system, which, at all events, would have 
 the advantage of using the rain and storm waters to effect the 
 flushing out of the sewers. The principle upon which the size 
 of the main sewers was constructed is thus given by Sir Joseph 
 Bazalgette : — 
 
 " It appeared from tables of rainfall that there were only from 
 14 to 21 days in the year on which the rainfall exceeded the rate 
 of a quarter of an inch in 24 hours ; therefore we said, if we can 
 divert the sewage from the river (within the metropolis) in dry 
 weather altogether on all those days, excepting the 14 to 21, 
 according to the season (a very wet season has been 30 days), 
 we shall sufficiently divert the sewage from the river to make 
 it clear." 
 
 The average amount of sewage per head was calculated to 
 be Sl| gallons, and in another part of his evidence Sir Joseph 
 Bazalgette said : " We take the sewage at so many gallons per 
 head, we take the maximum flow at double that quantity, and 
 then we take a quarter of an inch of rain running off added to 
 that, and taking the populations and the areas, we arrive at each 
 point at the quantity to be intercepted." 
 
 (150) General Principle of the Metropolitan Sewer System. 
 
 The general principle of the metropolitan main drainage system 
 is that of interception. 
 
 According to the natural hydrographical features of the district, 
 the portion of the Thames basin on which the metropolis stands is 
 drained by transverse streams flowing into the river on each side ; 
 and the sewers, which have been formed from time to time to , 
 effect the artificial drainage, have been made to follow the lines of 
 these streams. 
 
 In order, therefore, to prevent these sewers from discharging 
 into the river, the principle has been adopted of intercepting them 
 by lines of conduits lying nearly at right angles to them, i.e. in the 
 same general direction as the course of the river, but inclining 
 
XVII.] THE SEWERAGE OF THE METEOPOLIS. 207 
 
 towards it. These conduits fall in an easterly direction, and are 
 continued down to points on the banks of the river below 
 London, where the sewage, intercepted and carried off by them, 
 is discharged. 
 
 In such of these intercepting conduits as are at sufficient altitude, 
 the sewage flows away by gravitation. But as many parts of the 
 metropolis lie so low as to render this impossible, the contents of 
 the intercepting conduits there have to be pumped up by steam 
 power, in order to raise them to the necessary level of discharge. 
 
 The entire system is naturally separated into two great divisions, 
 lying on the north and south of the river respectively. 
 
 (151) Nm'tlum Intercejption. (See map.) 
 
 On the north side there are three great lines of interception : — 
 
 1. A line called the Northern High Level Sewer, which, be- 
 ginning in the north-west at Hampstead and Highgate, passing by 
 Hackney, descending by Stratford, and crossing over the river Lea 
 near Bow, abuts upon the Thames at Barking Creek. This conduit 
 acts entirely by gravitation. 
 
 2. A line at a lower level called the Northern Middle Level 
 Sewer, which begins in the west at Kensal Green, passes through 
 Oxford Street, Clerkenwell, and Bethnal Green, and joins the 
 Northern High Level Sewer near Bow. This conduit also works 
 entirely by gravitation. 
 
 3. A line at a still lower level called the Northern Low Level 
 Sewer. It begins in the extreme west at Chiswick, and passes 
 through Chelsea, near the bank of the river, as far as the Grosvenor 
 Road, Pimlico. Here, near the Victoria Railway Bridge, its con- 
 tents are pumped into another conduit lying slightly higher, 
 which runs along the northern Thames embankment, and near 
 the river to the Tower, then striking off to the north-east through 
 Stepney to Abbey Mills, near Stratford, where the contents are 
 again pumped up to the level of the Northern High and Middle 
 Level Sewers. 
 
 From this point the whole of the northern drainage flows 
 through the Northern Outfall Sewer to the Thames ; this outfall 
 sewer is formed of three parallel conduits, which take the con- 
 tents of the three sewers, but can be made to communicate when 
 necessary to equalize the flow. 
 
208 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (152) Southern Interception. (See map.) 
 
 On the south side of the river there are two great lines of 
 interception — 
 
 1. A line called tlie Southern High Level Sewer, which begins 
 at Balham and passes through Clapham, Brixton, Camberwell, and 
 New Cross, crosses under Deptford Creek by iron syphon pipes, 
 and continues through Greenwich, Woolwich, and Plumstead 
 Marshes to a pumping station on the right bank of the river at 
 Crossness. The sewage reaches that point by gravitation. 
 
 2. A line called the Southern Low Level Sewer. It begins in 
 the extreme south-west at Putney, and passes through Wands- 
 worth, Battersea, VauxhaU, Kennington, Peckham, and New 
 Cross, to a pumping station on the Ravensbourne, near Dept- 
 ford, where the contents are pumped into the Southern Outfall 
 Sewer. 
 
 At a certain point near Nine Elms there is a pumping station, 
 which lifts into this sewer the drainage brought down by the 
 sewers on the river Effra. 
 
 There is also a branch conduit from the districts of Bermondsey 
 and Eotherhithe, which delivers to the Deptford pumping station, 
 the contents being then pumped into the Southern Outfall Sewer. 
 
 From Deptford the united sewage flows down to Crossness by 
 the Southern Outfall Sewer. 
 
 At Crossness the whole is pumped by steam power to the height 
 necessary to allow it to flow into the river. 
 
 The following data, given in evidence before the Royal Com- 
 mission by Sir Joseph Bazalgette, will give a general idea of the 
 magnitude of the works : — 
 
 PUMPING STATIONS. 
 
 Total Nom-inal 
 
 
 Horse Power, 
 
 Lift. 
 
 For Northbun Sewage. 
 
 
 Feet. 
 
 Pimlico .... • . 
 
 480 . 
 
 18 
 
 Abbey Mills . ... 
 
 1,140 
 
 36 
 
 For Southern Sewage. 
 
 
 
 Deptford 
 
 500 . 
 
 18 
 
 Crossness 
 
 1,000 
 
 10 to 30 
 
 For Storm Relief Overflows 
 
 
 
 (South Side only. ) 
 
 
 
 Effra . . . 
 
 . 200 .. . 
 
 . 5 to 18 
 
 Falcon Brook 
 
 . 200 .. . 
 
 . 3 to lOi 
 
XVII.] 
 
 THE SEWERAGE OF THE METROPOLIS. 
 
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XVII.] THE SEWERAGE OF THE METROPOLIS. 211 
 
 (153) Arrangements at the Main Outfalls. 
 
 The outfall sewers do not discharge directly into the Thames ; 
 they terminate in large covered reservoirs, from which the sewage 
 is intended to be discharged only at certain times of the tide. 
 The discharge commences at high water, and it was intended^ 
 according to the report of Messrs. Bidder, Hawksley, and Bazal- 
 gette, to have been completed " during the first two and a half 
 hours of the ebb tide." As a matter of fact, however, it usually 
 continues for three or four hours, after which time it is intended 
 that the penstocks are to be closed, allowing the sewage to collect 
 in the reservoirs for discharge on the next tide. 
 
 The reservoir at Barking Creek covers about 9^ acres, and 
 holds 35,000,000 gallons, or 5,600,000 cubic feet. That at Cross- 
 ness covers about 6^ acres, and contains 25,000,000 gallons, or 
 4,000,000 cubic feet. (In the report of Messrs. Bidder, Hawksley, 
 and Bazalgette, it was recommended that the area of the Barking 
 Reservoir should be about 12 acres, and of that at Crossness about 
 7 acres.) 
 
 The bottoms of the reservoirs are 275 feet above ordnance 
 datum, or 1'19 feet above half tide level. At the top they are 
 provided with overflow weirs, from which, when the reservoirs are 
 full, the sewage passes into the river. 
 
 At Barking the overflow weirs are at the height of 16'25 feet 
 above ordnance datum, so that the available depth is 13'5 feet. 
 At Crossness the weirs are 2"5 feet higher, giving an available 
 depth of 16 feet. 
 
 The works are so constructed that at Crossness the discharge is 
 always below water; but at Barking this is not the case, the 
 discharge partly taking place over the foreshore. The latter 
 arrangement is a departure from the condition laid down in Messrs. 
 Bidder, Hawksley, and Bazalgette's report, that " in both cases 
 the sewage should be discharged into the river through submerged 
 pipes, terminating below low-water mark." 
 
 The sewers are capable of bringing down much more than the 
 reservoirs will hold, and when they do so, there will be an overflow 
 into the river from the reservoirs at any time of the tide, as at the 
 storm outlets. 
 
 P 2 
 
212 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 At the beginning of 1881 there were overflows on 43 days from 
 Crossness, and more days at Barking. 
 
 It was intended that the reservoirs were to be added to from time 
 to time, and there is no doubt that more storage room is 
 necessary. 
 
 The general direction of the main intercepting sewers is from 
 east to west, more or less parallel with the river, the other main 
 sewers flowing to the river. These sewers are all scheduled in the 
 Metropolis Local Management Act 1855, and are invested in the 
 Metropolitan Board of Works, which now of course gives place 
 to the London County Council. The schedule describes their general 
 course and outlet in that year (1855) ; for example take the King's 
 Scholars Pond Sewer,^ the schedule describes it as commencing " in 
 the Finchley Koad, at about 1500 feet above Junction Road toll 
 gate, and discharges into the River Thames at the Equitable Gas 
 Works, about 700 feet above Vauxhall bridge." This is not accurate 
 now for it discharges into the Main Low Level Sewer,but has a storm 
 overflow into the Thames. The other sewers not mentioned in the 
 Metropolis Local Management Act are under the control of the 
 various local boards, or vestries, and are vested in and maintained 
 by them. 
 
 Quantity of Sewage. — The daily quantity of sewage discharge 
 from Crossness and Barking is enormous. The flow of sewage proper 
 is estimated at an average of 16,000 cubic feet per minute, which 
 is 23,000,000 cubic feet per diem.^ The river at low water in the 
 neighbourhood of the outfalls is about 2,000 feet broad, and has a 
 sectional area of about 30,000 square feet, so that there is discharged 
 into it every day as much undiluted sewage as would fill a length 
 of 650 feet of this part of the river at low water. 
 
 If the quantity of foul matter which this discharge must of 
 
 ^ The old state of things was as follows : — "Nearlythe whole of the drainage of 
 the large and populous parishes of St. Marylebone, of St. George, Hanover Square, 
 of a portion of St. John, Hampstead, and of the greater part of St. James, West- 
 minster, is conveyed away by the King's Scholars Pond main sewer, which has its 
 source at Hampstead, and running through these parishes and this low flat of land 
 discharges itself into the Thames near Vauxhall Bridge. While the river water is 
 above its outlet, that is, during the space of five hours and six minutes in every 
 twelve hours, the drainage is locked in. This sewer therefore may he considered the 
 grand cesspool of the before-named parishes." (Mr. John Phillips's evidence Met. 
 San. Commission, 1847.) 
 
 Crossness outfall delivers, according to a six years' average, 74 '6 millions of 
 gallons a day; Barking, 85" 2. The proportion that Crossness bears to Barking is 
 therefore as 1 ; 1-14. 
 
XVII.] THE SEWERAGE OE THE METR0POLIS. 213 
 
 necessity contain, is estimated the quantities are astounding. The 
 quantity of faeces alone, in their natural state, passing from 
 3,800,000, people has been stated at something like 400 tons a day ; 
 but adding to this the urine, and the foul matter from other sources 
 and of other kinds, the total quantity must be very much larger. 
 
 The volumes which the outfall sewers are calculated to carry 
 are — 
 
 Cubic feet Millions of 
 
 per second. Gallons per day. 
 
 For the North 545 294 
 
 „ South 233 126 
 
 778 420 
 
 Storm Overflows. — It is a consequence of the system adopted that 
 there are certain times in the year when the rainfall is so great that 
 the total quantity flowing off must exceed the discharging capacity 
 of the intercepting conduits; and at these times there is no 
 alternative but to allow the superfluous quantity to be discharged 
 directly into the river, independently of the interception, and at 
 the old points of discharge within the metropolitan area. 
 
 Suitable arrangements are made for this purpose. The sizes of 
 the intercepting sewers being graduated to take the calculated 
 quantity, at the points of interception of each of the original sewers 
 there is formed a long weir ; and when the rain exceeds the 
 calculated quantity, the surplus contents of the sewer flow over this 
 weir and follow the former course down the original sewer, from the 
 mouth of which the fluid escapes directly into the river. 
 
 There are 48 of these storm or relief outlets Avithin the metro- 
 politan area, 35 on the north side and 13 on the south. A list of 
 them, showing their positions and dimensions, is given by Sir 
 Joseph Bazalgette in Q. 12,728 of his evidence before the Royal 
 Commission ; they are generally of large size, capable of delivering 
 large discharges when they come into action ; they have been added 
 to recently. 
 
 For the prompt relief of certain low -lying districts the storm 
 discharge is aided by steam power. On the banks of the Eflra at Nine 
 Elms there is a pumping station of 200 horse-power for lifting the 
 storm waters into the river, when they are penned up by the tide. 
 There is another at the Falcon Brook of the same power. 
 
 The fluid discharged from these storm outlets does not consist 
 merely of rain water, but must contain a mixture of sewage. 
 
214 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Cost. — ^The total cost of the Main Drainage works up to 1883 
 has been stated in the Reports of the Metropohtan Board to be 
 about 4,600,000^. 
 
 The portion of the Metropolitan drainage, that is admirably 
 conceived and executed is the great intercepting sewer system, 
 while the points which are most open to criticism, and indeed 
 cannot be well defended, are the number of storm ovei-flows 
 which in times of heavy rain, pollute the river within the metro- 
 polis, and the great and cardinal defect, that the sewage goes 
 into the river without being first passed through land ; this is 
 indeed the final recommendation of the Royal Commission their 
 recommendations being as follows : — • 
 
 "1. Our opinion of the evils described in our first report, as resultirg 
 from the present system under which sewage is discharged into the 
 Thames by the Metropolitan Board of Works, is much strengthened, 
 and we believe these evils demand a prompt remedy. 
 
 " 2. We are of opinion that it is neither necessary nor justifiable to 
 discharge the sewage of the metropolis in its crude state into any part 
 of the Thames. 
 
 " 3. We are of opinion that some process of deposition or precipita- 
 tion should be used to separate the solid from the liquid portions of the 
 sewage. 
 
 " 4. Such process may be conveniently and speedily applied at the 
 two present main outfalls. 
 
 "5. The solid matter deposited as sludge can be applied to the 
 raising of low-lying lands, or burnt, or dug into land, or carried away 
 to sea. 
 
 " 6. The entire processes of precipitation and dealing with the sludge 
 can be, and must be, effected without substantial nuisance to the 
 neighbourhoods where they are carried on. 
 
 " 7. The liquid portion of the sewage, remaining after the precipita- 
 tion of the solids, may, as a 'preliminary and temporary measure, be 
 suffered to escape into the river. 
 
 " 8. Its discharge should be rigorously limited to the period between 
 high water and half ebb of each tide, and the top of the discharging 
 orifice should be not less than six feet below low water of the lowest 
 equinoctial spring tides. 
 
 " 9. By these means much of the existing evil will be abated. 
 
 " 10. But we believe that the liquid, so separated, would not be 
 sufficiently free from noxious matters to allow of its being discharged 
 at the present outfalls as a permanent measure. It would require 
 further purification ; and this, according to the present state of know- 
 ledge, can only be done effectually by its application to land. 
 
 " 11. In the case of the metropolis, the best method of applying 
 
XVII.] , THE SEWERAGE OF THE METEOPOLIS. 215 
 
 the liquid to land, with a view to' its purification, would be by inter- 
 mittent filtration. We have reason to believe that suflBcient land, of a 
 quality suitable for this purpose, exists within a convenient distance of 
 the northern outfall. The liquid portion of the sewage would be 
 piimped up to this land from the separating works, and after filtration 
 would be conducted to the river. 
 
 " 12. We do not know whether suitable land, in sufficient quantity, 
 can be found in convenient positions near the southern outfall. If not, 
 the liquid must be conveyed across to the north side by a conduit under 
 the river. 
 
 " 13. If suitable land, in sufficient quantity and at reasonable cost, 
 cannot be procured near the present outfalls, we recommend that the 
 sewer liquid, after separation from the solids, be carried down to a 
 lower point of the river, at least as low as Hole Haven, where it may 
 be discharged. In this case, it will also be advisable that the liquid 
 from the southern sewage should be taken across the river, and the 
 whole conveyed down the northern side. It may be found that the 
 separating process can be effected more conveniently at the new than 
 at the present outfalls ; this will depend on various considerations of 
 cost and otherwise. 
 
 " 14. If the outfalls are removed further down the river, the main 
 conduit or conduits may, if thought desirable, be made of sufficient 
 capacity to include a general extension of the drainage to the whole of 
 the districts roynd London, as recommended by Sir Joseph Bazalgette 
 and Mr. Baldwin Latham. In new drainage works, the sewage should 
 be, as far as possible, separated from the rainfall." 
 
CHAPTER XVIII. 
 
 CALCULATIONS OF THE DISCHARGE OF SEWAGE OR WATER OR 
 OTHER LIQUIDS. 
 
 (154) Eytelwein's Formuloe. 
 
 The formulae for calculating the velocity of discharge, the 
 quantity of cubic feet per minute, and other data, are most accu- 
 rately obtained by the use of Eytelwein's formulae, the formulae 
 having been tested by experiment and found to agree closely. 
 
 Let d = the diameter of the pipe in inches, Q the quantity of 
 water in cubic feet per minute, I the length of the pipe in feet, 
 and Ji = the difference of level between the surface of the water 
 in the reservoir and at the end of the pipe, or the head ; any three 
 of the quantities being known, the fourth may be calculated by 
 the following formulae. 
 
 (V)d= ^/ •0^^8e^(Z + 4-2t^) 
 
 (2)e= V ^^' 
 
 0448 {I + 4-2(^) 
 
 ^^\„ 4<-2d 
 •0448 Q' 
 
 •0448 Q^ (J+4!-2d) 
 
 ^ ' -0448 q- 
 
 (4)A = 
 
 d" 
 
 These formulae are much easier worked by logarithms. Expressed 
 logarithmetically they become : — 
 
 (1) \ozd = \ [2 log Q + 2-6515 + log (1 + 4-2<i) - log h\ 
 
 (2) log g = i {1-3485 + log ;^ + 5 log cZ - log (Z + 4-2<^)} 
 
 (3) log / = 1-3485 + log /^ + 5 log d -2 log Q, [neglecting - 
 4-2i.] 
 
 (4) log A = 2 log q + 2-6515 + log (Z + 4-2cf) - 5 log d. 
 
CHAP, ivill.] 
 
 HYDRAULIC FORMULA. 
 
 217 
 
 The following are examples of the application of formulae 2 and 
 4, taken from Mr. Henry Law's useful treatise on logarithms : — 
 
 " What quantity of water will be discharged by a pipe 18 inches 
 in diameter, 5,371 feet long, and under a head of 75 feet ? 
 
 Ans. 761"9 cubic feet per minute. 
 
 "What head will be required to force 350 cubic feet per minute 
 through a pipe 15"6 inches in diameter, and 3,640 feet long 
 
 Ans. 22 789 feet." 
 
 The above formulae give the rate of discharge in pipes under 
 pressure ; but in the case of drains and sewers it is most frequently 
 required to ascertain both the velocity and rate of discharge when 
 only partially filled. Putting D for the diameter in feet of a 
 circular sewer, L for the length in feet in which the sewer falls 
 one foot, V the velocity in feet per minute, Q the quantity dis- 
 charged in cubic feet per minute, and c and s co-efficients the 
 values of which for every tenth of the diameter are given in the 
 table below, then 
 
 and. 
 
 «-v^ 
 
 Table XXIX. 
 
 Heiglit fllled. 
 Xi = l 
 
 Value of c. 
 
 Logarithm of 
 
 Value of g. 
 
 Logarithm of 
 
 8. 
 
 0-1 
 
 1424 
 
 3-153650 
 
 58 
 
 1-765107 
 
 0-2 
 
 1963 
 
 3-292853 
 
 219 
 
 2-341388 
 
 03 
 
 2337 
 
 3-368617 
 
 463 
 
 2-665651 
 
 0-4 
 
 2616 
 
 3-417631 
 
 767 
 
 2-885047 
 
 0-5 
 
 2826 
 
 3-451165 
 
 1110 
 
 3-045224 
 
 0-6 
 
 2978 
 
 3-473939 
 
 1465 
 
 3-165928 
 
 07 
 
 3076 
 
 3-488012 - 
 
 1806 
 
 3-256821 
 
 0-8 
 
 3117 
 
 3-493769 
 
 2100 
 
 3-322154 
 
 0-9 
 
 3086 
 
 3-489329 
 
 2297 
 
 3-361207 
 
 > 1-0 
 
 2826 
 
 3-461165 
 
 2220 
 
 3 346254 
 
 In the case of an oval sewer, of the usual form in which the 
 radii of the crown, sides, and invert are respectively equal to J, 
 
218 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 1 and ^, the height of the sewer being 1, putting 5" for the height 
 of the sewer in feet, and e and h co-efEcients the values of which 
 for every tenth of the height are given in the table below, the 
 values of the other letters being the same as before, then 
 
 H 
 L 
 
 and, Q = h^ 
 
 E^ 
 
 Table XXX. 
 
 Height filled. 
 
 Value of e. 
 
 Logarithm of 
 e. 
 
 Vali;eof A;. 
 
 Logarithm of 
 
 0-1 
 
 1344 
 
 3-128419 
 
 30 
 
 1-473257 
 
 0-2 
 
 1750 
 
 3 -242924 
 
 105 
 
 2-020306 
 
 0-3 
 
 2023 
 
 3-305938 
 
 219 
 
 2-340413 
 
 0-4 
 
 2231 
 
 3-348462 
 
 367 
 
 2-564759 
 
 0-5 
 
 2394 
 
 3-379206 
 
 542 
 
 2-734014 
 
 0-6 
 
 2524 
 
 3-402000 
 
 736 
 
 2-866758 
 
 0-7 
 
 2628 
 
 3-418773 
 
 939 
 
 2-972790 
 
 0-8 
 
 2686 
 
 3-429076 
 
 1134 
 
 3-054783 
 
 0-9 
 
 2687 
 
 3-429285 
 
 1283 
 
 3-108371 
 
 1-0 
 
 2484 
 
 3-395102 
 
 1268 
 
 3-103062 
 
 In the case of a circular sewer the velocity is greatest when 
 filled to 81 hundredths of the diameter, and the quantity dis- 
 charged is greatest when filled to 95 hundredths of the same ; and 
 in that of an oval sewer the greatest velocity is when filled to 85 
 hundredths of the height, and the greatest discharge when filled 
 to 96 hundredths of the same. 
 
 As an example, what will be the velocity and rate of discharge 
 in a circular sewer 2 feet in diameter, having a fall of 1 in 500, 
 -ft hen filled to a height of four-tenths of its diameter ? 
 
 Then log. D = 0-301030 
 
 log. L = 2-698970 
 
 2)3-602060 
 
 2-801030 
 3-417631 
 
 2-218661 = log. of 165. 
 
XVIII.] HYDRAULIC FORMULA;. 219 
 
 And log. 1)5=1.505150 
 log. L = 2-698970 
 
 2)2-806180 
 
 1-403090 
 
 2-885047 
 
 2-288137 = log. of 194. 
 
 Therefore the velocity will equal 165 feet per minute, and the 
 quantity discharged 194 cubic feet in the same time. 
 
 (155) Head of Water. 
 
 The terms " head " of water, " total head," " loss of head," are tech- 
 nical, and apply to height of water. Thus with a pipe 20 feet high 
 connected with a reservoir which has 6 feet of water in it; if the 
 pipe be filled, at the orifice of the tap, there would be a pressure 
 of water, equal to the height of the water above the orifice of the 
 tap and this would be a head equal to 26 feet. It could however be 
 proved, that the theoretical velocity due to a column 26 feet high, 
 at this point would not be quite attained, because of the more or 
 less rough state of the interior of the pipe ; this is expressed by 
 loss of head due to friction. The pressure of water in the pipe 
 just considered is called " hydrostatic pressure," to distinguish it 
 from " hydraulic pressure," which is the pressure in flowing water, 
 the other being the pressure in still water. There is an important 
 distinction between the two, for in the latter the pressure is 
 generally a changing pressure ; for instance, in the case of the cistern 
 being emptied, as the level of the water lowered there would be a 
 continual " loss of head." 
 
 Supposing that there is, no friction, the loss of head in producing 
 a given increase of velocity is equal to the height of vertical fall 
 which would produce the same increase of velocity in a body fall- 
 ing freely; this may be expressed as the loss of bead equals the 
 height due to the acceleration ; if the particle start from a state of 
 rest, that height is called the height due to the velocity, and is 
 given by the following formula, where v equals the velocity in feet 
 per second, and h = the height in feet. 
 
 Then v = 8-025 V^ ; and if A = 20, then v = 8-025 X 4-47 = 35-87. 
 
 If friction is taken into account a co-efficient F is got out by 
 
220 A MANUAL OF PUBLIC HEALTH. [cSap. 
 
 experiment expressing the proportion which the loss of head by 
 friction bears to the height due to the velocity, and the formula 
 becomes 
 
 .=8-025 ^Jy 
 
 Supposing it be required to find the velocity for the flow ef 
 liquid at two different inclinations, the velocity in the one case 
 being given, it is easy to find the other, for the velocity will vary 
 inversely as the square roots of the fall. 
 
 For example, if the velocity in a sewer is 65 ft. per second with 
 
 a fall of 25 ft. in 100, and it is desired to know what would the 
 
 velocity be if the same sewer had a fall of 4 ft. in 100, it may 
 
 be stated as follows : as \/4 : 65 : : V25 = 26 ft. per second, for the 
 
 2 
 square root of 4 is 2 and the square root of 25 is 5, and •= of 65 = 
 
 26 ft. per second, or putting it the converse way, supposing a fall 
 of 4 ft. per 100 gives a velocity of 26, what will a fall of 25 
 
 5 
 in the same length produce ? then ^ x 26 = 65 ft. per second. 
 
 If a fall of 1 in 100 gives a velocity of 13 ft. per second, what 
 will be the velocity if the same pipe is placed perpendicularly ? 
 
 In this latter case the fall is of course 100, then _ x 13 = 
 
 VI 
 
 130 ft. per second. 
 
 If again the question is put as follows : A sewer laid with a fall 
 of 9 ft. in 100 gives a velocity of 39 ft. per second, what will 
 be the velocity in a sewer of the same size laid with a fall of 
 1 ft. per mile ? 
 
 1 mile = 5,280 ft., hence ^^ = '01895 ; and the fall is 
 
 therefore '01895 in 100, ^"^-^''^ x 39 = '1768 ft. per second. 
 
 v''9 ^ 
 
 (156) Kutter's Formula. 
 
 This is a formula which has recently been simplified by Mr. R. 
 Hering.^ The original formula reads : — 
 
 1 Engineers' Club, Philadelphia, June, 1888 ; Sanitary News, December, 1888. 
 
XVIII.] HYDRAULIC FORMULA. 221 
 
 (1) 41.6 + 1:811 + 0:20^ _ 
 
 n s I rs. 
 
 ^"~' 7~~~ 0-00281 \ n ^ 
 
 i + (4r6f-^-;^ 
 
 in which : 
 
 V = velocity in feet per second. 
 
 n = coefficient of roughness of wetted perimeter. 
 
 r = hydraulic radius. 
 
 s = slope of water surface. 
 
 The term , which occurs twice, can be readily eliminated 
 
 by substituting for the value s the least grade that we are likely 
 'to have in sewers — namely, 1 : 2500. Then we obtain the constant 
 
 value : -7^^7777^7- = 7'0, which reduces the formula to : 
 0-0004 
 
 (2) 48-6 + 1:^ 
 
 1 + 48-6 -^ 
 
 4/rs. 
 
 This substitution influences the result but little. It tends to 
 make the smaller sewers slightly larger than the original formula. 
 There would be in fact no difference at all for a sewer about 
 13 ft. in diameter, whatever its grade, and the difference would 
 increase, as the size diminishes and the grade increases, up to an 
 excess of about 5 per cent, for a sewer of 1 ft. diameter, at a grade 
 of 4 ft. for 100. This excess of about 5 per cent, is practically 
 the maximum error for sewer application, and it is always on the 
 safe side. 
 
 But the formula can still further be simplified by substituting a 
 numerical value for n. 
 
 According to Kutter, for glazed pipe we would have to put 
 n = '010. But owing to .the frequency of joints and the imperfect 
 shape due to the process of burning, which causes projection in the 
 sewer at nearly every joint, it is not safe to assume so low a co- 
 efiieierit. Besides, the flow of sewage is slower than that of clear 
 ■watetj because the suspended matter drags at the perimeter and 
 tends to hold the water back. Allowing for these causes we 
 generally get nearer the truth if for pipe-sewers we put n = -013. 
 
222 
 
 A MANUAL OF PUBLIC HEALTH. [chap, xviii. 
 
 For brick sewers, on the other hand^ Kutter gives n = '013. 
 
 It has been found, however, that if well built n can often be 
 reduced to '012. Still, for sewage flow, the resistance is again 
 greater, and Hering finds that by adopting the value oi n = "013 
 also for brick sewers we are about as nearly correct as it is neces- 
 sary to be in the majority of cases, and err slightly on the safe side, 
 if we err at all. 
 
 By substituting this value in formula 2 we get : 
 
 (3) 
 
 188 V^s 
 
 1 + 
 
 0-63 
 
 or. 
 
 (4) 
 
 V = 
 
 sir 
 188 r Vs 
 
 0-64 + sir 
 
 which is, therefore, not only a sufliciently accurate, but also a 
 sufficiently simple, formula for general use in sewer work. 
 Stated in general terms, the formula reads: 
 
 (5) _ A r ^s 
 
 ~ B+Jr. 
 
 By substituting the following values for the coefficients A and B, 
 it can be used for any other degree of roughness than n = "013 as 
 may be thought proper. 
 
 Table XXXI. 
 
 Different Degrees of Roughness. 
 
 A. 
 
 B. 
 
 For = n O'Oll, very smooth, with even joints 
 For = n 0'012, very smooth, with even joints . . 
 
 For = n O'OIS, average, with even joints 
 
 For = n 0-014, average, with even joints 
 
 For = re 0'015, poorly built brick work, with \ 
 washed out joints J 
 
 213 
 
 200 
 188 
 178 
 
 169 
 
 0-54 
 0-59 
 0'64 
 0-69 
 
 0-73 
 
 For very smooth and regularly-shaped sewers we might say ; 
 
 V = 
 
 200 r sis 
 0-6 -I- sir' 
 solved. 
 
 which formula is easily remembered and easily 
 
CHAPTER XIX. 
 
 DISPOSAL OF SEWAGE. 
 
 (157) Irrigation of Zand. 
 
 There are two kinds of irrigation, " broad irrigation " and " inter- 
 mittent filtration." These are thus distinguished by the Royal 
 Commissioners on Sewage Discharge : " Broad irrigation means the 
 distribution of sewage over a large surface of ordinary agri- 
 cultural ground, having in view a maximum growth of vegetation 
 (consistently with due purification) for the amount of sewage 
 supplied. Filtration means the concentration of the sewage, at 
 short intervals on an area of specially chosen porous ground, as 
 small as will absorb and cleanse it ; not excluding vegetation, but 
 making the produce of it of secondary importance. The inter- 
 mittency of application is a sme qud nan even in suitably 
 constituted soils, wherever complete success is aimed at." 
 
 In broad irrigation, the sewage is simply delivered in special 
 channels on to the land, which should be well drained, and vege- 
 tables and crops grown thereon; it is a plan well adapted to certain 
 villages and small towns, where local circumstances are favourable. 
 The best soil is that of a sandy loam, its successful application 
 requires about 1 acre to every 120 of the population. Broad 
 irrigation has been lately carried out on a large scale at Berlin. 
 English examples are Croydon, Cheltenham, and Blackburn. 
 
 Intermittent downward filtration, has been for some years the 
 favourite method of dealing with sewage, the sewage going on to 
 the filter beds in the crude state, or after first previous precipi- 
 tation, the beds receive the effluent; a very perfect method of 
 purification is secured by this last process. 
 
 The principle of making filter beds for intermittent filtration 
 
224 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 may be exemplified by a brief description of those at Merthyr- 
 Tydvil (population 14,.500), 20 acres of land are used for the 
 filtering areas. 
 
 The sewage is first treated with lime, and is strained in special 
 tanks through cinders ; it then flows on to the conduit which conveys 
 it to the filtering areas, these last being arranged on a plan devised 
 by Mr. Bailey Denton. The land is a loamy soil, 18 in. thick 
 overlaying a bed of gravel. The whole area is underdrained to a 
 depth of from 5 to 7 ft. Lateral drains placed at regular distances 
 the one from the other run towards the main or effluent drain, 
 which drain is everywhere 6 ft. deep. The surface of the land 
 has been formed into beds ; these slope towards the main drain 
 with a fall of 1 : 150. The surface is ploughed iuto ridges; on 
 these, vegetables are planted or seeds sown ; the line of the ridged 
 furrow is in the direction of the under drain. Along the raised 
 margin of each bed in each area delivering carriers are placed, one 
 edge being slightly depressed. The strained sewage passes from 
 the conduits into the delivering carriers, and as it overflows the 
 depressed edges, runs gently into and along the furrows down 
 to the lowest and most distant part of the plot. The sewage 
 continues to be so delivered for six hours ; then an interval of rest for 
 eighteen hours takes place and again the land is thoroughly charged 
 with the fertilising sfream. The water percolates through the 
 6 ft. of earth, and reaches the lateral drains, which convey it to the 
 main effluent drain. In addition to this land, used as filtering 
 areas, there are a number of acres laid out for irrigation. 
 
 Intermittent irrigation is now carried on largely both at home 
 and abroad, with the most satisfactory results as regards purity 
 of effluent, but with varying results as to the money value 
 of the resulting crops, in some cases a considerable return being 
 received, in others the returns have not been satisfactory ; this is 
 what might be expected, the conditions of the soil and other things 
 varying. 
 
 One of the most unsuitable lands for intermittent irrigation is a 
 stiff clay soil, but even here it is stated that a good filter bed can 
 be constructed at a cost of about £600 to £800 per acre by 
 burning the clay into ballast and laying down the ballast to a 
 depth of about 3 ft. with layers of alluvial or other rich soil 
 interposed. 
 
XIX.] 
 
 THE PRECIPITATION OF SEWAGE; 
 
 225 
 
 (158) Chemical Processes for the Treatment of Se^oage. 
 
 The number of processes for the clarification of sewage which 
 have been proposed and patented are very numerous, as may be 
 seen from the following list of patents : 
 
 Table XXXII. 
 
 Names of Substances. 
 
 Inventor. 
 
 Date. 
 
 Sulphate of iron . . 
 
 Deboissieu 
 
 1762 
 
 Chlorine .... ... 
 
 Halle 
 
 1785 
 
 Lime . . 
 
 Estienne 
 
 1802 
 
 Powdered charcoal 
 
 Giraud ... 
 
 1805 
 
 Chlorine and chloride of lime ... 
 
 Guyton Morveau . 
 
 1805 
 
 Ashes . . . 
 
 Chaumette 
 
 1815 
 
 Sand 
 
 Duprat 
 
 1818 
 
 Sulphate of iron 
 
 Hriant . . . 
 
 1824 
 
 Chloride of sodium .... 
 
 Labarraque . . . 
 
 1824 
 
 Waste chloride of manganese 
 
 Payen and Chevalier 
 
 1825 
 
 Sulphate of lime . 
 
 Siret 
 
 1827 
 
 Animal charcoal ... ... 
 
 Frigerio : 
 
 1829 
 
 Peat 
 
 Guibourt and Sanson 
 
 1833 
 
 Charcoal and calcined marl or river mud 
 
 Pottevin 
 
 1836 
 
 Sulphates of iron and zinc with tan and tar . 
 
 Siret ... 
 
 1837 
 
 Earth, lime and waste substances 
 
 Rossier 
 
 1837 
 
 Peat ashes 
 
 DArcet 
 
 1840 
 
 Metallic oxides and carbon 
 
 Krafft and Suequet 
 
 1840 
 
 Chloride of zinc . 
 
 Sir Wm. Burnett . 
 
 1840 
 
 Schist coke .... 
 
 Hompesch . 
 
 1841 
 
 Trade refuse, charcoal, and ashes . 
 
 Albert . ... 
 
 1842 
 
 Powdered lignite . . . 
 
 Jourdan . 
 
 1843 
 
 Impure alum .... ... 
 
 Siret 
 
 1843 
 
 Sulphate of zinc, charcoal, and clay 
 
 Gaguage andRegnault . 
 
 1844 
 
 Persulphate of iron ... 
 
 Baronnet . 
 
 1845 
 
 Schist coke .... 
 
 Du Boisson 
 
 1845 
 
 Chlorides of iron and zinc ... 
 
 Dubois . ' . 
 
 1846 
 
 Lime and precipitating tanks 
 
 Higgs ... . . 
 
 1846 
 
 Nitrate of lead 
 
 Ledoyten 
 
 1847 
 
 Waste salts of iron, lead zinc, &c. , with pyrol ig- \ 
 neous matters, ashes, &c / 
 
 Brown . 
 
 1847 
 
 Pyrolignate and perchloride of iron 
 
 EUerman 
 
 1847 
 
 Impure chloride of manganese 
 
 Young 
 
 1847 
 
 Dried sea-weed, lime, and sulphate of lime and "1 
 
 zinc . . j" 
 
 Peat charcoal 
 
 Salman . .... 
 
 1848 
 
 Rogers 
 
 1848 
 
 Charcoal, soot, mineral salts &c. 
 
 Legras . 
 
 1849 
 
 Spent tan, carbonised 
 
 Tarling 
 
 1850 
 
 Fresh bark, sulphate of iron, and peat charcoal . 
 
 Angely . . 
 
 1850 
 
 Metallic sub-salts, as of iron, alumina, &o. 
 
 Browne . . . . 
 
 1850 
 
 Milk of lime and collecting the deposit .... 
 
 Wicksteed 
 
 1851 
 
 Acids and metallic salts, and flltrations \ 
 through charcoal, clay, peat, gypsum, &c. \ 
 
 
 
 Dover ... . ' 
 
 1851 
 
226 
 
 A MANUAL OF PUBLIC HEALTH. 
 Table XXXIT. (continued). 
 
 [CHAP« 
 
 Names of Substances. 
 
 Inventor. 
 
 Date. 
 
 Lime, sulphates of alumina, and zinc, and \ 
 
 charcoal j 
 
 Lime, magnesian earth, sulphate of zinc or 1 
 
 iron, and vegetable charcoal . . J 
 
 Sifted ashes, breese, or peat charcoal 
 
 Sulphate of zinc, potash, alum and sand with \ 
 
 waste tan, ashes, lime, soot, &c. . . / 
 
 Metallic sulphates, metallic chlorides, or char- \ 
 
 coal and magnesian salts ... . j 
 
 Salts produced in working galvanic batteries . 
 Peat or bog earth containing salts or oxides of 
 
 iron 
 
 Peat and other charcoal and chloride of sodium, 1 
 
 &c / 
 
 Animal charcoal, alum, carbonate of soda and j 
 
 gypsum ( 
 
 Magnesia and lime with sulphurous and car- 1 
 
 bolic acids ... . . . j 
 
 Lime and finely-divided charcoal 
 
 Boghead coke .... 
 
 Soft sludge from alum works with lime and 1 
 
 charcoal . . J 
 
 Peat charcoal carbonised with oil of vitriol . . 
 Alum schist or shale, and other aluminous \ 
 
 mineral, with lime and charcoal . . J 
 
 Manganates and permanganates 
 
 Superphosphate of lime with magnesia and lime 
 
 Stothert . 
 
 1852 
 
 Gilbee 
 
 1852 
 
 Perks 
 
 1852 
 
 Pinel 
 
 1853 
 
 Herapath 
 
 1853 
 
 Dering 
 
 1853 
 
 Dimsdale 
 
 1853 
 
 Macpherson 
 
 1853 
 
 Manning 
 
 1853 
 
 Smith and McDougall . 
 
 1854 
 
 Wicksteed . 
 Herapath 
 
 1854 
 1854 
 
 Manning 
 
 1854 
 
 Longmaid 
 
 1855 
 
 Manning 
 
 1855 
 
 Condy 
 Blyth .■ 
 
 1857 
 1858 
 
 The chief processes which have survived, and are in actual use 
 are those in which lime, salts of iron, and salts of alumina are 
 used either singly or in combination, examples therefore will 
 be considered under these respective headings ; but, it will first be 
 useful to state the nature of the liquid to be treated, and next the 
 chemical action by which a precipitate is formed and the method 
 of its action. 
 
 (159) Composition of Sewage. 
 
 Sewage is a very complex liquid, varying according to the season, 
 water supply and manufactories in reaction and content of solid 
 matter. It is usually alkaline, save the sewage of towns like 
 Birmingham, in which vast volumes of " pickling " or strongly acid 
 liquors are cast into the sewers. It contains soluble and insoluble 
 compounds of fatty acids with bases, ammonia, sulphide of am- 
 monia, finely divided cellulose derived from paper, fatty matters. 
 
XIX.] THE PRECIPITATION OF SEWAGE. 227 
 
 and many other soluble and insoluble substances. According to 
 the Rivers Pollution Commission, the average composition of water 
 closet towns sewage, in 100,000 parts is 4!4-69 parts of suspended 
 matters, of which 2418 are mineral, the rest organic, 72-2 parts of 
 solid matters are in solution ; that is to say, a sample of carefully 
 filtered sewage on evaporation would leave solid matter in that 
 proportion. A gallon therefore contains 50'5 grains of dissolved 
 matter, a quantity which might about fill a teaspoon; the total 
 nitrogen in the 100,000 parts is about 7"7 but the extremes vary 
 widely. The dry weather sewage of the metropolis is estimated 
 as containing 60 tons of sewage per annum per head (224 gallons 
 weigh a ton) ; the lowest money value which can be assigned to this 
 is over £1,000,000. 
 
 (160) General Reactions on the addition of Livie, Iron, or 
 
 Alumina. 
 
 If to this complex liquid either hydrated lime or a solution of 
 lime be added a precipitate is formed, the lime combines with the free 
 carbonic acid or it decomposes carbonates of the alkalis, and slowly 
 sinks to the bottom as lime carbonate ; in sinking it carries down a 
 considerable portion of organic matter and thus clears the liquid. 
 
 If a salt of iron is added, such as sulphate of iron, the reaction 
 is more complex, the sulphuric acid combines with the lime salts, 
 and the result is that protoxide of iron is first formed. This acts as 
 a carrier of oxygen, and the precipitate as before carries down in 
 subsiding large quantities of organic matter some of which it may 
 oxidise. If the iron salt is used alone the efiluent is slightly acid. 
 Subsequently any sulphide of ammonium present is decomposed 
 and iron sulphide formed, and the sewage becomes from this reason 
 more or less black. Sulphate of alumina when added to sewage is 
 decomposed very similarly to sulphate of iron, hydrated alumina 
 oxide being formed and slowly sinking to the bottom, lime or 
 carbonate of lime in the presence of sulphate of alumina is con- 
 verted into sulphate of lime. 
 
 (161) Lime Process. 
 
 Save when the sewage is acid, the proper amount of lime to add 
 according to Dr. Stevenson should not exceed the hardness of the 
 
 Q 2 
 
228 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 water supply, that is to say, if the water supply possesses 12 degrees 
 of hardness, then add 12 grains per gallon of lime. The lime is 
 usually added in the form of milk of lime, that is to say slacked 
 lime is mixed with water until a thin white sort of emulsion is 
 formed. The Commission reported that the lime process was very 
 simple and the least costly of any, but that it could not be profit- 
 able in an agricultural sense, and did not purify the sewage. 
 
 The lime process has been tried at Tottenham, at Blackburn and 
 at Leicester. 
 
 (162) Alumina Processes. 
 
 The phosphate process of Messrs. David Forbes, F.R.S., and 
 A. P. Price is an alumina process ; phosphate of alumina is dissolved 
 in hydrochloric or sulphuric acid and the solution added to the 
 sewage. 
 
 Bird's process is the addition of a crude sulphate of alumina to 
 sewage, the sulphate is formed by decomposing clay (that is alumina 
 silicate) by sulphuric acid. The proportions used are 6 cwt. of 
 pulverised clay and 120 lbs. of sulphuric acid to 200,000 gallons of 
 sewage. It is in use at Stroud. The effluent is acid. 
 
 (163) Salts of Iron. 
 
 The "Sewage Purification Company" treat a powdered magnetic 
 iron ore with sulphuric acid ; the result is of course a solution of 
 sulphate of iron, this is added in due proportion to the sewage; the 
 effluent is acid. 
 
 (164) Various Mixtures. 
 
 In General Scott's 'process 10 cwt. of lime, and 5 cwt. of clay are 
 added to 400,000 gallons of sewage, the sludge is burnt in a kiln, 
 and ground into cement. General Scott's process was tried at 
 Ealing. 
 
 Silk's process was tried at Wimbledon. It consists in adding to 
 the sewage a mixture of 100 parts of lime, 6 of tar and 12 of 
 calcined magnesium chloride. 
 
 Holdens process is the use of a precipitant consisting of a mixture 
 of sulphate of iron, lime, and coal dust. 
 
 The A, B, G process consists in adding a mixture of ammonia, alum, 
 clay, charcoal, Epsom salts (magnesic sulphate) and blood to sewage. 
 According to the second report of the Rivers Pollution Commission 
 
XIX.] THE PRECIPITATION OF SEWAGE. 229 
 
 the practical application of the process was as follows: 1,027 gallons 
 of river water held suspended or dissolved 3 cwt. of ammonia 
 alum, 6 cwt. of moist clay, 15 lbs. of animal and 20 lbs. of vege- 
 table charcoal, 20 lbs. of Epsom salts, and 4 lbs. of fresh blood in 
 a magma of clay ; this liquid the Commissioners found discharging 
 into the sewage at the rate of about 210 gallons per hours at 
 Leamington. 
 
 Br. Anderson's process has been tried at Coventry. The sewage 
 was mixed with a saturated solution of sulphate of alumina heated 
 to the boiling point, the crude sulphate being made on the spot by 
 means of sulphuric acid acting on clay or shale; after this treat- 
 ment the sewage flowed on and was treated with milk of lime. 
 According to the Commissioners the money results were not 
 encouraging. 
 
 (165) Sewage Sludge. 
 
 From any of the above processes result a sludge and an effluent ; 
 the latter is sent into the nearest watercourse, the former requires 
 special treatment. In some cases, as at Coventry, the sludge is 
 reduced in bulk and made fairly dry by compression in Johnson's 
 filter presses. These presses consist of a number of grooved discs 
 arranged in series, each disc having a central perforation and being 
 separated from the disc on each side by means of a filtering cloth. 
 The liquid sludge is filtered through these cloths by air compressed 
 at a pressure from 100 to 120 lbs. per square inch. The liquid 
 escapes fairly rapidly, while the solid matters remain behind in a 
 more or less solid cake : this is found the least expensive way of 
 drying. In some cases the sludge is burnt, as at Acton, where tlie 
 solid matters are mixed with house refuse and consumed without 
 nuisance in a destructor. 
 
 (166) Summary of Precipitation Processes. 
 
 Dr. Corfield sums up the matter with regard to the processes of 
 precipitation as follows : "All these precipitation processes to a certain 
 extent purify the sewage and prevent the pollution of rivers, chiefly 
 by removing the suspended matters from the sewage ; but they all 
 leave a very large amount of putrescible matter in the effluent 
 water, and at least all the ammonia contained in the sewage (some- 
 times they add to it) ; the greater part of the phosphoric acid is 
 
230 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 precipitated by some of them, while they increase the hardness of 
 the river -water, a matter of great importance if the stream be 
 a small one. 
 
 " The manures that they produce are in every case very inferior, as 
 may be expected from the known value of the sewage constituents 
 which can be precipitated. They have all failed in producing 
 valuable manure, because the valuable constituent of sewage par 
 excellence is the ammonia, which of course invariably escapes in the 
 effluent water and is lost to the manure; this shows the futility of 
 all attempts to utilise sewage by precipitation alone." 
 
 Finally, there can be little doubt that the ultimate solution of 
 the sewage problem is the utilisation of the sewage on land, either 
 carrying it direct to the land, or in certain cases a combination of 
 precipitation and irrigation by intermittent filtration. 
 
 Special Systems of Sewerage. 
 (167) The Shone System. 
 
 In this system sewage is raised to the required height by means 
 of compressed air. Its chief use is in towns which are unfavourably 
 situated for disposal of the sewage by gravitation ; it is in operation at 
 Eastbourne, Wrexham, Southampton, Warrington, Henley and the 
 Houses of Parliament, Westminster. 
 
 (168) The Liermir System. 
 
 This is in operation at Amsterdam and seems there to have given 
 good results. Two separate sets of drains are required ; the one is 
 devoted exclusively to the evacuation of household waste water, 
 rain water, and waste liquids from factories, these drains open into 
 the canals. The second system of pipes receives the urine and 
 sewage ; the pipes are of small diameter (5 inch) and are connected 
 with cylindrical iron reservoirs, in which a vacuum is maintained 
 by means of powerful air vacuum pumps worked from a central 
 station. The sewage is forcibly sucked into the reservoirs, 
 hence the air from these small sewers never escapes into the 
 house, any current set in motion being from the house to the 
 reservoirs. The concentrated sewage thus obtained is dried and 
 made into a poudrette, a valuable manure. 
 
XIX.] SPECIAL SYSTEMS OF SEWAGE DISPOSAL. 231 
 
 The Berlier system is in principle an exhaust pneumatic system 
 very similar to the Liernur, it has been applied to a portion of 
 Paris with great success. 
 
 (169) The Treatment of Sewage hy Electrolysis. 
 
 This is the most recent method of treating sewage and is being 
 carried on experimentally at Crossness. It is the invention of 
 Mr. Webster, F.C.S. The sewage is electrolysed by flowing 
 through long troughs, fitted at short intervals with large iron 
 plates, the electricity being supplied by an Edison-Hopkinson- 
 dynamo of 25 horse power giving an output of 1,600 amperes and 
 20 volts ; the quantity that such a dynamo can deal with is a million 
 gallons a day. 
 
 The chlorides in the water are split up at the positive pole, the 
 nascent chlorine and oxygen unite forming hypochlorous acid, 
 which partly attacks the organic matter, and partly attacks the 
 iron plate forming hypochlorite of iron ; at the negative plate, 
 potash, soda, magnesia, ammonia, &c., are set free. The ferrous 
 hypochlorite formed at the positive pole is acted upon by the free 
 bases, that is by ammonia, sodium, potassium and magnesium hydrate 
 and thus decomposed ; a precipitate of ferrous hydrated oxide is 
 produced. The bubbles of gas, buoy the hydrated oxide of iron 
 up for some little time, so that the first effect is the reverse of 
 precipitation, thd under liquid becoming clear while the surface is 
 thick with scum. As the fluid flows on to a precipitating tank, 
 the gases diffuse into the atmosphere and then the oxide of iron 
 falls to the bottom carrying with it most of the organic matters. 
 The effluent is a fair one, the sludge can be pressed through a 
 filter press or otherwise used. 
 
 (170) Dry Systems of Sewage Disposal. 
 
 Dry conservancy requires examination by modern bacteriological 
 methods, it is by no means certain that a great number of patho- 
 genic bacteria are by this system not preserved, instead of 
 destroyed, whereas we know from actual experiment that in 
 water carriage systems numerous harmful bacteria are absolutely 
 destroyed by soaking in water ; for example the bacillus anthracis, 
 when not in the spore state is rapidly disintegrated if placed in 
 
232 A MANUAL OF PDBLIC HEALTH. [chap. 
 
 water. Putting these unsolved questions on one side and pre- 
 suming that no harm results from the preservation of deodorised 
 excreta in the vicinity of dwellings for a longer or shorter period 
 according to facilities for scavenging, it has been found to be fairly 
 successful for small communities, as for instance at Wimbledon 
 camp and in various schools and institutions. 
 
 The type of the dry earth system is Moule's earth closet, which is 
 merely a wooden box with a pail beneath, a reservoir of dry earth 
 above and a simple apparatus for measuring and applying the 
 requisite quantity of dry earth. In the cheaper kinds of closet, the 
 earth is thrown on the excreta by hand ; in the dearer kinds, there 
 is an automatic arrangement. The quantity of dry earth necessary 
 to use each time is about 1 lb. 
 
 The suitability of various soils is in the following order : (1) rich 
 garden mould ; (2) peaty soils ; (3) black cotton soils ; (4) clays ; 
 (5) stiff clayey loams ; (6) red ferruginous loams ; (7) sandy loams ; 
 (8) sands. It will almost be necessary to provide some other means 
 of disposing of the slop water, which wiU also contain a considerable 
 portion of the urine. One of the best methods of disposing of the 
 slop water of a village provided with earth closets is by sub-irrigation. 
 That is, to convey the slop water to a suitable area, into drains as 
 follows : common agricultural drains are laid 12 in. deep upon a 
 bed of larger pipes divided longitudinally in half; the slop water 
 escapes at intervals between the joints of the agricultural pipes 
 and is absorbed by the earth, and serves as a fertilizer for 
 vegetation. In many cases an automatic flush tank connected 
 with the sub-irrigation area is necessary. In isolated communities 
 and villages favourably situated, the slop water runs into open 
 channels, into fields, or is received in streams, and so long as the 
 latter are not used for drinking purposes and no nuisance is created, 
 it is not wise to meddle with these primitive arrangements. 
 
 (171) The Pail System. 
 
 This is after all but a variety of dry conservancy. It is in use in 
 many of the large northern and midland towns, either wholly or 
 partially, such as e.g. Eochdale, Nottingham, Birmingham, Leeds, 
 Halifax, Edinburgh, Nottingham, Manchester and Salford. 
 
 In some places, notably in Glasgow, the excreta are placed in a 
 movable receptable without any absorbent material and carted 
 
xis.] WATER CLOSETS. 233 
 
 away daily. The pail system in its best form involves some kind 
 of absorbent material in the pail, for example in what is known as 
 the " Goux System," called also " The Patent Absorbent Closet 
 System" mixtures of any kind of vegetable and animal fibrous 
 substances useless for other purposes are used as absorbents and 
 these are mixed with a small proportion of iron or lime sulphate. 
 These matters are pressed closely to the bottom and sides of the 
 tub by means of a cylindrical mould which is afterwards withdrawn, 
 leaving a cavity in the centre for the reception of the excreta. 
 When these pails are emptied every two days, the results are good, 
 but longer keeping usually exhausts the absorptive power. 
 
 A method of receiving urine into a mixture of salt and soot was 
 exhibited in the Health Exhibition at Bolton in 1887, and received 
 an award. This mixture certainly preserves to a remarkable degree 
 urine and excrementitious matters generally, and the resulting 
 mixture has a high manurial value. The trough latrines of 
 Glasgow and Edinburgh Dr. Corfield considers as in effect the 
 pail system adapted to large collections of people. This differs 
 from the trough water-closets in not being connected with the 
 sewers and requiring special scavenging arrangements for removal. 
 A long fixed trough, slightly inclined towards one end, runs along 
 under the seats of a row of closets ; it is charged with only a small 
 quantity of water and receives the total fluid and solid excrement 
 of those using it. In the Glasgow factories there, is one of these 
 latrines to about every 180 to 200 hands ; the contents are emptied 
 daily down a vertical pipe into a large closed tank placed close to 
 the ground, from this tank the contents are transferred to a closed 
 cart and removed. 
 
 (172) Water Closets. 
 
 The position of a water closet should be where possible at the 
 back of the house, and if in structural connection with the house 
 a short passage or lobby interposed, possessing facilities for cross 
 ventilation. All modern houses are built this way, but occasionally 
 in old houses, the closet will be found in the centre of the building. 
 In such a case the author has ventilated the closet fairly satisfactorily 
 by carrying a Tobin's tube into the closet, and running up from the 
 ceiling a 4 in. zinc pipe to the roof, a continuous up draught being 
 created by a small jet of gas burning beneath the opening of 
 the shaft. 
 
234 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 There are three main types of water-closets, viz. : the pan water- 
 closet, the valve closet, and the hopper closet. The pan closet is 
 perhaps the most common form, and taking it all in all the most 
 insanitary. The closet pan is closed, see Fig. 41 at the lower end 
 by a sort of deep saucer which always contains a little water, and 
 can be made to swing downwards by pulling the handle of a lever 
 to which it is connected ; the cavity in which it swings is called a 
 container and is usually made of iron, from the container the closet 
 contents pass into a D trap. The result of this arrangement is 
 that the container gets soiled with offensive matter and cannot be 
 
 Fig. 41. 
 
 Fig. 42. 
 
 cleaned and is in effect a reservoir of foiil air, the Q trap is also 
 one of the worst forms, and gets coated with excretal matters and 
 often corroded by gases and liquids ; it is likewise a smaller foul air 
 reservoir. From these foul air reservoirs foetid gas bubbles up and 
 escapes whenever the closet is used. The original valve closet was 
 the " Bramah." The lowest part of the basin is closed with a tight- 
 fitting valve moving in a valve box, the box only being just large 
 enough to allow of this movement, below the valve box is a syphon. 
 To such closets there is an overflow pipe from the closet pan to prevent 
 the accidental overflow of the flushing water over the edge of the 
 basin (see Fig. 42). The overflow pipe as a rule passes into the valve 
 box, and has a syphon bend. There is however some difficulty in 
 keeping this overflow pipe properly trapped, and there have been 
 
XIX.] WATER CLOSETS. 235 
 
 invented various contrivances for this purpose, e.g. in " Jenning's '' 
 valve closet the overflow is trapped by means of an India rubber 
 ball, the ball allowing water to pass it in one direction, but any 
 pressure of gas in the other only causes the ball to fit more closely 
 to the end of the pipe. In Dent and Hillyer's valve closet, the 
 overflow pipe is made larger than usual, so that the water seal is of 
 greater bulk, besides which pressure in the valve box is rendered 
 impossible, for a ventilating pipe is inserted into the valve box and 
 continued into the open air. A better way to deal with the over- 
 flow pipe is to disconnect it from the valve box and carry it into 
 the open air similarly to the warning pipe of a cistern, or to let it 
 deliver it on the safe tray of the closet, and thus any waste will go 
 down the waste pipe of the safe tray. 
 
 The hopper closet differs from either of the two previous closets 
 in having no mechanical parts ; it is simply a funnel terminating in 
 a syphon, all that is required is a good flush of water and the 
 contents pass away (Fig. 43). An improved form of the hopper closet 
 
 Fig. 43. Fis. 44. 
 
 is what is known as the " wash-out closet ; " this again has no 
 mechanical parts, it is often made of glazed stoneware cast in a 
 single piece, the closet is simply cleansed after use by a good flush 
 of water (Fig. 44). 
 
 It is the custom to place a lead tray beneath closet pans on the 
 floor, to prevent any overflow soaking through into the ceiling 
 below. This is called a " safe ; " there is a waste pipe from the safe, 
 sometimes carried into the soil pipe, and sometimes into the D-trap 
 it ought of course to be carried into the open air direct. The safe 
 is usually boxed in together with the lower part of the closet by 
 wood casing, and the whole space is not unfrequently a receptacle of 
 dirt and filth and a cause of air contamination. The most modern 
 closets have no safe, nor wood casing ; the best form of all is without 
 
236 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 doubt, of the wash-out type, the basin and syphon of which are 
 freely exposed to view, in which mechanical parts are absent, and 
 in which deposits in the syphon or around the pan are rare. 
 
 The supply pipe to all the closets mentioned should be of 
 sufficient size, 1^ inch is the least admissible diameter for the supply 
 pipe of a closet ; the supply pipe should under no circumstances be 
 directly connected with the drinking water cistern, nor what is still 
 worse, with the service pipe of a constant supply system. Closets 
 should have a separate cistern, or what is called a water waste 
 preventing cistern. This holds a charge of two gallons, the whole 
 of which runs into the closet when the valve is pulled. The 
 mechanical arrangement of this cistern is usually as follows : a 
 spindle valve guards the opening of the flushing pipe going to the 
 pan, the spindle valve is connected with a lever to which is 
 attached a chain and ring; on pulling the chain, the spindle valve 
 is raised and the water rushes out. The supply pipe is connected 
 with the usual floating ball cock arrangement ; when the cistern is 
 full the ball cock floats up and shuts off the supply, when the 
 cistern is empty the ball falls and the supply is opened. It must 
 also be noted, that the apparatus connected with the spindle valve, 
 by which the cistern is emptied is so arranged, that when the chain 
 is pulled, the ball is also lifted and prevented from descending, so 
 that until all the water is run out of the small cistern, water from 
 the supply pipe does not enter. In this way also there is no chance 
 of contamination by any foul gas which has made its way into the 
 waste preventer. It may be necessary to observe that the waste 
 preventer cistern must be a sufficient height above the closet to 
 ensure a good flush, the writer has known them placed almost at 
 the seat level. 
 
 (173) Soil Pipes. 
 
 The best material for soil pipes is lead. Lead soil pipes used 
 formerly to be seamed, that is to say, each piece of the pipe was 
 made by taking a long strip of lead, rolling it into a cylinder and 
 joining the two edges by a seam. In this way there were not alone 
 the usual transverse joints between the different portions of the 
 soil pipe but also a seam or joint down the middle. Experience has 
 amply shown that seamed pipes are liable to open, and they are now 
 replaced by " drawn pipes " in which there are no longitudinal seams. 
 
XIX.] SOIL PIPES. ?37 
 
 The diameter of a soil pipe should be at least 4 inches ; its best 
 position is outside the house, not inside ; nevertheless a pipe carried 
 inside is not a source of injury providing the joints are tight ; in 
 many instances the soil pipe must be carried inside. The next best 
 material for a soil pipe is iron, but this is not suitable for inside 
 pipes from the difficulty in making the joints absolutely perfect. 
 Zinc soil pipes rapidly corrode and are therefore undesirable. The 
 soil pipe should be ventilated ; this is best done by carrying or 
 rather continuing the soil pipe full bore without curves or bends to 
 a few inches above the roof-ridge. It may be protected from the 
 entrance of dirt by a perforated conical cap fixed by wires so as to 
 stand well off the mouth, otherwise if placed close to the opening of 
 the pipe, there will be obstruction of air current. 
 
SECTION VI. 
 
 NUISANCES. 
 
CHAPTER XX. 
 
 OEDINAET NUISANCES DEALT WITH BY SANITARY AUTHORITIES. 
 
 (174) Distinction between Private and Public Nidsances. 
 The word nuisance has various meanings according as it is used 
 in a popular or legal sense. 
 
 Its primary meaning is annoyance, inconvenience, or some actual 
 injury. Blackstone said "Nuisance, nucumentum, or annoyance, 
 signifies anything which worketh hurt, inconvenience or damage." 
 
 In a legal sense nuisances are of two kinds, public and private ; 
 the latter are defined as " anything done to the hurt, or annoyance 
 of the lands, tenements and hereditaments of another." They are 
 those for which a private individual has an action, according to the 
 axiom that " the law gives no private remedy for anything but a 
 private wrong;" hence these classes of nuisances, such for example 
 as blocking up a private way, injury to a man's garden fence, and many 
 others can neither be remedied by indictment nor under the Public 
 Health or Sanitary Acts ; they have their own peculiar remedy. On 
 the other hand, public or common nuisances are species of offences 
 against the public order and economical regimen of the State ; they 
 are such as annoy the whole community in general and not merely 
 some particular person. 
 
 Of public nuisances only a certain class are contemplated by the 
 Sanitary Acts, viz. those in which more or less injury to health, 
 may be proved or inferred as likely to occur. In some cases also 
 though a nuisance in a Public Health sense may be proved, yet 
 there is no remedy under the Acts themselves, for example in a 
 recent case, a Sanitary Authority attempted to abate in the usual 
 way by notice and following magistrate's order, a nuisance arising 
 
 E 
 
242 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 from the depositing tanks and other sewage works of a neighbouring 
 authority, but the magistrate's order was quashed by the Court of 
 Appeal ; in the course of the judgment, Justice Wills said : ^ 
 
 "In our opinion the provisions section 91 — 98 have no applica- 
 tion to sewage works constructed under the powers of section 27 
 Public Health Act, 1875. We think the words of section 91 do not 
 include them, and we think were not meant to include them. 
 It is clear that the expresssion 'premises in such a state as to 
 be a nuisance ' has not the wide application claimed for it by the 
 respondents, who say that it is answered by any premises on which 
 a nuisance exists. If that were so the enumeration of, at all events, 
 the several kinds of nuisances specified under heads 2, 3, 4, and 6 
 would be unnecessary. We do not attempt to define every class of 
 case to which the first head applies, but we think it is confined to 
 cases in which the premises themselves are decayed, dilapidated, 
 dirty or out of order ; as for instance, where houses have been in- 
 habited by tenants whose habits .and ways of life have rendered 
 them filthy or impregnated with disease, or where foul matter has 
 been allowed to soak into walls or floors, or where they are so dilapi- 
 dated as to be a danger to life and limb. It is a significant fact 
 that under the second head the various receptacles for running or 
 stagnant water stop with drains which by the interpretation clause 
 are not sewers, and to take broader and higher ground, it seems to 
 us incredible that when the legislature had entrusted the local 
 boards with a most difficult and thankless task, in the execution of 
 which there were certain to be, as there have been in fact, a propor- 
 tion of failures, involving perhaps a cost to the district of tens, and 
 even hundreds of thousands- of pounds, and taxing to the utmost 
 resources of mechanical art and engineering skill to set them right, 
 a jurisdiction should be conferred upon two magistrates, with an 
 appeal to a recorder or to a bench of justices at quarter sessions, to 
 substitute their judgment of the mode in which, and the cost at 
 which the mischief should be cured, for that of the local board and 
 their skilled advisers." 
 
 When the interests are large, the case important, it is also neither 
 
 usual nor advisable to seek a summary remedy under the Sanitary 
 
 Acts, but to proceed by indictment or to obtain in the superior 
 
 Court an injunction. For example, the pollution of a river, the 
 
 ' Q.B., L.T., vol. Ix. N.S. 42. 
 
XX.] NUISANCES. 243 
 
 faulty disposal of sewage, nuisance arising from large manufactories, 
 and similar matters which injure or aggrieve a large section of the 
 commanity are most effectually and permanently dealt with in the 
 manner indicated and not in the simple way provided by the Public 
 Health and other acts. 
 
 The ordinary daily routine of a sanitary ofiScer is however for the 
 most part taken up, in discovering nuisances under the Health 
 Statutes, and applying the legal remedy provided by them, and it 
 is essential that he should possess a clear conception of " nuisance " 
 considered from a legal stand-point as set forth in certain leading 
 cases. 
 
 (175) Leading Gases as to Nuisance. 
 
 In the case of the Great Western Railway Gompany v. Bishop, a 
 complaint was made under 18 and 19 Vic, c. 121. s. 8 against 
 the company, in respect of a nuisance alleged to exist in and upon 
 their premises, viz. a railway bi'idge. It was proved that during 
 rainy weather, and for some time afterwards, water in a dirty state 
 percolated through the bottom of the bridge which was formed of 
 wooden planks and fell upon persons passing along the street. The 
 railway company appealed, and it was held, " That although there 
 might be a nuisance in respect of which the appellants were liable 
 to be indicted, they were not liable to be proceeded against under 
 the 18th and 19th Vict. c. 121, as the word ' nuisance ' in section 8 
 must be read in the sense injurious to health and the percolation of 
 water as above mentioned could only be said to be indirectly a 
 nuisance injurious to health." 
 
 This judgment has however been somewhat modified by the case 
 of the Bishop Auckland Sanitary Authority, v. the Bishop Auckland, 
 Iron and Steel Company (L. J. R. 52. p. 38.) 
 
 Complaint was made to justices under the Public Health Act, 
 section 91 (subs. 4) against the Iron Company in respect of aa 
 alleged nuisance occasioned by an accumulation of cinder refuse 
 which gave off smoke and gas. The justices found as a fact that the 
 matter complained of was a nuisance, but was not injurious to 
 health. But the superior Court held that nevertheless they ought 
 not to have refused to convict, as the mdsance was of a hind which 
 might he injurious to health, and it was not necessary in such cases 
 under the above provision to prove that it was in fact so, 
 
 R 2 
 
244 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 In the course of the judgment Mr. Justice Stephen said, ' I should 
 say that the words in the section 'nuisance or injurious to health,' 
 cannot mean the same as ' nuisance injurious to health,' and the 
 proper way to interpret them is to take them in their natural sense, 
 viz., something which interferes with comfort or is injurious to 
 health. A man might catch a deadly disease without having been 
 exposed to a nuisance, or there might be a nuisance existing which 
 did not injure his health or affect his comfort. There is the recent 
 case of Banbury v. Page, which seems to fully bear out the view 
 that I take, where under section 47, Public Health Act, 1875, the 
 offence of keeping swine so as to be a nuisance was held to be 
 complete without any evidence of there being injury to health 
 caused thereby." 
 
 (176) Nuisances under the 91st Section of the Ficblic Health 
 
 Act, 1S75. 
 
 The nuisances under the 91st section of the Public Health Act 
 are those which were in force at the time of the Act passing, by 
 virtue of similar clauses in the Nuisance Removal Act of 1855 and 
 the Sanitary Act of 1866, both of which Acts are in force in the 
 metropolis, but repealed as to the rest of the country. The 
 nuisances enumerated are : — 
 
 1. Insanitary premises. 
 
 2. Foul pools, ditches, gutters, watercourses, privies, urinals, 
 cesspits or drains, or ashpits. 
 
 3. Animals kept improperly. 
 
 4. Unwholesome accumulations or deposits. 
 
 5. Overcrowding of the whole or part of a house. 
 
 6. Factories or workshops not already under the operation of 
 any general Act for the regulation of factories or bakehouses kept 
 in an imclean state or overcrowded, or not properly ventilated. 
 
 7. Fireplaces or furnaces in manufacturing operations generally, 
 which do not so far as practicable consume their own smoke. 
 
 8. Chimneys, not being that of a private dwelling, sending forth 
 black smoke in such a quantity so as to be a nuisance. 
 
 1. Any premises in such a state as to he a nuisance and in urious 
 to health. — It is under this definition that nine-tenths of the 
 
xx.J NUISANCES. 245 
 
 sanitary orders are issued. The definition may fairly comprise 
 such nuisances as follows: — 
 
 Leaky roofs. 
 
 General repair of a dwelling. 
 
 Dampness of the walls or basement of the dwelling. 
 
 General dirtiness of walls, staircases, and floors. 
 
 Nuisances from bad paving of yards. 
 
 Nuisances so frequently arising in dwellings in towns that are 
 not detached, of the products of combustion of the neighbouring 
 chimney leaking through defective flues into the adjoining living- 
 room of either the same or the adjoining house. 
 
 Old rat runs. 
 
 Foundations saturated with filth. 
 
 Nuisances connected with the water supply, that is (a) absence ; 
 (&) polluted ; (c) improper connection with the closet. 
 
 Nuisances from defective fittings of sinks or closets. 
 
 Nuisances from want of ventilation, and a number of others. 
 
 2. JVuisance from drains, cesspits, aud the like. — In this category 
 the fact only has to be proved, and whether, for example, a drain 
 (see House Drains, pp. 183 — 188) or a cesspit is proper or im- 
 proper, a nuisance or not, is entirely a question of fact, which the 
 Medical Officer of Health is the proper person to decide. 
 
 3. Any animal so kept as to he a nuisance or injurious to health. — 
 The reader is referred to the special sections treating of pig- 
 keeping, of stables, of cow-keeping, &c. 
 
 4. Deposits — Under this subsection manure heaps and offensive 
 deposits generally can be dealt with, but it is necessary to look 
 carefully at the exception in the latter part of Section 91, viz., that 
 no penalty is to be imposed on any person in respect of any accu- 
 mulation or deposit necessary for the effectual carrying on any 
 business or manufacture, if it be proved to the satisfaction of the 
 Court that the accumulation or deposit has not been kept longer 
 than is necessary for the purposes of the business or manufacture, 
 and that the best available means have been taken for preventing 
 injury thereby to the public health. 
 
 As an example of the kind of cases which may arise, a magisterial 
 decision may be cited with reference to a deposit of manure at a 
 manure merchant's premises in Chelsea.^ The defence was that 
 1 Public Health, vol. ii. 124. 
 
246 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 the defendant, being a manure merchant, and that his business 
 not being scheduled as an " offensive trade," could not be interfered 
 with by the vestry, because at that particular season of the year, 
 owing to the occupation of farmers, and the difficulty of obtaining 
 barges, there had been a larger and longer accumulation of manure 
 than ordinary. The magistrate (Mr. D'Eyncourt), in the course 
 of an exhaustive judgment, reviewed the facts, and said it was 
 proved that the accumulation of manure on the wharf was from 
 180 to 200 cubic yards in extent. This was within ninety yards 
 of houses. There was a difference of opinion between the medical 
 experts who had given evidence in the case, but he had come to the 
 conclusion that the heap of manure was a nuisance, and its actual 
 removal must be very offensive. It might be true, to some extent, 
 that the trade could not be carried on unless the practice of the 
 defendant was allowed, but with that he had nothing to do ; and 
 he accordingly made an order with costs for the abatement of the 
 nuisance. 
 
 In dealing with such deposits as the above in connection 
 with a business, there will be mainly two things for the officer 
 of a sanitary authority to consider, viz., whether the accumu- 
 lation or deposit is kept longer than necessary, and whether 
 the best . available means have been adopted to prevent any 
 injury to the public during its retention. All this is a question 
 of fact, and each particular case must be dealt with on its 
 merits. 
 
 5. Overcrowding. — In dealing with overcrow^ding, the Medical 
 Officer of Health has not to depend entirely upon his own judg- 
 ment, but rather to follow precedent. The amount of cubic space 
 allowed by the Local Government Board in various regulations as 
 to houses let in lodgings, is 400 cubic feet each person for rooms 
 occupied day and night, and 300 cubic feet for each person for 
 rooms legitimately occupied as sleeping -rooms only, two children 
 under twelve counting as one adult. It requires very good ven- 
 tilation for this space to be really enough — in badly ventilated 
 rooms the space is not sufficient — and the rule of allowing two 
 children to count as one adult is a mistake, the quick respiration of 
 the young making up for chest capacity, besides which, in the case 
 of very young children, the rule is that all excreta is passed in the 
 room, and there is thus an additional defilement of the atmosphere. 
 
XX.] . NUISANCES. 247 
 
 The interpretation of the old A.cts ^ was that the overcrowding 
 must be by two different families, but the words, " whether or not 
 members of the same family" were added to the Public Health 
 Act (they are not in corresponding clause of Sanitary Act of 1866), 
 to clear up any difficulty of interpretation. 
 
 6. Factories, <&c. — The Factory and Bakeshop Acts are so com- 
 prehensive that little or no use has been made of this subsection. 
 
 7 and 8. ITis SmoJce Glauses. — There are several things to be 
 considered here. In the first place it is evident that any kind of 
 engine, such' for example, as a steam-engine working a dynamo, 
 although not in a factory, but on strictly private premises, comes 
 under the subsection, although probably in a legal case, the 
 barrister for the defence would argue that the disjunctive, " or any 
 manufacturing or trade process whatsoever," governed the section, 
 and that the section was only applicable to a trade process, and not 
 to a person manufacturing his own electricity for the supply of his 
 own house. The author is, however, decidedly of opinion that the 
 words, " which is used for working engines hy steam," should be 
 taken in their natural meaning. 
 
 In the second place, it is enacted that the chimney of any but a 
 private dwelling-house, sending forth black smoke in such quantity 
 as to be a nuisance, can be dealt with under the section. 
 
 There may be easily cases arise rendering it difficult to determine 
 whether a chimney is that of a private dwelling or not. The cases 
 which will present difficulty will be those in which a manufacturing 
 operation is carried on in a house used in part as a residence, or in 
 a shed or annex to a private house. Here again it will be mainly 
 a question of fact for the magistrate to determine. The smoke 
 under this subsection must be " black," and in appreciable quantity. 
 If the offender should by means of a steam-blower, or other means, 
 turn the vapour into white smoke, or in some way colour the 
 smoke", it is obvious the section does not apply, even though the 
 nuisance may be aggravated by such means, as indeed has happened 
 in the author's own experience. 
 
 Lastly, in all these cases it will be absolutely necessary, if legal 
 action be contemplated to enforce an order of the sanitary authority, 
 to prove by expert evidence that the fireplace or furnace is not of 
 
 ^ Tiat is, N. Kem. Act, 1865, and Sanitary Act, 1866, still in force in the 
 nietropolis. 
 
248 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 the best construction, or that known appliances have not been 
 made use of to consume the smoke or to prevent its emanation. 
 
 (177) Offensive businesses specifically mentioned in the Public Health 
 and Sanitary Acts. 
 
 Certain classes of trades which produce offensive effluvia are 
 specifically mentioned in the Public Health Act, 1875, sections 
 112-115, and the same trades are enumerated in the slaughter- 
 houses, &c.. Metropolis Act, 1874, 37 & 38 Vict., c. 67. These 
 trades are : — boiling offal, or blood ; boiling, burning, or crushing 
 bones ; the trade of a fellmonger ; the trade of a tallow melter ; 
 the trade of a soap maker ; the trade of a tripe boiler ; the trade 
 of a slaughterer. 
 
 Power is given by the above Acts both in the metropolis and in 
 the country, to the London County Council and Urban Sanitary 
 Authorities, to make bye-laws regulating the trades or businesses 
 mentioned, or as " to any offensive trades established with their 
 consent." (Public Health Act, 1875, section 113.) 
 
 In the Metropolis Slaughter-House Act, the trade of a 
 "knacker" is also specifically mentioned, and any business the 
 local authority (which in this case is the London County Council) 
 may wish to add to the list of offensive businesses and to regulate 
 by bye-law, must be declared so by order and be duly confirmed by 
 the Local Government Board (section 3). It may also be men- 
 tioned that section 116 of the Public Health Act, 1875, enabling 
 an Urban Sanitary Authority to take proceedings on the ground of 
 nuisance with respect to an offensive trade without their district is 
 in force in the Metropolis. 
 
 (178) Blood Brier, Blood Albumin, Blood Boiling. 
 
 In the manufacture of blood and in the drying of blood there 
 are various sources of nuisance, of which the following are the 
 chief : — 
 
 (1) EfHuvia from putrid blood arising from the exhausted clots 
 prior to removal. 
 
 (2) The disagreeable faint smell proceeding from the yard and 
 premises, especially when the most scrupulous cleanliness has not 
 been observed. 
 
sx.] TRADE NUISANCES. 249 
 
 (3) Effluvia from other processes, such as blood boiling, or 
 manufacture into manure, often carried on in the same premises. 
 
 The business of a blood drier is regulated in the Metropolis as 
 follows ; — 
 
 LONDON COUNTY COUNCIL. 
 
 The Slaughtekhotjses, &o. (Metropolis), Act, 1874, 37 & 38 Vic., c. 67. 
 
 Bye-Laws for regvilating the conduct of the business of a Blood Drier, and any 
 business in which blood or any of the constituent parts of blood is used, 
 provided that heat be in any way applied or used to the same, and that, 
 whether such blood or any of the constituent parts thereof be or be not at 
 the time of the application or use of such heat diluted or mixed with any 
 other substance ; and the structure of the premises on which such business 
 is being carried on ; and the mode in which application is to be made for 
 sanction to establish such business anew ; within the limits of the Metropolis 
 (except the City of London and the liberties thereof). 
 
 In pursuance of the Slaughterhouses, &c. (Metropolis), Act, 1874, by which the 
 Metropolitan Board of "Works ^ are constituted the Local Authority for the Metropolis 
 (except the City of London and the liberties thereof), the said Metropolitan Board of 
 Works ' do hereby make the following Bye-Laws : — 
 
 Bye-Laws for Regulating the Conckict of the Susiness, 
 
 1. Every Blood Drier shall cause all blood brought upon his premises to be brought 
 in closed vessels or receptacles constructed of galvanized iron or other non-absorbent 
 material. 
 
 2. Every Blood Drier shall cause every process of his business (except the diying 
 and packing processes) to be carried on in a building properly paved with asphalte, 
 concrete, or other suitable jointless material, having walls covered to a height of at 
 least six feet with hard, smooth, and impervious material. 
 
 3. Every Blood Drier shall cause every process of his business in which any 
 offensive effluvia, vapours, or gases are generated, to be carried on in such manner 
 that no offensive effluvia, vapours, or gases shall escape into the external atmosphere ; 
 and he shall cause all such offensive effluvia, vapours, or gases to be effectually destroyed. 
 
 4. Every Blood Drier shall cause all blood, blood-clot, or any refuse, residue, or 
 other matter from which offensive effluvia or vapours are evolved or are liable to be 
 evolved, to be placed in properly closed receptacles, or to be otherwise dealt with in 
 such manner as to prevent any offensive effluvia or vapours therefrom escaping into 
 the external atmosphere. 
 
 5. Every Blood Drier shall cause the floor of every place iu which any process of 
 the business (except the drying and packing processes) is carried on to be thoroughly 
 cleansed with water, at least once in twenty-four hours ; and he shall cause the 
 premises to be constantly provided with an adequate supply of water for the purpose. 
 
 6. Every Blood Drier shall cause every inner wall of the premises on which his 
 business is carried on to be kept at all times thoroughly clean and in good order and 
 repair. He shall (except as is hereinafter provided) cause every such wall or part of 
 such wall which is not covered with hard, smooth, and impervious material, and 
 every ceiling to be thoroughly washed with hot lime-wash in -the first week of each 
 of the months of March and September in every year ; provided always that this 
 requirement shall not be deemed to extend to any chamber used for the purpose of 
 drying albumen. 
 
 7. Every Blood Drier shall cause every vessel, receptacle, utensil, or instrument 
 provided or used upon, or in coimection with, the premises on which his business 
 may be carried on, to be kept at all times thoroughly clean, so as to prevent the 
 emission of any offensive smell from such vessel, receptacle, utensil, or instrument. 
 
 8. Every Blood Drier shall afford access to every part of the premises on which 
 
 ' Now London County Council. 
 
250 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 his business is earned on to every Member and Officer of the Board, authorised in 
 writiag under the hand of the Clerk of the said Board, at any reasonable time during 
 the hours within which such business may be carried on. 
 
 9. Ever}' person offending against any of the foregoing Bye-I/aws shall be liable 
 for every such offence to a penalty of Five pounds ; and in the case of a continuing 
 offence to a penalty of One pound for every day during which the offence may be 
 continued after the oonviation for the first offence. 
 
 10. Every Court of Summary Jurisdiction, as defined in the Slaughterhouses, &c. 
 (Metropolis), Act, 1874, may, as a penalty for the breach of any of the foregoing 
 Bye-Laws, by summary Order, suspend, or deprive any jjerson altogether of the right 
 of carrying on the business of a Blood Drier. 
 
 Bye-Laws for Regulating the Structure of the Premises. 
 
 11. Every Blood Drier shall cause the floor of the yard and every part of his 
 premises in which any process of his business (except the drying and packing 
 processes) is carried on, to be properly paved with asphalte, concrete, or other 
 suitable jointless material, laid upon a suitable bottom of at least four inches in 
 thickness, and such floor to have a proper slope towards a channel or gully ; and 
 shall cause his premises to be effectually drained by adequate drains communicating 
 with a public sewer. The drains shall be properly trapped, and the entrances thereto 
 shall be covered with fixed gratings, the bars of which shall not be more than 
 three-eighths of an inch apart. 
 
 12. Every Blood Drier shall cause the inner walls of every building in which any 
 process of his business (except the drying and packing processes) is carried on, to be 
 covered to a height of at least six feet with hard, smooth, impervious material.' 
 
 13. Every Blood Drier shall cause his premises to be provided with appliance.? 
 capable of effectually destroying all offensive effluvia, vapours, or gases arising in 
 any process of his business, or from any njaterial, residue, or other substance which 
 may be kept or stored upon his premises. 
 
 14. Every Blood Drier shall cause all needful works and alterations to the 
 premises to be forthwith done and executed as and when the same shall become 
 requisite, but shall not allow any alteration whatsoever to be made in respect of the 
 structure of the premises, without the consent of the Board. 
 
 15. Every person who shall not comply with any of the foregoing Bye-Laws 
 relating to the structure of the premises shall be guilty of an offence, and shall be 
 liable, for every such offence, to a penalty of Five pounds, and in the case of a 
 continuing offence, to a penalty of One pound for every day during which the offence 
 may be continued after the conviction of the first offence. Provided always that the 
 foregoing Bye- Laws for regulating the structure of the premises shall not, until after 
 the expiration of twelve months from the date of the confirmation of the Bye-Laws, 
 be deemed to apply to any premises where at such date the business of a Blood Drier 
 may be carried. on. 
 
 Bye-Laws for Begulating the mode of Application for Sanction to reew Establishment 
 
 of the Business. 
 
 16. Every person who may apply to the Board for their sanction to establish 
 anew the business of a Blood Drier, shall furnish with the application a plan of the 
 premises and sections of the buildings in which it is proposed to carry on such 
 business, such plans and sections being drawn to a scale of a quarter of an inch to 
 the foot, and showing the provision made, or proposed to be made, for the proper 
 conduct of such business, and for the drainage, ventilation, and water supply of such 
 premises, and shall also furnish a key plan of the locality, showing the buildings and 
 streets within one hundred yards of the premises, drawn to a scale of five feet to the 
 mile. 
 
 (179) Fat Melting, Dip Candle Making. 
 
 The materials used are kitchen stuff and fat collected from 
 various materials. 
 
XX.] TRADE NUISANCES. 251 
 
 The fat is melted either in pans : — (a) heated by the open fire ; 
 (h) by free steam and sulphuric acid ; (c) in pans, steam jacketed. 
 
 The sources of nuisance are ; — (1) The storage of the fat (this is 
 often spread out to sweeten) ; (2) melting the fat ; (3) ladling it 
 out ; (4) storage of greaves, i.e., residue ; (5) general filth. Remedies, 
 proper storage. " The method of preventing nuisance commences 
 at the slaughter-houses. As soon as the fat is removed from the 
 animals it should be laid on racks, and it should not be packed 
 until quite cold and hard " (Ballard). 
 
 The method of rendering has much to do with the creation of 
 nuisance : in towns the only method permissible will be by free 
 steam or in steam-jacketed pans. But this method is not a favour- 
 ite with the manufacturers, for the greaves, which are worth £16 
 a ton, are thereby lost. There is a method of consuming the 
 vapours even with free rendering. The fire is applied with air to 
 the top of the pan and thus the offensive vapour is burned up. This 
 is only successful with a good draught such as can be obtained by 
 a high chimney shaft. 
 
 Bye-laws regulating fat melting in the Metropolis are as. 
 
 follows : — 
 
 LONDON COUNTY COUNCIL. 
 
 The Slaughteehouses, &o. (Metropolis), Act, 1874, 37 & 38 Vic., o. 67. 
 
 Bye-Laws for regulating the conduct of the business of a Fat Melter, or Fat 
 Extractor, that is to say, any business in which Fat is melted, rendered, 
 extracted from any material, or remelted ; and the structure of the premises 
 on which such business is being carried on ; and the mode in which application 
 is to be made for sanction to establish such business anew ; within the limits 
 of the Metropolis (except the City of London and the liberties thereof. ) 
 
 In pursuance of the Slaughterhouses, &c. (Metropolis), Act, 1874, by which the 
 Metropolitan Board of Works ^ are constituted the Local Authority for the Metropolis 
 (except the City of London and the liberties thereof), the said Metropolitan Board of 
 "Works,^ do hereby make the following Bye-Laws : — 
 
 Bye- Laws for Megulating the Conduct of the Business. 
 
 1. Every Fat Melter or Fat Extractor shall cause every process of his business in 
 which any offensive effluvia, vapours, or gases are generated, to be carried on in such 
 manner that no offensive effluvia, vapours, or gases shall escape into the external 
 atmosphere, but shall cause all such offensive effluvia, vapours, or gases to be effectually 
 destroyed. 
 
 2. Every Fat Melter or Fat Extractor shall cause all material used or offensive 
 material or refuse from the boiling pans, and all refuse, residue, or other matter from 
 which offensive effluvia, vapours or gases are evolved or are liable to be evolved, to be 
 placed in properly closed receptacles, or to be otherwise dealt with in such manner as 
 to prevent any offensive effluvia, vapours, or gases therefrom escaping into the external 
 atmosphere. 
 
 I This now to be read " London County Council." 
 
252 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 3. Every Fat Melter or Fat Extractor shall cause all scraps or litter composed of 
 matters liable to become decomposed, to be constantly gathered or swept up and 
 placed in proper covered receptacles. 
 
 i. Every Fat Melter or Fat Extractor shall cause the floor of every place in which 
 any process of the business is carried on, to be kept thoroughly cleansed, and he shall 
 cause the premises to be constantly provided with an adequate supply of water for the 
 purpose. 
 
 5. Every Fat Mel ter or Fat Extractor shall cause every inner wall of the premises 
 on which his business is carried on to be kept at all times thoroughly clean and in 
 good order and repair. He shall cause every inner wall and every ceiling in every 
 part of his premises where any process of his business may be carried on, to be 
 thoroughly washed with hot lime-wash, at least twice in every year, that is to say, 
 in the months of March and September, and likewise as often as may be necessary 
 for the purpose of keeping such part of the premises in a cleanly and wholesome state. 
 
 6. Every Fat Melter or Fat Extractor shall cause every vessel, receptacle, utensil, 
 or instrument provided or used upon, or in connection with, the premises on which 
 his business may be carried on, to be kept, when not actually in iise, at all times 
 thoroughly clean, so as to prevent the emission of any offensive smell from such 
 vessel, receptacle, utensil or instrument. 
 
 7. Every Fat Melter or Fat Extractor shall afford access to every part of the 
 premises on which his business is carried on to eveiy Member and Officer of the 
 Board, authorised in writing under the hand of the Clerk of the said Board, at any 
 reasonable time during the hours within such business may be carried on. 
 
 8. Every person offending against any of the foregoing Bye-Laws shall be liable 
 for every such offence to a penalty of Five pounds ; and in the case of a continuing 
 offence to a penalty of One pound for every day during which the offence may be 
 continued after the conviction for the first offence. 
 
 9. Every Court of Summaiy Jurisdiction, as defined in the Slaughterhouses, &c. 
 (Metropolis), Act, 1874, may, as a penalty for the breach of any of the foregoing Bye- 
 Laws, by Summary Order, suspend or deprive any person altogether of the right of 
 carrying on the business of a Fat Melter or Fat Extractor. 
 
 Bye-Laws for Megulating the Structure of the Premises, 
 
 10. Every Fat Melter or Fat Extractor shall cause every floor upon which any 
 process of his business is carried on-, in any part of his premises, to be properly covered 
 with a layer of concrete, or other suitable jointless impervious material, laid (in the 
 case of a ground floor) upon a suitable bottom of at least four inches in thickness. 
 He shall cause every such floor to have a proper slope towards a channel or gully ; 
 and .shall cause every part of his premises wherein any such floor may be consbructed 
 to be effectually drained by adequate drains communicating with a public sewer. He 
 shall also cause every drain to be properly trapped, and the entrance thereto to be 
 covered with a fixed grating, the bars of which shall not be more than three-eighths 
 of an inch apart. 
 
 11. Every Fat Melter or Fat Extractor shall cause his premises to be provided 
 with appliances capable of effectually destroying all offensive effluvia, vapours or gases 
 arising in any process of his business, or from any material, residue, or other substance 
 which may be kept or stored upon his premises. 
 
 12. Every Fat Melter or Fat Extractor shall cause all needful works and alterations 
 to the premises to be forthwith done and executed as and when the same shall become 
 requisite, but shall not allow any alteration whatsoever to be made in respect of the 
 structure of the premises, without the consent of the Board. 
 
 13. Every person who shall not comply with any of the foregoing Bye-Laws 
 relating to the structure of the premises shall be guilty of an offence, and shall be 
 liable, for every such offence, to a penalty of Five pounds, and in the case of a con- 
 tinuing offence, to a penalty of One pound for every day during which the offence 
 may be continued after the conviction for the first offence. Provided always that the 
 foregoing Bye-laws for regulating the structure of the premises shall not until after 
 the expu-ation of six mouths from the date of the confii-mation of the Bye-Laws be 
 deemed to apply to any premises where at such date the business of a Fat Melter or 
 Fat Extractor may be carried on. 
 
XX.] TRADE NUISANCES. 253 
 
 Bye-Laws for JRegidating the mode of Application for Sanction to New Establishment 
 
 of the Business. 
 
 14. Every person, who.may apply to the Board for sanction to establish anew 
 the business of a Fat Melter or Fat Extractor, shall furnish with the application a 
 plan of the premises and sections of the buildings in which it is proposed to carry on 
 such business, such plans and sections being drawn to a scale of a quarter of an inch 
 to the foot, and showing the provision made or proposed to be made, for the drainage, 
 lighting, ventilation, and water supply of such premises, and shall also furnish a key 
 plan of the locality, showing the buildings and streets within one hundred yards of 
 the premises, drawn to a scale of five feet to the mile. 
 
 (180) Boim Boiling. 
 
 This is peculiarly offensive, and the vapours will travel a long 
 distance. The storage of the material and the conveyance to the 
 factory are aU possible sources of offence. At Deheer's manufac- 
 tory, Hull, the process is conducted in a closed building, and the 
 vapours from a covered boiling pan are conducted by a pipe passing 
 through the wall of the building to an ordinary worm condenser 
 outside. Such vapours as are not thus condensed go through a 
 furnace fire. The result Dr. Ballard found not to be perfect, for the 
 vapours escaped through cracks, and the condensed water passing 
 into the drains at a high temperature would burst up through 
 imperfectly sealed traps. 
 
 There is also nuisance after boiling, for recently boiled bones 
 when heaped together evolve an offensive steam possessing a 
 musty ammoniacal odour. 
 
 In all such operations as bone boiling there will be less nuisance 
 if the operation is conducted in steam-jacketed pans than in those 
 on which the fire plays direct, in the latter case the heat towards 
 the end of the operation is apt to be raised too high, and then 
 there is the production of empyreumatic stinking products. 
 
 The regulations which should be made as to this business are 
 given, page 254. 
 
 (181) Soap Boiling, Soap Making. 
 
 In the manufacture of soap, various fats are boiled with soda lye, 
 or if the manufacture be that of soft soap, the fats are boiled 
 with potash lye ; in this last manufacture various kinds of oils, such 
 as fish oil, seal oil, rape oil, white oil, linseed or cotton oil, are used. 
 
 The sources of nuisance are almost entirely due to the fats used, 
 so that the same remedies are to be applied as detailed in fat 
 melting, &c. 
 
254 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (182) Manufacture of Manure. 
 
 This is a somewhat indefinite appellation. Manure may be 
 simply crushing bones, and manufacturing into superphosphate by 
 the addition of sulphuric acid ; in this case acid and irritating 
 emanations may arise, unless the products are sufficiently con- 
 densed, or unless the products are conveyed by means of a tall 
 chimney shaft into the upper regions of the atmosphere ; or it may 
 be the drying of condemned fish, or meat, by a steam-jacketed 
 revolving pan, as practised on the east side of the Thames below 
 Woolwich ; manure is also manufactured from sewage sludge, and 
 from a variety of other refuse. Nevertheless whatever the manu- 
 facture the general regulations are pretty well the same as those 
 which may be applied to trades ej'usdem generis. 
 
 In the metropolis the following bye-laws are in force governing 
 the three or four trades just treated of : — 
 
 LONDON" COUNTY COUNCIL. 
 
 The SLAtrGHTERHOTJSEs, &c. (Meteopolis) Act, 1874, 37 and 38 Fie, e. 67. 
 
 Bye-laws for the regulation of the conduct of the business of a Blood Boiler, 
 Bone Boiler, Manure Manufacturer, Soap Boiler, or Tallow Melter, within the 
 limits of the Metropolis, as defined by this Act (except the City of London 
 and the liberties thereof), and the structure of the premises on which any such 
 business may be carried on. 
 
 In pursuance of the above Act, by which the Metropolitan Board of Works ^ is 
 constituted the Local Authority of the Metropolis, as defined in the said Act (except 
 the City of London and the liberties thereof), the said Metropolitan Board of Works ^ 
 (for the purposes of these Bye-laws called the ' ' Board "), doth hereby make the fol- 
 lowing Bye laws : — 
 
 Bye-Laxos for Regulating the Conduct of the Business. 
 
 1. Every Blood Boiler, Bone Boiler, Manure Manufacturer, Soap Boiler or Tallow 
 Melter, shall cause every boiler, mixer, or other vessel from which any offensive or 
 noxious vapour or gas may be evolved in any operation or process of his business, to 
 be properly covered, and in all other respects to be so constructed and used as to cause 
 all such vapour or gas to be eifectually conveyed into, or through, a furnace fire, or 
 otherwise to be prevented from escaping into the external atmosphere. 
 
 2. Every Blood Boiler, Bone Boiler, Manure Manufacture, Soap Boiler, or Tallow 
 Melter, shall cause every room, chamber, or other place which may be used on or in 
 connection with the premises where his business is carried on, for {the purpose of re- 
 ceiving or storing any manufactured product, residue, or any other matter, from which 
 any -offensive vapour or gas may be evolved, to be furnished with suitable appliances, 
 so constructed and used as to effectually prevent the escape of such vapour or gas into 
 the external atmosphere. He shall at all times adopt such precautions and employ 
 such means as may be necessary to cause all such vapour or gas to be conveyed iuto 
 or through a furnace-fire or to be so condensed as to be effectually destroyed. 
 
 3. Every Blood Boiler, Bone Boiler, Manure Manufacturer, Soap Boiler, or Tallow 
 Melter, shall cause all material, manufactured product, residue, refuse, or other 
 
 '■ This is now to be read " London County Council." 
 
XX.] TRADE NUISANCES. 255 
 
 matter used on or in connection with the premises where his business is carried on, 
 from which any offensive vapour or gas may be evolved, to be received or stored in 
 rooms, chambers, or other places, constructed so that there may be no opening from 
 such rooms, chambers, or other places into the external atmosphere. 
 
 4. Every Blood Boiler, Bone Boiler, Manure Manufacturer, Soap Boiler, or Tallow 
 Melter, shall afford free access to every part of the premises where his business is 
 carried on, to every Member and Officer of the Board, authorised in writing under the . 
 hand of the Clerk of the said Board, at any reasonable time during the hours within 
 which such business may be in operation. 
 
 5. Every person offending against any of the foregoing Bye-laws shall be liable 
 for any such offence to a penalty of £5, and in the case of a continuing offence, to a 
 penalty of £1 for every day during which the offence maybe continued after the con- 
 viction for the first oft'ence. 
 
 6. Every Court of Summary Jurisdictioh, a,s defined in the Slaughter-houses, &c. 
 (Metropolis), Act, 1874, may, by Summary^ Order, as a penalty for the breach of any 
 of the foregoing IBye-laws, suspend or deprive any person altogether of the right of 
 carrying on the business of a Blood Boiler, Bone Boiler, Manure Manufacturer, Soap 
 Boiler, or Tallow Melter. 
 
 Bye-law for Regulating the Structure of the Premises. 
 
 7. Every Blood Boiler, Bone Boiler, Manure Manufacturer, Soap Boiler, or Tallow 
 Melter, shall cause every room, chamber, or other place which may be used on or in 
 connection with the premises where his business is carried on, for the purpose of re- 
 ceiving or storing any manufactured product, residue, or other matter from which 
 any offensive vapour or gas may be evolved, to be constructed so that there may be 
 no opening from such room, chamber, or place into the external atmosphere. 
 
 (183) The Trade of a Fellmonger. 
 
 The fellmonger's business is to prepare skins for the leather 
 dresser. He receives either recent or foreign skins, and the pro- 
 cess is slightly different as to whether the one c|r the other has to 
 be treated. \ 
 
 Fresh Skins. — These are beaten with a mallet to free them from 
 dirt, and then soaked and washed in water. The skins are then 
 limed (the object of liming is to detach the hair) ; the skin is laid 
 with the hair undermost, and milk of lime is worked into the raw 
 or fleshy surface of the skin. This process finished, the skins are 
 hung up ; and when it is found that the wool can easily be detached, 
 the wool is removed by hand. 
 
 The skins denuded of wool are termed "pelts." The pelts are 
 thrown into a pit containing milk of lime, and from this pit go 
 direct to the leather dresser. 
 
 Foreign skins are hard and dry, and first require soaking. The 
 " burrs," with which the wool is often covered, are also removed by 
 a special machine. The wool is not loosened by liming, but is 
 removed by " the tainting process," that is, a certain decomposition 
 occurs which loosens the wool, and when this stage is reached the 
 wool as before is removed by hand. 
 
256 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 The chief nuisance is the storing of large quantities of skin, 
 none of which is absolutely free from adherent portions of flesh, 
 but the other operations can all be done without the creation of 
 nuisance. It is true that large quantities of skins undergoing the 
 "tainting" process smell slightly, but the smell seldom extends 
 beyond the sheds or works. The chief and essential thing is to 
 avoid cause of offence in the storing of the fresh skins. 
 
 (184) Chit Scraping — Gv,t Spinning — Preparation of Sausage 
 
 Skins. 
 
 These trades are all of a kin. Gut scraping is in the larger 
 establishments done by women. The intestine is scraped on a 
 bench by a wedge-shaped piece of wood, all the interior soft parts 
 being in this way detached, and pass along to go out of the cut 
 end ; only the peritoneum and a little of the muscular structure 
 of the gut is left. This is the whole operation for sausage skins. 
 
 For ordinary catgut, lengths of the scraped gut are sewn together 
 with needle and thread. They are then spun by means of a spin- 
 ning wheel. Gut spinning is therefore only the twisting of the 
 prepared gut into -a cord. The materials used are the small intes- 
 tines of hogs and sheep. The intestine of the latter measures 
 from 25 to 30 yards, that of the hog about 20 yards. The gut 
 is first, as a preliminary operation, freed by washing from its 
 contents. ' 
 
 With regard to these operations, Ballard says : — 
 
 " Speaking generally, gut scraping and gut spinning establish- 
 ments are the most intolerable of nuisances wherever they may 
 chance to be located. Within the workshops the stench is incon- 
 ceivably horrible ; few persons unaccustomed to it could bear to 
 remain for a single minute in some scraping rooms that I have 
 visited : I myself have had sometimes a difficulty to restrain 
 vomiting and to carry on the inquiries I was bent upon. The 
 stench, after I have been in some of them for twenty minutes or 
 half an hour, has so pertinaciously attached itself to my clothing 
 and hair, that only repeated ablutions have removed the odour 
 from my hair ; my clothing has retained the stench for days. It 
 spreads from the workshop and yard all round the neighbour- 
 hood, and often gives rise to such loud complaints that local 
 
XX.] TRADE NUISANCES. 257 
 
 authorities in some towns have insisted upon the entire removal 
 of them." 
 
 As an example of the regulations necessary to be enforced the 
 following byelaws in force in the metropolis may be quoted : — 
 
 LONDON COUNTY COUNCIL. 
 
 The Slattghterhotjses, &c. (Metropolis), Act, 1874, 37 and 38 Vie., o. 67. 
 
 Bye-Laws for regulating the conduct of the business of a Gut Scraper, that is 
 to say, any business in which gut is cleansed, scraped, or dealt with otherwise 
 than for the manufacture of cat-gut : and the structure of the premises on 
 which such business is being carried on ; and the mode in which application 
 is to be made for sanction to establish such business anew, within the limits 
 of the Metropolis (except the City of London and the liberties thereof). 
 
 In pursuance of the Slaughterhouses, &c. (Metropolis) Act, 1874, by which the 
 Metropolitan Board of "Works ' are constituted the Local Authority for the Metropolis 
 (except the City of London and the liberties thereof), the said Metropolitan Board 
 of Works ^ do hereby make the following Bye-Laws : — 
 
 Bye-Laws for Begulating the CoTiduot of the Business. 
 
 1. Every Gut Scraper shall cause all gut, and every other offensive material 
 which may at any time be brought or kept upon the premises, to be so brought or 
 kept in close vessels or receptacles ; and shall in all other respects adopt such pre- 
 cautions in the bringing or keeping of any such gut or other material upon the 
 premises as effectually to prevent the emission of any offensive smell from such gut 
 or other material. 
 
 2. Every Gut Scraper shall cause every vessel or receptacle which maybe used for 
 the bringing, keeping or manipulation of such gut or other offensive material upon 
 the premises, to be constructed of galvanized iron or other non-absorbent material, 
 and to be furnished with tight and close-fitting covers. 
 
 3. Every Gut Scraper shall cause his business to be so carried on, and shall in all 
 other respects cause such precautions to be taken, as may be necessary to prevent the 
 emission of any offensive smell into the external atmosphere from any part of the 
 premises where such business may be carried on. 
 
 4. Every Gut Scraper shall cause all offensive gut, garbage, filth, refuse, or other 
 offensive matter upon the premises, to be placed in proper vessels or receptacles con- 
 structed of non-absorbent materials and effectually closed. 
 
 5. Every Gut Scraper shall cause the floor of any part of the premises where gut 
 scraping may have been carried on, and every tank, tub, vessel, or receptacle, 
 scraping board, and other utensil or instrument which may have been in use, or 
 which may be in a foul or offensive condition, to be effectually cleansed, and to be 
 disinfected by the application thereto of a sufGeient ctuantity of chloride of lime, 
 carbolic acid, or other effectual disinfectant. 
 
 6. Every Gut Scraper shall, from time to time, as often as occasion may require, 
 cause all garbage, filth, or refuse to be removed from his premises in properly 
 closed vessels or receptacles, constructed of galvanized iron or other non-absorbent 
 material. 
 
 7. Every G;it Scraper shall cause the premises on which his business is carried on 
 to be constantly provided with an adequate supply of water, and he shall cause every 
 part of such premises to be thoroughly washed, from time to time, as often as ma}' be 
 necessary, and to be kept at all times thoroughly clean. 
 
 8. Every Gut Scraper shall cause every inner wall of the premises on which his 
 business is carried on to be kept at all times thoroughly clean and in good order and 
 repair. He shall cause the upper part of every inner wall and also every ceiling in 
 
 ^ See previous footnotes. 
 
258 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 every part of Ms premises where any process of his business may b3 carried on, to 
 be thoroughly washed with hot lime- wash in the first week of each of the months of 
 March and September, and also as often as may be necessary for the purpose of keeping 
 such part of the premises in a -clean aad wholesome state. 
 
 9. Every Gut Scraper shall cause every vessel, receptacle, utensil, or instrument 
 provided or used upon, or in connection with, the premises on which his business 
 may be carried on, to be kept, when not actually in use, at all times thoroughly clean, 
 so as to prevent the emission of any oftensive smell from such vessel, receptacle, 
 utensil or instrument. 
 
 10. Every Gut Scraper shall afford access to every part of the premises on which 
 his business is carried on to every Member and Officer of the Board, authorised in 
 writing under the hand of the Clerk of the said Board, at any reasonable time 
 during the hours within which such business may be carried on. 
 
 11. Every person who shall not comply with any of these Bye-Laws shall be 
 guilty of an oft'ence, and shall be liable for every such offence to a penalty of Five 
 pounds ; and in the case of a continuing offence, to a penalty of One pound for every 
 day during which the offence may bo continued after the conviction for the first 
 ofi'encer 
 
 12. Every Court of Summary Jurisdiction, as defined in the Slaughter-houses, 
 &c. (Metropolis), Act, 1874, may, as a penalty for the breach of any of the foregoing 
 Bye-Laws, by Sunmiary Order, suspend or deprive any person altogether of the right 
 of carrying on the business of a Gut Scraper. 
 
 Bye-Laws for Regulating the Strvxture of the Premises. 
 
 13. Every Gut Scraper shall cause every floor upon which any process of his 
 business is carried on, in any part of his premises, to be properly covered with a layer 
 of concrete, or other suitable jointless, impervious material, laid (in the case of a 
 ground floor, upon a suitable bottom of at least four inches in thickness. He shall 
 cause every such floor to have a proper slope towards h. channel or gully ; and shall 
 cause every part of Ms premises wherein any such floor may be constructed to be 
 effectually drained by adequate drains communicating with a public sewer. He shall 
 also cause every drain to be properly trapped, and the entrance thereto to be covered 
 with a fixed grating, the bars of which shall not be more than three-eighths of an 
 inch apart. 
 
 14. Every Gut Scraper shall cause the inner walls of every part of his premises 
 within which gut scraping is carried on, to be covered with hard, smooth, impervious 
 material, to the height of four feet at the least ; and such covering shall be always 
 kept in good repair. 
 
 15. Every Gut Scraper shall cause all needful works and repairs to the premises 
 to be forthwith done and executed as and when the same shall become requisite, but 
 shall not allow any alteration whatsoever to be made in respect of the structure of 
 the premises, without the consent of the Board. 
 
 16. Every person who shall mot comply with any of the foregoing Bye-Laws 
 relating to -the structure of the premises shall be guOty of an offence, and shall be 
 liable, for every such offence, to a penalty of Five pounds, and in the case of a con- 
 tinuing offence, to a penalty of One pound for every day during which the offence 
 may be continued after the conviction for the first offence. 
 
 Bye Laws for Regulating the Mode of Application for Samtion to New Establishment 
 
 of the Business. 
 
 17. Every person who may apply to the Board for sanction to establish anew 
 the business of a Gut Scraper, shall furnish with the application a plan of the 
 premises and sections of the buildings in which it is proposed to carry on such 
 business, such plans and sections being drawn to a scale of a quarter of an inch to 
 the foot, and showing the provision made, or proposed to be made, for the drainage, 
 lighting, ventilation, and water supply of such premises; and shall also furnish a 
 key plan of the locality, showing the buildings and streets within one hundred yards 
 of the premises, drawn to a scale of five feet to the mile. 
 
XX.] TRADE NUISANCES. 259 
 
 LONDON COUNTY COUNCIL. 
 
 The Slatjghteehouses, &c. (Meteopolis) Act, 1874, 37 and 38 Vic, c. 67. 
 
 Bte-Laws for regulating the conduct of tlie business of a Cat Gut Maker or Cat 
 Gut Manufacturer, i.e., a person whose business it is to manufactui-e articles 
 from the gut or intestines of animals ; and the structure of the premises on 
 which such business Is being carried on ; and the mode in which application 
 is to be made for sanction to establish such business anew ; within the limits 
 of the Metropolis (except the City of London and the liberties thereof). 
 
 In pursuance of the Slaughterhouses, &c. (Metropolis), Act, 1874, by which the 
 Metropolitan Board of Works'- are constituted the Local Authority for the Metropolis 
 (except the City of London and the liberties thereof), the said Metropolitan Board of 
 "Works ^ (for the purposes of these Bye-Laws called the "Board ") do hereby make the 
 following Bye-Laws : — 
 
 Bye-Law for Begulating (he Conduct, of (he Business. 
 
 1. Every Cat Gut Maker shall cause all gut, other than dried gut, and every 
 other offensive material which may at any time be brought or kept upon the premises, 
 to be so brought or kept in closed vessels or receptacles ; and shall in all other 
 respects adopt such precautions in the bringing or keeping of any such gut or other 
 material upon the premises as effectually to prevent the emission of any offensive 
 smell from such gut or other material. 
 
 He shall cause every vessel or receptacle which may be used for the bringing, 
 keeping, or manipulation of such gut or other offensive material upon the premises, 
 to be constructed of galvanised iron or Other non-absorbent material, and to be 
 furnished with tight and close-fitting covers. 
 
 2. No Cat Gut Maker shall, after the expiration of twelve months from the date of 
 the publication of these Bye-Laws, open or permit to be opened any vessel or 
 receptacle containing gut or other offensive material, or carry on or jiermit to be 
 carried on, the processes of cleansing and scraping the gut, except in a chamber con- 
 structed in accordance with the requirements of the Bye-Law in that behalf herein 
 contained, and effectually closed so as not to allow any offensive smell to escape 
 therefrom into the external atmosphere, or into the other parts of the premises. 
 
 3. Every Cat Gut Maker, at all times while the process of cleansing or scraping 
 any gut may be carried on, shall cause such process to be so carried en and in all 
 other respects such precautions to be taken, as may be necessary to prevent the 
 emission of any offensive smell into the external atmosphere from the chamber in 
 which such process may be carried on. 
 
 4. Every Cat Gut Maker, on every day during which the processes of cleansing and 
 scraping any gut may be carried on, shall, immediately after the completion of such 
 cleansing and scraping, cause all offensive gut, garbage, filth, refuse, or other offensive 
 mattar retained upon the premises, to be placed in proper vessels or receptacles con- 
 structed of non-absorbent materials and effectually closed. 
 
 He shall, at the same time, cause the floor of the chamber in which any such 
 processomay have been carried on, and every tank, tub, vessel, or receptacle, scraping 
 board, and other utensils or instrument which may have been in use during the day, 
 or which may be in a foul or offensive condition, to be effectually cleansed, and to be 
 disinfected by the application thereto of a sufficient quantity of chloride of lime 
 carbolic acid, or some other effectual disinfectant. 
 
 5. Every Cat Gut Maker shall, after the expiration of the time aforesaid, during 
 the process of opening, any vessel or receptacle, or of cleansiug or scraping any gut, 
 or of cleansing or disinfecting any close chamber or any utensil, cause the atmosphere 
 of the close chamber wherein such process may be carried on, to be continuously 
 drawn into a shaft and conveyed into or through a furnace fire in such a manner as 
 to effectually consume or destroy all noxious and offensive gases or vapours which 
 may have arisen from such process therein. 
 
 1 To be now read " London County Council." 
 
 S 2 
 
260 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 6. Every Cat Gut Maker shall, from time to time, as often as occasion may re- 
 c[uirc, cause all garbage, filth, or refuse to be removed from his premises in properly 
 closed vessels or receptacles constructed of galvanised iron or other non-absorbent 
 material. 
 
 7. Every Cat Gut Maker shall cause the premises on which his business is carried 
 on to be constantly provided with an adequate supply of water, which shall be received 
 and stored in a cistern or other suitable receptacle, properly constructed ; or, in the 
 case of a constant supply of water, by a pipe communicating with a "Water Company's 
 main ; and he shall cause every part of such premises to be thoroughly washed, from 
 time to time, as often as may be necessary ; and to be kept at all times thoroughly 
 clean. 
 
 8. Every Cat Gut Maker shall cause every inner wall of the premises on which 
 his business is carried on to be kept at all times thoroughly clean and in good order 
 and repair. He shall cause every such wall and every ceiling to be thoroughly 
 washed with hot lime-wash in the first week of each of the months of March, June, 
 September, and December. 
 
 9. Every Cat Gut Maker shall cause every vessel, receptacle, utensil, or instru- 
 ment provided or used upon, or in connection with the premises on which his business 
 may be carried on, to be kept, when not actually in use, at all times thoroughly clean, 
 so as to prevent the emission of any offensive smell from such vessel, receptacle, 
 utensil or instrument. 
 
 10. Every Cat Gut Maker shall, at the expiration of the time aforesaid, cause 
 every room, chamber, or other place which may be used on or in connection with 
 the premises where his business is carried on, and in which any offensive vapour, gas, 
 or fume may be evolved, to be furnished with suitable appliances, so constnicted and 
 used as to effectually prevent the escape of any of such vapour, gas, or fume into the 
 external atmosphere. He shall at all times adopt such precautions and employ such 
 means as may be necessary to cause every such vapour, gas, or fume to be conveyed 
 into or through a furnace fire, or to be condensed, so as to be effectually destroyed. 
 
 11. Every Cat Gut Maker shall afford access to eveiy part of the premises on 
 which his business is carried on to every Member and Officer of the Board, authorised 
 in writing under the hand of the Clerk of the said Board, at any reasonable time 
 during the hours within which such business may be carried on; 
 
 12. Every person who shall not complj- with any of these Bye-Laws shall be 
 guilty of an offence, and shall be liable, for every such offence, to a penalty of Five 
 pounds, and in the case of a continuing oBence, to a penalty of One pound for every 
 day during which the oflence may be continued after the conviction for the first 
 offence. 
 
 13. Every Court of Summary Jurisdiction, as defined in the Slaughterhouses, 
 &c. (Metropolis), Act, 1874, may, as a penalty for the breach of any of the foregoing 
 Bye-Laws, by summary Order, suspend or deprive any person altogether of the right 
 of carrying on the business of a Cat Gut Maker. 
 
 Bye-Laws for Regulating the Structure of the Premises, which shall be complied with as 
 regards all Buildings now used for the Business, before the expiration of twelve 
 Calendar Months from the date of the Publication thereof ; and as regards 
 Buildings to he used hereafter, before the Business shall be commenced therein, 
 
 14. Every Cat Gut Maker shall provide, or cause to be provided, upon the 
 premises, a chamber or chambers in which the offensive processes of the business are 
 to be carried on, and such chamber or chambers shall be constructed in the following 
 manner, viz. — 
 
 {a) The walls shall be of brick, stone, or concrete ; and the walls and the 
 ceiling shall be constructed in such manner that the atmosphere of the close 
 chamber cannot escape into the external atmosphere. 
 
 (J) The windows or lights shall be of glass, not less than one-quarter of an inch 
 in thickness, and shall be fixed in the walls or roof in such a manner as not 
 to open, and to be air-tight, and such windows or lights shall be covered 
 externally with a wire netting. 
 
XX.] TEADE .NUISANCES. 261 
 
 (c) There shall be only one doorway in a close chambei;, and the door thereto 
 
 shall be made to closely fit the doorway in such a manner that when shut 
 the atmosphere of a close chamber cannot escape through such doorway. 
 
 (d) The paving shall be asphalte, Yorkshire flagstone, Stourbridge paving 
 
 bricks, closely set in cement, upon a bottom of four inches of good concrete, 
 or other suitable material ; and shall be laid with a proper slope and channel 
 towards a gully, and shall be effectually drained by an adequate drain of 
 glazed pipes communicating with the public sewer, and properly ventilated. 
 The drain shall be properly trapped, and be covered with a fixed grating, 
 the bars of which shall not be more than three-eighths of an inch apart. 
 
 (e) The inner walls shall be covered with hard, smooth impervious material, to 
 
 the height of four feet at the least ; and such covering shall be always kept 
 in good order and repair, 
 
 (/) There shall be provided one or more inlet valves for air, adequate for 
 supplying a sufficient quantity of fresh air from the outside of the chamber 
 for the persons employed and working therein, and so constructed as not to 
 allow the atmosphere of the chamber to escape thereby ; and such valve or 
 valves shall be always kept in good working order and repair. 
 
 (g) There shall be provided a shaft to lead from the upper part of a close 
 chamber to a fiu'nace, and such shaft shall be so constructed that any gas 
 or air drawn through the shaft shall be consumed in the furnace fire. 
 
 (h) There shall be no room or loft over any such chamber, other than a room 
 used solely for the purpose of the business ; and such room shall be provided 
 with separate means of access from without, and shall not communicate 
 directly or indirectly with any close chamber. 
 
 15. Every Cat Gut Maker shall provide, or cause to be provided, upon the 
 premises on which his business is carried on machinery or appliances for effectually 
 drawLQg the atmosphere from a close chamber or chambers, and from every room or 
 place in which any offensive vapour or gas may be evolved, through a shaft and into 
 a furnace fire. 
 
 16. He shall cause all needful works and repairs to the premises to be forthwith 
 done and executed as and when the same shall become requisite, and shall not allow 
 any alteration whatsoever to be made in respect of the structure of the premises 
 without the consent of the Board. . 
 
 17. Every person who shall not comply with any of the foregoing Bye-Laws 
 relating to the stracture of the premises shall be guilty of an offence, and shall be 
 liable, for every such offence, to a penalty of Five pounds, and in the case of a con- 
 tinuing offence, to a penalty of One pound for every day dui-ing which the off'ence may 
 be continued after the conviction for the first offence. 
 
 Bye-Law for Eegulating the Mode of Application for Sanction to New Eslahlishment 
 
 of the Business. 
 
 18. Every person who may apply to the Board for their sanction to establish anew 
 the Business of a Cat Gut Maker shall furnish with the application a plan of the 
 premises and sections of the buildings in which it is proposed to carry on such 
 business, such plans and sections being drawn to a scale of a quarter of an inch to the 
 foot, and showing the provision made, or proposed to be made, for the drainage, 
 lighting, ventilation, and water supply of such premises, and for the construction of 
 close chambers thereon, and shall also furnish a key plan of the locality, showing the 
 buildings and streets within one hundred yards of the premises, drawn to a scale 
 of five feet to the mile. 
 
 (185) The Boiling of Tripe. 
 
 The nuisance (and its remedy) from the boiling- of tripe is 
 sufficiently detailed in the following byelaws in force in the 
 Metropolis : — 
 
262 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 LONDON COUNTY COUNCIL. 
 
 The Slattghteehousbs, &c. (Meteopolis) Act, 1874, 37 & 38 Fjc, e. 67. 
 
 Bye-Laws for the regulation of the conduct of the business of a Tripe Boiler, 
 the structure of the premises on which such business is carried on, and the 
 mode in which application is to be made for sanction to establish such business 
 anew, within the limits of the Metropolis (except the City of London and the 
 liberties thereof.) 
 
 In pursuance of the above Act by which the Metropolitan Board of "Works ' is 
 constituted the Local Authority for the Metropolis as defined in the same Act 
 (except the City of London and the liberties thereof), the said Metropolitan Board 
 of "Works 1 (for the purpose of these Bye-Laws called the " Board ") doth hereby make 
 the following Bye-Laws : — 
 
 Bye-Laws for Eegidating the Conduct of the Business. 
 
 1. Every Tripe Boiler shall cause the premises on which his business is carried 
 on to be constantly provided with an adequate supply of water, which shall be 
 received and stored in cisterns, or other suitable receptacles, properly consti'ucted, 
 and he shall cause such premises at all times to be well and thoroughly ventilated 
 by suitable openings, windows, Louvre boards, or otherwise. He shall cause every 
 part of such premises to be thoroughly washed from time to time, as often as may 
 be necessary, and to be kept at all times thoroughly clean. 
 
 2. Every Tripe Boiler shall cause every inner wall of the premises on which his 
 business is carried on to be kept at all times thoroughly clean and in good order and 
 repair. He shall cause every such wall to be thoroughly washed with hot Ume- 
 wash in the first week of each of the months of March, June, September, and 
 December. 
 
 3. Every Tripe Boiler shall provide asufilcient number of tubs, boxes, or vessels, 
 constructed of galvanized iron or other non-absorbent material, and furnished with 
 tight and close-fitting covers, for the purpose of receiving and conveying away all 
 manure, garbage, offal, and filth. He shall, from time to time, as often as occasion 
 may require, cause such manure, garbage, off'al, and filth to be placed in such tubs, 
 boxes, and vessels, and to be removed from his premises without delay. 
 
 4. Every Tripe Boiler shall cause every boiler or other vessel from which any 
 offensive or noxious vapour or gas may be evolved in the operation of boiling, or 
 otherwise, to be properly covered, and in all other respects to be so constructed 
 and used as to cause all such vapour or gas to be effectually conveyed into, or 
 through, a furnace fire, or otherwise to be prevented from escaping into the external 
 atmosphere. 
 
 6. Every Tripe Boiler shall cause every tub, box, vessel, boiler, or receptacle 
 provided or used upon, or in connection with, the premises on which his business 
 may be carried on, to be kept at all times thoroughly clean, so as to prevent any 
 offensive smell. 
 
 6. Every Tripe Boiler shall cause all offal, or other materials used in his 
 business, when delivered on to the premises across a public footpath, to be conveyed 
 in vessels properly covered and constructed. 
 
 7. Every Tripe Boiler shall remove, or cause to be removed, from the premises 
 on which his business is carried on, every bone, fat, offal, garbage, or other similar 
 article before it has become putrid or offensive. 
 
 8. Every Tripe Boiler shall afford access to every part of the premises on which 
 his business is carried on, to every Member and Officer of the Board authorised 
 in writing under the hand of the Clerk of the said Board, at any reasonable time 
 during the hours within which such business may be carried on. 
 
 9. Every person offending against any of the foregoing Bye-laws shall be liable 
 for every such offence, to a penalty of Five pounds, and in the case of a continuing 
 
 1 To be now read " London County Council." 
 
XX.] TRADE NUISANCES. 263 
 
 offence, to a penalty of One pound for every day during which the offence may be 
 continued after the conviction for the first offence. 
 
 10. Every Court of Summary Jurisdiction, as defined in the Slaughterhouses, 
 &o., (Metropolis) Act, 1874, may, as a penalty for the breach of any of the foregoing 
 Bye-laws, by summary Order, suspend or deprive any person altogether of the 
 right of carrying on the business of a Tripe Boiler. 
 
 Bye-law for Segulating Mode of Application for Sanction to new EstahlisJiment of 
 
 ] 1. Every person who may apply to the Board for their sanction to establish 
 anew the business of a Tripe Boiler, shall furnish with his application a plan of the 
 premises and sections of the building in which it is proposed to carry on such 
 business, such plan and sections being drawn to a, scale of a quarter of an inch to 
 the foot, and showing the provision made, or proposed to be made, for the drainage, 
 lighting, ventilation, and water supply of such premises ; he shall .at the same time 
 furnish the Board with a key plan of the locality, showing the buildings adjacent 
 to the premises, such plan being drawn to a scale of five feet to the mile. 
 
 Bye-laws for Megulating the Structure of the Premises. 
 
 1 2. Every Tripe Boiler shall cause the premises on which his business is carried 
 on to be well paved with asphalte, Yorkshire flag-stone, Stourbridge paving bricks, 
 closely set in cement upon a bottom of four inches of good concrete, or with other 
 suitable material, and to be laid with a proper slope and channel towards the gully, 
 and to be effectually drained by an adequate drain of glazed pipes communicating 
 with the public sewer, and properly ventilated. He shall cause such gully to be 
 properly trapped, and to be covered with a grating, the bars of which shall not be 
 more than three-eighths of an inch apart. ■ 
 
 13. Every Tripe Boiler shall cause all works and repairs to the premises to be 
 forthwith done and executed as and when required by the Board ; and shall not 
 make or allow to be made any alteration whatsoever in respect of the structure of 
 the premises, without the consent of the Board. 
 
 (186) Slaughterhouses. 
 
 It is hoped the time is not far distant when private slaughter- 
 houses in large population centres will be abolished. The public 
 health cannot be protected, nor the sale of diseased animals con- 
 trolled, except in abbatoirs. 
 
 Nuisances arise in private slaughterhouses from the keeping of 
 the animals previous to killing them, from the operations them- 
 selves, and from the garbage and refuse. 
 
 The place where cattle are kept and fed for several days before 
 killing is technically called a "lair," but where they are tempo- 
 rarily detained before slaughter is called " a pound ; " but in small 
 businesses the one shed or place serves for both lair and pound. 
 
 The neighbours of slaughtering places frequently— and with 
 reason — complain of the bleating of sheep and the lowing of cattle. 
 There may be also a good deal of odour from a number of animals 
 being crowded together. Although noise, perse, does not come 
 
264 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 within the scope of the Public Health and Sanitary Acts, it is at 
 all events an annoyance, and aggravates other causes of complaint. 
 
 In slaughtering, the oxen in this country are usually poleaxed ; 
 in a few places they are shot, the gun being loaded with a marble 
 (a bullet breaking up the tissues too much) : through the hole in 
 the animal's skull, thus produced, a cane is thrust down the spinal 
 marrow. Death is not so rapid as is generally thought. The 
 author has seen bullocks struggle for several minutes. Sheep have 
 their throats cut ; pigs are killed by cutting into the great vessels 
 of the neck. The squeals, or almost human shrieks, of the latter 
 are peculiarly distressing, and, from the high pitch of the sounds, 
 are heard a long distance. Some butchers stun the pig first in 
 order to avoid the noise. 
 
 The butcher in one way or another is able to dispose of almost 
 all dihris arising from the operation of slaughtering. The blood 
 is used as a food for man or pigs, or it is deiibrinated and utilised 
 in Turkey-red dyeing, or it is sent to the manufacturer of blood 
 albumen. The skins, hoofs, horns, all find buyers. Parts of the 
 intestines and internal organs, not readily saleable, are converted 
 into dogs' and cats' meat ; the contents of the intestines are used 
 as manure. 
 
 Nevertheless, unless the slaughterhouse itself is constructed 
 with proper tanks or receptacles for the blood, unless it is properly 
 paved, lighted, and drained, and supplied with ample water supply, 
 and above all if the greatest cleanliness be not observed, it is 
 likely to become, more especially in summer time, an intolerable 
 nuisance. Probably blood putrefaction is liable to produce septic 
 diseases and puerperal fever ; in medical literature general state- 
 ments are to be found giving some support to this theory. That 
 putrefying blood contains poisonous elements is capable of proof: 
 witness the practice of many uncivilized tribes who smear their 
 weapons with blood, such weapons acquiring specially dangerous 
 qualities. Hence, pits used for the receipt of blood, or vessels 
 generally which have been used in a slaughterhouse, should not 
 alone be thoroughly cleansed, but also disinfected daily. 
 
 The methods to be adopted and recommended in the conserva- 
 tion and establishment of slaughterhouses cannot be better eluci- 
 dated than by a perusal of the following Metropolitan Byelaws 
 under the Metropolitan Slaughterhouse Act : — 
 
XX.] TRADE NUISANCES. 265 
 
 LONDON COUNTY COUNCIL. 
 
 37 and 38 Vict., c. 67. 
 
 Bye-laws for SlaugMerhov.ses in the County of London. 
 
 In pursuance of the Slaugliterhouses, &c. (Metropolis), Act, 1874, and of the Local 
 Government Act, 1888, the London County Council hereby make the following Bye- 
 laws for regulating — 
 
 [a) The conduct of the business of a slaughterer of cattle ; 
 (6) The structure of the premises in which such business is being can'ied on ; and 
 (c) The mode in which application is to be ir.ade for sanction to establish such 
 business anew within the County of London (except the City of London 
 and the Liberties thereof), that is to say — 
 
 Bye-laws for Begulating the Conduct of the Business of a Slaughterer of Cattle in the 
 
 County of London. 
 
 1. Every occupier of a slaughterhouse — 
 (a) Shall cause all animals intended for slaughter to be kept upon the premises 
 
 only in pounds, pens, or lairs. 
 (6) He shall not keep in a slaughterhouse, or in such pounds, pens, or lairs any 
 animals not intended for slaughter, or any animals the flesh of which would 
 be unfit for use as human food. 
 
 (c) He shall not keep in such pounds, pens, or lairs a greater number of animals 
 
 than is herein provided, that is to say — 
 
 1. In the case of cattle, one animal to every twenty-four square feet of floor 
 
 space therein. 
 
 2. In the case of calves, one animal to every eight square feet of floor space 
 
 therein. 
 
 3. In the case of sheep, lambs and pigs, one animal to every six square feet 
 
 of floor space therein. 
 
 (d) He shall not keep therein any animals for a longer period than may be 
 
 necessary for the purpose of preparing such animals for slaughter. 
 
 (e) He shall provide such animals with a suflioient quantity of wholesome water 
 
 and food. 
 2. Every occupier of a Slaughterhouse — 
 (a) Shall slaughter all animals in the slaughterhouse, and shall not slaughter or 
 permit to be slaughtered any animal in any pound, pen, or lair, or in any 
 part of the premises other than the slaughterhouse. 
 (5) He shall, in slaughtering animals use such instruments and appliances, and 
 adopt such method of slaughtering, and otherwise take such precautions, 
 as may be requisite to prevent unnecessary suffering to any animal. 
 
 (c) He shall not slaughter or permit to be slaughtered any animal within public 
 
 view, or within the view of other animals. 
 
 (d) He shall provide^ sufficient vessels or receptacles, properly constructed of 
 
 galvanised iron or other non-absorbent material, and furnished with close 
 fitting covers ; and shall cause all blood from any animal slaughtered to be 
 caught and placed in such vessels or receptacles . 
 
 (e) He shall, upon the completion of any slaughtering, cause all manure, garbage, 
 
 filth, or any refuse residues from the animals slaughtered, to be forthwith 
 
 placed in such vessels or receptacles. 
 (/) He shall cause such vessels or receptacles to be kept closed while containing 
 
 any of the aforesaid substances. 
 (g) He shall cause all such substances to he removed and conveyed from the 
 
 premises in such closed receptacles. 
 (h) He shall cause the fat of any animal slaughtered to be kept freely exposed to 
 
 the air while upon the premises. 
 (i) He shall cause all blood, manure, garbage, filth, or any refuse residues from 
 
 animals slaughtered, and all hides, skin, fat, and offal therefrom, to be 
 
 removed from -the premises within twenty-four hours of the completion of 
 
266 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 slaughtering, in sucli manner and by such means as will not cause nuisance 
 either at the premises or in the public streets. 
 (k) He shall, as far as is reasonably practicable, prevent any blood, manure, 
 garbiige, filth, or any refuse residues from animals slaughtered entering any 
 drain or sewer, or any inlet to any drain or sewer. 
 3. Every occupier of a Slaughterhouse — 
 
 (a) Shall cause every part of the floor of such slaughterhouse, and every other 
 
 internal part of such slaughterhouse, and also the fittings thereof, upon 
 which any blood, or refuse, oi' filth may have been spilled, splashed, or 
 deposited, to be thoroughly washed and cleansed within three hours after 
 the completion of any slaughtering. 
 
 (6) He shall cause every part of such floor and all internal walls and fittings 
 within six feet of such floor to be at all times kept in good order and repair, 
 so as to prevent the absorption therein of any blood, or liq[nid refuse, 
 tor filth. 
 
 (c) He shall not permit the surfaces of the walls and fittings within six feet of 
 the floor to be covered with cementwash, limewash, or other like substance. 
 
 {d) He shall cause all utensils, receptacles, and appliances used in such business 
 to be kept, when not in actual use, in a thoroughly clean condition. 
 
 (e) He shall cause all internal walls and fittings of such slaughterhouse not 
 
 within six feet of the ground, and the internal walls and fittings of any 
 pound, pen, or lair, to be thoroughly limewashed with hot limewash at 
 least four times in every year : that is to say, between the 1st and the 
 10th days of the months of March, June, September, and December 
 respectively. 
 
 (/) He shall cause all dung and offensive litter to be swept up and removed from 
 every pound, pen, or lair at least once a day, and such place to be thoroughly 
 cleansed as often as may be necessary to keep the same in a clean condition. 
 i. Every occupier of a Slaughterhouse — 
 
 {a) Shall cause the means of ventilation provided thereto, and to any pound, 
 pen, or lair to be kept in proper order and efficient action so that at all 
 times such slaughterhouse, pound, pen or lair shall be effectually ventilated 
 by direct communication with the external air. 
 
 (b) He shall cause the means of drainage provided in or upon his premises to be 
 
 kept at all times in proper order. 
 
 (f) He shall cause the means of water supply provided upon his premises to be 
 
 kept in proper order, and shall at all times provide a sufficient supply of 
 water for the proper cleansing of his slaughterhouse, pounds, pens, or lairs, 
 and of the vessels and receptacles therein. 
 
 5. Every occupier of a Slaughterhouse^ 
 
 (a) Shall allow the slaughterhouse to be used for no other purpose than the 
 
 slaughtering and dressing of animals the flesh of which is fit for, and is 
 
 intended to be sold as, human food. 
 (5) He shall allow no person other than himself and his servants to slaughter 
 
 animals or dress the carcases thereof upon his premises, unless he is 
 
 authorised to do so by the Council in writing. 
 
 6. Every occupier of a Slaughterhouse shall at all times employ such means and 
 adopt such precautions as may be necessary for preventing nuisance arising upon his 
 premises. 
 
 7. Every occupier of a Slaughterhouse shall at all reasonable times afford free 
 access to every part of his premises to the Inspectors and other persons authorised by 
 the Council in writing to inspect slaughterhouses, and he shall enable such Inspectors 
 or other persons to examine the premises without obstruction or unnecessary delay. 
 
 8. Every person breaking any of the foregoing Bye-laws shall be liable for every 
 offence to a penalty of not exceeding Five pounds ; and in the case of a continuing 
 offence to a penalty of One pound for every day dnring which the offence may be 
 continued after conviction for the first offence. 
 
 9. In pursuance of the provision in that behalf contained in Section 4 of the 
 Slaughterhouses, &c.. Metropolis Act, 1874, power is hereby given to every Court of 
 Summary Jurisdiction, by nummary order, to suspend or deprive any person altogether 
 
XX.] TEADE NUISANCES. 267 
 
 of the right of carrying on the business of a Slaughterer of Cattle, as a penalty for 
 brealdng any of the foregoing Bye-laws. 
 
 Bye-laws for Regulating the Struetitre of the Premises upon which the Business of a 
 Slaughterer of Cattle is being carried on in the County of London. 
 
 10. Every such premises shall include a Slaughterhouse and one or more pounds, 
 pens, or lairs, and — 
 
 ' (a) Such slaughterhouse shall have a floor space of at least one hundred square 
 feet, and the walls thereof to a height of six feet from the ground shall he 
 substantially constructed of brick, stone, iron or concrete ; and such 
 slaughterhouse shall be covered with a properly constructed roof. 
 (6) Such pounds, pens, or lairs shall- be separated from such slaughterhouse by 
 means of close partitions to a height of at least five feet in the case of 
 cattle, and at least three feet in the case of sheep, lambs and pigs, and all 
 doors in such partitions shall be closely boarded, 
 (c) Such premises shall have an approach to the slaughterhouse which shall be 
 throughout of a width of at least three feet six inches, and such approach 
 shall not be up or down steps, or over slopes having a steeper gradient than 
 one foot in four feet ; provided that where sheep, lambs and pigs only are 
 killed, the width of the approach shall be at least two feet nine inches 
 throughout. 
 
 11. Every Slaughterhouse and pound, pen, or lair upon such premises — 
 
 {a) Shall be well and sufficiently lighted and ventilated by louvred openings in 
 the walls and roofs, or by other approved openings, windows, or lights. 
 
 (6) ShaU be well paved with granite, cement, concrete, or with other approved 
 hard and impervious material set with cement properly bedded on concrete ; 
 and such paving shall have a proper slope towards a gully-hole ; and such 
 gully-hole shall communicate by an adequate drain of glazed stoneware 
 pipes with the public sewer, and be trapped by an appropriate fixed trap, 
 and be covered with a fixed grating, the bars of which shall be not more 
 than I inch apart. 
 
 (c) Shall be provided with means for an adequate supply of water ; and where 
 there is not a constant water supply, with a slate, metal, or metallic-lined 
 tank, the bottom of which shall be not less than six feet from the floor ; 
 and such tank shall be properly covered, and an adequate water trough 
 shall be in every pound, pen, or lair. 
 
 12. Every Slaughterhouse shall have the inner walls, doors, and woodwork 
 covered with hard, smooth, and impervious material to a height of at least six feet 
 from the floor. 
 
 13. A Slaughterhouse shall not have any rooms or lofts thereover, and a slaughter- 
 house, pound, pen, or lair — 
 
 (ffi) Shall not have any openings therefrom directly into any building used as a 
 dwelling. 
 
 (V) Shall not contain any water-closet, privy, urinal, or stable ; and a water- 
 closet, privy, urinal or stable shall not be in direct communication with, or 
 ventilate into, any slaughterhouse. 
 
 14. Every person who shall not comply with any of the foregoing Bye-laws 
 relating to the structure of the premises shall be guilty of an off'ence, and shall be 
 liable, for every such offence, to a penalty of not exceeding Five pounds, and, in the 
 case of a continuing offence, to a penalty of One pound for every day during which 
 the offence may be continued after the conviction for the first off'ence. Provided 
 always, that the foregoing Bye-laws for regulating the structure of the premises shall 
 not, until after the expiration of six months from the date of the confirmation of the 
 Bye-laws, be deemed to apply to any premises where at such date the business of a 
 Slaughterer of Cattle may be carried on ; and further provided, that a requirement 
 of such Bye-laws for regulating the structure of the premises shall not be deemed to 
 apply to any premises in respect of which the London County Council shall have, by 
 endorsement in writing on the back of any current license to use such premises as a 
 slaughterhouse, exempted such premises from such requirement. 
 
268 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Bye.-lawsfor Regulating the Mode in whieJi Application is to he made for Sanction to 
 Establish Anew the Business of a Slaughterer of Cattle in the County of London. 
 
 15. Every person applying for such sanction — 
 
 (a) Shall furnish, in the form prescribed by the Council, the particulars specified 
 
 in such form, as to the situation of the premises, and as to the arrangement 
 and construction of the buildings in which such business is proposed to be 
 established. 
 
 (b) He shall also furnish a plan of such premises and sections of the buildings, 
 
 drawn to a scale of one-eighth of an inch to one foot, showingthe buildings 
 proposed to be used as slaughterhouse, pounds, pens or lairs, their 
 construction, the provision foi; drainage, and the means proposed for 
 lighting and ventilation. 
 («) He shall also furnish a key plan of the locality, showing the site, and all 
 buildings, dwellings, streets and places within 250 yards of such site, and 
 such key plan shall be drawn, to a scale of five feet to one mUe. 
 
 Bepeal. 
 
 In further pursuance of the Acts aforesaid, the said London County Council 
 hereby repeal the Bye-laws regulating the conduct of the business of a Slaughterer of 
 Cattle, the structure of the premises on which such business is being carried on, and 
 the mode in which application is to be made for sanction to establish such business 
 anew, made on the seventh day of May, 1875, by the Metropolitan Board of 
 "Works, and confirmed by the Local Government Board on the twenty-seventh day of 
 May, 1875. 
 
 (187) Knackers' Yards. 
 
 The same principles previously detailed as to the slaughtering 
 of cattle are also applicable to knackers', yards, or, as they are 
 otherwise called, "knackeries." But there is this difference be- 
 tween the two : the slaughterer of cattle is presumed to kill 
 healthy animals, the knacker those that are old or diseased ; added 
 to which, the knacker usually unites with his business the offen- 
 sive operation of boiling a large quantity of the flesh and offal for 
 cats' meat. 
 
 A well-managed knacker's yard in close vicinity to houses must 
 itself be considered a nuisance, provided there is much business 
 done. It cannot but be detrimental to health to have a collection 
 of diseased material — such as horses suffering from glanders and 
 farcy or tuberculosis, or animals with suppurating sores — within a 
 short distance of dwelling-houses; and it may be taken as a 
 general advice to a sanitary authority to oppose the establishment 
 of any new business of the kind within a quarter of a mile of any 
 collection of inhabited houses. 
 
 The following are the regulations in force in the metropolis as 
 to knackeries : — 
 
XX.] TRADE NUISANCES. 269 
 
 LONDON COUNTY COUNCIL. 
 
 The Slaughterhouses, &c. (Mbtbopolis), Act, 1874, 37 and 38 Vic., c. 67. 
 
 Bye-laws for regulating the conduct of the business of a Knacker, i. e. , a person 
 ■whose business it is to slaughter any horse, ass, or mule, or any cattle, sheep, 
 goat, or swine, which is not killed for the purpose of its flesh being used as 
 butcher's meat, and the structure of the premises on which such business is 
 being carried on, within the limits of the Metropolis (except the City of London 
 and the liberties thereof). 
 
 In pursuance of the above Act, by which the Metropolitan Board of Works ■^ is 
 constituted the Local Authority for the Metropolis, as defined in the said Act (except 
 the City of London and the liberties thereof), the said Metropolitan Board of Works ^ 
 (for the purposes of these Bye-laws called the "Board") doth hereby make the 
 following Bye- Laws. Throughout and for the purposes of these Bye-Laws "the 
 premises " shall mean and include the slaughterhouse, and all the premises used for 
 and forming part of the business of a Knacker as defined by the Act, and " slaughter- 
 house " shall mean the portion of the premises used for the slaughtering and dressing 
 of the animals above-mentioned, and ' ' occupier " shall mean the occupier of premises 
 where the business of a Knacker is carried on, and ' ' contagious or infections disease ' ' 
 shall include Cattle Plague, Pleuro-pneumonia, Foot and Mouth Disease, Sheep Pox, 
 Sheep Scab, Glanders, and Farcy. 
 
 As to the Conduct of the Business of a Knacker. 
 
 1. The occupier shall not slaughter, or permit to be slaughtered, on the premises 
 any animal that is intended or fit to be used for human food, nor keep or permit to 
 be kept, any fowl, pig, or other animal used for human food in or about the premises 
 nor any dog thereon. 
 
 2. The occupier shall not allow any room situated over a slaughterhouse to be 
 inhabited under any pretext whatsoever. 
 
 3. The occupier shall not allow the slaughterhouse to be used for any purpose 
 other than that for which it is licensed, nor any slaughtering to be conducted within 
 public view. 
 
 i. The occupier shall keep the inner walls of the slaughterhouse always thoroughly 
 clean and ru good order and repair, and shall cause the internal surface of the roof and 
 upper portions of the walls to be thoroughly washed with quicklim.e,at least once in 
 every three months, and he shall also keep every yard and other part of the premises 
 clear. 
 
 5. The occupier shall provide and keep a sufficient number of tubs, boxes, or 
 vessels, formed out of proper non-absorbent materials, with tight and close-fitting 
 covers thereto, for the purpose of receiving and conveying away all manure, garbage, 
 offal, and filth ; and shall, in all oases, immediately after the slaughtering is com- 
 pleted, cause all such manure, garbage, offal, and filth to be placed in such tubs, 
 boxes, and vessels ; and shall cause alL the blood arising from the slaughtering to be 
 put into separate tubs or vessels formed out of the like materials as above with close- 
 fitting covers ; and every such tub, box, and vessel, together with their contents, to 
 be removed from the premises within twenty-four hours. 
 
 6. The occupier shall keep every covered and other receptacle used in the slaugh- 
 terhouse at all times thoroughly cleansed and piu'ified, so as to prevent any offensive 
 smell. 
 
 7. The occupier shall cause every boiler and vessel from which any offensive or 
 noxious vapour or gas may be evolved in the operation of boiling or otherwise, to be 
 covered over and constructed so that every such gas and vapour shall be effectually 
 conveyed into or through a furnace-fire, or shall be otherwise prevented from escaping 
 into the external atmosphere. 
 
 8. The occupier shall cause every hide and skin to be removed from the premises 
 
 ^ Read now London County Council. 
 
270 A MANUAL OF PUBLIC HEALTH. [chap. xx. 
 
 within forty-eight hours after slaughtering, and every hide of a glandered or farcied 
 horse, mule, or ass to be disiufected before removal. 
 
 9. The occupier shall remoTe, or cause to be removed from the premises, every 
 carcase, bone, hide, skin, and all meat, fat, offal, blood, garbage, and other articles 
 before the same have become putrid or offensive. 
 
 ] 0. In case of any horse or other such animal as above-mentioned that is affected 
 with either an infectious or contagious disease being brought to the premises of a 
 Knacker, he shall not suffer it to be removed, but shall forthwith give information 
 thereof to the Board, and to the Cattle Inspector for the District, appointed under 
 the Contagious Diseases (Animals) Act, 1869, with all details in his knowledge as to 
 the name and address of the person bringing the horse or animal, and the owner and 
 the place from which the same was brought, and the time when it was brought. 
 
 11. The occupier shall allow every Member of the Board, in addition to all other 
 persons lawfully entitled to admission, to have free access to the premises during the 
 times of slaughter, and at all reasonable hours. 
 
 12. The occupier, if he neglect or omit to observe or perform or shall in any way 
 break any one of the above Bye-Laws, shall be subject to a penalty of the sum of £3, 
 and in the case of a continuing offence the sum of £1 for every day during which such 
 offence is continued after a conviction for the first offence. 
 
 13. Every court of Summary Jurisdiction, as defined by the Slaughterhouses, &c. 
 (Metropolis), Act, 1874, having jurisdiction to hear and decide complaints of the 
 breach of the above Bye-Laws, may, by Summary Order, suspend or deprive any 
 Knacker altogether of the right of carrying on any such business, as a penalty for the 
 breach of any one of the above Bye-Laws. 
 
 As to the Structure of the Premises upon which the Business of a KnacTeer is 
 
 carried on, 
 
 14. The occupier shall cause the slaughterhouse to be provided with an adequate 
 tank or other proper receptacle for water and water supply, and so placed that the 
 bottom thereof shall not be less than six feet above the level of the floor ; and shall 
 cause the slaughterhouse to be well and thoroughly ventilated. 
 
 15. The occupier shall cause the slaughterhouse to be well paved with asphalte, or 
 flag stone, or proper paving bricks, set in cement, to be laid with proper slope and 
 channel towards a gully, and to be effectually drained by an adequate drain 'of glazed 
 pipes or in other sufficient manner communicating with the public sewer, and the 
 gully to be trapped by an appropriate trap, and to be covered with a grating, the 
 bars of which shall not be more than three-eighths of an inch apart. 
 
 16. The occupier shall cause every inner wall of the slaughterhouse to be covered 
 with hard, smooth, impervious material, to the height of four feet at the least, and 
 to be always kept in good order and repair. 
 
 17. The occupier shall cause all needful works and repairs to the premises to be 
 forthwith done and executed as and when the same shall become requisite ; and shall 
 not allow any alteration whatsoever to be made in respect of the paving, drainage, 
 ventilation, or water supply to or in the premises which have been licensed, without 
 the consent of this Board. 
 
 18. The occupier, if he neglect or omit to observe or perform, or shall in any way 
 break any one of the Bye-Laws, as to the structure of the premises, shall be subject 
 to a penalty of the sum of £5, and in the case of a continuing offence, the sum of £1 
 for every day during which such offence is continued after a conviction for the first 
 offence. 
 
CHAPTER XXI. 
 
 EFFLUVIUM NUISANCES CONNECTED WITH TRADES. 
 
 (188) Glassijkation of Effluvvum Nuisances} 
 
 The most offensive nuisances, says Ballard, are those which 
 are given off from trade processes in which the materials used 
 consist mainly of animal matters, or which contain elements of 
 animal origin. The most disgusting of all are the efHuvia from 
 the process of gut-scraping and the preparation of sausage skins 
 and catgut, the preparation of artificial manures from "scutch" 
 (refuse matters in the manufacture of glue), the manufacture of 
 some other kinds of artificial manures, and the melting of some 
 kinds of fat. Manufacturing businesses which deal with vegetable 
 substances are often very offensive, but only rarely can be said to 
 give rise to distinct effluvia. 
 
 Among the most offensive are those in which the effluvia are 
 thrown off during the heating of vegetable oils, as, for example, 
 during the boiling of linseed oil, the manufacture of palmitic acid 
 from cotton oil foots, from palm oil, the manufacture of some kinds 
 of varnish, the drying of fabrics coated with such varnishes, and 
 the burning of painted articles, such as disused meat tins. Among 
 the trades which deal with neither animal nor vegetable sub- 
 stances the most offensive effluvia are produced from the manu- 
 facture of ammonium sulphate or ammonium chloride, and some 
 other processes or manufacture in which the copious evolution of 
 SH^ occurs, and from gas making and the distillation of tar; 
 
 ^ In this chapter nmoh use is made of Dr. Ballard's exhaustive report on 
 effluvium nuisances in Supplemental Reports of Local Government Board, 1876, 
 1877. 
 
272 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Dr. Ballard classifies efiSuvium nuisances as follows : — 
 
 (1) The keeping of animals. 
 
 (2) The slaughtering of animals [see ante, chap. xx. p. 263]. 
 
 (3) Other branches of industry, in which animal matters or 
 substances of animal origin are principally dealt with. 
 
 (4) Branches of industry in which vegetable matters are princi- 
 pally dealt with. 
 
 (5) Branches of industry in which mineral substances are princi- 
 pally dealt with. 
 
 (6) Branches of mixed origin in which mineral, vegetable, and 
 animal substances are dealt with. 
 
 (189) Fig-keeping. 
 
 It is specially stated by the Public Health Act that pigs must 
 not be kept in towns so as to be a nuisance (sec. 47). The sources 
 of offence are chiefly : — The " wash," or other offensive food ; the 
 excreta. 
 
 It seems to be a popular prejudice that no substance is too 
 nasty or repulsive to throw to pigs, hence the horribly foetid putre- 
 fying liquid, the waste of the kitchen known as " wash," now so 
 largely used. As however with other animals, cleanliness of food 
 tends to health ; the pig thrives most and produces the healthiest 
 flesh when nourished on cleanly, wholesome food. The species 
 of feeding most to be condemned is however that practised by 
 many butchers, viz. giving to the pig the uncooked dilris and 
 blood of the slaughter-house ; it is in this way that pork is so 
 liable to be contaminated with tubercle and parasites. 
 
 The excreta of the pig are peculiarly offensive ; there is no more 
 penetrating stink than that evolved in cleaning out a pigstye. 
 If pigs are to be kept at all in towns it must be under stringent 
 regulations, one of which may well be a thorough daily cleansing 
 of the stye and removal of the manure in proper closed receptacles 
 either at night or early in the morning. Dr. Ballard points out 
 that aU the pachydermata roll in the mud in order to get rid of 
 the irritating effete epidermis. The mud cakes on the skin and 
 when dry falls off, carrying with it the cutaneous dAhris. If a pig 
 is well sciubbed with water, he does not wallow in his own manure, 
 so that in this way the animals themselves may be kept in a fairly 
 cleanlv state. 
 
XXI.] NUISANCE FROM STABLES. 273 
 
 (190) Bacon Curing. 
 
 The singeing of the hair of the pig, which is one of the 
 first operations, may cause an unpleasant smell, especially if 
 this is done in the open, and not underneath a hood adapted 
 to lead the fumes into a shaft. Much of the American pork is 
 converted into bacon. It is first soaked in water to remove salt ; 
 it is then rapidly dried in a closed chamber by the heat of a central 
 coke fire ; the windows of the chamber are theu opened and the 
 bacon exposed to a current of fresh air. In one case quoted by 
 Dr. Ballard, observed by Dr. Spear, the process was conducted in 
 South Shields in an unventilated cellar beneath an inhabited room, 
 the inhabitants of which complained bitterly of the smell of the 
 steam which entered their room through the loosely-boarded floor. 
 In Liverpool, nuisance has also been caused from this business by 
 the discharge of warm water into the drains from the washing of 
 the pork, the effluvia bursting up through the gullies. 
 
 (191) Nuisaince from Stables {Horse Keeping). 
 
 The sources of nuisance are — 
 
 (1) Soakage of urine into the ground from imperfect paving. 
 
 (2) Emanations from the dung. 
 
 (3) Impurity of the atmosphere due to cutaneous and lung 
 exhalations of the animals kept therein. 
 
 A country stable, a reasonable distance from human habitation, is 
 not likely to be complained of, although against the interests of the 
 horses it may be ill-ventilated, ill-kept, and the manure only dealt 
 with at long intervals. The keeping of stables and mews in order 
 is a daily care to the sanitary authorities of large towns, the more 
 especially when the floor above is used as a habitation. 
 
 In the metropolis there are many thousands of persons living 
 over stables and constantly breathing an atmosphere impregnated 
 with ammonia. There are no reliable statistics on the subject, 
 but such conditions cannot be conducive to high vigorous health. 
 Stables should of course have a perfectly impervious floor, and 
 the drains should be well laid and of good materials. There 
 should also be no difficulty in making the floors of the living rooms 
 above stables of impervious material, and I think a sanitary autho- 
 rity would be justified on complaint of nuisance owing to stable 
 
 T 
 
274 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 emanations rising through a pervious floor, in giving notice to 
 remedy the nuisance. 
 
 1 have found in several instances that the drinking water stored 
 in a cistern within stables has been so impregnated with ammonia 
 as to actually smell and taste of that substance. Hence it is 
 important to notice the position of the cistern, and to insist that 
 it shall have a proper cover. 
 
 The nuisance from dung is mainly in its removal, when it has 
 been previously stored in heaps. The heap is liable to ferment, 
 and then when disturbed gives off watery vapour charged with a 
 peculiarly strong-smelUng ammonia. The method adopted in 
 some large stables is to each morning put the dung direct into a 
 cart and thus avoid making a heap at all. In any case dung-pits 
 are unmitigated nuisances in towns and should be discountenanced. 
 A cage of iron bars at or near the door of each stable is about the 
 neatest and most unobjectionable form of storage receptacle, the 
 free admission of air preventing fermentation. Ammoniacal ema- 
 nations, and consequently loss of a valuable fertilizing agent, may 
 be controlled by wetting the manure with dilute sulphuric acid ; 
 its commercial value in this way is certainly increased. 
 
 (192) Cow Keeping. — Dairies. 
 
 As in the case of keeping horses so in the case of cow keeping, 
 the question of nuisance mainly arises in towns. 
 
 The sources of nuisance from the keeping of cows are — 
 
 (1) Impurity of the atmosphere in and around the shed. 
 
 (2) Emanations from the dung of the animals. 
 
 (3) The storing of grains. 
 
 Cow-sheds are seldom adequately ventilated, for the cow-keeper 
 knows by experience that unless he keeps the shed warm the cows 
 do not secrete so much milk. To transform the cow into a milk- 
 producing machine the animal must be kept in-doors, fed highly, 
 and kept at a temperature of from 65° to 75°. Hence the health 
 officer will find all proposals to sweeten the atmosphere by free 
 ventilation looked at with much disfavour. The cow passes daily 
 an immense quantity of semiliquid manure and a large quantity 
 of urine ; there is also atmospheric contamination from the lungs, 
 and it is to be remembered that in addition to carbon dioxide, the 
 
XXI.] DAIRIES AND COWSHEDS. 275 
 
 cow passes from the intestine much marsh gas. It is of the 
 utmost importance that the floor be properly paved with im- 
 pervious material and that the drainage be perfect; there must 
 also be an abundant supply of water; this is best stored in a 
 capacious tank, to which a long hose may be attached. The 
 manure from a large cowhouse should be removed at least once 
 a day, and the floor washed down morning and evening; in no 
 other way can the air be kept even moderately free from odour. 
 
 A third source of nuisance arises from the grains so generally 
 in towns used as a food. The grains are stored up in a wet state, 
 and unless they are freed from the liquid, acetous fermentation 
 proceeds and a penetrating sour smell is very evident. It is best 
 to store the grains in two receptacles, and directly the one is 
 empty it should be well washed and scrubbed with hot water. 
 The reason for this precaution is, that unless the receptacles them- 
 selves are regularly washed, they become impregnated with the 
 acetous liquor, and, quite irrespective of the grains, are a source 
 of nuisance. 
 
 In model cowsheds the racks and partitions are made of iron, 
 which is a great improvement on wood. The walls themselves 
 are preferably lined with glazed tiles. Any living room over a 
 cowshed, the atmosphere of which is in direct communication 
 with it, should most decidedly be condemned as unfit for human 
 habitation. 
 
 The general regulations in force as to cow-keeping are as 
 follows : — 
 
 (193) Dairies, Cowsheds', and Milk Shops' Order. 
 
 LONiDON COUNTY COUNCIL. 
 
 41 and 42 Fie., Ch. 74, and 49 and 50 Vic, Ch. 32. 
 
 EegtjlatiOjSTS as to Dairies, Cowsheds, and Milkshops. 
 
 The Dairies, Cowsheds, and Milkshops Order of 1885, as Amended by 
 THE Dairies, Cowsheds, and Milkshops Amending Order of 1886, 
 Provides as Follows : — 
 
 Registration of Dairymen and others. 
 
 Section 6. — (1.) It shall not be lawful for any person to cany on in the District 
 of any Local Authority the trade of cowkeeper, dairyman, or purveyor of milk unless 
 he is registered as such therein in accordance with this Article. 
 
 (2. ) Every Local Authority shall keep a Register of persons from time to time 
 carrjring on in their District the trade of oowkeepers, dairymen, or purveyors of 
 milk, and shall from time to time revise and correct the Registers. 
 
 T 2 
 
276 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (3.) The Local Authority shall register- every such person, but the fact of such, 
 registration shall not be deemed to authorise such person to occupy as a dairy or 
 cowshed any particular building, or in any way preclude any proceedings being taken 
 against such person for non-compliance with or infringement of any of the provisions 
 of this Order or any Regulation made thereunder. 
 
 (4.) The Local Authority shall from time to time give public notice by advertise- 
 ment in a newspaper circulating in their District, and, if they think fit, by placards, 
 hand-bills, or otherwise, of registration being required,' and of the mode of 
 registration. 
 
 (5.) A person who carries on the trade of cowkeeper or dairyman for the purpose 
 only of making and selling butter or cheese or both, and who does not carry on the 
 trade of purveyor of milk, shall not, for the purposes of registration, be deemed to 
 be a person carrying on the trade of cowkeeper or dairyman, and need not be 
 registered. 
 
 (6.) A person who sells milk of his own cows in small quantities to his workmen 
 or neighbours, for their accommodation, shall not, for the purposes of registration, 
 be deemed, by reason only of such selling, to be a person carrying on the trade of 
 cowkeeper, dairyman, or purveyor of milk, and need not, by reason thereof, be 
 registered. 
 
 Construction and Water Supply of New Dairies and Cowsheds. 
 
 Section 7. — (1.) It shall not be lawful for any person following the trade of cow- 
 keeper or dairyman to begin to occupy as a dairy or cowshed any building not so 
 occupied at the commencement of - this Order, unless and until he - first makes 
 provision, to the reasonable satisfaction of the Local Authority, for the lighting and 
 the ventilation, including air-space, and the cleansing, drainage, and water supply of 
 the same, while occupied as a dairy or cowshed. 
 
 (2.) It shall not be lawful for any such person to begin so to occupy any such 
 building without first giving one month's notice in writing to the Local Authority of 
 his intention so to do. 
 
 Sanitary Slate' of all Dairies and Cowsheds. 
 
 Section 8. It shall not be lawful for any person following the trade of cowkeeper 
 or dairyman to occupy as a dairy -or cowshed any building, whether so occupied at 
 the commencement of this Order or not, if, and as long as, the lighting and the 
 ventilation, including air-space, and the cleansing, drainage, and water supply 
 thereof, are not such as are necessary or proper — ... ^ 
 
 {a. ) for the health and good condition of the cattle therein ; and 
 (J.) for the cleanliness of milk- vessels used therein for containing milk for sale ; 
 
 and 
 (c.) for the protection of the milk therein against infection or contamination. 
 
 Contaminatiop, of Milk. 
 
 Section 9. It shall not be lawful for any person following the trade of cowkeeper 
 
 or dairyman or purveyor of- milk, or being the occupier of a milk-store or 
 
 milk-shop — 
 
 {a.) To allow any person suffering from a dangerous infectious disorder, or having 
 recently beeii in contact with a person so suffering, to milk cows or to handle 
 vessels used for containing milk for sale, or in any way to take part or 
 assist in the conduct of the trade or business of the cowkeeper or dairy- 
 man, purveyor of milk or occupier of a milk-store or milk-shop, so far as 
 regards the production, distribution, or storage of milk ; or 
 (6.) If himself so suffering or having recently been in contact as aforesaid, to 
 milk cows, or handle vessels used for containing milk for sale, or in any 
 way to take, part in the conduct of his trade or business as far as regards 
 the production, distribution, or storage of milk — 
 
 until in each case all danger therefrom of the communication of infection to the milk 
 
 or of its contamination has ceased. 
 
Xxi.]. . MiRIES AND COWSHEDS. 277 
 
 Section 10. It shall not he lawful for any person following the trade of cowkeeper 
 or dahyman or purveyor of milk, or being the occupier of a milk-store or milk-shop 
 after the receipt of notice of not less than one month from the Local Authority, 
 calling attention to the provisions of this Article, to permit any water-closet, earth- 
 closet, privy, cesspool, or urinal to be within, communicate directly with, or ventilate 
 into, any dairy or any room used as a milk-store or milk-shop. 
 
 SeeHon 11-. It shall not be lawful for any person following the traile of cowkeeper 
 or dairyman or purveyor of milk, or being the occupier of a mUk-store or milkshop 
 to use a milk-store or milk-shop in his occupation, or permit the same to be used as 
 a sleeping apartment, or for any purpose incompatible with the proper preservation 
 of the cleanliness of the milk-store or milkshop, and of the milk-vessels and milk 
 therein, or in any manner likely to cause contamination of the milk therein. 
 
 Section 12. It shall not be lawful for any person following the trade of cowkeeper 
 or dairyman or purveyor of milk, to keep any swine in any cowshed or other building 
 used by him for keeping cows, or in any milk-store or other place used by him for 
 keeping milk for sale. 
 
 Existence of Disease among Cattle. 
 
 Section 15. If at any time disease exists among the cattle in a Dairy or Cowshed, 
 or other building or place, the milk of a diseased cow therein — 
 (a. ) shall not be mixed with other milk ; and 
 (b. ) shall not be sold or used for human food ; and 
 
 (c.) shall not be sold or used for food of swine, or other animals, unless and 
 until it has been boiled. 
 
 Ebgtjlatioks as to Dairies, Cowsheds, Milk-Shops, &c., and as to Precau- 
 tions AGAINST THE INFECTION AND CONTAMINATION OF MiLK IN THE 
 
 Metropolis. 
 In pursuance of Section 13 of The Dairies, Cowsheds, and Milk-shops Order of 
 1885, the Metropolitan Board of Works ^ being the Local Authority for the Metropolis 
 (except the City of London and the Liberties thereof) hereby made the following 
 regulations — 
 
 {a.) For the inspection of cattle in Dairies. 
 
 (J.) For prescribing and regulating the lighting, ventilation, cleansing, drainage, 
 and water supply of Dairies and Cowsheds in the occupation of persons 
 following the trade of Cowkeepers or Dairymen, 
 (c.) For securing the cleanliness of Milk-stores, Milk-shops, and of Milk-vessels 
 
 used for containing milk for sale by such persons. 
 (d.) For prescribing precautions to be taken by purveyors of milk, and persons 
 selling milk by retail, against infection or contamination. 
 
 1. These regulations shall commence and take effect from and immediately after 
 the third day of August, 1885. 
 
 Kbgulation for the Inspection of Cattle. 
 
 2. Every Inspector appointed by the Board under this Act is hereby authorised 
 to inspect all cattle upon the premises of all persons registered by the Board under 
 the Act. 
 
 BEGtTLATIONS FOR PRESCRIBING AND EeGULATING THE LIGHTING, VeNTILATIONj 
 
 Cleansing, Drainage and "Water Supply of Dairies and Cowsheds in 
 THE Occupation of Persons following the Trade of Cowkeepers or 
 Dairymen. 
 
 Cowsheds. 
 
 3. Every Cowshed shall be well and sufficiently lighted by openings in the sides 
 or roof, or by windows therein. 
 
 4. Every Cowshed shall be thoroughly -ventilated by lantem-louvred ventilator^ 
 in the roof thereof, or by louvred ventilators in the walls, or by openings in the 
 sides or roofs. ' 
 
 5. In every Cowshed there shall be sufficient air-space for the health and gopd 
 
 ' Now London County Council. ' 
 
278 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 condition of the cattle therein, i.e., there shall be for each animal kept in a separate 
 stall a superficial space of at least 8 feet by 4 feet, and for two animals kept in one 
 stall a superficial space of 8 feet by 7 feet ; and there shall be an air-space of at least 
 600 cubic feet in respect of every animal kept in a Cowshed, where, taking into 
 consideration the position and construction of the shed, there are perfectly satisfactory 
 means of ventilation ; but in other cases there shall be an air-space of 800 cubic feet 
 in respect of every animal kept, and in any case the height of the shed in excess of 
 16 feet shall not be taken into account in estimating the air-space. 
 
 6. Every Cowshed shall be well paved with Stourbridge or other impervious 
 brick, or other impervious material, set with cement properly bedded on concrete, 
 with a proper slope towards a gully-hole, which shall, where practicable, be outside 
 the shed ; and such gully-hole shall communicate by an adequate drain of glazed 
 stoneware pipes with the public sewer, and be trapped by an appropriate fixed trap, 
 and be covered with a grating, the bars of which shall be not more than | inch apart ; 
 excepting that, not exceeding 3 feet of the foremost part of the stalls may be paved 
 with chalk or other similar material. 
 
 7. Every Cowshed shall be provided with an adequate supply of water, and 
 where there is not a constant water supply, with a slate, metal, or metallic-lined tank, 
 properly covered and provided with an overflow or warning pipe, and with piping 
 for conveying the water to the Cowshed ; such tank to be so placed that the bottom 
 thereof shall be not less than 6 feet above the floor level. Every such tank shall 
 be of a capacity equal to 12 gallons of water for each cow lawfully kept ; it shall 
 have no communication with any water-closet or drain by means of a waste-pipe ; 
 and it shall be supplied with good and wholesome water, which, if practicable, shall 
 be procured by the occupier fi'om a public water company, and such tank shall be 
 cleansed as often as is necessary for keeping the same in a clean condition. 
 
 8. Each stall or standing-place for cows in every Cowshed shall be provided with 
 a water-trough or receptacle, constructed of or lined with hard, smooth and impervious 
 material, and each such trough or receptacle shall be supplied with water by means 
 of a pipe communicating with a water tank, or, in the case of a constant water supply, 
 with the Water Company's pipes, and each such trough or receptacle shall also be 
 provided with a waste-pipe or waste-hole in the lowest part thereof. 
 
 9. The inner walls, doors, and woodwork (except the partitions between the cows) 
 of every Cowshed shall be covered with hard, smooth, and impervious material to a 
 height of at least 5 feet from the floor of such Cowshed, and such hard, smooth, and 
 impervious material shall not be covered with cement-wash, lime-wash, or other 
 substance. 
 
 10. Every Cowshed shall be provided with properly constructed places or recep- 
 tacles for storing any brewers' grains intended for the animals therein, and also places 
 or receptacles for receiving the dung and litter from the Cowsheds, and such places 
 or receptacles shall be constructed of or lined with impervious material and be 
 properly drained ; but no such places or receptacles shall be within, or communicate 
 directly with, any Cowshed. 
 
 11. No water-closet, privy, cesspool, or urinal shall be within, communicate 
 directly with, or ventilate into a Cowshed. 
 
 12. No dung, grains, or other substance from which effiuvium is liable to be given 
 off, shall be kept in any Cowshed ; nor shall any dung, grains, or other substance as 
 aforesaid be so kept that any effluvium therefrom can enter any Cowshed. 
 
 13. The upper parts of the inner surface of the walls of every Cowshed shall be 
 thoroughly cleansed and limewashed in the months of March and September, and at 
 other times within 7 days of the Board giving notice in writing that such cleansing 
 and limewashing are necessary. 
 
 14. The floor of every Cowshed, and all troughs or utensils used for supplying the 
 cows with food and water, shall be thoroughly cleansed with water at least once 
 every day ; and the portions of the walls, partitions, doors and other parts of the 
 Cowshed within 5 feet of the floor shall be thoroughly cleansed as often as may be 
 necessary for keeping the same in a clean condition. 
 
 15. AH drmg and offensive litter shall be carefully swept up and removed from 
 every Cowshed at least twice every day, and shall be removed from the premises as 
 frequently as may be necessary to prevent nuisance. 
 
XXI.] DAIRIES AND COWSHEDS. 279 
 
 16. All utensils and vessels used by a cowkeeper for the reception, storage, or 
 delivery of milk shall be thoroughly cleansed with steam or scalding water as 
 frequently as may be necessary for keeping such vessels and utensils perfectly clean 
 and sweet, and only clean water shall be used for this purpose. 
 
 17. Every Cowkeeper shall at all times employ such means, and adopt such pre- 
 cautions, as may be necessary for keeping any Cowshed in his occupation, and the 
 cows therein, in a clean and wholesome condition. 
 
 IS. Every Dairy shall be sufficiently lighted, and shall be thoroughly ventilated 
 by louvred ventilators, ventilating shafts, or openings in the walls or roof. 
 
 19. Every Dairy shall be well paved with flagstones, concrete, or other suitable 
 material, properly set in cement, and the inner walls thereof shall be covered with 
 hard, smooth, and impervious material to a height of at least 6 feet from the floor of 
 such Dairy, and such hard smooth, and impervious material shall not be covered with 
 cement-wash, lime-wash, or other substance. 
 
 20. The floor of every Dairy shaU fall or slope towards an opening in the walls 
 thereof, leading to a properly trapped gully-hole outside such Dairy ; and no inlet to 
 a drain shall be within any Dairy. 
 
 21. Every Dairy shall be provided with an adequate supply of water, and, where . 
 there is not a constant supply, with a slate, metal, or metallic-lined tank, properly 
 covered, and provided with an overflow or warning pipe, and with piping for convey- 
 ing the water to the Dairy. The tank shall have no communication with any water- 
 closet or drain by means of a waste pipe, and shall be supplied with good and whole- 
 some water, which, if practicable, shall be procured by the occupier from a public 
 water company, and such tank shall be cleansed as often as may be necessary for 
 keeping the same in a clean condition. 
 
 22. The floor of every Dairy, and the portions of the walls and other parts of the 
 Dairy within 6 feet of the floor thereof, as well as all fixtures and tables therein, 
 shall be cleansed with water as frequently as may be necessary for keeping such 
 Dairy, fixtures, and tables, in a thoroughly clean and wholesome condition, and the 
 ceilings and the upper parts of the inner surface of the walls shall be thoroughly 
 cleansed and limewashed as frequently as may be necessary for keeping the same in a 
 clean condition. 
 
 23. All utensils and vessels used by a Dairyman for the reception, storage, or 
 delivery of milk shall be thoroughly cleansed with steam or scalding water as 
 frequently as may be necessary for keeping such utensils and vessels perfectly clean 
 and sweet, and only clean water shall be used for the purpose. 
 
 24. Every Dairyman shall, at all times, employ such means and adopt such {pre- 
 cautions, as may be necessary for keeping any dairy in his occupation, and the utensils 
 and vessels used by him for containing mUk, in a clean and wholesome condition, so 
 as to preserve the purity of such milk. 
 
 Kegtjlations fok sbciteing the Cleanliness of Milk-stoees, Milk-shops, 
 AND Milk-vessels used for containing Milk foe Sale by pbesons 
 
 FOLLOWING THE TEADB OF CoWKEEPEES OE DAIEYMEN. 
 
 25. Every Milk-store or Milk-shop, as well as all fixtures and tables therein, used 
 in connection with the keeping or sale of milk, shall at all times be kept in a cleanly 
 condition. 
 
 26. All utensils and vessels used for the reception, storage, or delivery of milk, 
 shall he thoroughly cleansed with steam or scalding water as frequently as may be 
 necessary for keeping such utensils and vessels perfectly clean and fc weet, and only 
 clean water shall be used for the purpose. 
 
 27. Every person following the trade of Cowkeeper or Dairyman shall, at all 
 times, employ such means and adopt such precautions, as may be necessary for 
 keeping the utensils and vessels used by him for containing milk in a clean and 
 wholesome condition, so as to presei?ve the purity of such milk. 
 
280 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Regulations rRESORiBiNO precatjtions to be taken by ptrRVEyoES of milk, 
 
 AND PERSONS SELLING MILK BY RETAIL AGAINST INFECTION OR CON- 
 TAMINATION. 
 
 28. Every Purveyor of milk, or person selling milk by retail, shall immediately 
 op any outbreak of infectious or contagious disease within the building or upon the 
 premises in which he keeps milk, or amongst the persons employed in his business, 
 give notice of such outbreak to the Board at their Office in Spring Gardens. 
 
 29. Every Purveyor of milk, or person selling milk by retail, shall immediately 
 on .such outbreak coming to his knowledge, remove all milk for sale, and all utensils 
 for containing milk for sale from such building ; and shall cease to keep milk for sale 
 or to sell milk in such building until the same has been disinfected and declared by 
 the Medical Officer of Health for the disti'ict to be free from infection. 
 
 30. Every Purveyor of milk, or person selling milk by retail, shall not keep 
 toilk for sale in any place where it would be liable to become infected or contaminated 
 by gases or effluvia arising from any sewers, drains, gullies, cesspools, or closets, or 
 by any offensive effluvia from putrid or offensive substances, or by impure air, or by 
 any offeilsive or deleterious gases or substances. 
 
 31. Every Purveyor of milk, or person selling milk by retail, shall only keep 
 milk for sale in clean receptacles ; and all utensils used in connection with the keeping 
 
 _ or sale of such milk shall be at all times kept clean. 
 
 32. Every Purveyor of milk, or person selling milk by retail, shall at all times 
 employ such means, and adopt such precautions, as may be necessary for preserving 
 the purity of milk, and for protecting it against infection or contamination. 
 
 EeVOCATION of FORMER REGULATIONS. 
 
 33. The Regulations made by the Board in pursuance of the Dairies, Cowsheds, 
 and Milkshops Order of July, 1879, are hereby revoked. 
 
 NOTE. Any person guilty of an offence against the foregoing Order 
 OR Regulations, is liable to a penalty of Five Pounds, and in 
 the case of a continuing offence, to a further penalty of Forty 
 Shillings for bach day after written notice of the offence from 
 the Board. 
 
 (194) Tanning. 
 
 The hides converted into leather by the tanner are divided by 
 the trade into three classes, viz : — 
 
 (1) Fresh English hides, known technically as " market hides." 
 
 (2) Salted hides, mainly from S. America. 
 
 (3) Dry hides, these come from S. America, the Cape, India and 
 other places (kips). 
 
 These different classes all require variation in treatment but 
 the essential process at the basis of all the modifications is as 
 follows : — 
 
 (1) Liming. This is the first process, the skins being soaked 
 in pits containing lime and water. 
 
 (2) Unhairing. The hair loosened by the lime is removed. 
 
 (3) " Fleshing." The hide after well washing in clean water to 
 remove the lime, is " fleshed," that is to say the loose inner tissue 
 
XXI.] TANNING. 281 
 
 of the hide is sliced off with a very sharp curved knife. The 
 matters sliced off are called " fleshings " and are sent to the glue 
 maker. 
 
 (4) Bounding. That is the shoulders and irregular jagged 
 parts are cut off to be separately dealt with, the small scrips being 
 sent to the glue maker. This operation performed, the technical 
 name for the hide is a " butt." 
 
 (5) The " butts " are put into clean water and soaked for a few 
 hours to get rid of any lime still adhering. If the " butts " are 
 intended to be converted into " uppers " or soft leather they next 
 go into a " cleaning pit ; " this is a pit containing a solution of 
 pigeons' dung, called " grainers," which softens the material. 
 Instead of pigeons' dung, sometimes diluted urine is used, or fowls' 
 dung or weak ammonia water. . Probably the rationale of the action 
 of the dung is the development of ammonia. The grainers are 
 used cold. 
 
 (6) " Scudding." Ail superfluous water and dirt are removed by 
 a special instrument and the small hairs still xemaining shaved off 
 with a sharp knife. 
 
 (7) " Splitting." Skins which are to be split are sent to a 
 machine which separates them into two layers. 
 
 After these preliminary operations the actual tanning process 
 begins, the butts being now sent through a series of "floaters" 
 and " dusters." The floaters are pits of tan liquor of gradually 
 increasing strength, after passing which the skins go into the 
 " dusters," which consist of pits containing, tan liquor of 25° 
 strength of the barkometer. The butts being laid in these pits are 
 sprinkled over with crushed bark. The butts go through three or 
 four such liquors, remaining a week in each. Other very similar 
 operations follow, that is they are laid in pits of increasing strength, 
 the whole process lasting as long as ten months. 
 
 The sources of nuisance from tanneries are : the passage to 
 and fro of more or less offensive material such as imperfectly 
 cured foreign hides ; the putridity of " old soaks " — these not 
 unfrequently become horribly offensive, especially when they are 
 being cleaned, the most offensive being not the liquor but the 
 deposit at the bottom. Added to these the scraping processes, 
 the handling of the hides when transferring from one lime pit to 
 another, and the running of old soaks into the drains. In some 
 
282 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 places they have got rid of waste tan by burning, and this has 
 caused nuisance. There may also be nuisance from general untidi- 
 ness and uncleanliness. 
 
 The remedies for these causes of complaint are pretty obvious. In 
 the first place, in the conveyance of offensive skins or other debris 
 to and from the tan yard, covered carts should alone be used, nor 
 is there any reason why a disinfectant should not be applied ; the 
 ordinary disinfectants will not hurt the skin nor injure its 
 properties as regards tanning. Old soaks before being cleaned out 
 can certainly be disinfected by iron sulphate or other cheap 
 substance. It has been found, notably in Bermondsey, that 
 attention to little details and great cleanliness confines the smell 
 to the immediate neighbourhood of the yards, so that houses a little 
 way off are but little if any affected. There has been no injury to 
 health actually proved, but an ill-managed tan-yard, one that 
 smells offensively 50 or 60 yards beyond the works, must be 
 considered in itself a nuisance, one that fairly comes under the 
 term of an " offensive trade." 
 
 (195) Leather Dressing. 
 
 There is a distinction between a leather dresser and a tanner — 
 the leather dresser only deals with "pelts," the tanner with 
 bullocks' hides. 
 
 The only operation in leather dressing calling for comment is 
 the one known as " puering." At a certain stage the pelts are 
 soaked in a solution of dogs' dung, technically called " pure or 
 puer." In the summer the solution is used at the ordinary tempera- 
 ture of the air, in winter it is warmed. The " puer," as might be 
 anticipated, has an abominable odour, and unless this process is 
 performed in a suitable shed so constructed that the contaminated 
 air sweeps up either into a lofty chimney or through a fire, a 
 nuisance is likely to be created. 
 
 (196) Manufactiore of Chamois Leather. 
 
 In the making of chamois leather it is necessary to work fish 
 oil (generally cod liver oil) into the skin ; afterwards the skin is 
 dried in a hot chamber; at 120° the odour of acrolein and fish oil 
 is usually very perceptible. The remedy should complaint arise 
 
2X1.] GLUE MANUFACTURE 28S 
 
 is obvious, viz., to insist on arrangements to carry on the oiling in 
 sheds properly constructed, so that the foul vapours are either led 
 into a shaft so as to discharge into the air at a sufficient height or 
 are swept into a furnace fire. 
 
 (197) Olue-mahing. 
 
 The manufacturer of glue boils out the animal gelatin from 
 the following materials. 
 
 (a) Wet. Sheep pieces or " spetches " from fellmongers,. 
 " fleshings " from the leather dressers and tanners, the " roundings "^ 
 of hides previously limed, portions of bones to which tendons ar& 
 attached, ears of animals, clippings of salted and alumed skins- 
 used for covering cricket bat handles, &c. 
 
 (6) Dry. Damaged pelts, salted ox feet, calves pates, horn 
 sloughs (that is, the core or pith of horns), the clippings and 
 roundings of parchment, glue pieces from fellmongers, leather 
 dressers and tanners, and other similar substances. 
 
 These matters are first " limed " and the lime afterwards well 
 washed out with water. The matters are then boiled, the fatty 
 matters being skimmed off the top, and the warm Hquid glue run 
 into shallow troughs and allowed to solidify. The solidified mass 
 is then cut into slices. 
 
 Nuisance is liable to arise from the offensive nature of the raw 
 material, and the process of boiling is accompanied by a good deal 
 of odour. In one case there seems to have been fair grounds for 
 ascribing direct injury to health from emanations from a glue 
 manufactory. 
 
 This case is related by BaUard ^ in the following words : " Pro- 
 bably the high rate of mortality in the population immediately 
 exposed to the ef&uvia arising from Hunslet Works just mentioned, 
 has been due to this cause. Dr. Goldie, Med. Officer of Health 
 for Leeds, in whose district the works are situated, is decidedly of 
 opinion that such is the case. He tells me that during six years 
 ending December, 1875, in an estimated population of 1,935 
 persons, not exceptionally poor or overcrowded, and situated in a 
 comparatively open part of the borough, the mean annual mor- 
 tality from aU causes amounted to 35'6 per 1,000, while that from 
 the five zymotic diseases — small-pox, scarlet fever, measles, ' fever,' 
 1 Ann. Report Local Gov. Board. Med. OfiF. Report. 1876. 
 
284 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 and diarrhoea, amounted to 912 per 1,000. Taking the whole of 
 the Hunslet ward in which this little colony is situated, the annual 
 death-rate from all causes during the same six years varied from 
 27'0 to 29'9, the mean being 27'9, and the death-rate from the 
 five zymotic diseases mentioned varied from 4'6 to 6'0, the mean 
 being 5 4. The annua,l mortality of the whole borough during the 
 same six years varied from 26'4 to 28 5 per 1,000, and that for the 
 five zymotic diseases mentioned from 3'6 to 5'9 per 1,000. Dr. 
 Goldie tells me from his knowledge of the district that he is not 
 aware of any conditions of locality or character of the population 
 that could possibly account for so great a mortality about the glue 
 works other than that of the presence of the offensive works 
 themselves." 
 
 The greatest source of nuisance is without doubt accumulations 
 of " scutch," that is the deposit left in the pan after running off 
 the glue ; besides this there are, as before stated, the emanations 
 from theT)oiling, and the fleshings are apt to putrefy, especially if 
 a greater store is obtained than can be immediately used. It is 
 stated that the best way to deal with a stock of fleshings which 
 cannot be at once utilized is to dry them, and if this cannot be 
 done the next best thing is to stack them, alternate layers of 
 lime and fleshings being piled in a well drained spot. The 
 inethod adopted to prevent nuisance from the vapours given off 
 from the glue pots in boiling is to operate in closed vessels, each' 
 pot having a pipe leading the steam into the furnace flue. In 
 some places the " scutch " instead of being carried off for manure 
 is first boiled up with acid, and the fat it contains extracted by 
 skimming the residue is utilized as manure. No accumulation 
 of offensive scutch should of course be permitted. The general 
 rules and regulations to be put into force in dealing with such 
 manufactories, may be gathered from the London County Council's 
 bye-laws, which are as follows : — 
 
 LONDON COUNTY COUNCIL. 
 
 The Slaughteehouses, &o. (Meteopolis), Act, 1874, 37 aTid 38 Vic., c. 67. 
 
 Bye-Laws for regulating the conduct of tlie business of a Glue and Size Manufac- 
 turer, and tlie structure of the premises on which such business is being carried 
 on ; and the mode in which application is to he made for sanction' to establish, 
 such business anew ; within the limits of the Metropolis (except the City of 
 London and the liberties thereof).- 
 
XXI.] „_ .GLUE MANUFAGTUEB. 285 
 
 In pursuance of tlie Slaugtterliouses, &o. (Metropolis), Act, 1874, by which the 
 Metropolitan Board of Works * are constituted the Local Authority for the Metropolis 
 (except the City of London and the liberties thereof), the said Metropolitan Board of 
 Works, for the purposes of these Bye-Laws called the " Board," do hereby make the 
 following Bye-Laws :■ — 
 
 Bye-Laws for Regulating the Conduct of the Business. 
 
 1. Every Glue and Size Manufacturer shall cause all moist fleshings and other 
 material liable to decomposition, which may be kept or stored upon his premises, to 
 be kept or stored only in such part or parts of his premises as are properly paved 
 with asphalt, concrete, or other suitable jointless material, and covered with a water- 
 tight roof ; and he shall keep or store such material in such manner that no oifensive 
 eflluvia or vapours therefrom shall escape into the external atmosphere. 
 
 2. Every Glue and Size Manufacturer shall cause every process of his business in 
 which any offensive effluvia, vapours, or gases are generated, to be carried on in such 
 manner that no offensive eifluvia, vapours, or gases shall escape into the external 
 atmosphere in such a way as to create a nuisance; and he shall cause all such offensive 
 eflluvia, vapours, or gases to be effectually destroyed, or discharged into the atmos- 
 phere at a sufficient elevation to render them iuotiensive. 
 
 3. Every Glue and Size Manufacturer shall cause all scutch or refuse from the 
 boiling pans, and all refuse, residue, or other matter from which offensive effluvia or 
 vapours are evolved or are liable to be evolved, to be placed in properly closed recep- 
 tacles, or to be otherwise dealt with in such manner as to prevent any offensive 
 effluvia or vapours therefrom escaping into the external atmosphere. 
 
 4. Every Glue and Size Manufacturer shall cause all scraps of glue and size, and 
 all litter composed of fleshings, trimmings, clippings, and other matters liable to 
 become decomposed, to be constantly gathered or swept up and placed in proper 
 receptacles. 
 
 5. Every Glue and Size Manufacturer shall cause the floor of every place in which 
 glue or size is boiled, and of every place in which any process of the business (except 
 the drying and packing processes) is carried on, to be thoroughly cleansed with water 
 at least once in 24 hours ; and he shall cause the premises to be constantly provided 
 with an ade'quate supply of water for the purpose. 
 
 6. Every Glue and Size Manufacturer shall cause every inner wall of the premises 
 on which his business is carried on to be kept at all times thoroughly clean and in 
 good order and repair. He shall cause every inner wall and every ceiling in every 
 part of his premises, where any process of boiling, cooling, cutting, or washing may 
 be carried on, to be thoroughly washed with hot lime-wash in the month ot March in 
 every year, and from time to time thereafter, as often as may be necessary for the 
 purpose of keeping such part of the premises in a cleanly and wholesome state. 
 
 7. Every Glue and Size Manufacturer shaU cause evei-y vessel, receptacle, utensil, 
 or instrument provided or used upon, or in connection vrith, the premises on which 
 his business may be carried on, to be kept, when not actually in use, at all times 
 thoroughly clean, so as to prevent the emission of any offensive smell from such 
 vessel, receptacle, utensil, or instrument. 
 
 8. Every Glue and Size Manufacturer shall afford access to every part of the pre- 
 mises on which his business is carried on to every Member and Officer of the Board, 
 authorized in writing under the hand of the Clerk of the said Board, at any reasonable 
 time during the hours within which such business may be carried on. 
 
 9. Every person offending against any of the foregoing Bye-Laws shall be liable 
 for every such offence to a penalty of £5; and in the case of a continuing offence to 
 a penalty of £1 for every day during which the offence may be continued after the 
 conviction for the first offence. 
 
 10. Every Court of Summary Jurisdiction as defined in the Slaughtcjhouses, &c.. 
 Metropolis, Act, 1874, may, as a penalty for the breach of any of the foregoing Bye- 
 Laws, by Eummary Order, suspend or deprive any person altogether of the right of 
 carrying on the business of a Glue and Size Manufacturer, 
 
 ^ Now London County Council. 
 
286 A MANUAL Of PUBLIC HEALTH [chap. 
 
 Bye-Laws for BeCjUlating the Structure of the Premises. 
 
 11. Every Glue and Size Manufacturer shall cause every floor upon which any 
 process of his business (except the drying and pacMng processes) is carried on, in any 
 part of his premises to be properly covered with a layer of concrete, or other suitable 
 jointless and impervious material, laid (in the case of a ground iloor) upon a suitable 
 bottom of at least four inches in thickness. He shall cause such floor to have a proper 
 slope towards a channel or gully; and shall cause every part of his premises wherein 
 any such floor may be constructed to be effectually drained by adequate drains com- 
 municating with a public sewer. He shall also cause every drain to be properly 
 trapped, and the entrance thereto to be covered with a fixed grating, the bara of which 
 ^hall not be more than three-eighths of an inch apart. 
 
 12. Every Glue and Size Manufacturer shall cause his premises to be provided 
 with appliances capable of effectually destroying all offensive effluvia, vapours, or gases 
 arising in any process of his business, or from any material, residue, or other substance 
 which may be kept or stored upon his premises ; or with such appliances as shall be 
 effectual for drawing off and discharging such effluvia, vapours, or gases, into the 
 atmosphere at a sufficient elevation to render them inoffensive. 
 
 13. Every Glue and Size Manufacturer shall cause all needful works and altera- 
 tions to the premises to be forthwith done and executed as and when the same shall 
 become requisite, but shall not allow any alteration whatsoever to be made in respect 
 •of the structure of the premises, without the consent of the Board. 
 
 14. Every person who shall not comply with any of the foregoing Bye-Laws 
 relating to the structure of the premises shall be guilty of an offence, and shall be 
 liable, for every such offence, to a penalty of £5, and in the case of a continuing 
 ■offence, to a penalty of £1 for every day during which the offence may be continued 
 after the conviction of the first offence. Provided always that the foregoing Bye- 
 Laws for regulating the structure of the premises shall not, until after the expiration 
 of twelve months from the date of the confirmation of the Bye-Laws be deemed to 
 apply to any premises where at such date the business of a Glue and Size Manu- 
 facturer may be carried on. 
 
 Bye-Law for Regulating the Mode of Application for Sanction to New Establishment 
 
 of the Business. 
 
 15. Every person who may apply to the Board for sanction to establish anew 
 -the business of a Glue and Size Manufacturer, shall furnish with the application a 
 plan of the premises and sections of the buildings in which it is proposed to carry on 
 such business, such plans and sections being drawn to a scale of a quarter of an inch 
 to the foot, and showing the provision made, or proposed to be made, for the drainage, 
 lighting, ventilation, and water supply of such premises, and shall also furnish a key 
 plan of the locality, showing the buildings and streets within one hundred yards of 
 the premises, drawn to a, scale of five feet to the mUe. 
 
 Dated the First day df August, One thousand Eight hundred and Seventy-nine. , 
 
 (198) Nuisance from Fried Fish Shops. 
 
 The frying of fish is frequently complained of. The fish are 
 fried in dripping or other fatty matter; should the fat burn, 
 acrolein is produced, but, as a rule, the fumes are not specially 
 irritating. The stove where the fish is fried should be provided 
 with a suitable hood or other appliance to carry off the volatile 
 materials ; there ought to be no difficulty in carrying the vapours 
 ■evolved either through a fire or into a chimney shaft high enough 
 to prevent the odour being offensive to neighbours. 
 
XXI.] INDIA RUBBER MANUFACTURE. 287 
 
 (199) Roasting of Vegetable Substances, such as Malt, Chicory, Coffee. 
 
 There is considerable odour in all these cases. The roasting is 
 usually performed in revolving cylinders, the cylinders being in- 
 closed in casings to which the heat is applied. The nuisance may 
 be greatly reduced, if not altogether prevented, by carrying the 
 vapours themselves into a tall chimney shaft, and by the use of 
 proper hoods connected with the chimney. 
 
 (200) Niiisances from the Manufacture of India-rubber. 
 
 The crude india-rubber is boiled, washed in a machine called a 
 " masticator," incorporated with flowers of sulphur or antimony 
 sulphide, and goes through Various other processes. It is subse- 
 quently vulcanized by either the American process or the English 
 process. The American or Goodyear process is chiefly mechanical, 
 but in the English process a solvent called " solvent naphtha " 
 is used. 
 
 The nuisances produced are a peculiar india-rubber odour, 
 together with the odour of tar-oil and sulphuretted hydrogen. 
 These odours are perceptible at times at distances of a quarter of 
 a mile. According to Dr. Ballard, the processes concerned in 
 creating nuisance are as follows : — 
 
 (1) The boiling of the rubber, the steam having an "india- 
 rubber" odour. 
 ' (2) The several processes in which naphtha are used. 
 
 (3) The discharge of steam from the vulcanizers. 
 
 (4) The drying of sheets of vulcanized india-rubber upon steam 
 chests after washing them, the process giving an odour of burning 
 rubber. 
 
 The methods proposed to prevent these nuisances are as 
 follows : — 
 
 (1) The boiling of the rubber to be conducted in closed vessels, 
 and the steam to be condensed or burnt up in a fire. 
 
 (2) The naphtha condensed, as is done in Messrs. Moseley's 
 works, or else passed, as in Messrs. Quin's factory at Leyland, 
 into a scrubber supplied with creasote oil; the oil absorbs the 
 naphtha, and the naphtha may be subseqiiently recovered by 
 distillation. 
 
288 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (201) Flax Betting. 
 
 The flax plants are soaked in pits under water, and the infusion 
 thus produced is allowed to ferment ; this process is called " retting." 
 Afterwards the plants are spread out in a field to dry. The fer- 
 mentation is productive of nuisance, for the process is decidedly 
 offensive. Carbonic acid and other gases are produced in con- 
 siderable quantities, but according to analyses by Professor Hodges, 
 of Belfast, no sulphuretted hydrogen can be detected. The odour 
 of the flax pool is ascribed to small quantities of butyric and other 
 volatile fatty acids. The " grassing " is still more productive of 
 nuisance ; for here large quantities of offensive matters are spread 
 out in the fields, and the vapours impregnate the air for a long 
 distance. 
 
 (202) The Manufacture of Oxalic Acid, from Sawdust. 
 
 Sawdust is introduced into a semicircular iron pan heated by 
 a fire beneath, and the sawdust is mixed with a strong solution of 
 potash or soda, or both. The mixture is evaporated down to a 
 pasty mass and constantly stirred. During this part of the process 
 vapours are abundantly given off, which are variously described as 
 " sickly " or as " disagreeable," but no direct injury to health has 
 been proved. 
 
 When the material is dry, it is lixiviated with water, and the alka- 
 line oxalate crystallized out. A solution of this crude oxalate is 
 precipitated by. means of lime, and the oxalate of lime is boiled 
 with sulphuric acid so as to set the oxalic acid free ; the solution 
 of oxalic acid is crystallized out, and to aid in bleaching it, 
 before crystallizing a little nitric acid is added. During the 
 treatment with sulphuric acid, very irritating acid fumes are 
 given off. 
 
 The remedy for the nuisance during the evaporation down with 
 alkali is evidently to cover the vessel in which the process takes 
 place, and to convey the fumes away either to a tall chimney shaft 
 or through a fire. 
 
 The evolution of corrosive acid fumes can be dealt with by 
 leading the fumes to a coke tower in which the coke is kept moist 
 by a stream of water. 
 
XXI.] DISTILLATION OF WOOD. 289 
 
 (203) The Manufacture of Paper from Esparto Grass. 
 
 The esparto grass is boiled with a solution of caustic soda ; the 
 liquor from this boiling is in some places turned into the nearest 
 stream, polluting it and destroying the fish present ; in other places 
 it is concentrated by evaporation, incinerated, and the soda 
 recovered. 
 
 Esparto liquid is of the colour of strong tea, is alkaline from the 
 soda in solution, is strongly reducing, and emits a very peculiar and 
 offensive odour. It should never be permitted to be run into a 
 stream or ditch near inhabited places. 
 
 During the process of incineration for the recovery of the soda 
 there is a strong empyreumatic odour. There may also be nuisance 
 from the evaporation in the old-fashioned vray by boiling it down 
 in shallow pans. 
 
 In the best arrangements, such as " Roeckner's patent evapora- 
 tor" and the " Porion-Davis' evaporator," there would, however, seem 
 to be little cause of complaint. 
 
 (204) The Manufadure of Wood Pulp. 
 
 The manufacture of wood pulp is very similar to the above. 
 Chips or shavings are heated with steam under pressure, a solution 
 of caustic soda being added. The soda is generally recovered as 
 in that from esparto liquor. Nuisance has been experienced from 
 offensive steam, and from the turning of the hot liquid into the 
 public sewer. 
 
 (205) Distillation of Wood for the Purposes of obtaining 
 Wood Naphtha and Pyroligneous Acid. 
 
 Wood, exhausted dye-woods, or sawdust are distilled in ovens, 
 cylinders, or other forms of retorts, and the volatile products con- 
 densed. Nuisance arises from the evolution of uncondensed 
 gases, and from operations involved in changing the retorts and 
 in luting them. 
 
 In Bowers's apparatus for the distillation of sawdust, the pipe 
 conveying the vapours for condensation often gets blocked and 
 has to be cleared ; the operation takes little time, but during the 
 short interval there is abundant escape of gaseous products. 
 
 u 
 
290 A MANUAL OP PUBLIC HEALTH. [chap. 
 
 The recommendations of Dr. Ballard with regard to the 
 remedy of these nuisances are briefly as follows : — 
 
 To burn up the uncondensed gases, or to carry them up a tall 
 chimney shaft. 
 
 The nuisance arising from an escape from Bowers's apparatus, 
 in clearing the exit pipes, may be obviated by stopping the feed 
 rollers for five minutes before the opening of the pipes ; under 
 these circumstances no escape of vapour takes place. 
 
 The nuisance caused in drawing the charge may be lessened 
 by hastening the process. The charge from a cylinder should 
 be drawn into boxes fitted with covers, in which after luting 
 down it may be left to cool, or which may be used to convey it to 
 the underground brick chambers technically called " extinguishers." 
 But in the large square ovens, the process of drawing the charge 
 is necessarily a long one ; here the most feasible plan seems to be 
 to construct the " extinguisher " as close as possible to the oven, 
 so that the charge may be directly raked out into it ; if in addition 
 to these precautions the ovens and shoots opened into a closed 
 building ventilated by means of a wide pipe leading to a pipe 
 flue or tall chimney shaft with good draught, such an arrangement 
 would minimise the danger of external nuisance. 
 
 When the charge is drawn into boxes, there should be no delay 
 in luting down the covers. The boxes should not be carried into 
 the open air until the luting is finished. The buildings into which 
 the ovens open should be closed, and arrangements made for venti- 
 lating them into a fire or tall chimney. 
 
 (206) Nuisances depending chiefly on the Production 
 of Acrolein. 
 
 Acrolein is a product of the decomposition of glycerin ; hence 
 whenever a fat or oil is heated to a decomposition temperature it 
 is produced. Acrolein is a light, volatile liquid of low specific 
 gravity, boiling-point about 120° F. It is extremely irritating to 
 the eyes, throat, and to the mucous membranes of the bronchial 
 tubes. It is readily combustible. 
 
 Acrolein vapours are given off during the bleaching of palm oil, 
 the boiling of linseed oil (which is in point of fact decomposing 
 rather than boiling), the manufacture of oil varnishes, the manufac- 
 
XXI.] 
 
 COAL GAS MANUFACTURE. 
 
 291 
 
 ture of leather cloth, enamelled table covers, the enamelling of 
 leather, the manufacture of floor cloth and linoleum, the recover- 
 ing oil from oily clothes and shoddy, the distillation of palm oil, 
 cotton oil, " foots " and other kinds of grease. 
 
 In all these processes, at some stage or other, oils and oily 
 matters are heated to a high temperature, and as a consequence 
 irritating fumes are given oflf. 
 
 The principle to be adopted is to either condense the fumes by 
 conveying them through pipes where they can be waslied by a spray 
 of water, or to lead the tube into a furnace fire so as to burn the 
 fumes up. In certain cases it seems to be necessary to boil 
 acrolein-producing substances in an 
 open vessel, and in that case the 
 adoption of the principle of Hey- 
 wood's and Lloyd's arrangement 
 for collecting and condensing va- 
 pours from varnish-making may be 
 adopted. The apparatus is as fol- 
 lows : A is the boiling pot ; on the 
 top of this is fitted a funnel-shaped 
 cover, B; from this cover a pipe, 
 C, is led, which pipe is attached 
 to an extracting fan D, and the fan 
 
 drives the vapours to a series of condensing tubes E, to a fire, 
 or to a high chimney shaft as occasion requires. The conse- 
 quence of this arrangement is that there is always a strong down- 
 current through B into A to supply air rushing through C, and no 
 vapour can escape into the air except by the channel provided 
 for it. 
 
 Fig. 45, 
 
 (207) The Manufacture of Coal Gas. 
 
 Coal is submitted to destructive distillation in a close retort, 
 volatile and gaseous matters are expelled, and a carbonaceous resi- 
 due left behind. A brief description of the outlines of the process 
 is as follows : — The coal' is placed in a retort, and the retort heated 
 to dull redness. The volatile substances in the ordinary manufacture 
 pass up a pipe called "the ascension pipe," the upper end of which, 
 is curved downwards so as to discharge near the floor of a large 
 horizontal pipe called "the hydraulic main"; in this pipe water 
 
 V 2 
 
292 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 and tarry matters condense to a thick liquid whicli forms at tte 
 end of the ascension pipe a trap or liquid seal (In some places, 
 as at the Fulham works, the hydraulic main is dispensed with.) 
 The gas at a high temperature streams from the hydraulic main 
 into a series of cooling pipes called condensers ; the pipes are simply 
 exposed to the air, and it is found not advisable to cool the gas 
 below 60° or 65° F. The condensers free the gas from a good deal 
 of watery vapour, from tar, and from as much ammonia as the 
 deposited water is capable of absorbing ; the condensed substances 
 fall into a space below, and are received into the tar well. In 
 works of any size, the gas now passes to the exhauster or air pump 
 as crude coal gas ; containing as impurities, carbonic acid, ammonia, 
 sulphuretted hydrogen, bisulphide of carbon, some cyanogen com- 
 pounds, and small quantities of tarry matters, with aqueous 
 vapour. The more special purifying processes now commence. 
 First the gas passes to a " scrubber," i.e. a tower or cylindrical 
 vessel of considerable size in which by means of ingeniously ar- 
 ranged trays or other contrivances the gas is made to pass 
 through water, and is thus deprived of all ammonia, besides 
 some proportion of the other impurities already detailed. The 
 " scrubbed " gas next passes into the lime purifiers — that is, boxes on 
 which are trays of hydrate of lime. The lime combines with the car- 
 bonic acid gas to form carbonate of lime, and with sulphuretted 
 hydrogen to form calcic sulphide. When all the lime is turned 
 into calcic carbonate and sulphide, and the gas still streams in, 
 then the carbonic acid gas decomposes the calcic sulphide, and 
 sulphuretted hydrogen is given off, until the whole of the lime 
 becomes carbonate of lime. Hence lime alone cannot be con- 
 veniently used to cleanse the gas of sulphuretted hydrogen. The 
 gas freed from carbonic acid gas is next passed into the oxide 
 of iron purifier ; here it is deprived of the sulphuretted hydrogen, 
 which combines with the iron, forming iron sulphide. Where by 
 the conditions under which the company is governed, the gas 
 must be purified from carbon disulphide, it is got rid of by inter- 
 posing a small purifier filled with calcic sulphide between the lime 
 purifier and the oxide of iron ; with this substance bisulphide of 
 carbon forms a sulpho-carbonate. 
 
 The process described is not followed in all the works, some one 
 or other detail varying; thus ammonia which has escaped the 
 
XXI.] SULPHATE OF AMMONIA MANUFACTUEE. 293 
 
 scrubber is sometimes absorbed in sawdust alone, or sawdust mixed 
 with sulphuric acid. Instead of oxide of iron, sulphate or chloride 
 of iron is sometimes used. 
 
 There is some nuisance in the drawing of the retorts, an opera- 
 tion permitting of the escape of a certain amount of gases, and 
 attendant with the production of offensive steam, the red-hot 
 coke being raked out into water ; but this seldom travels beyond 
 the works. The chief source of nuisance is the emptying of the 
 lime purifiers, and the conveyance of the spent lime to its destina- 
 tion. Nuisance from the Jime purifiers is much aggravated by 
 improper working. In small country places the writer has seen 
 purifiers changed so seldom that practically crude coal gas was 
 delivered to the consumers. Directly the purifier gets at all foul 
 from sulphur compounds it should be emptied. Dr. Ballard, in 
 his report on effluvium nuisances, has described in great detail 
 the method in use at the Fulham works, where, despite the large 
 scale of the works, by carefully covering up with sacking those 
 portions of the foul lime in a purifier not in actual process of 
 being dug out, and having special covers for every part of the 
 subsequent operations — covers, that is, for the trucks, and for the 
 barges into which the spent lime is conveyed — and by previously 
 watering the foul lime in the purifier to prevent the rising of 
 dust, this usually offensive operation is done with but little odour. 
 
 In one case, in which the writer was a witness, a gas-works 
 was a considerable source of nuisance to a watering-place, from 
 defects in the construction of the works themselves ; in particular 
 the scrubber had only a wooden top ; through this wooden top 
 abundance of gas streamed, blackening lead paper. Sometimes 
 there is nuisaiice from the revivification of the spent oxide, defects 
 in the scrubbing process allowing ammonia compounds to reach 
 the iron oxide ; in such cases, as the oxide always heats in the 
 revivification, much ammoniacal vapour may be given off. 
 
 (208) Hie Manufacture of Sulphate of Ammonia and of Sal 
 
 Ammoniac. 
 
 The ammoniacal liquor from the gas-works is mixed with lime , 
 distilled, and the ammonia received into either sulphuric or hydro- 
 chloric acid until saturated, and the salt crystallized out. 
 
294 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Nuisance may be caused during the transference of the liquor 
 from the gas-works, from the storage of the liquor, or during the 
 manufacturing process. The main cause of complaint is the escape 
 of sulphuretted hydrogen. The methods in use for abatement 
 of this nuisance are mainly two : (1) burning the fumes, (2) 
 absorbing them by chemical agents. The sulphuretted hydrogen 
 and other matters are burnt by carrying them either into a 
 special furnace or into the same furnace which distils the 
 liquor ; in either case, the vapours, consisting of sulphurous acid 
 and other gases, should be carried into a tall chimney shaft; 
 otherwise one nuisance will only be replaced by another. The 
 absorption of SHj is effected by lime, or by hydrated oxide of iron 
 mixed with sawdust. The latter is preferable. 
 
 (209) Distillation of Tar. 
 
 Coal tar, mixed with more or less ammoniacal liquor, is distilled 
 in suitable stills. The products are (1) "light oils," floating 
 in water, from which benzole and solvent naphtha are obtained ; 
 (2) " heavy oils," or creasote oils, sinking in water, and containing 
 cresylic and carbolic acids ; (3) anthracene oil, still heavier than 
 creasote oils ; and lastly, (4) pitch. 
 
 The sources of nuisance, according to Dr. Ballard, are as 
 follows : — 
 
 1. The reception of the tar in uncovered barges, and its trans- 
 ference to the tanks or storage receptacles at the works; the 
 offensive odour is chiefly from sulphide of ammonium. 
 
 2. The escape into the atmosphere of offensive distillation pro- 
 ducts. These come off mostly towards the end of the distillation. 
 
 3. The escape of a more or less dense white vapour when hot 
 pitch is run off from the stiU or pitch oven into the pitch bay, 
 or a similar vapour from the pitch bay or tubs before they cool. 
 
 4. The escape of offensive vapours from the pitch oven. 
 
 5. The combustion of creasote oil as fuel for the stills, where 
 the arrangements for its proper combustion are incomplete. 
 
 All these nuisances have been dealt with successfully at properly 
 designed and conducted works, e.g. like those of Messrs. Burt, 
 Boulton, and Haywood, Silvertown. The main points are trans- 
 ference of the crude material in air-tight vessels, absorption of 
 
XXI.] 
 
 CARBOLIC ACID MANUFACTURE, 
 
 295 
 
 sulphide of ammonium by hydrated oxide of iron, passing the 
 gases through water and then burning them up in the furnace 
 fire, running the pitch into a closed vessel to cool, and lastly, 
 where creasote oil is used as a fuel, burning the oil in furnaces 
 specially constructed for that purpose. 
 
 (210) The Maimfaclure of Carbolic Acid. 
 
 The carbolic oil obtained from the distillation of coal tar is 
 treated in an iron tank with caustic soda, which dissolves out 
 the carbolic and cresylic acids, and leaves " tar oils " unacted upon. 
 The caustic soda solution is separated from the "tar oils" by 
 syphoning, and then the alkaline liquid is supersaturated with 
 sulphuric acid; thereupon the crude carbolic and cresylic acids 
 separate, and the acids are ladled off and distilled. The dis- 
 tillation is fractional and is carried to dryness, the residue in 
 the retort consisting of a light coke which subsequently is used 
 as a fuel. 
 
 Nuisance is liable to be caused by the odour of carbolic acid, 
 by the escape of offensive gases towards the end of the distillation, 
 
 Fig. 46. 
 
 and by the removal of the coke from the retorts. The general 
 odoui- of carbolic acid is much lessened by receiving the condensed 
 liquids into, covered vessels. The offensive gases are dealt with 
 at Mr. Lowe's works at Eeddish in the following way : The 
 
296 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 pipe from the worm condenser a divides into an ascending and a 
 descending branch ; the descending branch, h, carries the condensed 
 liquids and is trapped by a syphon at i, while the ascending pipe 
 delivers gases into a 6-inch main pipe, c, which runs along the 
 whole range of stills. From the main a pipe conveys the gases 
 to a small worm condenser, d, and from this to a stoneware 
 bottle, 6, which receives any liquid matter condensing; a pipe 
 from 6 is supplied with a steam exhauster jet,/ which causes a 
 greater or less vacuum in the gas main, and drives the gases 
 onwards through water or milk of lime, contained in a cask, g, 
 whereby sulphuretted hydrogen is arrested, and from this washer 
 a pipe conveys any gases not arrested into the ash-pit of a fire. 
 This arrangement of Mr. Lowe's seems generally applicable to 
 offensive distillations, and is highly ingenious. 
 
 Nuisance occasioned by the removal of coke from the retorts 
 is said not to occur, provided the distillation is complete, and the 
 coke only removed when cold. There ought to be no difficulty 
 in passing the products of combustion through scrubbers of 
 coke through which water trickles. 
 
 (211) The Manufacture of Alkali. 
 
 The materials used are common salt, sulphuric acid, limestone 
 and coal. The salt is decomposed by sulphuric acid, assisted by 
 heat. The reaction here is a simple case of double decomposition, 
 sulphate of soda, is formed and hydrochloric acid escapes. The 
 crude sulphate of soda, termed technically " salt cake," is mixed 
 with crushed limestone, or chalk and coal, and heated strongly, 
 the ultimate result being a mixture of sodic carbonate, calcium sul- 
 phide and unburnt carbon ; the latter gives the mass a black colour, 
 hence it is termed technically " black ash." The black ash is 
 treated with water which dissolves out the sodic carbonate ; the 
 residue is known as " tank waste." 
 
 The manufacture has been the subject of special legislation, the 
 more particularly with reference to the acid fumes or gases which 
 are necessarily produced. These are defined by the Act to be sul- 
 phuric acid, sulphurous acid, nitric acid, or other noxious oxides of 
 nitrogen, sulphuretted hydrogen and chlorine. At the present 
 time great improvements in the apparatus for "scrubbing" or 
 
sxi.] ALKALI MANUFACTURE. 297 
 
 washing the issuing gases have generally reduced the nuisance 
 from the acid gases, and the fact that special inspectors are ap- 
 pointed to see that the requirements of the Act are observed 
 rather take the matter out of the hands of the medical officer 
 of health and his subordinates. 
 
 What, however, will directly concern the sanitary chief, is 
 nuisance arising from tank waste. These form mounds, embank- 
 ments, and even small hills of an artificial earth consisting of 
 various compounds of sulphur and calcium, the oldest layers 
 being oxidized to a greater or less degree to sulphite and sul- 
 phate of calcium, while the more recent layers have a large 
 proportion of sulphide, and if from any cause moistened are liable 
 to give forth sulphuretted hydrogen. 
 
 The chief source of waste heap nuisance is the soluble matter, 
 which is " a sulphuretted compound of calcium of indefinite com- 
 position, but which is mainly composed of sulphide of calcium, partly 
 converted by oxidation into hyposulphite of calcium, and holding 
 in solution with it a considerable but indefinite quantity of 
 sulphur." The solution of the sulphur matter occurs from being 
 washed by the rain, from being lixiviated by springs, or, as at the 
 St. Kollox works, the heaps being situated on the banks of a 
 tidal river, and being washed by its waters as it rises and falls. 
 
 In recent years successful attempts have been made for the 
 utilization of the waste, the sulphur contained in them being 
 extracted by appropriate chemical treatment. 
 
 In Mond's process, air is blown through the fresh tank waste, 
 and by this means the sulphur compounds oxidized to sulphite 
 and sulphate; these soluble compounds are lixiviated out by 
 means of water, the aqueous solution is then treated by steam 
 and hydrochloric acid, sulphur is precipitated and allowed to 
 subside, it is afterwards collected, and forms a very pure kind of 
 sulphur. The process is not productive of nuisance in theory, 
 but in practice there is no doubt that sulphuretted hydrogen is 
 not unfrequently evolved. 
 
 Mactear's process in use at the St. Rollox works is as follows : 
 The sulphur heaps, which are situated in this instance on ground 
 permeated with springs, supply a large and regular amount of 
 liquid holding in solution calcic sulphite and hyposulphite. 
 Hydrochloric acid is added, and both salts decomposed ; in the 
 
298 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 decomposition of the hyposulphite, sulphur is thrown down and 
 sulphurous acid evolved ; in the decomposition of the sulphide 
 sulphuretted hydrogen is evolved, but this gas coming in contact 
 with the sulphurous acid is immediately decomposed, and sulphur 
 falls, so that if there is always a sufficiency of the hyposulphite 
 to evolve enough sulphurous acid to decompose all the sul- 
 phuretted hydrogen, there is no nuisance, and the whole of the 
 sulphur of the sulphide is recovered. If there is not a sufficiency 
 in the liquid itself the requisite quantity of the hyposulphite is 
 added. 
 
 (212) The Manufacture of Picric Acid and the Manufacture of 
 Aniline and Aniline Colours. 
 
 The different processes in use for the manufacture of picric acid, 
 of nitro-benzole, of arsenic acid, of magenta and of the aniline 
 dyes generally, are all liable to permit the escape of nitrous acid or 
 other acid fumes. Since however the escape of any acid is a 
 distinct loss to the manufacturer, in all well-managed works they 
 are condensed as much as possible. 
 
 The best method to obviate nuisance seems to be to pass the 
 gases through water, and lastly through fire. 
 
 A heavy odour of essence of myrbane often pervades aniline 
 works, this is due to small leakages. 
 
 (213) The Manufacture of Sulphuric Acid. 
 
 Sulphuric acid is made by burning either sulphur, cupreous 
 pyrites, mundic, sulphur holding oxide of iron from the gas works, 
 or from sulphuretted hydrogen. The sulphurous acid produced by 
 the burning of these forms of sulphur or sulphides is oxidized into 
 sulphuric anhydride in large lead chambers by means of the higher 
 oxides of nitrogen, set free by the action of sulpburic acid on sodic 
 nitrate. The weak acid is subsequently concentrated in platinum 
 stills and in glass retorts. 
 
 Nuisance may be caused by the escape of sulphurous acid gases 
 and by the higher oxides of nitrogen. The gases may escape from 
 (a) the chimney ; (&) leakages in the burners and escape in the 
 openiDg of the feeding doors ; (c) leakage from the lead chambers 
 arising from defective joints ; {d) concentration of the chamber acid ; 
 
XXI.] SALT MANUFACTURE. 299 
 
 e) evolution of acid fumes from accidental breaking of a glass 
 retort. Escapes of gas by the chimney will not occur in large 
 works where the Gay Lussac and Glover towers are used. The 
 Glover tower is essentially a coke tower, and the principle of its 
 action is that when strong sulphuric acid charged with nitrous acid 
 is mixed with either water or weak acid, most of the nitrogen 
 compounds are given off. The gases from the burners stream up 
 this coke tower and meet two streams of acid, viz., weak chamber 
 acid and acid charged with nitrous fumes from the Gay Lussac 
 tower ; the reaction mentioned ■ above takes place, and the nitro- 
 sulphuric acid is almost completely denitrated. The gases pass on 
 into the chambers, the denitrated acid passes into the Gay Lussac 
 tower, which is a leaden scrubber packed with coke ; the strong 
 denitrated acid being forced up to the top of this tower, trickles 
 down through the coke, absorbing any nitrous fumes, and thus the 
 acid is turned into nitro-sulphuric acid, the destination of which is 
 as before to the Glover tower. Hence there is a perpetual circula- 
 tion, and theoretically the same nitrogen could be used over and 
 over again ; leakages and some other chemical changes prevent the 
 entire realization of this. It is however clear that where these 
 towers are used no nitrous fumes should escape from the chimneys. 
 
 The other sources of nuisance are more or less remediable by 
 proper fittings, suitable stoking, suitable covers, condensing arrange- 
 ments and obvious precautions. 
 
 (214) The Manufacture of Salt. 
 
 This manufacture consists in the evaporation of brine which lias 
 been raised from salt mines. The chief salt mines are in Cheshire 
 and Worcestershire. The brine is first pumped into reservoirs to 
 deposit and then run into large shallow evaporating pans. Each 
 pan is heated either directly by a fire placed underneath it or by a 
 system of flues. The flues from the fires of the salt pans usually 
 terminate in a number of low chimneys from 30 to 60 feet in 
 height, the reason assigned for not replacing the short chimneys 
 by one tall shaft, is the danger to the tall shaft from the subsidence 
 of the land, which as is well known is constantly taking place 
 in salt districts. 
 
 Salt works are productive of two kinds of nuisance, viz., the 
 
300 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 evolution of black smoke at a low level, and of acid fumes. The 
 acid fumes are produced (1) by the decomposition of magnesic 
 chloride ; (2) by sulphurous acid produced by burning the slack ; 
 
 (3) by a reaction between sulphurous acid gas and sodic chloride ; 
 
 (4) decomposition of sodic chloride by the silica of the bricks, 
 silicate of soda being formed and hydrochloric acid produced. The 
 acid fumes are therefore mainly hydrochloric acid with some 
 sulphurous acid. 
 
 There is also some nuisance caused by waste heaps. Several 
 patents have been taken out for a more economical method of salt 
 manufacture enabling manufacturers to dispense with the use of 
 open pans altogether. So long as the system of open pan evapora- 
 tion continues the abatement of these nuisances is difficult. 
 
 The sulphurous acid can be much diminished by the use of a good 
 form of slack or coal containing only a small proportion of sulphur; 
 the fear of injuring the long chimney shafts from subsidence is 
 said not to be so great as the manufacturers make out, at all events 
 light long sheet iron chimneys lined with lire brick and secured by 
 wire rope stays could surely be used ? 
 
 (215) The Manufacture of Chloride of Lime {Bleaching Powder). 
 
 The ordinary process is the decomposition of hydrochloric acid 
 by manganese dioxide ; the chlorine evolved is conducted to chambers 
 where hydrated lime is exposed to its action in thin layers. The 
 decomposition takes place in a square chamber made of Yorkshire 
 flags, and the reaction is aided by means of steam. The residue is 
 a strong acid solution of manganese chloride. 
 
 The Weldon process of making chlorine differs from this in 
 recovering the manganese and using it over again. The solution 
 of manganese chloride is neutralized by means of limestone, which 
 precipitates the impurities, viz., oxide of iron, alumina and 
 carbonate of lime ; these are allowed to settle, and the clear liquid, 
 containing calcic qhloride, manganese chloride and some calcic 
 sulphate, is transferred to an iron cylinder where it is mixed with 
 inilk of lime ; manganese protoxide is precipitated as a thick black 
 mud. Air is blown through this mud, which effects an oxidation, 
 oxidizing the protoxide into binoxide of manganese. 
 
 In the Deacon process hydrochloric acid gas is passed at a high 
 
XXI.] GLASS MANUFACTURE. 301 
 
 temperature over bricks saturated with sulphate of copper solution ; 
 under these circumstances the acid gas is decomposed, the hydrogen 
 forming with the oxygen of the air, water and the chlorine passing 
 on in the free state. The gas is washed with water and dried by 
 means of strong sulphuric acid. It is then pure enough to be used 
 to saturate the lime. 
 
 The Deacon process. Dr. Ballard says, is free from nuisance out- 
 side the works. 
 
 The source of nuisance from bleaching works is the escape of 
 chlorine from leakage, and from chlorine being only mechanically, 
 not chemically, combined with the lime, from the chambers them- 
 selves, and lastly from the packing and transferring the powder to 
 casks or other receptacles. 
 
 One method of reducing the " chamber " nuisance is as follows : — 
 the door of the chamber is slightly opened, and by means of a fan 
 the chlorine atmosphere is driven into another chamber in which 
 there are layers of fresh lime ; another good plan is to use divided 
 chambers, that is, chambers divided into two by a partition, and 
 then when one part is saturated, remove the partition and thus 
 allow the excess of chlorine to be absorbed. 
 
 It has also been proved that with proper arrangements the 
 transference into casks need cause no nuisance. For instance in 
 Messrs. Deacon's works the powder is transferred direct to the cask 
 from the chamber through a tube of sacking. 
 
 (216) The Manufacture of Glass. 
 
 In the manufacture of glass, especially that of the poorer kinds, 
 sulphate of soda and common salt are heated with silica and 
 other substances, the result being that sulphuric and hydrochloric 
 acids are expelled. There is besides generally a considerable 
 amount of nuisance from smoke. Where the works are large, the 
 amount of acid sent into the atmosphere is of course proportionate ; 
 for instance at the St. Helen's plate glass works more than 190 tons 
 of sodic sulphate are decomposed weekly. 
 
 No way of abating the acid emanations from glass works which 
 will not interfere seriously with the trade itself has yet been 
 devised ; of course neither sodic sulphate nor sodic chloride are 
 essential to use at all, it would be far better to employ sodic 
 
302 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 carbonate, but it is said the great competition, especially with 
 foreign manufacturers, prohibits the use of the dearer material. 
 
 A good deal has been effected to remedy the smoke nuisance, e.g. 
 with the Siemens gas furnace there is no nuisance from smoke. 
 There are also several improved furnaces which with careful stoking 
 consume most of their own smoke. 
 
 (217) The Calcining of Ironstone and Tap Cinder. 
 
 Ironstone whether in the form of " clay band " or " black band ' 
 is calcined in order to drive off carbonic acid, to peroxidize the iron, 
 bum off the sulphur, and reduce the bulk of the ore. The 
 calcining is done either in clamps or iu kilns. The slag drawn 
 from puddling furnaces is treated similarly. 
 
 In both instances there is nuisance from smoke and sulphurous 
 acid gas. Kiln burning is much less offensive than clamp burning, 
 and where the nature of the stone will allow of this process to be 
 used, it should be insisted upon. 
 
 (218) Hardening of Steel Springs and Saws. 
 
 In the tempering of various steel articles the red hot steel is 
 plunged into a bath of oil. The result is the evolution of irritating 
 fumes of acrolein and other volatile substances. The nuisance 
 can be remedied like others of the same kind, viz., by conducting 
 the evolved vapours through a furnace fire and thus burning 
 them up. 
 
 (219) The Calcining of Spelter. 
 
 In the smelting of zinc ores, containing sulphur such as blende, 
 copious sulphurous acid fumes are evolved. There is also much 
 dust in the form of oxide of zinc produced. Dr. Ballard states 
 that in one instance the nuisance from the fumes was successfully 
 abated by carrying them up a flue 300 yards long and then into a 
 tall chimney shaft. This effectually removed the vapours from the 
 vicinity of inhabited houses. 
 
 (220) Galvanising Iron. 
 
 The iron is first chemically cleaned by means of acid, it is then 
 dipped into a bath of melted zinc. During this process hydrogen 
 is evolved, and very frequently some hydrocarbons, the hydrogen 
 
XXL] TIN PLATE MANUFACTURE. 303 
 
 uniting with the carbon of the iron. Should the iron contain 
 sulphur or phosphorus, then sulphuretted or phosphuretted hydro- 
 gen gases are likely to be eliminated. Where chloride of ammonium 
 is sprinkled upon the bath from time to time then chloride of 
 arsenic is evolved. In most cases there is indeed an arsenical 
 odour from the fumes during the galvanizing of iron. The spent 
 pickle is a strongly acid solution of chloride of iron. 
 
 There can be no question that the fumes from galvanizing iron 
 are directly injurious to health, and should be removed from the 
 works by suitable fans, hoods, and flues, and either properly con- 
 densed or discharged at a considerable height into the upper layers 
 of the atmosphere. If the spent pickle is likely to damage the 
 sewers it should be neutralized by means of limestone. 
 
 (221) Tin Plate Manufacture. 
 
 The plates are first pickled in acid. The pickle consists of slightly 
 diluted oil of vitriol heated up to boiling point by means of steam. 
 After pickling, the plates are immersed in a series of dipping 
 pots, the first of which is filled with palm oil, and the others 
 contain melted tin covered with a layer of palm oil. 
 
 The emanations from tin plate works consist of acid fumes, 
 of odours of palm oil and acrolein. There is also more or less 
 hydrogen gas evolved, the gas having a peculiar odour. The 
 practice seems to be to use a number of small chimneys, instead of 
 collecting the fumes into one large shaft. So long as the traditions 
 of the trade remain unbroken, great difficulty will be necessarily 
 experienced in effectually dealing with the vapours. There is little 
 doubt that the general principles of conveying the various fumes 
 collected by hoods and flues to scrubbers and then to a furnace fire, 
 would arrest the acid and burn up the organic emanations. 
 
 The strongly acid spent pickle is often concentrated by boiling 
 for the purpose of crystallizing out the iron sulphate it contains ; 
 this is necessarily accompanied by the evolution of acid fumes. 
 Any nuisance from this source can be readily obviated by covering 
 the concentrating vessels and condensing the fumes in a scrabber. 
 Where the spent pickle is not dealt with in this way it should not 
 be cast down the sewers until neutralized with limestone or some 
 form of lime. 
 
304 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (222) Tin Burning. 
 
 Tin burning is the burning by fire of refuse heaps containing 
 old tins for the purpose of extracting the solder they contain. If 
 the refuse does not already contain enough combustible matter, 
 wood shavings are added in alternate layers. From the ashes 
 solder and other saleable matter are picked out by hand. Tin 
 burning generally gives rise to much offence, the vapours are 
 often most irritating, especially when the refuse contains an oily 
 matter, such as paint, there is also a large volume of smoke given 
 off at a low level. Tin burning is only practised by the very 
 poor in large cities, hence the crude method employed. Of the 
 nuisance of the process there can be little doubt. 
 
 (223) The Calcining of Arsenic and Arsenical Ores. 
 
 In bhe roasting of arsenical pyrites and in the refining of arsenic 
 large volumes of sulphurous acid are given off, the sublimed 
 arsenic also is a real danger to the work people. It appears, 
 unfortunately, that attempts to wash the sulphurous acid fumes, 
 which are always mixed with a large volume of air, have not been 
 successful, for the washing always interferes with the draught of 
 the furnaces. Where it can be done, the uncondensed fumes 
 should be discharged at such an elevation and at such a distance 
 from inhabited houses that they shall be thoroughly dispersed 
 before they have time to fall in such quantities as to occasion 
 nuisance. 
 
 (224) The Smelting of Capper Ores. 
 
 In the various complicated operations in use for the smelting of 
 copper ores containing sulphur, there are volatile emanations 
 consisting of sulphurous acid gas, arsenious acid, and, if fluorine 
 be present, fluoride of silicon, with dust and smoke. The vapour 
 well-known as " copper smoke " is a mixture of these volatile and 
 dusty matters. The copper will occasionally travel some distance, 
 but the arsenic has not been discovered save in the immediate 
 neighbourhood of the works. 
 
 According to Mr. Hussey Vivian's evidence before the " Noxious 
 Vapours Commission " the principle to be adopted in lessening the 
 
XXI.] COKE AND BREEZE MANUFACTURE. 305 
 
 fumes from copper works, is to have large deposit flues so as to 
 lessen the velocity of the vapour, the flues terminating in lofty 
 shafts. 
 
 (225) Lwie Burning, 
 
 Lime is either burnt in a close or open kiln. Nuisance may 
 arise from lime burning if low class fuel is used, especially fuel 
 containing much vegetable or animal matter, also if the gases, 
 which always contain some considerable proportion of carbon oxide, 
 get entrance into adjacent dwellings. In Dr. Ballard's report on 
 effluvium nuisances there is a distinct case of chronic carbon 
 oxide poisoning from this cause. Lime burned in close kilns, the 
 vapours being carried into the upper part of the atmosphere, appears 
 to be productive of little or no nuisance. 
 
 (226) Manufacture of Gohe and Bree&e. 
 
 In principle the manufacture of coke and breeze is nothing more 
 than destructive distillation of carbonaceous matter by the agency 
 of heat, the air being partially excluded ; water, compounds of 
 hydrogen and carbon, and volatile matters generally, are driven off, 
 and there is left, if the process is stopped at a certain time, an 
 impure carbon with incombustible mineral matters. The manu- 
 facture is either done in heaps, " pile coking," or in ovens. Pile 
 coking is most productive of nuisance, dense volumes of smoke 
 are emitted at a low elevation with sulphurous acids and other 
 irritating gases. The amount of sulphiirous acid gas depends on 
 the amount of sulphur in the fuel which is coked, some classes of 
 fuel containing but a small quantity, other classes containing much 
 pyrites and therefore a large quantity. The mean quantity of 
 sulphur in coal is a little under 1 per cent., but some of the 
 Welsh coal contains as much as 5 per cent, of sulphur. One 
 method of pile coking is to build a hollow, permanent, brick dome, 
 perforated at intervals ; around the base are iron pipes for the 
 admission of air extending radially like the spokes of a wheel ; 
 the coal to be coked is piled up around the dome, the whole being 
 covered with coke dust, such a pile is lighted at the centi-e and 
 burns slowly to the circumference. The burning is continued for 
 five or six days, and then the fire is extinguished by covering the 
 
 X 
 
306 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 heaps with damped coke dust. Dr. Ballard describes a fairly effec- 
 tual means of mitigating the nuisance from coke-pile burning, the 
 invention of Mr. E. Jones ; it briefly consists in connecting a flue 
 with the central dome, drawing off the products of combustion by 
 means of a fan through underground flues, and condensing the 
 products by passing them through a water jacketed condenser. 
 These condensed products' are commercially valuable. 
 
 When coking is done in ovens, the vapours are passed into a tall 
 chimney shaft, and are thus discharged at a sufficient elevation to 
 abate more or less the nuisance. 
 
 (227) Brick Burning. 
 
 Bricks are burnt either in clamps or kilns. Clamp burning, is 
 burning the bricks in a quadrangular pile. The green bricks 
 made of clay and mixed with a small proportion of ashes being 
 arranged in layers alternating with breeze. The breeze is set 
 alight by means of small fires of wood and coal. 
 
 (a) Kiln Burning. — In kiln burning no combustible substance 
 is mixed M'ith the brick material. The bricks are burned 
 by the aid of coal. The kilns are either open, that is the smoke 
 finds its way from the top of the kiln into the atmosphere, or 
 the kilns are provided with a special flue for discharging the 
 smoke. 
 
 (6) damp Burning. — Clamp burning is especially offensive. 
 The emanations are watery vapour, thick smoke, the usual gases of 
 combustion, very often sulphuretted hydrogen, and certain pyrolig- 
 neous matters which have an offensive odour. Where, as is often 
 the case, household refuse is used containing animal and other 
 organic matter, the odour is intensely disagreeable. The emana- 
 tions are often acid, irritating to the mucous membranes and 
 injurious to vegetation. 
 
 The fumes from burning bricks differ in composition very much 
 in the different stages of the process, the clay used, and the fuel 
 employed. Clamp burning as the most offensive process should be 
 entirely prohibited in the neighbourhood of large towns. Kiln 
 burning by careful stoking, by the use of certain special kilns, and 
 by the aid of a long chimney shaft, can be caiTied on with but 
 trifling offence. 
 
XXI.] PORTLAND CEMENT MANUFACTURE. 307 
 
 (228) Ballast Burning. 
 
 Ballast burning is converting stiff clay by the agency of heat 
 into a bricklike material for use on the roads. The clay is usually 
 burned in heaps mixed with breeze and ashes. It is, without 
 doubt, a great nuisance. Dr. Ballard remarks, " Should it at any 
 time be held essential that clay should be burned where the 
 burning is likely to be a nuisance, it should be burned in such a 
 way as to bring the effluvia under control. I see no reason why it 
 should not, under such circumstances, be burned in a kiln with due 
 provision against nuisance from the empyreumattc vapours and 
 smoke emitted. If it is absolutely necessary that ballast should be 
 burned in heaps, it appears to me that the method adopted by Mr. 
 Jones (see page 306) to prevent coking in- heaps, or some similar 
 method, would be applicable. If it is worth while to burn the 
 clay at all it ought also to be considered worth while to do it 
 inoffensively. 
 
 (229) The Manufacture of Portland Cement. 
 
 Two kinds of hydraulic cement are in use — the one, " Roman 
 cement," made from the septaria nodules found in the London clay 
 formations ; the other, " Portland cement," made from an artificial 
 mixture of clay and limestone. In the manufacture of the Roman 
 cement the stones are calcined in open kilns, like limekilns, and 
 there is but little nuisance. The manufacture of Portland cement 
 has, however, often been complained of, and has formed the subject 
 for injunction. The chalk and clay are mixed under water, and 
 then the mixture is either run into depositing-tanks, or when only 
 a small quantity of water is used (Goreham process), the substances 
 are ground together. In either case a wet mud is produced, which 
 is technically called "slurry." The slurry has to be dried, and 
 then burned in kilns. The chief nuisance is in the burning, and 
 especially, if this is done in open kilns. The emanations consist 
 of gases, some of which, like carbon dioxide and sulphuretted 
 hydrogen, are poisonous. In certain cases, when the clay used 
 contains much nitrogenous matter, it appears to be definitely 
 proved that either hydrocyanic acid or a volatile cyanide is pro- 
 duced. At Southampton, for instance, the fume from a cement 
 
 X 2 
 
308 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 works was observed to colour the gravel in its neighbourhood blue, 
 and the blue colour Dr. Dupr^ found to be produced by cyanide of 
 iron ; moreover, the gases drawn from the kiln were found to 
 contain volatile cyanides. The emanations from a cement-kiln 
 vary according to the different stages ; this is well shown in some 
 analyses by Dr. Russell and Mr. Fleming, made in 1877, of gases 
 from an open kiln at Greenhithe : — 
 
 Table XXXIIL 
 
 
 FiKBT Stage. 
 
 Second Stage. 
 
 Third Stage. 
 
 Combustion com- 
 mencing. Gases 
 rank. Plenty of 
 white smoke. Temp, 
 not very high. 
 
 About halfway to greatest heat. 
 
 Gases veiy rank and strong 
 
 smelling. On sucking out 
 
 gases, water and tarry matter 
 
 pa.ssed over. The water not 
 
 acid ; at this period most smell. 
 
 Full red heat. Not 
 much smell or mois- 
 ture. White dust in 
 tube. 
 
 Oxygen . . 
 Carbonic acid . 
 Carbon oxide 
 Nitrogen . . . 
 
 17 03 
 3-89 
 1-34 
 
 77-74 
 
 11-70 
 4-27 
 6-27 
 
 77-76 
 
 2-35 
 20-56 
 
 8-59 
 68-50 
 
 
 100-00 
 
 100-00 
 
 10000 
 
 Besides gaseous products there are also sublimations and dusty 
 matter ; these are composed of soot, cement dust, and sulphates of 
 lime and potash, chlorides of the alkalies, with silica, alumina and 
 some lime compounds. Some of these collect as a white deposit 
 in the neighbourhood of the kiln. 
 
 Dr. Ballard's report gives good grounds for saying that emana- 
 tions from open kilns during the process of manufacturing Portland 
 cement are positively injurious to health. 
 
 There have been attempts to mitigate the nuisance of cement- 
 making in three directions — viz., washing the fume with water; 
 passing it through fire ; and delivering it at a high elevation by 
 means of a tall chimney shaft. The first method seems not to have 
 been very successful ; burning the fume has to a certain extent been 
 found to answer, but the best method of dealing with it, according 
 to experience, is to discharge it from a tall chimney shaft, that is 
 one from ].50 feet to 200 feet high. 
 
XXI.] SALT-GLAZING. 309 
 
 (230) The Firing of Pottery — Salt-glazing. 
 
 In salt-glazing, the articles of clay are subjected to a high heat 
 with common salt. A decomposition of part of the salt takes 
 place : silicate of soda is formed, producing a glaze, and hydro- 
 chloric acid gas escapes with the portion of salt in excess ; there is 
 also always some sulphurous acid gas from the fuel employed, and 
 more or less smoke. It has been hitherto found impracticable to 
 arrest the acid vapours by scrubbers, because their interposition 
 interferes with the draught necessary to properly fire the articles, 
 and the only feasible means to m'+igate the nuisance is to convey 
 the vapours into the upper regions of the atmosphere by a tall 
 chimney shaft. 
 
SECTION VII. 
 DISINFECTION.— DISINFECTANTS. 
 
CHAPTER XXII. 
 
 EXPEEIMENTAL METHODS FOE TESTING THE VALUE OP A 
 DISINFECTANT. 
 
 (2.31) Distinction hetiveen Disinfectants and Antiseptics.- 
 
 A TRUE disinfectant is a chemical substance which is capable of 
 killing by its poisonous action a pathogenic, or disease-producing 
 germ; it is therefore synonymous with "germicide." Disinfection 
 is to be distinguished from " destruction," as, for instance, by fire 
 or by the corrosive action of strong mineral acids ; a genuine dis- 
 infectant does not necessarily change the structure of the tissues or 
 bacteria submitted to its influence. 
 
 Antiseptics are substances that arrest the development of germ- 
 life ; all disinfectants are also antiseptics, if employed in quantities 
 insufficient to destroy life, but antiseptics are not necessarily 
 germicidal. 
 
 The elements modifying disinfection are quantity of disinfectant 
 in relation to the thing to be disinfected, temperature and time. 
 In other words, the disinfectant must be of sufficient strength — 
 must act on the substance to be disinfected for a sufficient period 
 of time. 
 
 (232) Temperature. 
 
 Temperature is important, for the writer has proved that, e.g. 
 1'15 per cent, of lutidine, acting for twenty-four hours at 15°, 
 failed to disinfect a thread infected with bacterium termo, but 
 '5 per cent, at 35°.5 of lutidine disinfected absolutely. The 
 element of time is all important ; nevertheless, the experiments of 
 Cash have proved that a disinfectant in a too dilute state may act 
 for a lengthened time on pathogenes without any effect, but if the 
 
314 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 disinfectant be of such a strength that it is capable of disinfecting 
 at all, the longer the time ceteris paribus, the more complete the 
 disinfection. 
 
 (233) Experimental Methods. 
 
 There are two methods by which a chemical agent may be 
 tested : — First of all, to find out whether it is a disinfectant at all ; 
 and secondly, if it should be a disinfectant, what dose or strength 
 should be used ? 
 
 1. Inoculation into Animals of Disinfected Matter. — The virus of 
 a disease, or a pure cultivation of a pathogene, is taken, such as 
 tuberculosis, mouse septicasmia, anthrax, submitted to the action of 
 a disinfectant of a definite strength for a definite time and tem- 
 perature, and then the product is injected into an animal known to 
 be susceptible. At the same time a similar quantity of the undis- 
 infected virus is injected into another animal, called " the control," 
 and the effects noted. This method of experiment is by far the 
 most satisfactory and conclusive. 
 
 2. Testing " Cultures." — The second method is of great utility, 
 because it enables an observer to arrange disinfectants in their 
 order of strength, and essentially consists in submitting cultivations 
 of microbes to the action of disinfectants, and then ascertaining 
 their power of development in nutrient soils. The writer has 
 employed certain processes for this purpose, which he has thus 
 described (" Studies of Disinfectants by New Methods," Proceedings 
 of the Boyal Society, 1886). 
 
 (234) The Drop Method. 
 
 Sterilised pure water is infected with a few c.c. of gelatin liquefied 
 by the bacterium ; measured volumes of this infected water are then 
 added to measured volumes of the disinfectant, and the whole 
 allowed to act for a definite time. A drop of this liquid is then 
 added to from 10 — 20 grams of the nutrient gelatin, first liquefying 
 it at a very gentle heat. As the proportion of the weight of the 
 drop to the weight of the nutrient gelatin varies from about 1 :500 
 to 1 : 1000, the dilution is in most cases sufficient to reduce any 
 antiseptic or inhibitory action of the minute quantity of the 
 chemical agent in the drop itself to a minimum, so as to exercise 
 no appreciable effect. 
 
XXII.] METHOD OF TESTING DISINFECTANTS. 315 
 
 (235) The Thread Method. 
 
 In the thread method capillary glass rods are made by drawing 
 out ordinary glass tubing in the blow-pipe flame, these are tipped 
 with sealing-wax, and to the wax a little bit of sterilized cotton 
 wool is made to adhere. 
 
 The end of the rod thus prepared is infected with the bacterium 
 by a short immersion in a pure cultivation and then placed in the 
 disinfectant for a definite time. The rod on removal is soaked for 
 a little time in sterilized water until all trace of the disinfectant 
 has been removed. 
 
 The rod thus charged and purified is next inserted into a mass of 
 solid nutrient gelatin in a test-tube, and put on one side at the 
 ordinary temperature of the atmosphere, protected of course from 
 external contamination by a suitable plug of sterilized wool. 
 Whether the process used is the " drop " or the " thread," in each 
 case " control " experiments are made with threads infected with 
 the bacterium, but which have not been submitted to disinfection. 
 Enumeration of Colonies. — This is an entirely different method 
 of procedure. The number of colonies in a gram of sewage or 
 other suitable liquid are carefully determined by a modification of 
 known methodsi 
 
 The same sewage is then treated by substances the disinfectant 
 properties of which 'form the subject of inquiry, and the number of 
 colonies capable of growing in a nutrient soil, representing 
 the micro-organisms which have escaped destruction, „ 
 
 again enumerated. 
 
 The only special apparatus used requiring descrip- 
 tion is the " drop-bottle " and the " rings and plates." 
 
 The Drop-bottle. — The figure represents its shape 
 and size, the capacity is about 25 c.c. The stopper 
 is hollow and terminates in a pipette ; it has a pin- 
 hole at a, which can be closed by the finger. 
 
 The Glass Plates and Rings. — The glass plates are 
 4 by 2 inches square, the rings 4 inches in diameter, 
 ^ inch thick, and J inch high. The plates have FigTIt! 
 a ground surface the size of the ring thickness; 
 the rings are cemented to the plates in the following manner. 
 After heating the rings and plates in a hot air oven for many 
 
316 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 hours a little peptone gelatin is run on to the ribbon of ground 
 surface, the ring adjusted, and the whole allowed to cool in a 
 glass chamber formed by a small dish covered by a slightly 
 larger one ; at the bottom of the dish is some filter-paper moistened 
 with a solution of mercuric chloride. The plates are not used until 
 the gelatin cement has perfectly set. The plates are ruled by 
 means of a diamond into squares for the purpose of easy 
 enumeration. 
 
 Solid substances, such as ferrous sulphate, may be weighed and 
 dissolved in definite quantities of the sewage ; in other cases 
 solutions of known strength are mixed with the sewage. 
 
 The method of cultivation is as follows : — A small quantity, 
 whether of diluted or disinfected sewage, is transferred to the 
 previously cleansed and sterilized drop-bottle, the bottle and its 
 contents carefully weighed, then by means of the pipette stopper 
 one or two drops spotted on to the surface of the glass cell formed 
 by the plate and ring already described ; the weight of the drops is 
 ascertained by reweighing the drop-bottle. 
 
 Ordinary nutrient gelatin liquefied at a gentle heat is run from 
 a Lister flask into the glass cell, and mixed equally with the drops 
 by inclining the plate in different directions. During these several 
 operations dust is excluded as far as possible by covering the glass 
 cell by a second glass plate, merely shifting the plate sufficiently 
 on one side to allow the insertion of the nozzle of the Lister flask 
 or the point of the pipette. The cells thus charged are plactid in 
 the moist chamber ; the gelatin rapidly sets, and at the end of 
 from three to five days the colonies of growth are counted in the 
 usual way and their general nature determined. 
 
 The weight of the drop or drops taken may vary from 20 to 100 
 mgrs., the gelatin in which the drop is cultivated from 15 to 20 
 grams, so that the minute quantity of disinfectant contained in the 
 drop itself is diluted from 200 to 1000 times. This amount of 
 dilution with the comparatively weak percentages of most dis- 
 infectants save those approaching corrosive sublimate in power 
 reduces the action of the disinfectant on the gelatin, the cultivating 
 soil — to a minimum, so that practically as soon as the micro- 
 organisms still surviving are floated into the nutrient gelatin they 
 are removed from the sphere of disinfectant influence, the follow- 
 ing is an example of this method : — 
 
XXII.] METHOD OF TESTING DISINFECTANTS. 317 
 
 Two quantities of sewage were respectively treated with phenol 
 and cresol, so that the mixtures were equivalent to 19 per cent, 
 and allowed to act for twenty-four hours ; the mean of two strictly 
 concordant experiments gave the following as the number of 
 colonies which at the end of four days could be enumerated — 
 
 No. of colonies per gram 
 of the sewage taken. 
 
 Phenol . . . . 33,333 
 
 Cresol ... 33,410 
 
 The control . 1,490,000 
 
CHAPTER XXIII. 
 
 DISINFECTION BY HEAT. 
 
 (236) Experiments of Parsons and Klein. 
 
 Valuable experiments have been made in this country by Drs. 
 Parsons and Klein, as to the details of heat disinfection ; the 
 following is condensed from Dr. Parsons's report on the subject. 
 {Supplement, \4sth Annual Report, Local Government Board.') 
 
 The infective materials employed were : — 
 
 (1) Blood of guinea pig dead of anthrax, containing spore free 
 bacillus anthracis. (2) Pure cultivation of b. anthracis in rabbit 
 broth, without spores. (3) Spore holding b. anthracis in gelatin 
 cultivation. (4) Cultivation of bacillus of swine fever (infectious 
 pneumo-enteritis of the pig) in pork broth. (5) Tubercular pus, 
 from an abscess in a guinea pig which had been inoculated with 
 tubercle. 
 
 Strips of clean flannel were steeped in the respective infective 
 fluids, dried in the air, wrapped separately and loosely in a single 
 layer of thin blotting paper, and suspended in the centre of the 
 apparatus in company with a thermometer, so placed that its 
 bulb was close to the packets of infected material. The results 
 of the disinfection were tested by inoculation of animals. Con- 
 trol inoculations with unheated portions of the same materials 
 were also in all cases made. 
 
 (237) Experiments with Dry Heat. 
 
 They found that spores of anthrax lost their vitality after ex- 
 posure for four hours to a temperature a little over that of boiling 
 
CHAP. XXIII.] DISINFECTION BY HEAT. 319 
 
 water (212° — 216° F.) ; or for one hour at a temperature of 
 245° F. Non-spore-bearing anthrax, as well as the bacilli of swine 
 fever, were rendered inert by exposure for an hour to a tempera- 
 ture of 212° — 218°, and even five minutes' exposure to this 
 temperature sufficed to destroy the vitality of the former and 
 impair that of the latter. 
 
 (238) Experiments with Moist Heat. 
 
 (a) Boiling Water. — Dr. Klein found that spore holding 
 bacillus anthracis was killed by boiling for so short a space as 
 one minute. 
 
 (b) Steam at 212°. — The experiments were conclusive that it 
 destroyed all contagia ; in one instance only, was there room for 
 doubt, this was in the case of highly resisting anthrax spores 
 exposed to steam for five minutes only. 
 
 (239) On the Penetration of Seat into Articles Submitted for 
 Disinfection. 
 
 Experiments were made to ascertain how far the enclosing of 
 infective objects in blotting paper or test-tubes plugged with 
 cotton wool hindered the full access of heat to them. Two similar 
 registering thermometers were taken ; the bulb of one was tied up 
 in a single layer of thin white blotting paper, that of the other 
 was placed in a test-tube f inch wide, in such a manner as not 
 to touch the sides, and a plug of white cotton wool 1 inch deep 
 was pushed into the tube around the stem of the thermometer, 
 but not as far as the bulb. Both the paper and cotton wool were 
 previously dried. The two thermometers were then suspended in 
 a proper apparatus which need not be here described. It took 
 two and a half hours before the thermometers thus covered 
 attained the same heat as the naked thermometer. In a second 
 experiment in which a thermometer was covered with a single 
 layer of blanket; the blanket-covered thermometer marked 4° 
 lower than the control at the end of two and a half hours. 
 
 The following tables give results of similar experiments on 
 pillows, and show conclusively how difficult it is to secure the 
 penetration of a dry heat sufficient for disinfection into the in- 
 terior of such an article as a pillow. It can only be efiected by 
 
320 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 either employing a high degree of heat, or by continuing its 
 employment during many hours, the length of exposure compen- 
 sating for a lower degree of heat. 
 
 Table XXXIV. 
 
 1. — Dry Air. 
 
 
 
 Temperature 
 
 
 
 Temp. 
 
 
 Description of 
 
 Weight. 
 
 to which 
 
 
 Time. 
 
 in 
 
 
 Pillow. 
 
 lbs. 
 
 exposed 
 
 Apparatus 
 
 centre. 
 
 Scorched or not. 
 
 
 
 •F 
 
 
 hrs. 
 
 °F 
 
 
 Feather 
 
 5 
 
 312 
 
 Leoni 
 
 i 
 
 140 
 
 Scorched. 
 
 Flock 
 
 4 
 
 280 
 
 Langstaff 
 
 2 
 
 147 
 
 
 Feather( tight) 
 
 3 
 
 344 
 
 Scott 
 
 4 
 
 138 
 
 
 Flock 
 
 i 
 
 2 
 
 Fraser 
 
 1 
 
 134 
 
 
 Feather (loose) 
 
 3 
 
 1 (ahove 
 f 275) 
 
 !:: 
 
 1 
 
 275 
 
 
 Flock 
 
 6 
 
 2 
 
 138 
 
 
 99 
 
 4 
 
 ; 
 
 99 
 
 6 
 
 298 
 
 
 9) 
 
 a 
 
 318 
 
 
 1 
 
 136 
 
 
 
 3 
 
 250-260 
 
 Ransom 
 
 5A 
 
 227 
 
 Not Scorcheil. 
 
 Horsehair 
 
 ? 
 
 276 
 
 Scott 
 
 1 
 
 149 
 
 ,j 
 
 Feather 
 
 5 
 
 290 
 
 Taylor 
 
 1 
 
 122 
 
 9 9 
 
 2.— Moist Am. 
 
 Description 
 of Pillow. 
 
 Weight. 
 
 Temperature to 
 which exposed. 
 
 op 
 
 Apparatus. 
 
 Time. 
 
 Temp. 
 
 Readings of wet bulh 
 maximum thermometer 
 
 
 
 
 
 
 
 "F. 
 
 Flock 
 
 4 
 
 220-240 
 
 Bradford 
 
 2J 
 
 217 
 
 184 
 
 
 H 
 
 268 
 
 
 1 
 
 252 
 
 212 
 
 Feather 
 
 5i 
 
 295 
 
 Taylor 
 
 1 
 
 162 
 
 192 
 
 Flock 
 
 a 
 
 299 
 
 Fraser (portable) 
 
 1 
 
 188 
 
 189 
 
 " 
 
 H 
 
 264 
 
 
 1 
 
 209 
 
 192 
 
 3.— Steam. 
 
 Pillow. 
 
 Weight, 
 lbs. 
 
 Temperature 
 to which 
 exposed. 
 
 Apparatus. 
 
 Temp. 
 
 in 
 centre. 
 
 Time. 
 
 Pressure of steam 
 above that of 
 atmosphere. 
 
 Feather (tight) 
 
 6i 
 
 251 
 
 Lyon 
 
 185 
 
 i hour 
 
 151bs. constant 
 
 Same 
 
 
 251 
 
 99 
 
 212 
 
 i hour 
 
 ) 151bs. once re- 
 > laxed and then 
 
 Feather 
 
 H 
 
 251 
 
 
 237 
 
 i hour 
 
 ) reapplied. 
 
 Flock 
 
 H 
 
 240 
 
 Benham 
 
 171 
 
 2 min. 
 
 lOlbs. 
 
 
 H 
 
 240 
 
 
 234 
 
 10 min. 
 
 lOlbs. 
 
 Feather 
 
 H 
 
 240 
 
 
 234 
 
 10 min. 
 
 lOlbs. 
 
 
 2J 
 
 212 
 
 Bradford 
 
 182 
 
 10 min. 
 
 — 
 
 99 
 
 2f 
 
 252 
 
 99 
 
 251 
 
 4 hour 
 
 221bs. 
 
 J 
 
xxni.] DISINFECTION BY HEAT. 321 
 
 (240) Explanation of the Superior Penetrating Power of Steam. 
 
 The superior penetrating power of high heat in the form of steam 
 over hot air having been thus demonstrated, Dr. Parsons points 
 out the cause of this as follows : — 
 
 (1) Probably the most important is the large amount of latent 
 heat in steam. To convert 1 lb. of water at 212° F. into steam at 
 212° F., requires nearly 1,000 times as much heat as it does to 
 raise 1 lb. of water from 211° to 212° F. Conversely a correspond- 
 ing amount of heat is liberated when 1 lb. of steam at 212° F. is 
 condensed into water at 212° F. When an object is heated by 
 being placed in hot dry air, not only is no latent heat yielded up 
 to it by the air, but on the other hand before the object can attain 
 the temperature of 212° any water which it may contain (and 
 all textile fabrics, even though dried at ordinary temperatures, 
 retain a quantity of hygroscopic moisture) must be evaporated ; 
 in this evaporation heat passes into the latent form, and the 
 attainment of the required temperature is thus delayed. 
 
 (2) When steam penetrates into the interstices of a cold body, 
 it undergoes condensation in imparting its latent heat as aforesaid 
 to tlie body. When condensed into water it occupies only a very 
 small fraction (about -jS^) of its former volume. To fill the 
 vacuum thus formed more steam presses forward, in its turn 
 yielding up its heat and becoming condensed, and so on until 
 the whole mass has been penetrated. On the other hand hot air 
 in yielding up its heat undergoes contraction in volume it is 
 true, but only to a very small extent as compared with that 
 undergone by steam in condensing into water. Thus air at 250° 
 in cooling to 50° F. would contract to -f of its previous volume. 
 
 (3) The heat which is evolved in the moistening of a dry 
 porous substance is another source of advantage on the side of 
 steam. Pouillet (Annates de Ghimie, II., xx., p. 141) has shown 
 it to be a general law : — (1) That when a liquid wets a solid, 
 there is a disengagement of heat. (2) That when a solid absorbs 
 a liquid there is a disengagement of heat. The amount of heat 
 liberated in the incorporation of a liquid into the substance of 
 a solid is much greater than that liberated by mere superficial 
 wetting ; this is owing to the multiplication of points of contact. 
 In proportion as a wetted substance is finely divided, the number 
 
 Y 
 
322 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 of particles which are moistened and take part in the evolution 
 of heat is multiplied, while the number is diminished of those 
 which not being wetted, do not give out heat but absorb it at 
 the expense of others. Hence, porous organic substances, as being 
 most finely divided, are those which in moistening evolve most 
 heat. (Chemical reactions like the slaking of lime are of course 
 excluded.) If a clinical thermometer be wrapped up in a few 
 turns of flannel which, has recently been highly dried before the 
 fire and cooled, and the roll be held in the mouth and the expired 
 breath forced through it, a temperature considerably over that of the 
 breath will be found to be registered by the thermometer. la such an 
 experiment Dr. Parsons found the thermometer to reach 110°-6F., 
 the temperature of the breath as taken by the same thermometer 
 being 99°-2. If the flannel in which the bulb of the thermometer 
 is wrapped have been dried merely in the air at ordinary tempera- 
 ture and humidity, an elevation of temperature above that of the 
 breath will still be obtained, but of less extent than in the previous 
 case ; while if the flannel is damp no elevation at all will be obtained. 
 
 The following experiment shows that the same action takes 
 place at higher temperatures. 
 
 A thermometer was wrapped in a few rolls of flannel, and was 
 beated in dry air to 220° F. for some time ; it was then allowed to 
 cool a little, and as the mercury fell, the index was shaken down 
 till it stood at 212° F. The dry roll of flannel was then placed in 
 a tin cylinder and exposed for five minutes' steam at 212° F. ; at 
 the end of which time the thermometer included was found to 
 register 239° F. 
 
 (4) The specific heat of steam is greater than that of air in the 
 proportion of 30 to 23'7 or about 5 to 4 ; in other words 4 volumes 
 of steam in falling 1° without condensing into water yield up as 
 much heat to other objects as 5 volumes of air at the same tem- 
 perature yield. 
 
 (5) The diffusion of two gases into one another takes place with 
 a velocity inversely as the square roots of their respective densities. 
 The specific gravity of steam, air being taken as 1 is '623 ; 
 hence the rate at which steam would diffuse into air as compared 
 with that at which air would difiuse into steam at the same tem- 
 perature would be as 100 is to 79, or about 5 to 4. Between air 
 and air the rate of diffusion would be equal, or as 4 to 4 ; thus 
 
XXIII.] DISINFECTION BY HEAT. - 323 
 
 excluding the influence of differences of temperature, steam would 
 diffuse into air witli a rapidity one-fourth greater than air would. 
 
 (6) The penetration of heat in the form of steam, is. Dr. Parsons 
 maintains (contrary to Koch), aided by pressure. This seems to 
 be proved by the following experiment made with a model of 
 Lyons's apparatus. 
 
 A registering thermometer loosely wrapped in a sheet of cotton 
 wool was exposed for half an hour to steam at 28 lbs. pres- 
 sure = 273° F, ; the index marked 270°, It stood equally high 
 after exposures of a quarter of an hour and of five minutes, but 
 after an exposure of three minutes only 260° was recorded. In 
 another experiment a thermometer similarly wrapped, and another 
 one naked were placed in the machine, and the door loosely closed ; 
 steam at 30 lbs. pressure was admitted into the casing, but into 
 the interior of the chamber only sufficient to moisten the air of the 
 chamber. After half an hour the naked thermometer registered 
 250°, the one in the cotton wool only 217°. 
 
 By relaxing the pressure of steam, and then reapplying the 
 pressure from time to time, the penetrative power of the steam is 
 greatly increased. 
 
 A pressure of steam 15 lbs. to the square inch above that of the 
 atmosphere compresses the air in the interstices of the material to 
 half its original volume, and thus the space originally occupied 
 with cold air becomes partly occupied with hot steam ; steam 
 partly mixed with air occupying the interstices near the surface 
 and air those in the centre. Equilibrium of pressure having been 
 obtained, the interchange of air and steam particles and of tem- 
 perature would take place comparatively slowly. On relaxing the 
 pressure, however, the air again expands to its original volume, 
 and thus becomes mixed with the steam, and on the pressure 
 being reapplied the steam is forced further into the interstices. 
 
 Experiments are also given showing that hot moist air has an 
 advantage over hot dry air. 
 
 (241) On the Liability to Injury of Articles Disinfected hy Heat. 
 
 The modes in which injury may occur are somewhat different 
 in the case of steam and that of dry heat. Dr. Parsons classifies 
 the possible injuries under the following headings : — 
 
 (1) Scorching or partial decomposition of organic substances by 
 
 Y 2 
 
324 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 heat. In its incipient stage this manifests itself by change of 
 colour, of texture, and weakening of strength. 
 
 (2) Overdrying, rendering things brittle. 
 
 (3) Fixing of stains so that they will not wash out. 
 
 (4) Melting of fusible substances, as wax and varnish. 
 
 (5) Alterations in colour, gloss, &c., of dyed and finished goods. 
 
 (6) Shrinkage and felting together of woollen goods. 
 
 (7) Wetting. 
 
 Overdrying can only occur of course when dry ; wetting when 
 moist heat is employed ; scorching is more an effect of dry heat 
 than of moist heat or steam. 
 
 (242) Scorching. 
 
 (1) Scorching occurs with different materials at different tem- 
 peratures. It occurs sooner in woollen materials, such as flannels 
 and blankets, than with cotton or linen ; horsehair bears a high 
 temperature, in fact the process of curling it for stuffing chairs is 
 effected by exposing it to a temperature of over 300° F. 
 
 Most materials will bear a temperature of 250° F. without much 
 injury, but when this temperature is exceeded signs of damage 
 soon begin to show. Flannel and blankets exposed to steam at 
 260° for half an hour acquire a distinct yellow tinge, and their 
 tensile strength is somewhat diminished. Exposed to a dry heat 
 of 220° F. for four hours, or a steam heat of 228° for half an hour, 
 white flannel acquired a slight yellow tinge, but its textile strength 
 was not appreciably impaired. 
 
 Ransom -^ found that wool, cotton, linen, silk, and paper could be 
 heated to 250° F. without injury if the action be only continued 
 for three hours ; 295° F. he found, if continued for three hours, to 
 decidedly singe white wool, and less so grey and white cotton, and 
 white silk and white paper and linen, but does not injure their 
 appearance greatly. If the heat is continued for five hours at 295° 
 then the articles mentioned are both singed and their appearance 
 injured. 
 
 The experiments of de Chaumont,^ of Vallin,^ and of Koch and 
 Wolffhugel,* give lower temperatures than those quoted as causing 
 
 1 British Med. Journ., Sept. 6, 1873. 
 
 ^ Lancet, Dec. 11, 1875. ' M. Vallin, Traiti des Disinfectants. 
 
 ■* Mittheilungen aiis dem Kaiserlichen Gesundheitsamtc. Berlin, 1881. 
 
XXIII.J 
 
 DISINFECTION BY HEAT. 
 
 325 
 
 change. Pai'sons's experiments are more definite, because the 
 tensile strength was tested. The results are contained in the 
 following table : — 
 
 Table XXXT. 
 
 Dk. Parsons's Experiments on Effects of Heat on various Fabrics.- 
 
 Material. 
 
 Exposed to. 
 
 Time. 
 
 Shrink- 
 age per 
 cent. 
 
 Tensile 
 
 Strength 
 
 before and 
 
 after. 
 
 Colour. 
 
 White flannel (length) 
 „ (breadth) 
 
 Steam 264t> T. 
 
 ^hour 
 
 6-0 
 
 100 : 88 
 
 Distinct yellow tinge 
 
 
 J, 
 
 6-7 
 
 100 : 88 
 
 jj 
 
 „ (length) 
 (breadth) 
 
 „ 2280 
 
 ,j 
 
 6-4 
 
 100: 97 
 
 Yellowish tinge 
 
 )' •> 
 
 ,j 
 
 4-1 
 
 100 : 96 
 
 ,, 
 
 (length) 
 
 ., 212= 
 
 ,, 
 
 6-8 
 
 100 : 92 
 
 Slight yellowish tinge 
 
 „ (breadth) 
 
 
 ,, 
 
 6-0 
 
 100 : 100 
 
 jj 
 
 Oength) 
 
 Dry 'heat 220o 
 
 4 hours 
 
 16 
 
 100 : 107 
 
 Yellowish tinge 
 
 „ (breadth) 
 
 tt >t 
 
 ,, 
 
 ■8 
 
 100 : 98 
 
 jj 
 
 „ aength) 
 
 » 280O 
 
 2 hours 
 
 20 
 
 100 : 100 
 
 Yellow tinge, dark in 
 places 
 
 „ (breadth) 
 
 J, 
 
 „ 
 
 •4 
 
 100 : 95 
 
 „ 
 
 „ (length) 
 „ (breadth) 
 
 Simple washing 
 
 — . 
 
 6-6 
 
 100:132 
 
 Very slight change 
 
 J, 
 
 , — . 
 
 Y-4 
 
 100 : 102 
 
 , 
 
 „ (length) 
 (breadth) 
 
 Boiling water 
 
 J hour 
 
 8-4 
 
 ino : 86 
 
 Dirty yellowish change 
 
 J, 
 
 „ 
 
 6-9 
 
 100 : 96 
 
 „ 
 
 Tape (cotton) 
 
 Steam 260° 
 
 4 hours 
 
 ? 
 
 100 : 82 
 
 Little alteration 
 
 ,, 
 
 „ 261° 
 
 ^hour 
 
 1-4 
 
 100 : 80 
 
 
 ,, 
 
 „ 2120 
 
 Ihour 
 
 2-0 
 
 100 : 77 
 
 ,, 
 
 " 
 
 Dry heat 230o 
 
 4 hours 
 
 0-35 
 
 100: 78 
 
 No discolouration, lost 
 Blaze 
 Slightly darkened 
 
 „ 
 
 280O 
 
 2 hours 
 
 0-7 
 
 100: 73 
 
 ,, 
 
 Boilmg water 
 
 ihour 
 
 2-7 
 
 100 : 73 
 
 Lost glaze 
 
 Black cloth 
 
 Steam 251o 
 
 ihour 
 
 0-9 
 
 100 : 100 
 
 No alteration 
 
 tt 
 
 „ 2I20 
 
 ihour 
 
 
 
 100 : 90 
 
 Slightly discoloured 
 
 )) 
 
 Dry heat 230° 
 
 4 hours 
 
 
 
 100 : 100 
 
 Slightly rusty as if 
 from long wear 
 
 " 
 
 280O 
 
 2 hours 
 
 0-8 
 
 100 : 100 
 
 Slightly rusty, more 
 marked 
 
 X 
 
 Boiling water 
 
 ihour 
 
 
 
 100 : 100 
 
 Discoloured ; dye hav- 
 
 White silk ribbon 
 
 Steam 251° 
 
 ihour 
 
 21 
 
 100 ; 100 
 
 ing run 
 No alteration 
 
 ,, 
 
 „ 212° 
 
 ihour 
 
 2-0 
 
 100 : 100 
 
 
 It 
 
 Dry heat 230o 
 
 4 hours 
 
 •r 
 
 100: 87 
 
 No change in colour ; 
 less glossy 
 
 
 „ 280O 
 
 2 hours 
 
 •35 
 
 100 : 60 
 
 Brownish tinge ; scor- 
 ched 
 
 jt 
 
 Boiling water 
 
 i hour 
 
 1-00 
 
 100 : 100 
 
 Lost glaze 
 
 Kid glove 
 
 Sleam 260° 
 
 ihour 
 
 
 
 Shrivelled up and con- 
 verted into a gelatin- 
 ous substance, very 
 hard when dry 
 
 )! 
 
 „ 2120 
 
 5 minutes 
 
 
 
 Ditto 
 
 ,. 
 
 Dry heat 212° 
 
 1 hour 
 
 
 
 Unaltered 
 
 A felt hat 
 
 Steam 228o 
 
 5 minutes 
 
 
 
 Greatly distorted by 
 softening of felt and 
 disorganisation and 
 shrivelling of leather 
 lining 
 
 Unaltered 
 
 „ 
 
 Dry heat !ibove260o 
 
 1 hour 
 
 
 
 Feathers 
 Blankets 
 
 Steam 260o 
 „ 2610 
 
 4 hours 
 ihour 
 
 
 
 Yellowish and brittle 
 Yellowish tinge 
 Ditto somewhat hard 
 
 " 
 
 Dry heat 240'— 268" 
 
 2i hours 
 
 
 
 
 
 
 
 
 and threadbare ; 
 
 Dyed silk ribbon i 
 vaiions colours / 
 
 230° 
 Steam 251o 
 
 4 hours 
 ihour 
 
 
 
 puckered 
 Unaltered 
 Ditto 
 
 
 
 
 
 
 _ 
 
326 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Scorching is especially liable to take place when the heat is in 
 the form of radiant heat. In one of the experiments with different 
 forms of apparatus, it was found that the ticking of a pillow was 
 uninjured, although exposed to heat of 276° F. as tested by a 
 thermometer laid beside it. In this case the pillow had been 
 sereened from the direct access of heat rays from the source of 
 heat, whereas in other instances, in which the pillows were laid 
 on wooden bars directly over the heated bottom of the chamber, 
 it showed distinct stripes of scorching corresponding to the inter- 
 spaces between the bars, although a thermometer laid beside it 
 did not record a temperature any higher than, or even so high 
 as, in the former case. 
 
 Scorching is brought about by radiant heat in two ways — First, 
 textile articles, specially wool, are good radiators, as we may 
 see by the copious deposit of dew or hoar frost which takes place 
 upon them when exposed in the open air on a clear night, and 
 therefore with converse facility they absorb the rays of heat, and 
 are thus heated to a higher degree than the surrounding air. 
 Secondly, in the chamber heated primarily by radiation the walls 
 of the chamber and solid objects in its interior, such as shelves, 
 bars, and hooks, become by absorption of heat-rays hotter than the 
 air, and consequently organic substances, such as articles of dress, 
 are liable to be burnt where they may chance to come in contact 
 with the hot metal. On the other hand, if the chamber be heated 
 by hot air warmed before its entrance, as in the Ransome stove, 
 the walls of the chamber are no hotter than the air, and objects 
 may come in contact with them without injury. 
 
 (243) Over-drying. 
 
 (2) Over-drying, short of actual scorching, renders many organic 
 substances brittle ; it is by this means that in pharmacy tough 
 vegetable drugs, as roots, barks, and others, are^ prepared for 
 grinding into powder. On the other hand, on exposure to moist 
 air this brittleness is again lost ; we know how the crispness of 
 the new-baked biscuit is soon lost unless kept in a well-closed 
 canister. 
 
 It was found by Dr. Henry, in his experiments, that the tensile 
 strength of textile materials was weakened by exposure to dry 
 
XXIII.] DISINFECTION BY HEAT. 327 
 
 heat, but was in a great measure regained if the materials were 
 allowed to remain in the air a day or two before testing. 
 
 M. Vallini took hair and wool, which had been previously well 
 beaten, and exposed them for four hours to a temperature of 
 248° F. Portions beaten again immediately after being taken out 
 of the stove yielded a layer of detritus, while other portions, beaten 
 only after a lapse of twenty-four or forty-eight hours, when they 
 had time to regain their hygroscopic moisture, did not yield more 
 waste than unheated portions of the original material. 
 
 It is evident that injury from over-drying can easily be avoided 
 by allowing the materials which have been subjected to dry heat 
 to remain in the air long enough to recover their natural degree 
 of moisture before manipulating them. 
 
 (244) The Fixing of Stains. 
 
 (3) An exposure to heat of 212°, whether in the form of dry 
 heat, of boiling water, or of steam, has the effect of fixing many 
 organic colouring matters in animal and vegetable fibre, so that 
 they cannot be removed by subsequent washing ; in fact high 
 pressure steam is used by dyers and calico printers in an appa- 
 ratus called a " keir," for the very purpose of fixing their colours. 
 This fixing of stains is specially marked in the case of albuminous 
 materials coagulable by heat, such as blood. It is well known that 
 in order to remove blood stains the cloth or garment must be 
 steeped in cold water. 
 
 The following experiments were made on this point : — -Pieces of 
 linen sheeting, marked distinctively, were steeped at one end in 
 fresh sheep's blood, in dirty animal grease, and in claret, strips of 
 calico were also steeped in ox-gall and in urine, and after exposure 
 to heat the strips were washed in Messrs. Lyons's establishment in 
 the ordinary manner with boiling water and soap and soda. The 
 results are in the table on the following page. 
 
 This property of heat is an inconvenient one from our present 
 point of view, and seriously limits the field for practical usefulness 
 of disinfection by heat. It is very desirable that linen articles, 
 sheeting, body linen, and such matters, which have been in con- 
 
 1 Op. cit. 
 
328 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 tact with infection, should be disinfected before coming into the 
 laundry, since otherwise they may infect the washerwomen and 
 possibly the linen of other households. Such objects however, if 
 soiled with blood and faecal matter, cannot be disinfected by heat, 
 not even by boiling water, without indelibly fixing the stains. 
 The only alternatives therefore are to put up with damage to this 
 extent, to allow the articles to pass through the earlier processes 
 in an undisinfected state, or to attempt their disinfection by 
 chemical means. When the grosser diit has been removed, by 
 soaking and rubbing in cold or tepid water, the articles may 
 be boiled without injury, and are then doubtless effectually 
 disinfected. 
 
 Table XXXYI. 
 
 Treatment before 
 washing. 
 
 Results after treatment and subsequent washing with soap and water. 
 
 Blood. 
 
 Dirty grease. 
 
 Starch. 
 
 Ox-gall. 
 
 Urine. 
 
 None 
 
 Soaked in cold 1 
 
 water J 
 Boiled in water \ 
 
 J hour j" 
 Steam 212° "1 
 
 J hour f 
 Steam 260° \ 
 
 J hour J 
 Dry heat 240° \ 
 
 i hours / 
 
 No stain. 
 
 Black stif- 
 fened stain 
 Do. rather 
 darker 
 Dark brown 
 stiff stain. 
 
 No stain 
 
 No stain 
 
 Hardly any 
 
 stain 
 Very slight 
 
 stain 
 Hardly any 
 
 stain 
 
 Brownish stain 
 
 Hardly any stain 
 
 Brownish stain 
 
 Reddish stain 
 
 darker 
 Brownish stain 
 darker than first 
 
 No stain 
 
 No stain 
 
 Yellow 
 stain 
 
 Yellow 
 stain 
 
 No stain 
 
 No stain. 
 
 No stain. 
 
 No stain. 
 
 Faint brown- 
 ish stain. 
 Brown stain 
 likescorching. 
 
 (245) Melting of Fusible Substances, such as Wax and Varnish. 
 
 (4) Injury may in some instances be caused by the melting of 
 wax and such like fusible materials in ornaments or contained in 
 the pockets of garments. Articles occasionally catch fire when the 
 heat of the apparatus does not exceed the normal degree, doubtless 
 owing to lucifer matches being left in the pockets. 
 
 It is sometimes necessary to disinfect articles of furniture with 
 stuffed seats, such as chairs and sofas. If the heat be too intense 
 the varnished wood-work will blister, and in steam the softening 
 of the glue will loosen the veneer. 
 
XXIII.] DISINFECTION BY HEAT. 329 
 
 (246) AlteratioTis in Colour, and Shrinking. 
 
 (5) Dry heat short of actual scorching does not often affect the 
 colours of dyed goods. If not properly fixed or, in technical 
 language, " fast," steam or boiling water -will cause them to run. 
 
 (6) Dry heat causes little shrinkage in woven materials. Moist 
 heat, on the other hand, or even wetting without much heat, 
 causes permanent shrinkage, more especially in the case of woollen 
 goods, as cloth, flannel, and blankets. The cloth of which men's 
 clothes are made is, " or should be," shrunk before they are made 
 up ; this shrinking is effected by exposing the cloth to steam. It 
 will be seen however from the preceding Table that the amount 
 of shrinkage of flannel was quite as great after simple washing as 
 after exposure to steam. A piece of washed flannel 50 inches 
 long (measured after washing) only shrunk \ inch further, or 
 \ per cent., on exposure for half an hour to steam at 228°. 
 
 A more serious drawback is the felting together and loss of 
 elasticity and fluffiness, upon which the warmth and softness of 
 woollen materials depends. This elasticity depends upon the 
 presence of the natural grease of the wool. M. Leblanc (quoted by 
 Vallin) states that this grease (sidnt), which is a product of the 
 perspiration of the sheep, is a mixture of mineral salts and organic 
 compounds ; in unwashed wool it amounts to nearly 50 per cent, of 
 the total weight of the wool, and even in washed wool never falls 
 below 15 per cent. This grease is of a nature highly putrescible 
 under the combined influence of moisture and heat; so that the 
 quantity of it contained in a mattress, together with the contaminat- 
 ing infiltrations from human bodies and the excrements from moth 
 larvae (amounting in bedding often to 1 per cent, of the whole) 
 form collectively a very large mass of decomposing matter, which 
 must add considerably to the contamination of the air of inhabited 
 dwellings. On the other hand, if the wool is too well cleaned, so 
 as to entirely remove the natural grease, it loses its strength, 
 suppleness, and elasticity, the qualities for which it is specially 
 valued. The suint is soluble in boiling water : water in which 
 wool has been boiled for an hour is charged with an extremely 
 fetid matter, rich in sulphur products ; after this treatment the 
 wool resembles cotton, it easily felts, and has permanently lost its 
 elasticity. 
 
330 A MANUAL OF PUBLIC HEALTH. [chaf.- 
 
 These observations explain how it is that blankets will not bear 
 boiling in water ; by the removal of the grease and felting together 
 of the wool they lose their softness and warmth, and become hard 
 and threadbare. They may be washed in cold water or exposed to 
 dry heat of moderate temperature without much deterioration, but a 
 frequent repetition of these processes brings about in time a change 
 similar to that effected by boiling water. Moreover, if wool be 
 piled together when hot, the hairs, through the softening of the 
 coatings of grease surrounding them, become glued together so that 
 when cold the wool is felted into masses. 
 
 (247) Wetting. 
 
 (7) Wetting is undesirable in the case of some kinds of goods for 
 it produces shrinkage and causes the colours to run and involves 
 the labour of subsequent drying. We need only consider wetting 
 in connection with steam. When a cool body, such as a pillow, is 
 placed in an atmosphere of steam, some of the steam will be con- 
 densed upon it, and if the relative volume of the steam be sufficient, 
 the temperature of the cool body will be raised to 212° F., and this 
 temperature baving been attained no further condensation of steam 
 into water will take place. Owing, however, to the high specific 
 and latent heat of steam, the weight of steam thus condensed will 
 be much less than the weight of the body heated to 212° F., by its 
 condensation. 
 
 In the experiments with Benham's apparatus, in which the 
 steam is not superheated, the increase of weight in a pillow exposed 
 to the action of the steam was found in two experiments to be 
 13 and 14 per cent, respectively, of the previous weight of the 
 pillows. On the other band when one of the pillows was placed 
 under a tap and saturated with cold water, it was found to have 
 increased in weight 140 per cent. The amount of water derived 
 from the condensed steam was therefore only one-tenth of the 
 quantity which the pillow would hold when saturated. A roll of 
 flannel in the same machine increased in weight 22 per cent., a 
 coat 36 per cent. The amount of moisture absorbed depends not 
 only on the nature of the materials, but upon their previous state 
 of dryness or dampness ; if wet, extra heat would be required to 
 
XXIII.] DISINFECTING APPARATUS. 331 
 
 raise them to the temperature of the steam, and more steam would 
 thereby be condensed. 
 
 In Lyon's apparatus, in which the steam is used at a higher 
 temperature, being superheated by the higher degree of heat cor- 
 responding to the extra pressure on the outer case, the amount of 
 wetting is less ; in experiments with bales of rags the increase of 
 weight varied from 3-5 to 5 per cent., the greater part of which 
 was again lost on a few hours' exposure to air. 
 
 (248) The different Forms of Apparatus for Disinfection ly 
 
 Heat. 
 
 In Dr. Parson's paper, already so largely quoted from, he considers 
 that the most important requisites of a disinfecting chamber are 
 the following : (a) uniform distribution of heat in the interior ; 
 (V) a constant temperature maintained during disinfection ; (c) 
 facilities for ascertaining the actual temperature of the interior at 
 any given moment. 
 
 In apparatus heated by steam, the threes requirements are satis- 
 factorily met, and in some of the best dry heat chambers the results 
 are also fair, but in most of them condition (a) is not fulfilled. 
 
 As a type of a steam apparatus Lyon's will be described ; as types 
 of hot air apparatus, Bradford's, which is heated by coal, and the 
 Nottingham self-regulating apparatus, heated by gas. 
 
 (249) Washington Lyon's Patent Steam Disinfeetor. 
 
 The machine consists of a large strong iron chamber with double 
 walls of boiler plate, and a tightly-fitting door at either end, the 
 door shuts against an india-rubber collar, and is secured by 
 vice handles so as to form a steam-tight joint ; it is hung on hinges 
 and its weight when swung open is borne by a castor running on a 
 curved rail. By means of a steam pipe, steam from a boiler can be ad- 
 mitted into either the hollow casing or the interior of the chamber ; 
 a,nother pipe serves to let off the steam when no longer required, 
 and there is also a means of escape for condensed water which may 
 accumulate in the casing. The casing and chamber are each pro- 
 vided with a safety valve and pressure guage, by which the pressure 
 of steam, and hence the temperature, can at any moment be seen, 
 
332 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 the degrees of temperature being marked on a dial and indicated 
 by a needle. 
 
 In using the apparatus steam is first turned on so as to heat 
 the casing or jacket, and in this way the walls are warmed up. 
 
 The articles to be disinfected are then put into the chamber and 
 the doors closed. It is well to allow the steam to circulate in 
 the outer casing some time, so that the articles will become quite 
 hot, for in this way when steam is admitted into the chamber 
 itself, there will be little condensation or wetting. The steam 
 is admitted ultimately into the interior of the chamber, until the 
 gauge marks the desired temperature. On the conclusion of 
 the disinfection, the steam is shut off from the interior, but 
 allowed to circulate in the casing. On opening the doors, in a 
 very little time the articles will be quite dry. 
 
 (250) Bradford's Patent Disinfecting Apparatus. 
 
 It essentially consists of two parts, the one a container, the other 
 the heating apparatus. The container is a large rectangular iron 
 box, covered with a non-conducting composition, open below and sus- 
 pended by chains and counterpoises from pillars something like a 
 gas-holder. The roof has a ventilating aperture, a thermometer 
 is at the side, the bulb projecting into the interior, the stem being 
 placed outside. 
 
 The heating apparatus consists of three longitudinal compart- 
 ments side by side, the central one containing the fire waggon. The 
 fuel is preferably peat, but coal, coke, or charcoal may be used ; the 
 fire is in a waggon which may be drawn in or out. The fire- 
 chamber containing this waggon has a roof of hollow iron bars, in 
 section triangular, open at the ends. The fire chamber has a flue 
 at one end, a door at the other. The two side chambers are for 
 purposes of ventilation and communicate with the fire chamber by 
 means of side valves. 
 
 The articles to be disinfected are placed on a galvanized iron 
 rack which stands over the fire chamber. 
 
 The container resting on a layer of sand, a large shallow vessel 
 containing water is placed at the bottom over the fire chamber so 
 as to keep the air of the chamber moist. 
 
 The whole apparatus may run on wheels so that it can be moved 
 from place to place. 
 
XXIII.] DISINFECTING APPAKATLTS. 333 
 
 (251) The Nottingham Self-Bsgulating Disinfecting Apparatus. 
 
 This is the invention of Dr. Ransome, F.R.S. It consists of a 
 cubical iron chamber cased in wood, with an intervening layer of 
 felt, access to the interior being obtained by double doors. The 
 furnace, placed at the side of the chamber and on a lower level, 
 consists of a ring of atmospheric gas burners, enclosed in an iron 
 tube. The heated air, containing the products of combustion, passes 
 along a horizontal flue and enters the chamber at the bottom, 
 which is perforated by a number of holes for its equable distri- 
 bution. In the horizontal flue are fixed the bulbs of a thermometer 
 and of a self-acting mercurial regulator. Through the latter the 
 gas supply to the burners can be made to pass, and it is so con- 
 structed that as the temperature of the apparatus rises the mercury 
 expanding encroaches upon a slit, through which the gas passes, 
 and thus gradually cuts off the supply. At the top of the chamber 
 there is an outlet flue, controlled by a valve and furnished with a 
 thermometer. In connection with the outlet is an arrangement 
 designed for the extinction of fire ; when the temperature at the 
 outlet exceeds 300° F. a link of fusible metal melts, closing a 
 damper and shutting the supply of gas. The chamber is fitted 
 with bars and hooks for suspending articles of clothing. When the 
 stove is first lighted the gas is admitted to the burners direct 
 through a short circuit pipe, without passing through the regu- 
 lator, but when the mercury in the latter has risen high enough to 
 reach the sHt, this pipe is closed by a trap so as to compel the gas 
 to pass through the regulator. The regulator is furnished with an 
 adjusting screw, so that it can be set to work at a higher or 
 lower temperature as required. 
 
CHAPTER XXIV. 
 
 CHEMCCAL DISINFECTANTS. 
 
 (252) List of Practical Disinfectants. 
 
 Resteicting as before the term disinfectant to a substance which 
 is capable by its own inherent poisonous action upon a pathogenic 
 micro-oiganism to destroy its life and therefore prevent its develop- 
 ment, the list oi practical disinfectants is a small one ; all disinfec- 
 tants that are expensive must be thrown out, all those which do not 
 admit of being applied by reason of their insolubility in water, or 
 from other causes must also be excluded, hence in this work the 
 following disinfectants will alone be treated of at any length : — Cor- 
 rosive sublimate, the halogens, iodine trichloride, the tar acids, 
 sulphur dioxide. To this list might be added aniline on account of 
 its remarkable disinfecting action upon the tubercle bacillus, but 
 there is no hkeUhood of it becoming a disinfectant in general use. 
 The salts of zinc, of manganese, of lead, of iron, the mineral acids, 
 and a number of mixtures vaunted by their proprietors, may be 
 shown genei-ally to be of doubtful value, save in large doses, and 
 under conditions which are only occasionally met with in practice. 
 
 (253) Memtrie Ghl&rid(. Comsire Sublimate. Bichloride of 
 Mavury, HgCl^ 
 
 This well-known highly pois^iiious salt is in the form of a heavy 
 crystalline powder or ciystalune Eiasses, A saturated aqueous 
 solution contains aKiut 10 per cent, but two parts of boUing 
 water dissolve one part of corrosive subimate. It is also readily 
 soluble in alcohol or ether. 
 
CHAP. XXIV.] CHEMICAL DISINFECTANTS. 335 
 
 Klein^ has studied systematically both the disiafectant and anti- 
 septic action of perchloride of mercury when applied in the form 
 of a solution in distilled water. Various bacteria were added 
 to such solutions of different strengths and kept therein for a 
 variable length of time ; afterwards the vitality of the organism 
 was tested in the usual fashion. The modus operandi was as fol- 
 lows : Into a freshly drawn out glass pipette a droplet was drawn 
 up of the bacterial fluid, and into the same pipette the mercurial 
 solution was drawn up in such a way that the original bacterial 
 droplet was diluted by the mercurial solution 100 times. After 
 leaving the bactetium and the disinfectant thus in apposition for a 
 given time, samples of the mixture were used for inoculation of 
 culture tubes containing sohd nutritive gelatin or fluid media 
 (generally sterile faintly alkaline broth peptone 1 per cent.) or 1 
 per cent, meat extract peptone. These tubes were then placed in 
 the incubator, and the growth occurring in them if any, its 
 character, and its differences from those of the normal organism 
 noted. 
 
 The lacillus subtilis, in the spore state, was not killed in a less 
 dilution than 1 per cent ; the sporeless bacillus subtilis was killed 
 in solutions of a strength of from 1 : 1 0,000 ; and from 1 : 1.5,000. 
 As regards the restraining or antiseptic power of corrosive 
 sublimate on the growth of the bacillus subtilis, it was found that 
 one part of sublimate added to 10,000 of gelatin prevented growth. 
 Very similar, almost identical results were obtained with Finkler's 
 comma bacillus and the comma bacillus of Koch. 
 
 Micrococcus prodigiosis was somewhat easier killed than the 
 foregoing, the restraining power of medicated gelatin was the 
 same. 
 
 Anthrax. — Spores are only killed in solutions of sublimate 1 
 per cent, and above. Klein thus sums up the results of his 
 numerous experiments on the antisepsis of anthrax spores: — 
 Sublimate in nutritive gelatin in the proportion of 1 in 10,000 
 does not always prevent anthrax spores from germinating and 
 -producing there a crop of bacilli ; but in those cases in which 
 such amount of sublimate failed to inhibit their germination and 
 growth, the salt had nevertheless a certain restraining influence 
 
 1 SupplemeiU, Fifteenth Annual Report of the Medical Officer to the Local Government 
 Board, 1885, p. 155, 
 
336 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 since the growth was retarded, was very small in amount, and its 
 infective power was diminished, and moreover this diminution of 
 infectivity increased with time until its total extinction was 
 achieved. But gelatin sublimate 1 in 60,000, and in lesser pro- 
 portion, has no restraining power. Sporeless bacilli are killed 
 when treated with solutions of sublimate 1 : 2,000. One part of 
 sublimate added to 2,000, 3,000, or 4,000 of gelatin inhibit growth 
 as a rule ; in solutions of sublimate of 1 : 5,000, the bacillus 
 grows, but in some cases its infective properties are remarkably 
 modified. 
 
 The Bacillus Septicceviia of Cfuinea Pigs. — Sublimate solutions of 
 1 : 10,000 kill both spores and threads when acting for thirty 
 minutes. One part of sublimate in 10,000 of gelatin inhibit 
 growth. 
 
 Tuhercidar virus experiments made by Lingard show that a 
 solution of sublimate, strength 1 : 960, destroys in from four to eight 
 hours human tubercular virus ; the exposure requires to be longer 
 in the case of bovine tubercular virus. 
 
 The Halogens. 
 
 (254) Chlorine, at. weight 35'4, a yellowish green Gas, 2 '4 
 times heavier than Air. 
 
 It may be prepared for the purposes of disinfection by 
 heating together a mixture of common salt, manganese bin- 
 oxide, and sulphuric acid, the following reaction occurring: 
 2 NaCl + MnO^ + 2H2 SO, = Cl2-hNa2 SO^ + MnSO^ + 2H2O, 
 or simply by the action of hydrochloric acid on manganese 
 binoxide, MnOg 4- 4 HCl = MnCl2 + CI2 + 2H2O, but both these 
 processes are somewhat inconvenient, and it is in practice almost 
 invariably evolved from bleaching powder by the addition of 
 an acid. 
 
 Bleaching powder may be considered to have the formula 
 CaCljOj + (CaClg CaO) 2 HjO, that is, to be a mixture of hypo- 
 chlorite and oxychloride of calcium, although its composition is 
 much disputed. Theoretically it should contain 41 per cent, of 
 chlorine, but in practice it is seldom that more than 35 per cent, 
 can be obtained. 1 lb. of good bleaching powder on being 
 
XXIV.] THE HALOGENS AS DISINFECTANTS. 337 
 
 treated with sufficient acid to completely decompose it, will evolve 
 about 1'8 cubic foot of chlorine gas. To obtain anything approach- 
 ing the percentages that Fischer and Proskauer found most 
 efficacious, 2 lbs. of bleaching powder decomposed by 3 lbs. 
 of strong hydrochloric acid will be necessary for every 1,000 cubic 
 feet of space ; this is of course on the assumption that chlorine gas 
 will alone be used, but if as recommendedat page 359 the disinfec- 
 tion be a combined operation, that is fumigation, heat, and after- 
 wards mechanical processes of cleansing, then a less quantity 
 suffices, and in practice 1 lb. of bleaching powder to 1,000 
 cubic feet of space will be ample. 
 
 (255) Iodine, at. weight 126'5, density 1265. 
 
 Iodine forms rhomboidal lustrous greyish black plates. Iodine 
 dissolves but sparingly in water, but its solubility is much in- 
 creased by certain salts, e.g., potassic iodide ; it dissolv,es freely in 
 alcohol, in ether, and in carbon disulphide. It is not well adapted 
 for use as a fumigating agent chiefly on account of the density 
 of its vapour which is 8"5 times heavier than air; hence it is 
 extremely difficult to diffuse it properly. 
 
 (256) Bromine, at. weight 79'8, density 79'8. 
 
 Bromine is a dark red liquid of an exceedingly irritating odour. 
 It is soluble in water, a saturated solution containing about 3 per 
 cent, at ordinary temperatures. A method of using it as a fumi- 
 gating agent is given at page 344. 
 
 (257) The Experiments of Gash on the Halogens. 
 
 The most important experimental determination of the value of 
 the halogens has been made by Dr. Cash, F.R.S. {Supplement to the 
 Sixteenth Annual Report to the Local Government Board) The object 
 of the inquiry was to determine the lethal limits of chlorine, 
 iodine, and bromine, as well as sulphurous acid, to anthrax, to 
 human and bovine tuberculosis. 
 
 Dr. Cash thus describes the methods he adopted : — 
 With the object of rendering the investigation as precise as 
 possible, I have when testing the effect of solutions of these 
 
 z 
 
338 A MANUAL OF PUBLIC HEALTH; [chap. 
 
 halogens, employed graduated strengths which could be readily 
 controlled by means of occasional standardizing. 
 
 Water solutions of chlorine lose strength with more or less 
 rapidity, solutions of sulphurous acid rapidly, a partial conversion 
 into sulphuric acid as a result of oxidation taking place. Bromine 
 in solution is moderately stable, and iodine practically perfectly so. 
 
 Using a solution of iodine of known strength as the starting 
 point for the standardizing of the other solutions, and taking of it 
 an Y^ solution (i.e. 12'653 grms. of iodine per 3,000 c.c. distilled 
 water, or 1'27 per cent), it is easy to satisfy ourselves that an equal 
 volume of standard hyposulphite solution discharges the colour of 
 the iodine, starch being used as the indicator. The hyposulphite 
 being found up to strength, the standardizing of the chlorine and 
 bromine solutions is effected by estimating their power of 
 liberating iodine from iodide of potassium, starch as before being 
 used as indicator. 
 
 Koch places the solutions of the halogens which arrest the 
 development of anthrax bacillus as follows : — - 
 
 Iodine 1 : 5,00'0', Bromine' 1 : 1,500, Chlorine 1 : 1,500. 
 
 He farther found that spores of anthrax were destroyed in 
 iodine (1 : 7,()0&) one day ; bromine (two per cent) one to five days ; 
 chlorine (freshly made) one to five days. The original solutions 
 employed were of ibdine y^, of bromine -^, of chlorine ^. From 
 these more dilute soliitions were made by careful measurement and 
 controlled by standardization the -j^ solutions having the following 
 values : — iodinfe 1'27 grms. in 1,000 c.c. of water : chlorine "SSS? 
 in 1,000 c.c. 'Water ; bromine '7975 in 1,000 c.c. water. 
 
 The real qiiestion at issue is not merely the action of a certain 
 solution having a given percentage strength, but the action of 
 such a fraction, say of a cubic centimetre containing a known 
 quantity of the disinfectant upon a given quantity of blood or 
 cultivating medium within which the particular micro-organism is 
 present. 
 
 Supposing, for instance, that we expose one twentieth of a drop 
 of anthrax blood to the action of iodine, we obtain no definite 
 notion of its disinfecting power by stating that the latter was 
 present in the proportion of one per cent, in the solution unless we 
 know farther the actual quantity of the solution available for 
 action upon the micro-organisms. By exposure in a hermetically 
 
xsiv.] THE HALOGENS AS DISINFECTANTS. 339 
 
 sealed bulbous pipette the strengtli of the solution is well insured 
 during its action, its complete mixture having been accomplished 
 beforehand in a watch glass. 
 
 Supposing, to complete the example, that 1 c.c. of xrc iodine 
 solution is mixed with one twentieth drop of anthrax blood, we 
 then have as iodine actually present, in 1 c.c. '00127 and one 
 tenth c.c. = '000127 grm. We can state therefore that this quan- 
 tity of iodine acting for five minutes upon one twentieth drop 
 of anthrax blood destroys the contained bacilli, in other words 
 thoroughly disinfects it in a given time. 
 
 The experiments hitherto made with the haloid bodies and 
 sulphurous acid are in so far double, as they test the disinfectant 
 action of these bodies in solution and as vapours passed through 
 a solution containing the micro-organism to be disinfected. 
 
 In the end it is true that the effect is — as the menstruum 
 becomes more and more highly charged with gas which is dissolved 
 in it — in both cases that of the exposure of a cultivation of what- 
 ever the microbe may be to a disinfectant solution ; but it is in the 
 first instance a matter of considerable interest and utility to 
 determine how far the passage of gas through an infusion of some 
 pathogene will destroy its life, when, by reason of the speed of its 
 transmission probably not all but a part only of the gas acts directly 
 upon it, It is in the first instance less a question of the action of 
 a saturated fluid than it is of the affinity of the passing gas, so to 
 speak, for the microbe with which it is in conflict. Even at very 
 low speeds of delivery of air charged with disinfectant vapour, of 
 say, 12 to 20 bubbles per minute, it is found that from the first a 
 certain amount of gas, be it chlorine, bromine, or SOj, passes 
 through the infusion of the pathogene and discharges iodine on the 
 distal side from an iodide of potassium solution. If, on the other 
 hand, a substance such as KI, upon which the generated gas acts 
 chemically, liberating iodine, be substituted for the pathogenic 
 infusion so that we have two vessels containing KI solution in 
 series, we find that a very rapid discharge of the gas is necessary 
 to decolourize the solution situated distally ; not until all the KI is 
 decomposed in the vessel into which the gas first passes, does the 
 farther vessel begin to show decolourization likewise. 
 
 Experiments were made with solutions of the halogens and also 
 on infusions of virus traversed by the gas. 
 
 z 2 
 
340 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 " The general method followed when solutions were employed was 
 to take for example 1 part of -the blood of an animal just dead from 
 anthrax, to mix it with 49 parts of the standard chlorine water, or a 
 dilution of it, mix in a watch glass, draw it up in a pipette, seal 
 the pipette for a definite time, at the end of which the end of the 
 pipette was broken off and an animal inoculated. In this way it 
 was found that "00035 grm. chlorine disinfected in five minutes 
 one fiftieth of its bulk anthrax blood, but that a dilution to one 
 half was not certain in its action. The blood from an animal 
 dying of anthrax is always spore free, so that this statement only 
 applies to the bacilli. With regard to anthrax spores it was found 
 that chlorine solution of -^-^, mixed in the proportion of 20 to 1 of a 
 strong solution of anthrax spores, destroyed them within 24 hours. 
 With regard to tubercular material, one twentieth of a drop of 
 strong infusion of a tuberculous spleen, mixed with one drop of 
 y^-g chlorine solution kept in a pipette respectively for 1 hour and 
 for 24 hours, did not disinfect within the shorter time but did in 
 the longer time : the quantity of chlorine in this case was '000035 
 grm. In another experiment in which a similar dosing took 
 place, and it was submitted to the action of a disinfectant for 28 
 hours, the result was not so good, for the inoculated animal died 
 from tuberculosis. Using a strong solution of a tubercular lung. 
 Cash found that 4 minims of a chlorine solution containing "0008 
 grm. of chlorine destroyed the virus in one drop of such infusion 
 within one hour and a half. 
 
 "In the second method, air from a gas-holder was passed slowly 
 through strong chlorine solution and thus charged with the gas 
 passed through nitrogen bulbs containing a solution of the patho- 
 genic substance to be acted upon. From time to time, usually at 
 the beginning and end of an experiment, this bulb was replaced by 
 another, which contained fresh acidulated solution of iodide of 
 potassium, in order that the amount of escaping gas might be 
 estimated for a given time by the liberation of iodine as calculated 
 by subsequent titration with a standard hyposulphite solution." 
 
 One point Dr. Cash endeavoured to obtain information on, viz. 
 — " If a stream of air laden with a certain ascertained amount of 
 disinfectant gas be passed with a given speed through a solution 
 containing pathogenic micro-organisms, how soon will the dis- 
 infectant's action make itself felt as evidenced in the destruction 
 
XXIV..] THE HALOGENS AS DISINFECTANTS. 341 
 
 of sucli pathogenes ? If we bring two nitrogen bulbs containing 
 iodide of potassium into connexion distally with a bottle containing 
 chlorine solution through which air is slowly forced to them from a 
 Pepy's gas-holder, we observe that in the bulb nearer to the 
 gas supply the iodide of potassium is rapidly decomposed, iodine 
 being set free, but in the second bulb no decomposition whatever 
 occurs, at any rate for a considerable time, the fluid remaining 
 perfectly colourless. 
 
 " If now we substitute for the proximal bulb another containing 
 say, an infusion of tubercular lung, and continue the circulation of 
 air charged with chlorine through this and through the distal KI 
 bulb, we notice almost immediately a liberation of iodine in the 
 latter; this simple experiment shows us that an escape of the 
 gaseous disinfectant takes place before its maximal action has been 
 attained (as demonstrated by experiment), the maximal action for 
 our purpose being death of all micro-organisms, coagulation of 
 albuminous bodies, and other actions. Whilst in its passage through 
 the bulb a portion of the chlorine acts on the contents causing cer- 
 tain effects by liberation of oxygen, a portion remains behind in 
 general solution having a potentiality for further action, and still 
 another portion passes a,way without having produced any disin- 
 fectant action. Small portions of the nascent oxygen are probably 
 lost in the same manner.'' 
 
 The following are the details of an experiment by Dr. Cash : — 
 " Took one tubercular lung of a guinea-pig killed when suffering 
 from human tuberculosis. The lung was studded with translucent 
 pearls, the spleen enlarged, and the liver slightly necrotic. The 
 lung was broken up in a mortar with a little distilled water, the 
 fluid strained through muslin, diluted up to 10 c.c. and transferred 
 to a nitrogen bulb. 
 
 "Air was passed slowly (10 bubbles per minute) from a Pepy's 
 gas-holder through a bottle with the proximal tube dipping beneath 
 the surface of a considerable volume of chlorine solution. 
 
 " The second tube communicated by means of an air-tight joint 
 with the nitrogen bulb. The chlorine coming over was determined 
 by means of liberations of iodine from a slightly acidulated KI 
 solution. min., circulation commenced through the nitrogen bulb 
 containing tubercular material. 10 min., infusion has changed 
 much in colour, is now of turbid appearance, deep brownish red. A 
 
342 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 sample was taken and at once inoculated into a guinea-pig. The 
 circulation of the gas was interrupted only for a few seconds and 
 was then continued for 40 minutes more without stoppage. At 
 the expiration of this time -the infusion was of a deep muddy 
 brown colour. A second guinea-pig was then inoculated. The 
 total chlorine passed through the solution as estimated by the 
 discharge of colour from the liberated iodine by sodic hypo-sulphite 
 solution was before the first inoculation 'OIG grm. ; before the 
 second, -064 grm. (-064 + -016 = -08 grm.). 
 
 " In spite of this relatively large discharge of chlorine both 
 animals became tubercular, and when killed the usual appearances 
 were found in their organs. 
 
 " In the next two experiments the tubercular virus was success- 
 fully destroyed. 
 
 "The lung employed was that of a guinea-pig suffering from 
 human tuberculosis, and the preparation of its infusion was the 
 same as in the last experiment. 
 
 "A variation was, however, made in this experiment by generating 
 larger quantities of chlorine from hydrochloric acid and manganese 
 dioxide under gentle heat and conducting the gas through a small 
 wash bottle originally containing water, before leading it through 
 the nitrogen bulb. 
 
 " A control animal was inoculated with the lung infusion before 
 the circulation of the disinfectant was commenced. An estimation 
 of the escaping gas was made as before, and then the nitrogen 
 bulb with its contained infusion was put into connexion with the 
 second bottle. 
 
 " Inoculations were made after the passage of air laden with 
 chlorine at the rate of 16 bubbles per minute, for (a) 2 minutes, 
 for (b) 6 minutes, and for (c) 10 minutes, respectively. The issuing 
 chlorine was again estimated at the end of the experiment. 
 
 " It was calculated that before the first inoculation '0710 grm. 
 of chlorine had been passed. In all before the second (6) 
 •213 grm. In all before the third (c) not more than 'SSS grm. But 
 a the third estimation of chlorine showed a slight falling off in 
 the evolution of the gas, the total may have been somewhat less. 
 
 " The control guinea-pig and the guinea-pig (a) became distinctly 
 tubercular (though some delay in the development of glandular 
 swelling appeared to occur in the latter). The other two (&) and 
 
XXIV.] THE HALOGENS AS DISINFECTANTS. 343 
 
 (c) guinea-pigs escaped infection altogether. There is only one 
 conclusion to be drawn from this experiment, namely, that air 
 strongly laden with chlorine gas can rapidly disinfect or destroy a 
 great mass of tubercular virus by transmission through a solution 
 of the latter. 
 
 " In a third experiment an infusion of a tubercular lung was 
 disinfected in 4 minutes, the quantity of chlorine being about 
 •05 grm., and in another, '0355 grm. acting for 2 minutes failed 
 to disinfect, but ■0768 acting for 6 minutes disinfected." 
 
 Very similar experiments were made with iodine and bromine, 
 the general result being to show that there was no very decided 
 difference between the three, but that in order of disinfecting 
 power when employed in quantities proportional to their atomic 
 weight, iodine was the best, next bromine, and last chlorine. 
 
 The value of chlorine as a disinfectant has been strikingly 
 shown by Klein {Thirteenth Annual Meport Loa. Gov, Board, 
 Supplement). Klein's experiments were made on swine plague, 
 a disease easily reproduced and highly infectious, for he had 
 already proved (1877-78) that the infection spread from a 
 diseased to a healthy animal living in the same stable with it, 
 this even when the animals were separated by considerable space ; 
 and if a diseased and healthy animal were placed in the same 
 building in two different compartments, but both compartments 
 opened into each other, the healthy animal contracted the malady. 
 He found that if the air of the stable was kept pungent with 
 chlorine, healthy and diseased animals might occupy adjoining 
 compartments and also that one good fumigation of a stable 
 infected from animals which had died of the swine fever, was 
 effective. 
 
 (258) The Experiments of Fischer and Proskauer. ' 
 
 Fischer and Proskauer^ made some very important researches on 
 the disinfectant action of chlorine and bromine. The substances 
 submitted were sometimes in a large glass vessel of 21'35 litres 
 capacity, and sometimes placed in a cellar which was made into an 
 experimental room. The gas was developed from binoxide of 
 manganese and hydrochloric acid. In some of the experiments 
 
 ^ MiUheilungen cms dem Kaiscrlichen Gesundheitsamie. Bd. ii. Berlin, 1884. 
 
344 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 the air was specially dried by means of strong sulphuric acid, ia 
 others the air was saturated with moisture. 
 
 The pathogenic substances submitted for disinfection were : — 
 
 (1) Spore-holding micro-organisms such as anthrax in the spore 
 state, the so-called earth bacillus, and dried tuberculous sputum. 
 
 (2) Spore free micro-organisms such as the bacillus anthracis 
 (spore free), the microbe producing septicaemia in mice and rabbits, 
 fowl-cholera, yeast, sarcinse, and several others. 
 
 The results were tested mainly by ascertaining how far the 
 disinfected bacteria were capable of growing on nutrient soil, but 
 in a few cases inoculation of animals was resorted to. The 
 original paper must be referred to for full details, but the chief 
 results were as follows ; — ■ 
 
 No less percentage than 5-38 chlorine per 1,000 of air in rooms 
 to be disinfected can be considered efficacious. 
 
 It is best to keep the air of the room moist for some time before 
 disinfection.. 
 
 Disinfection in dry air is uncertain. 
 
 Chlorine fumigation carried out under the best conditions may 
 fail to disinfect spore-holding material covered over or lurking in 
 chinks and cracks. 
 
 In all cases chlorine is far more efScacious than sulphurous acid gas. 
 
 In their experiments on the disinfecting power of bromine, they 
 used for the purpose of developing bromine vapour the ingenious 
 process of Dr. Frank — fluid bromine is made to soak into a porous 
 siliceous earth, the earth is preserved in well stoppered bottles 
 ready for use ; on removing the stopper the heavy bromine vapour 
 pours over the neck of the bottle and gradually diffuses itself 
 about the room ; the bottle should of course be placed as near 
 the ceiling' as possible. This process is far above all others in 
 the single point of ease of application. 
 
 They found that provided the air of the room was sufficiently 
 moist a good superficial disinfection could be attained with 
 bromine but even with such high quantities as 35'7 grms. of 
 bromine per cubic metre of air, spore-holding anthrax escaped dis- 
 infection. They also found that bromine was more destructive of 
 organic tissues such as cotton or woollen goods than chlorine ; these 
 disadvantages and the higher price led them to give the preference 
 to chlorine. 
 
XXIV.] THE HALOGENS AS DISINFECTANTS. 345 
 
 (259) Iodine Trichloride, ICI3. 
 
 Iodine tricliloride is in the form of orange-yellow needles. It is 
 formed by heating iodine pentoxide (iodic anhydride) in hydric 
 chloride. The iodine pentoxide liquefies, and is converted into 
 iodine trichloride according to the following equation : — 
 
 I2O5 + 10 HCl = 2 ICI3 + 5 HgO -1- 2 Clg. 
 
 The crystals are soluble in water; the solution has no action on 
 starch. 
 
 Iodine trichloride will probably be an important disinfectant, 
 its power having been carefully determined by Dr. Otto Reidel. 
 The following is an abstract of his research ^ : — 
 
 Threads infected with anthrax spores were steeped in 1 per cent, 
 and 1 per 1,000 solutions of ICI3 for 24 and 48 hours. In all 
 these cases there was complete disinfection, as proved by cultiva- 
 tion and also experiments on animals. Hay bacillus spores, 
 experimented with in the same way, but using a 1 per cent, solution, 
 were not disinfected in 8^ hours, in 12 hours were imperfectly 
 disinfected, in 24 were completely disinfected. Garden earth 
 spores were disinfected in 19 hours with the same solution. 
 Anthrax threads, containing no spores (because derived from, the 
 blood of an animal dying from anthrax), were completely disin- 
 fected in 2 hours by a 1 per cent, solution, and it was shown by 
 experiment that this strength in activity was about equal to a 
 3 per cent, solution of phenol. A similar result was obtained in 
 experiments with the Staphylococcus aureus, and the Staphy- 
 lococcus derived from osteo-myelitis, a 3 per cent, solution of 
 phenol and a 1 per cent, solution of IClg acted effectually in equal 
 times, the former, S. aureus, being killed in 14 minutes, the S. 
 osteo-myelitis in 60 minutes. The cholera comma bacillus was 
 killed in 1 minute by 5 per cent, solution ICI3 ; in 3 minutes by 
 phenol of the same strength. Experiments were also made on the 
 effect of small quantities of ICI3 added to the nutrient material 
 serving as a soil for the cultivations. It was found that so little 
 as 1 : 3,000 prevented the growth of a variety of pathogenic 
 
 1 Arieit am dem Kaiserlichen Oesundlieitsamte, 2 Band, 1887. 
 
346 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 organisms, such as the micrococcus from erysipelas, the strepto- 
 coccus pyogenes, the anthrax bacillus, and the cholera bacillus; 
 but others required the proportion of ICI3 to be in the nutrient 
 gelatin as 1 : 850, and the bacillus derived from typhoid excreta 
 resisted in even 1 : 500. This latter property of the typhoid bacillus 
 has been utilized by Chantemesse and Widal to raise it from 
 typhoid excreta {Gaz. Held, de Med. et de Chir., 1887, No. 9, 146). 
 A practical test of its use to the surgeon was made by placing the 
 hands in a putrid liquid, washing them in the ordinary way, then 
 rinsing with a 1 per cent, solution of ICI3, getting rid of the dis- 
 infectant by washing it off with sterilized water, finally submitting 
 scrapings of the skin of the hands to cultivation ; no growth 
 followed. Lastly, the author compares the poisonous properties of 
 ICI3 weight for weight with HgClg (corrosive sublimate) and 
 phenol. These experiments were all made on rabbits, the poisons 
 being administered by peritoneal and subcutaneous injection. 
 ICI3 in 1 per cent, solution, injected into a rabbit in the proportion 
 of '45 grm. per 10 grms. of rabbit, had neither local nor general 
 effect, but the same relative quantity in 10 per cent, solution 
 caused local necrosis. The animals mostly lived; one died after 
 10 days. Other experiments showed that a fatal dose for a rabbit 
 was somewhere near 9 grms. ; while a subcutaneous injection of a 
 1 per cent, solution of corrosive sublimate killed '15 per 10 grms. of 
 rabbit, and in a greater dilution of 1 per 1000. "32 per 10 grms. 
 killed. Phenol was fatal when injected subcutaneously in the 
 proportion of 3 "48 per 10 grms. of rabbit. 
 
 (260) Phenol. Carbolic Acid. 
 
 Phenol. CgHjHO. When pure and absolute, phenol is in the 
 form of white crystals ; the crystals melt at 42-2° (108° F.). Boiling 
 point, without decomposition, = 182° C. Water gradually added 
 to phenol, so long as it dissolves, gives a liquid hydrate of the 
 composition CgHg02H20, equal to 27'7 per cent, of water. The 
 solubility of the crystals in water is very nearly that of 1 in 11 ; 
 a saturated solution in water will contain about 8"6 per cent, of 
 phenol. It is far more soluble in weak alkaline solutions than in 
 water. It is (when absolute) soluble in all proportions in alcohol, 
 ether, benzine, carbon disulphide, and chloroform. 
 
XXIV.] PHENOL AND CRESOL AS DISINFECTANTS. 347 
 
 (261) Cresol. Cresylic Acid, C^HyHO. 
 
 Cresol is known in three forms — meta-, para-, and ortho-cresol. 
 Para- and ortho-cresol are respectively obtained by fusing the pure 
 potassic salts of the two isomeric sulphonic acids produced on 
 heating toluene with sulphuric acid with potassic hydrate. The 
 three modifications are not in ordinary commerce. Specimens the 
 author obtained from Kahlbaum had the following general appear- 
 ance and properties : — Meta- and para-cresol were both liquid, of a 
 reddish colour: para-cresol had a most unpleasant odour; meta- 
 cresol had the smell of ordinary cresol; ortho-cresol was in the 
 form of needle-like crystals, odour pleasant and aromatic. 
 
 The commercial cresol, which makes up the bulk of the cheaper 
 fluid so-called carbolic acid, is of a red colour, and contains 
 meta- and para-cresol, with perhaps some small quantity of ortho- 
 cresol; the boiling point varies from 198° to 200° C. It is less 
 soluble than phenol; a saturated aqueous solution will contain 
 about 3"3 per cent. It is soluble in weak alkaline liquids, but 
 is precipitated with excess of alkali. 
 
 (262) Estimation of Imptirities in Commercial Carbolic Acid. 
 
 The chief impurities of the dark liquid carbolic acid of commerce 
 are tar oils; their presence is ascertained, and their quantity 
 approximatively estimated, by shaking a measured volume of the 
 acid with twice its volume of pure soda solution of 9 per cent, 
 strength. The cresylic and carbolic acids are dissolved by the 
 alkaline liquid, while the oils separate — " heavy oils '' sinking to 
 the bottom, " light oils " rising to the top ; the volume in either 
 case can be read off. These tar oils have not been shown to 
 possess any disinfectant properties. If it is required to ascertain 
 the relative mixtures of cresylic and carbolic acids, this is best 
 done by a fractional distillation, collecting the various products 
 and carefully measuring them. A process for this purpose has 
 been given by Mr. Lowe, and has been quoted by Allen; the 
 process is as follows: — 
 
 100 c.c. of the sample are placed in a retort and distilled into a 
 graduated vessel. The first 10 c.c. of the distillate contains water 
 and oil; the volume of each is determined, and the receiver 
 
348 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 changed. The next portion should consist of anhydrous acid, and 
 when the distillate amounts to 62'5 c.c, the receiver is removed 
 and the distillation stopped. The residue in the retort consists 
 wholly of cresylic acid and the higher homologues of cresylic acid. 
 To ascertain the relative proportions of cresol to phenol in the 
 62'5 c.c, it is necessary to carefully ascertain the solidifying point 
 which should be between 15'5° and 24° C, then imitation mixtures 
 of phenol and cresol are made until a known mixture is obtained 
 with the same solidifying point, or of course the reverse process 
 may be used, i.e., the liquefying point determined. 
 
 (263) Carlolic Acid Poivders are Powders which should contain 
 Free Tar Acids. 
 
 All carbolic acid powders that have for their basis lime, and are 
 hence mixtures of carbolate and cresylate of lime, are absolutely 
 useless, exerting no appreciable disinfecting properties. A good 
 carbolic acid powder is that which is merely a mechanical mixture 
 of the acid and the powder, as for example " Calvert's carbolic acid 
 powder," which is made by adding carbolic acid to the siliceous 
 residue resulting from the manufacture of aluminium sulphate 
 from shale. Macdougall's disinfecting powder is also to be men- 
 tioned with approval ; it is made by adding a certain proportion of 
 crude carbolic acid to an impure sulphite of calcium prepared from 
 the action of sulphur dioxide on ignited limestone. 
 
 Carbolic Acid Soaps are soaps containing more or less free car- 
 bolic acid ; it is doubtful whether they are of the slightest use for 
 disinfecting purposes or are at all superior to ordinary soap. Trust- 
 worthy and impartial experiments of a strictly comparative 
 character have however not yet been made as to this. 
 
 (264) The Author's Experiments on the Disinfecting Powers 
 of Phenol and Cresol. 
 
 The author has made many experiments on the relative disinfec- 
 tant powers of pure phenol, and the purest commercial samples of 
 cresol obtainable (this is as stated a mixture of ortho-, para-, and 
 meta-cresol) and with pure samples obtained from Kahlbaum of 
 ortho-, meta-, and para-cresol. Some of these experiments have been 
 already published, others appear here for the first time. 
 
XXIV.] PHENOL AND CEESOL AS DISINFECTANTS. 
 
 34£> 
 
 Experiments on the Disinfection of the Bacterium Termo. 
 
 Phenol and Cresol. — These experiments were made by the 
 "drop" method. 
 
 Weighed quantities of pure crystalline phenol and of pure 
 liquid cresol were dissolved in 20 per cent, alcohol in such pro- 
 portion that the strength was exactly 1 per cent. Water which 
 had been infected with the bacterium was measured from a burette 
 into test-tubes, and definite quantities of the phenol or cresol solu- 
 tions added ; the volume of the whole being kept at 10 c.c, e.g., 
 3 c.c. of phenol solution, and 7 c.c. of the infected water would equal 
 0'3 per cent., 1 c.c. of phenol solution and 9 of the infected water 
 would equal O'l per cent., and so on. At the end of twenty-four 
 hours nutrient gelatin was infected by means of dipping a clean 
 recently ignited platinum wire in the liquid, and then inserting 
 the wire for a second or two in the gelatin, which had been pre- 
 viously liquefied. The following short table summarizes these ex- 
 periments ; the — sign denotes no growth, the + sign denotes the 
 first appearance of evident growth and liquefaction. 
 
 Table XXXVII. 
 
 Phenol and Cresol. 
 
 Days . . 
 
 2. 
 
 3. 
 
 4. 
 
 5. . 
 
 6. 
 
 7. 
 
 8. 
 
 9. 
 
 10. 
 
 At 15-5° C— 
 
 Phenol O'Ol per cent. 
 0-01 
 
 „ 0-10 
 
 „ 0-25 „ 
 0-50 
 Cresol 0-01 „ 
 „ 0'05 „ . . . . 
 „ 0-10 „ ... 
 „ 0-25 „ 
 „ 0-50 „ ... 
 Control . . 
 
 + 
 
 
 — 
 
 + 
 
 + 
 
 + 
 + 
 + 
 + 
 
 + 
 
 + 
 + 
 
 + 
 
 + 
 
 At 35-5° C— 
 
 Phenol O'Ol per cent 
 
 „ 0-05 „ .... 
 „ 0-10 „ ... 
 
 „ 0-25 
 
 Cresol 0-01 „ .... 
 „ 0-05 „ . . 
 
 0-10 „ ... 
 „ 0-25 „ .... 
 
 — 
 
350 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 From which it may be concluded that at ordinary temperatures 
 commercial cresol disinfected the hacterium termo in somewhat 
 less dosage than phenol, 10 per cent, cresol being equal to 50 per 
 cent, phenol ; at higher temperatures the action was equal. 
 
 (265) Experiments on the Disinfectant Action of Phenol 
 and the Gresols on Sewage. 
 
 The phenol was absolute crystalline phenol, the cresols were ob- 
 tained from Kahlbaum ; 1 per cent, solutions were used, but the 
 volumes added to the sewage were proportional to the molecular 
 weights of phenol and cresol. Equal quantities of sewage were 
 placed in test tubes ; to some of the tubes 4'7 c.c. of the 1 per 
 cent, solution of phenol were added, into others 5'4 c.c. of the 
 cresols ; these reacted for twenty-four hours, the^disinfected solu- 
 tions were then madfe up by the aid of sterilized water, with suitable 
 precautions; to a definite bulk of which weighed drops were taken 
 and cultivated in the manner detailed at p. 315. It may be neces- 
 sary to observe that the quantities of disinfectants being mutually 
 equivalent, the relation of the weights was 36 cresol to 30 phenol. 
 
 On the eleventh day the colonies were counted : 
 
 Mean number of colonies 
 per lOO.mgms. sewage. 
 Ortho-cresol . ... 99 
 Phenol 136 
 
 Mean number of colonies 
 p6r 100 mgms. sewage. 
 Meta-cresol . . . 146 
 
 Para-cresol 170 
 
 From which it may be deduced that ortho- cresol is a little superior 
 to phenol and the other cresols, and that the disinfecting action of 
 phenol and meta-cresol is pretty well equal.^ Experiments were 
 also made as to the relative power of these substances to destroy 
 the odour of highly offensive sewage. The sewage was diluted, 
 and a sufficient quantity of the disinfectant added so that the 
 strength was equal to '5 per cent. The mixture was allowed to 
 stand for about an hour. The disinfected sewage was then slightly 
 warmed, sucked up and down a wide tube, and the lower end of 
 the tube being stiU in the flask just above the liquid, the nostril 
 was applied to the upper end of the tube, and the vapour sniffed 
 up. The results were : 
 
 Phenol ... A very faint urinous odour. I Meta-cresol . . Feeble aromatic odour. 
 Ortho-cresol . Aromatic odour. | Para-cresol . . Decided urinous odour. 
 
 ' On the other hand, Carnelley and Frew find that with regard to the di- 
 derivatives of benzene, the para-compounds are more antiseptic than the ortho- and 
 meta- compounds. Journ. Chem. Soc, 1890. Chemical Ncios, June 13, 1890. 
 
xsiv.] PHENOL AND CEESOL AS DISINFECTANTS. 351 
 
 There is no doubt of the superiority of ortho-cresol over any of 
 the others; the more especially when it is considered that the 
 odour is unmistakably agreeable. Unfortunately ortho-cresol is at 
 present only a scientific curiosity and of a high price. In practice 
 there is no real difference in the action between pure phenol and 
 the so-called carbolic acid of commerce, provided equal strengths 
 be compared ; the crude dark coloured 90 per cent, carbolic acid 
 used extensively by local bodies mostly contains large quantities of 
 cresol, and only small quantities of phenol, the manufacturer 
 having as far as possible separated all crystalline materials, but as 
 it has been shown that cresol is a little superior to phenol, and the 
 price is very much less, it is folly to use the dearer article for 
 disinfecting purposes on a large scale. 
 
 (266) Koch's Experiments on Phenol. 
 
 Koch has made many experiments on the effect of phenol on 
 anthrax. He found that a couple of minutes steeping of threads 
 contaminated by spore-free anthrax in a 1 per cent, aqueous 
 solution of phenol, was sufficient to destroy the bacilli ; on the 
 other hand spore anthrax was not killed save by prolonged contact 
 with much stronger solutions ; e.^., an aqueOus 3 per cent, solution 
 acting for five days failed to disinfect ; 4 per cent, succeeded in 
 destroying the spores after three days, and 5 per cent, after two 
 days. He found that carbolic acid dissolved in oil or strong 
 alcohol had no disinfecting power, and that of the phenol salts, a 
 5 per cent, solution of sulfo-carbolate of zinc was capable of destroy- 
 ing anthrax spores if the latter were soaked in the solution for 
 five days, but sodium-phenol as well as sodium sulfo-carbolate had 
 little effect. 
 
 (267) ScMll and Fischer on the Action of Phenol on 
 Tuberculous Matters. 
 
 Schill and Fischer in their elaborate investigation on the dis- 
 infection of tuberculous matters, by various disinfectants, found 
 that fresh ^sputa still produced tuberculosis when injected into 
 animals after being treated for twenty hours with solutions of 
 phenol from 1 up to 3 per cent., a 5 per cent, solution acting 
 for two hours failed to disinfect, but acting for twenty-four 
 hours was invariably successful. On the other hand, if an 
 
352 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 antiseptic action only is desired, there are plenty of observa- 
 tions to show that traces of phenol inhibit the growth of a 
 large number of micro-organisms. 
 
 (268) Sumrnary of the Action of Phenol and Gresols as Disinfectants. 
 
 Phenol and the cresols hold a high position as disinfectants : a 
 1 per cent, solution is strong enough to destroy the more feeble 
 infections, but to be certain that the more resistant forms of germ 
 life are annihilated it will be necessary to use at least 5 per cent, 
 solutions in water, and the action must be prolonged j if specific 
 excreta are treated it is doubtful whether 5 per cent, solutions 
 are of sufficient strength, because associated with the hurtful 
 material there is a quantity of organic matter which must on 
 the one hand remove some of the phenol from the sphere of 
 action, and on the other impede the contact of the phenol with 
 the substances which we wish to disinfect. 
 
 (269) Creasote. 
 
 Wood tar creasote is a mixture of several phenol-like bodies, the 
 chief of which are guiacal, or oxycresol, C^HgOg, boiling point 200°- 
 210°, and creasol, CgH^gOj, boiling point 217°. 
 
 The considerable insolubility in water of creasote is a bar to its 
 extensive use as a disinfectant. It is otherwise probably about 
 equal to cresol, but few experiments of an exact kind, made in the 
 modern way have been hitherto published, besides which, the un- 
 certain composition of commercial creasotes renders any but a 
 general statement impossible. Its powerful antiseptic properties, 
 as for instance in the preservation of timber, are well known. 
 
 (270) Phenyl-propionic and Phenyl-acetic Acids. 
 
 Phenyl-propionic and Phenyl-acetic acids have been investigated 
 by Klein [Thirteenth Annual Report to the Local (Government Board, 
 Supplement). He found that as regards spore-free bacillus anthra- 
 cis, the bacilli were certainly killed on exposure, even for a few 
 minutes, to solutions of either of the acids in the strength of 1 : 400 
 or less ; with regard to greater dilutions a longer time was 
 necessary, and phenyl-acetic proved to be a little weaker than 
 phenyl-propionic. These aromatic acids were also efficacious 
 in destroying the virus of swine plague, when the strength was not 
 
XXIV.] SULPHUROUS ACID GAS AS A DISINFECTANT. 353 
 
 less than 1 : 800, but experiments on tubercle bacillus, even with 
 strong solutions, produced no very appreciable effect. 
 
 Mr. G. F. Dowdeswell {op. dt. p. 193), while recognising both 
 these acids as powerfully antiseptic, did not find in experiments on 
 symptomatic charbon that they had any constant or determinate 
 action on the virus. 
 
 (271) Sulphur Dioxide (Sulphurous Acid Gas), SO^. 
 
 This gas is formed whenever sulphur is burnt in air or oxygen. 
 Its molecular weight is 64, vol. weight 82, sp. gr. 2,217. Its 
 composition by weight is equal parts of sulphur and . oxygen ; its 
 composition by volume is 1 volume of sulphur, and 2 volumes of 
 oxygen condensed into two. 
 
 Sulphurous acid, or more accurately sulphur dioxide, is in its 
 concentrated form an irrespirable gas, and even when dilute causes 
 considerable laryngeal irritation ; it bleaches many organic colours, 
 and reddens litmus. 
 
 It is injurious to vegetation, and when present in the, atmosphere 
 in but minute quantity some plants are affected by it. 
 
 It is the most common acid in the air of towns, being derived 
 from the burning of sulphur contained in the coal. 
 
 Sulphur dioxide may be condensed to a liquid by the applica- 
 tion of cold or pressure, or both combined. The pure liquid anhydride 
 is a thin blue liquid of sp. gr. 1'491, and is an article of commerce, 
 , and may be bought in quantity, but the liquefied anhydride may 
 be dangerous if trusted to unskilled hands. 
 
 Sulphur dioxide has been for a long time the most common and 
 
 favourite disinfecting agent, by reason of its cheapness, and the 
 
 ease with which it can lie generated. The usual way has been to 
 
 take about a pound of roll sulphur, seal up a room as hermetically as 
 
 possible, light the sulphur in some proper receptacle, and let it 
 
 burn as long as it will. Or, a still more convenient method is to 
 
 take an ordinary benzoline lamp, charge it with carbon bisulphide 
 
 and light ; as the carbon bisulphide is consumed the sulphur is 
 
 emanated as sulphur dioxide.^ Seabury's sulphur candles are also 
 
 ^ Ckiand Bey's lamp is used in some of the continental hospitals for the purpose 
 of burning safely CSj. It is very ingenious, and is so arranged that as the volatile 
 liquid sulphide burns away water takes its place ; finally, when all is burned, the 
 water rises to a level with the wick. It is described and figured in Dujardin Dumetz's 
 L'ffygUne Prophylactique. Paris, 1889. 
 
 A A 
 
354 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 convenient ; they consist of a cake of sulphur, in the centre of which 
 are two or three wicks, saturated with nitre ; the wicks light easily, 
 and the whole cake bums gradually away. 
 
 It is however doubtful whether sulphur dioxide will retain its 
 place as a disinfectant ; for although there are remarkable discrep- 
 ancies as to the results obtained by different experimenters, the 
 impression remains that it is an uncertain agent. 
 
 When sulphur is burnt in a perfectly close space, its consumption 
 is limited by the quantity of air in that space : theoretically a cubic 
 foot of air will bum up 624 grains of sulphur, but it will not do 
 this unless copiously supplied with air. 
 
 The best results are obtained in imperfectly ventilated places by 
 well moistening the sulphur with methylated spirit ; under the best 
 conditions the air of the room thus disinfected may contain 10 per 
 cent of SOg. 
 
 (272) Wolffliugel's Researches on the Disinfecting Prvperiies of 
 Sulphurous Acid Gas. 
 
 Gustav Wolffhugel ^ has made the most elaborate research on the 
 value of sulphur dioxide as a disinfectant. The following is a brief 
 abstract of his research. With the addition of alcohol under strict 
 experimental conditions, 40 per cent, of the possible total quantity 
 of sulphur in a closed space can be burnt, and in rooms the volume 
 percentage may reach 10 per cent. To attain the maximum 
 amount the sulphur must be broken up into pieces not larger than 
 a hazel nut, and divided about a room, never putting more than 
 a pound in one vessel. 
 
 Experiments were made on loss of SOj during the process of disin- 
 fection in rooms, this was found to range from 38 to over 90 per cent 
 of the gas developed. The causes of loss being leakage, oxidation 
 to sulphuric acid, precipitation with water, and absorption by 
 porous substances (this latter can of course hardly be called waste 
 in a disinfecting point of- view). In some of the experiments 
 the walls were moistened with water, but the results obtained 
 were not encouraging, the volume of free SOg in the air being 
 notably diminished. The diffusion of SOg evolved in a room 
 was found to' be fairly equal, samples of air taken from different 
 
 ^ Mittheilungen aus dem Kaiserlichen Oesundheitsamte. Bd. i. 1881. 
 
XXIV.] SULPHUROUS ACID GAS AS A DISINFECTANT. 
 
 355 
 
 heights showing unimportant deviations. Experiments were also 
 made as to the power of penetration into plaster, but this was 
 found most irregular. The following table gives results of experi- 
 ments made with lime paste exposed on glass plates : — 
 
 Table XXXVIII, 
 
 Volume of SO2 in the 
 experimental room. 
 
 Duration of experiment. 
 Hours. 
 
 SO2 absorbed (mgrms.). 
 
 3-1 
 3 1 
 
 2-6 
 2-6 
 2-5 
 2-5 
 
 21 
 21 
 5 
 5 
 5 
 5 
 
 371-5 
 486-5 
 66-7 
 323-2 
 145-0 
 216-0 
 
 Of greater interest is the determinations of amounts of SOg. 
 absorbed by square metres of cloth exposed to the gas. 
 
 Table XXXIX. 
 
 Duration 
 of experi- 
 ment 
 (hours). 
 
 SO2 
 Vol. °u 
 
 Material. 
 
 Surface 
 exposed 
 Square 
 metres. 
 
 Thick- 
 ness, 
 mm 
 
 Number of 
 tlireads per 
 
 square 
 centimetre. 
 
 Permea- 
 biUty. 
 
 8O2 
 absorbed 
 (mgrms.) 
 
 5 
 
 2-5 
 
 Dry and clean. 
 Linen shirting 
 Cotton Stuff 
 Flannel 
 
 1-3 
 1-3 
 1-3 
 
 •25 
 
 •80 
 
 1-00 
 
 36 : 36 
 26 : 19 
 28 :28 
 
 2-28 
 2-18 
 2-40 
 
 4-0 
 
 7-8 
 
 28-5 
 
 
 
 Dry hut dirty. 
 Linen shirting 
 Cotton stuff 
 Flannel 
 
 1-3 
 1-3 
 1-3 
 
 •25 
 
 ■80 
 1-00 
 
 36 : 36 
 26 : 19 
 28 : 28 
 
 2-28 
 2-18 
 2-40 
 
 3-5 
 3-5 
 24-6 
 
 5 
 
 4-6 
 
 Moist and clean. 
 Linen shirting 
 Cotton stuff 
 Flannel 
 
 1-3 
 1-3 
 1-3 
 
 -25 
 
 -80 
 
 1-00 
 
 36 : 36 
 26 :19 
 
 28 : 28 
 
 2-28 
 2-18 
 2-40. 
 
 6-1 
 11-6 
 
 58^7 
 
 
 
 Moist and dirty. 
 Linen shirting 
 Cotton stufif 
 Flannel 
 
 1-3 
 1-3 
 1-3 
 
 -25 
 
 -80 
 
 100 
 
 36 : 36 
 26 : 19 
 28 : 28" 
 
 2-28 
 2-18 
 2-40 
 
 5-7 
 
 8-9 
 
 38-7 
 
 A A 2 
 
356 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 From these experiments it may be generally gathered that 
 clean things absorb more SO2 than dirty, and that moist things 
 absorb more than dry. As might be expected, flannel absorbs 
 more than linen or cotton, and of the latter two, linen is the least 
 absorbent. 
 
 The applicability of SO2 as a general disinfectant for goods in 
 transit was tested in the following manner : — 
 
 Two overcoats, a bundle of linen, a bundle of wadding, three 
 envelopes of various thickness, a roll of dark green flannel, and 
 a mass of tow pressed in a cubical shape, the side of which 
 was 70 cm., were exposed to the gas in a room, the volume of 
 the gas being 1 per cent. Litmus paper was placed in suitable 
 positions within these different articles. The duration of the 
 experiment was 24 hours. The gas penetrated through all the 
 articles save through the cubical mass of tow, but a second ex- 
 periment, in which the amount of the gas was raised to 10 per 
 cent, of the air, was more successful, complete penetration of the 
 tow being effected. This result would, however, not be obtained 
 in practice ; therefore Wolf hugel condemns the use of SO2 on a 
 large scale for the disinfection of goods in transit. 
 
 Wolfhugel next turned his attention to the question of the 
 injurious action of SO2 on clothing, iron, and other objects. 1 per 
 cent, of SOg, acting for many hours, attacked bright metal objects 
 so slightly that the film deposited was easily rubbed off; woollen 
 fabrics were also not injured. When the percentage volume 
 of the gas was raised to 10 per cent., acting for 24 hours, two 
 overcoats and a roll of flannel exposed were changed to a red 
 colour. Washing with ammonia water imperfectly restored the 
 colour. 
 
 Wolfhugel finally made experiments on pathogenic and non- 
 pathogenic micro-organisms, and found that bacilli, such as the 
 bacillus anthracis, were readily destroyed if free from spores by 
 exposure to sulphur dioxide disinfection ; but if the micro- 
 organisms contained spores, prolonged exposure and concentration 
 of the gas had little effect. By steaming a room first, keeping it 
 at the same time at a high temperature, and then afterwards 
 disinfecting, some of the spore-holding material was destroyed, 
 but not all ; likewise infected articles wrapped in tow were not 
 disinfected. Small doses of SOg, acting for long periods of time. 
 
XXIV.] SULPHUROUS ACID GAS AS A DISINFECTANT. 357 
 
 likewise led to no satisfactory result. Wolfhugel's verdict is, 
 renounce disinfection bj' sulphurous acid gas, for only sucli 
 agencies should be employed which are fatal to every kind of 
 micro-organism. 
 
 (273) Cash's Experiments on Sulphurous Acid. 
 
 Dr. Cash, F.RS., has also made experiments with a view to 
 determine the disinfectant value of sulphurous acid. (Supplement 
 to the IQth Annual Report Local Government Board.) 
 
 These experiments are not comparable with Wolfhugel's, for they 
 were made either on solutions of the gas or upon substances sus- 
 pended in water, and known volumes of the gas passed through 
 the water ; nevertheless the information acquired is of the highest 
 value, the acid being made to act upon living infectious material, 
 and the result being tested by inoculation into animals. Solutions 
 of the gas were prepared, the strength of which had some definite 
 relation to the atomic weight of SOg ; for example, 64 parts by 
 weight of SOj solution in 1000 grms. of water would be a standard 
 or normal, while 100 c.c. of this solution made up to 2000 would 
 
 be ^ ; 100 of the normal solution made up to 3000 would be 
 
 ^, and so with other dilutions. 
 
 Cash found in a strictly quantitative experiment that '00012 
 grm sulphurous acid destroyed the spore-free anthrax bacillus in 
 •^ min. of anthrax blood in 5 minutes. 
 
 That '0001 grm. sulphurous acid did not destroy | min. of anthrax 
 blood in 5 minutes. 
 
 That '00001 grm. sulphurous acid did not destroy 1 min. of 
 anthrax blood in 5 minutes. 
 
 Further that '00002 grm. of sulphui'ous acid did not destroy 
 -^ min. of anthrax blood in 5 minutes. 
 
 With regard to spores, he found that '0004 grm. (i.e. '4 mgrm.) 
 sulphurous acid, acting for 24 hours on -^ min. of a minim of 
 an anthrax spore cultivation, destroys it ; but if only acting for an 
 hour, the spores are still active. 
 
 Experiments were made as to the effect of sulphurous acid 
 solution on the disinfection of tuberculous matter. 
 
358 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 A grumous fluid obtained by pounding the tuberculous lungs of 
 a guinea-pig which had died from tuberculosis, in a glass mortar, 
 was diluted with distilled water to 10 c.c. This was found to be 
 disinfected thoroughly when acted upon in an incubator at 37°, in 
 
 the proportion '0041 SOj to 1 c.c. ; but equal parts oij^ acid 
 
 solution and a strong infusion could act for 28 hours without 
 destroying the virus. 
 
 Other experiments were made with tubercular materials placed 
 in a nitrogen bulb with water, and the gas passed through, the 
 result being tested by direct inoculation. A piece of a tubercular 
 lung treated in this way with 'OlS SOj, and removed at the end of 
 1 minute, produced tuberculosis in a guinea-pig ; but "18 grm. SOj 
 and above, acting for 20 minutes, disinfected perfectly. 
 
 The writer has also made experiments on the effect of SO2 on 
 anthrax bacilli, both with and without spores, and obtained very 
 similar results to those already quoted. 
 
 We may presume that the infection of most maladies contains 
 resistant spores, and until we have evidence to the contrary, it is 
 safest to discard sulphurous acid, whether as gas or in solution. 
 It is sufSciently proved that only the best results can be obtained 
 when this agent acts under very strict experimental conditions — 
 conditions which may be met with in the scientific laboratory, but 
 not in the practical application of disinfecting agencies in ordinaiy 
 life, and on a more or less technical scale. 
 
 (274) The Practice of JDisinfedion. The Disinfection of the 
 
 Sick-room,. 
 
 As an example may be a room in which a person has been 
 suffering from small-pox. The first thing that the disinfector 
 should do is to paste up window and chimney and other crevices 
 with brown paper. Bleaching powder is then distributed in 
 three or four lots about the room. It is best to put some at 
 the highest practical level, others on the ground, all in suitable 
 basins or receptacles. The amount may be in the proportion 
 of 1 lb. to 1000 cubic space. The operator having first seen 
 that the door is open so that his retreat will not be cut off, 
 
XXIV.] DISINFECTION OF DRAINS AND CLOSETS. 359 
 
 and that no living creature remains in the room,^ rapidly evolves 
 the chlorine by tipping one after the other the requisite quantity 
 of strong hydrochloric or diluted sulphuric acid on to the chloride 
 of lime, and makes his escape (if he should care to breathe through 
 a cloth well charged with moist lime, he may do matters less 
 hurriedly). On closing the door, the next thing is to paste the 
 keyhole and the space around the door, so as to make the chamber 
 as airtight as possible. The room should now be left for 12 hours, 
 then opened, and well ventilated. The room must be now con- 
 sidered sitperficially disinfected, and there will only be trifling 
 danger in handling any article of apparel, or in removing matters 
 for " stoving " through the streets. The next operation is to 
 remove all things that can be washed to the wash-tub, and the 
 bed, cushions, pillows, carpets, and the like to a hot air or steam 
 chamber. This done, the walls may be stripped of their paper, or 
 otherwise cleaned, the floor thoroughly scrubbed, and the articles 
 of furniture well cleansed and polished. There are, however, cases 
 in which the bedroom contains such valuable furniture, or pictures, 
 or other articles of vertu, that chlorine fumigation would entail a 
 considerable money loss. In this case some risk may be run, and 
 sulphur fumigation be resorted to, after which the floor may be 
 sprayed with a 1 per cent, solution of corrosive sublimate, all 
 matters which can be disinfected by heat or steam removed, and 
 the room and its furniture very thoroughly cleansed. 
 
 (275) Disinfection of House Drains and Closets. 
 
 House drains should not require disinfection save when there is 
 sickness in the house. A saturated watery solution of crude car- 
 bolic acid, or a 1 per cent, corrosive sublimate solution constantly 
 kept in every closet, and in the bed pans used by the patient, will 
 answer the purpose well. The disinfectant should, of course, be 
 kept in bottles or jars labelled poison, and where there are children 
 the stock should always be under lock and key, and the closets 
 charged by a responsible person. 
 
 Other details on practical disinfection will be given when treating 
 of infectious maladies. 
 
 ^ I have known cats to have hcen tinder articles of furniture and to have heen 
 killed by chlorine fumigation. 
 
SECTION VIII. 
 ZYMOTIC (Micro-Paeasitic) DISEASES. 
 
CHAPTER XXV. 
 
 THE MODEEN THEORY OF MICKO-PAEASITES. 
 
 (276) Micro-Strife. 
 
 Modern research has amply shown that the greatest proportion 
 of the maladies, which are more or less preventable, belong to the 
 domain of parasitism. Life prejdng upon life. The micro-tragedy 
 which may be watched in a highly-magnified drop of pond-water, 
 a voracious monad swallowing up a weaker, is repeated within the 
 body of the mammal. It is scarcely necessary to call to mind, that all 
 the higher animal bodies are but communities of monads or living 
 points, some floating free, others stationary, these last attached to 
 their neighbours by protoplastic bonds of great tenuity (just as ad- 
 joining households may have telephonic connection), but with their 
 individuality and automatism unimpaired. A colony of inimical 
 microbes obtaining access to this republic is similar to a hostile ■ 
 armed band entering a city — strife at once commences, the strangers 
 attack and are attacked. If the invaders are all killed, no dis- 
 turbance of health is produced ; in any other event, the strangers 
 increase and multiply at the expense of the normal inhabitants, 
 the latter being rather destroyed by some special toxic substance 
 excreted by the enemy than in any other way. 
 
 The analogy of invasion and defence is rendered closer by a 
 knowledge of the fact that the mammalian body has its fighting 
 cells, a soldier-like community, one of whose special offices is to 
 fight ; these have been called " macrophages." Under appropriate 
 conditions the fight between macrophage and microbe has been 
 actually witnessed, the former swallowing, as it were, the latter and 
 digesting it. The details of the process have also been followed by 
 
364 A MANUAL OF PUBLIC HEALTH. [ohap. 
 
 removal of the affected tissues, appropriate staining and observa- 
 tion of the combatants in the several stages — the free microbe and 
 macrophage, the microbe within the substance of the macro- 
 phage, but still preserving its outline intact, the microbe becoming 
 cloudy, and final disappearance by complete absorption or digestion. 
 The macrophages themselves are nothing more than leucocytes, 
 cells endowed with automatism and powers of movement, capable 
 of amoeba-like pushing out and retracting of portions of their 
 protean bodies. 
 
 Each micro-organism seems to have a particular rate of multi- 
 plication and those that are pathogenic excrete some toxic substance. 
 We may presume that when a sufficient quantity of the toxic 
 substance is excreted, then and then only the phenomena of general 
 systemic disturbance are experienced. So far as experimental 
 research has gone, there is no true but only an apparent incuba- 
 tion ; there is no mysterious localisation for days or weeks of the 
 enemy in lymphatic gland or other tissue. The battle at once 
 commences, and when the victory inclines to the invader then 
 there is sufficient disturbance of function to produce fever, or other 
 symptoms. In some cases there is a general infection," everywhere 
 the microbe can be found, slices of liver, of kidney, of lung, reveal 
 countless myriads of the foreign host, in others, as, for instance, in 
 diphtheria, a portion only of the body is affected, but the poison 
 thus locally developed is carried to every part of the circulation in 
 the same way as when an alkaloid in solution is injected sub- 
 cutaneously. 
 
 (27,7) Acquired Immunity. 
 
 By the same theory the curious fact that an animal body having 
 once recovered from one of these micro-parasitic diseases obtains a 
 shorter or longer immunity is capable of a plausible explanation. 
 The macrophages have a rapid cycle of existence, a few hours may 
 represent several generations, so that acquired properties are 
 rapidly transmitted ; those poisoned by the excretion of pathogenic 
 microbes perish, those that more or less effectually resist, continue 
 to live and propagate, until by a repetition again and again of 
 this process, the body may be full of resistant living particles, and 
 the foreign tribe is annihilated or expelled. If now a second 
 inimical colony of the same kind obtains access to the body, it 
 
XXV.] CLASSIFICATION OF MICRO-PAEASITIC DISEASES. 365 
 
 meets with tlie fighting descendants of the old heroes, and the 
 attack is immediately repulsed, and this is the nature of protection 
 conferred from a recovery from a first attack. Since it would seem 
 that the weapon of the microbe is its venom, it is not surprising 
 that the macrophages may be educated in their resistance by being 
 dosed with the excretory products of pathogenic organisms ; the 
 method of education being first doses feeble in either quantity or 
 strength, to be followed by gradually successive doses of increasing 
 virulence, until no health disturbance is produced by an otherwise 
 mortal dose. The efficacy of ordinary vaccination against small- 
 pox may be explained on the theory that vaccine contains a 
 number of degenerate colonies of the same genus as the small- 
 pox microbe, these are conquered with comparative ease ; neverthe- 
 less the result is that a race of macrophages are left which, from 
 their education, successfully cope with the virulence of true variola. 
 The remarkable recent investigations of Ferd. Hueppe and Dr. 
 Cartwright Wood, tend to show that even saprophytic bacteria may 
 be used to confer a certain kind of immunity, if they be nearly 
 allied in form, to the pathogenic bacteria, the possible theory 
 being, that the ancestral form of the saprophytic bacteria was patho- 
 genic, but that it has lost nearly all pathogenic properties, save 
 that of splitting up albumen. (See Public Smith, Vol. II., 269.) 
 
 (278) Glassificaiion of Micro-Parasitic Diseases. 
 
 At the present time it is impossible to classify micro -parasitic 
 diseases on a scientific basis. All that can be done is to provi- 
 sionally arrange these diseases into groups for the purpose of 
 convenience, and for this purpose the author proposes the 
 following : — 1. Eruptive fevers. 2. Micro-parasitic diseases affecting 
 the nervous system. 3. Micro-parasitic diseases mainly attacking 
 the respiratory passages. 4. Septicaeinic maladies. 5. Tubercular. 
 6. Malaria. 7. Micro-parasitic maladies primarily affecting the 
 intestine. In considering these different maladies, the chief points 
 which concern the sanitarian, are their method of propagation, the 
 period of quarantine necessary, and the suitable means for isolation 
 and disinfection. Properly speaking the medical officer of health 
 still less the sanitary inspector, has little to do with diagnosis, none 
 with treatment, these things being the business of the medical 
 attendant. 
 
CHAPTEK XXVI. 
 
 ERUPTIVE FEVEES, 
 SMALL-POX, MEASLES, SCARLET FEVER, AND TYPHUS. 
 
 1. Eruptive Fevers. — To this class belong small-pox, chicken-pox 
 scarlet fever, measles, and true typhus. 
 
 Small- Pox. 
 
 (279) Incubation and Ericption. 
 
 The incubation period averages fourteen days, or, to speak more 
 accurately, twelve days intervene, from the first infection to the 
 symptoms preceding the eruption, on the second day of which 
 spots appears, fourteen days being the general period from infec- 
 tion to actual eruption ; if, however, small-pox virus be actually 
 inoculated then the incubation period is shorter, about nine days 
 being considered the average. 
 
 The general course of an uncomplicated case of ordinary small- 
 pox, is that the patient feels ill, has high fever, the temperature 
 being 104° or above, there is intense pain in the back, a pain not 
 situated in the muscles, and not particularly aggravated by move- 
 ment, and usually located in the central part of the sacrum. As with 
 all fevers, the high temperature itself disturbs the nervous centres, 
 children have convulsions, adults are drowsy, dull, or may be 
 delirious. Vomiting is a frequent symptom. The eruption 
 appears in three successive crops, first the head and face, then the 
 body, and lastly the legs. The first appearance of the eruption is 
 that of papules, that is, small red spots about the size of a pin's 
 head, although not at first projecting above the surface. On feeling 
 
CHAP. XXVI.] SMALL POX. 367 
 
 the spots there is a sensation of a solid body, and as the eruption 
 farther develops each spot becomes a solid nodule ; on either the 
 second or third day of the eruption the spots become vesicular, and 
 of a peculiar shape, for they are flattened at the top, and bound 
 down or umbilicated at the centre ; this vesicular stage lasts about 
 four days, it then becomes pustular but the process is gradual, even 
 on the fifth or sixth day, the central part may be vesicular and on 
 puncture yield clear lymph, while the outer part is purulent and 
 on puncture yields matter. When the vesicle becomes wholly 
 purulent the " bride," which bound down the centre of the vesicles, 
 ruptures, and the vesicle, now becomes acuminated, from this stage 
 to the falling off of the scabs, there is most swelling of the 
 face, when the eyelids are closed, and the disease is in its most 
 repulsive stage. About the eighth day of the eruption a dark spot 
 is seen at the centre of each pustule, here the cuticle ruptures and 
 weeps out purulent fluid, which on drying forms a scab. Now is 
 developed the peculiar sickly smell always to be smelt in cases of 
 bad small-pox. From the eleventh to tbe fourteenth days tbe 
 crust becomes detached, and the period of convalescence com- 
 mences. The general period of actual illness being from fourteen 
 to sixteen days, and eighteen after the falling off of the crusts, it 
 will be usually safe to allow the sufferer to return to his avocations 
 within thirty-two days, precautions to be detailed having first been 
 taken. From the returns of the Asylums Hospital Board, London, 
 it appears that the mean duration of the disease from first eruption 
 to discharge from hospital, in cases returned as " vaccinated," is 
 twenty-five days, the maximum being fifty-five days, the minimum 
 eighteen days, a sufficient number of cases of non-vaccinated 
 cases have not been received to obtain a true average, but it 
 would probably be more than thirty days (the maximum being the 
 same). 
 
 The varieties of small-pox are not of the greatest importance to 
 the health officer ; thus, when the eruption is composed of vesicles 
 perfectly distinct one from the other it is called " distinct," -when 
 the pustules are so thick that they run one into the other it is 
 called " confluent " small-pox ; when the vesicle dries up and does 
 not develop into a purulent centre it is the mild form of small-pox 
 known as " horn." The method of prevention is however the same 
 in all, and all must be treated as equal in public danger. 
 
368 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 (280) Mortality of Small-pox. 
 
 This varies with regard to the vaccinated or unvaccinated state 
 of the individual attacked, with the virulence of the disease 
 itself, and with the general hygienic condition of the patient's 
 surroundings. The latest experience of small-pox in England of 
 any magnitude is the Sheffield outbreak, which was investigated 
 with so much care' by Dr. Barry. Of 4,703 cases of small-pox in 
 Sheffield, of all ages of both sexes, and some being vaccinated, 
 others not, 474 died, equal to a mortality of 10 per cent of those 
 actually attacked. Separating these into two general age groups, 
 581 children under ten years of age attacked, 106 died, giving a 
 mortality of 18'2 per cent. ; of 4,096 persons over ten, 368 died, 
 equal to a mortality of 8 9 per cent. 
 
 On separating the cases into two groups, vaccinated and un- 
 vaccinated, the following were the very remarkable differences 
 recorded : — 
 
 Vaccinated. 
 
 Out of 4,151 cases of all ages 200 
 died, equal to a case mortality of 4 '8 per 
 cent. 
 
 Out of 353 cases of children below 
 10 years of age 6 died, equal to a mor- 
 tality of 1'7 per cent. 
 
 Out of 3,774 cases of persons 10 years 
 of age and upwards 194 died, equal to a 
 mortality of 5"1 per cent. 
 
 Unvaccinated. 
 
 Out of 552 cases of all ages 274 died, 
 equal to a case mortality of 49 '6 per 
 cent. 
 
 Out of 228 cases of cMIdren below 
 10 years of age 100 died, equal to a case 
 mortality of 43 '8 per cent. 
 
 Out of 322 cases of persons 10 years of 
 age and upwards 174 died, equal to a 
 mortality of 54 per cent. 
 
 So that it may be laid down that the mortality of all ages and 
 both sexes in a vaccinated community will be under 5 per cent. ; 
 in an unvaccinated community it will be over 49 per cent, of those 
 attacked ; and if the ratio of the two classes of cases, vaccinated or 
 unvaccinated, be known, the mortality will be in accordance with 
 what may be calculated from the above figures. 
 
 (281) Seasonal Prevalence of Small-Pox. 
 
 Small-pox has a very definite relation to season ; the cases are 
 above the average from Christmas till the end of June, the 
 maximum being about the last week in May, the minimum the 
 
XXVI.] 
 
 SMALL-POX. 
 
 369 
 
 last week in September. The following curve is one based upon 
 mortality returns, from Buchan and Mitchell's paper h — 
 
 + 50 per cefff.i j I '| 
 
 Mean Line 
 — 50 per cent 
 
 Feb. Karch Aptil Man June Julil Aim. Sept. Oct. Nov. Dec. 
 
 Fig. 48. 
 
 The curve represents the average mortality of thirty years, from 
 1845 to 1874 inclusive, in London. The straight black line repre- 
 sents the mean weekly average death-rate on an average of the 
 fifty-two weeks ; with this the average death-rate of each week is 
 compared, and the difference above or below is calculated in per- 
 centages of the mean weekly death-rate for the whole year. Thus 
 the mean weekly death-rate for the year is 19'2 ; the average of 
 the death-rate for smaU-pox in the first week was 22, which is 2"8 
 above the average, or 15 per cent; the average for the first week 
 of October is 13, being 6'2 below the average of fifty-two weeks, 
 or 32 per cent. 
 
 Death from small-pox usually takes place from the seventh to 
 to the twelfth day. Hence, although the curve is that of mortality 
 only, it is a fair indication of the number of cases, and a medical 
 officer of health, by watching carefully the progress of small-pox in 
 his district, can with confidence early forecast whether it is likely 
 to become epidemic or not. Thus, if there should be_ cases in 
 December and January, and these increase in the succeeding 
 months, the probability of an epidemic is strong, whereas small- 
 pox absent during the early months of the year would indicate 
 that there would be no epidemic that particular year. 
 
 (282) The Infection of Small-Pox. 
 
 The usual spread of small-pox is from person to person, but from 
 inquiries which have taken place as to the influence of small-pox 
 hospitals upon a surrounding population, and the experience of the 
 Sheffield epidemic, it is certain that the infection can strike at a 
 
 Journ. of the Scottish Meteorological 
 
 1 "The Influence of "Weather on Mortality.' 
 Society, 1874. 
 
 B B 
 
370 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 distance. Whether the contagious particles are conveyed by the 
 air itself or by the mediiira of the common household fly or other 
 insects, the important fact remains that the infection may travel 
 far. The influence of the Sheffield Hospital could be distinctly 
 traced for a circle of 4,000 feet ; for instance, the following per- 
 centages of households attacked at successive distances from the 
 hospital are given in the original report ^ : — ■ 
 
 0—1,000 feet. 
 
 1—2,000 feet. 
 
 2—3,000 feet. 
 
 3—4,000 feet. 
 
 Elsewhere. 
 
 1-75 
 
 •50 
 
 ■14 
 
 ■05 
 
 •02 
 
 This possibility of small-pox spreading by aerial infection increases 
 greatly both the hospital difficulty and that of individual isolation. 
 
 (283) l%e Ditty of the Sanitary Authority and of its Medical Officer 
 in Small-Pox Outbreaks. 
 
 It is specially in the first cases of small-pox breaking out in a 
 town or district that energy and promptitude of action is neces- 
 sary. The power of mischief that a single case will effect is well 
 seen in the epidemic at the St. Joseph's Industrial School, Man- 
 chester,^ in 1888, in which an imported undiagnosed case infected 
 at one time forty-six inmates and subsequently twenty-three 
 others.^ It is also well shown in the following case taken from 
 Dr. Birdwood's Report to the Asylums Board, 1888 : — 
 
 4, Sailor from Port Said, 7th Feb. 
 I 
 ' . IConjectured cases, representing a donble 
 r. ' j period of incubation. 
 
 I 
 7, A Man who died at home 22nd March — iU sitice lOth March, 
 I 
 
 ( i \ i 1 '. i ) 
 
 8, Brother, 9, Friend, 10, Betrothed, 11, Sister, 12, Father. 13, Lodger, 14, Brother, 
 2nd April. 3rd April. 4th April. 3rd April, ill 8rd April, about SrdAp. ill 3rd April. 
 
 A primary duty is the removal of the patient to an infectious 
 hospital, presuming the sanitary authority to possess one, and that 
 one a sufficient distance from centres of population. Every one 
 
 1 "Report of an Epidemic of Small-pox at Sheffield, 1887-8." By Dr. Barry. 
 Local Government Board. London, 1889. 
 
 2 Public Health, vol. i., 174. 
 
 ' See also the elahorate report of Mr. Power. "Statistics of small-pox incidence 
 upon the registration districts of London relative to the operations of small-pox 
 hospitals in the Metropolis, in a succession of chapters." By Mr. W. H. Power. 
 Sixteenth Annual Report of the Local Government Board {Supplement). 
 
XXVI.] SMALL-POX. 371 
 
 in or around the house or coming to the house should be vac- 
 cinated. No person, whatever his position is in life, and however 
 elaborate his nursing arrangements or so-called isolation may be, 
 can be isolated satisfactorily in a private town house ; hence, 
 whatever the social position of the sufferer, if the law does not 
 compel, he should at least be persuaded to allow himself to be put 
 apart in a place remote from other habitations. 
 
 In many places of course there can be no removal, and in these 
 the medical officer of health will have to exercise his personal 
 authority, all his resources, and ingenuity. It ..may be possible 
 to empty the house (after vaccination) of all the inhabitants 
 save those nursing the sick : this is the next best thing to re- 
 moving the patient himself. If there should be choice of a room, 
 one at the top of the house will be preferable, and all unnecessary 
 furniture should be removed, as well as all those carpets, rugs, 
 clothes, curtains, and things not essential to comfort. All excreta 
 should be received in a 1 per cent, solution of corrosive sublimate ; 
 the discharges from nose, mouth, or from the eruption generally, 
 should be received on soft old rags and immediately burned. The 
 patient should have a complete set of eating utensils, cups, saucers, 
 &c., devoted to his exclusive use ; there should properly be two 
 nurses, one to relieve the other ; special dresses or aprons should 
 be supplied to all necessary visitors, who would cover their usual 
 dress during the visit by wearing these garments. Before leaving, 
 washing the hands and face should be insisted upon. The nurses 
 should of course not wear the same dress out as in nursing the 
 sick. In short, the strict management of an infectious hospital 
 should be insisted upon. If the patient should die, the body should 
 be covered with carbolised lime and early coffined. Cases of 
 small-pox attended with delirium may be difficult to manage ; 
 the author remembers in his own experience such a case escap- 
 ing from a house in Lisson Grove and walking down Bond 
 Street, very likely infecting in his passage several people. In 
 such cases personal temporary restraint is absolutely necessary. 
 On convalescence being established a hot bath should be taken 
 daily, and it may be well to oil the skin thoroughly, to wash the 
 oil off, and finally to take a bath of corrosive sublimate solution, 
 1 per 1,000 ; there is no danger in such a bath, the solution being 
 too weak to be absorbed in sufficient quantity to poison. After 
 
 B B 2 
 
372 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 taking the baths for two or three days, and clean, well disinfected 
 or new clothing being put on, and every scab having fallen, it is 
 probable that the patient is no longer infectious, and he may mix 
 with other people. In those cases however in which the eruption 
 only consists of some twenty or thirty spots, most of which do not 
 go on to suppuration, it is not likely that the amount of infection 
 can be so great as in the severe cases, and it may be safe to con- 
 sider the case terminated at a shorter period than the month 
 from the appearance of the eruption. There is indeed every 
 probability that three weeks from the first eruption in mild cases 
 may be, with the precautions indicated, a sufficient period of 
 isolation. 
 
 (284) Vaccination and Small-Pox. 
 
 The experimental and statistical evidence as to the efficiency of 
 vaccination in modifying, and in most instances entirely pre- 
 venting small-pox, is of such a conclusive nature that it is 
 difficult to see why it has been rejected by a section of the com- 
 munity. It is impracticable within the limits of this work to enter 
 into the history of the subject, the last enquiry at Sheffield will 
 therefore alone be summarized, the more especially as the results 
 finally dispose of the assertion that the evident diminution of small- 
 pox mortality is owing to general sanitary improvement rather than 
 to vaccination. 
 
 Special instructions were given to Dr. Barry ^ to observe and note 
 carefully every influence that could bear upon the incidence of the 
 epidemic in Sheffield, but no inflnence was found that had not 
 been dominated by the single influence of vaccination. This in- 
 fluence may be studied first in two great age-groups, and secondly 
 as affecting the population of all ages and both sexes. 
 
 First, Children under 10 year's of age. — Per thousand of the 
 number of children in each class : the attack-rate of the vaccinated 
 was 5 ; the attack-rate of the unvaccinated was 101 ; the death- 
 rate of the vaccinated was '09 ; the death-rate of the unvaccinated 
 was 44; or stated in other terms : for 100,000 vaccinated children 
 the rate of small-pox mortality actually observed in Sheffield gives 
 9 deaths; for 100,000 unvaccinated children, the rate of small-pox 
 
 ^ "Report on an Epidemic of Small-pox at Sheffield, 1887-8." Local Government 
 Board, 1889. In the above Dr. Buchanan's summary is used. 
 
XXVI.] VACCINATION AND SMALL-POX. 373 
 
 mortality actually observed gives 4,400 deaths. The above relates to 
 the general children population of the borough. Children living 
 in houses actually invaded were of course exposed to an intenser 
 and more continuous infection, but similar results were obtained 
 thus : Per thousand of the number of children of each class living 
 in invaded houses ; the attack-rate of the vaccinated was 78 ; the 
 attack-rate of the unvaccinated was 869 ; the death-rate of the 
 vaccinated was 1 ; the death-rate of the unvaccinated was 381. 
 
 Secondly, Persons over 10 years of age. — (a) Under ordinary con- 
 ditions, per thousand of the number of persons over 10 in each 
 class : the attack-rate in persons twice vaccinated was 3 ; the 
 attack rate in persons once vaccinated was 19 ; the attack-rate in 
 persons not vaccinated was 94 ; the death-rate among persons 
 twice vaccinated was '08 ; the death-rate among persons once 
 vaccinated was 1 ; the death-rate among persons not vaccinated 
 was 51. (6) Persons in invaded houses: the attack-rate of the 
 vaccinated was 281 ; the attack -rate of the unvaccinated was 686 ; 
 the death-rate of the vaccinated was 14 ; the death-rate of the 
 unvaccinated was 371. 
 
 Influence of Vaccination upon the Attack and Death-rate of people 
 of all ages living in Sheffield. — (a) Living under ordinary conditions : 
 the attack-rate of the vaccinated was 15"5 per thousand; the 
 attack-rate of the unvaccinated was 97"0 per thousand ; the death- 
 rate in the vaccinated was "7 per thousand ; the death-rate in the 
 unvaccinated was 480 per thousand, (b) Living in invaded houses : 
 the attack-rate of the vaccinated was 230 per thousand; the attack- 
 rate in the unvaccinated was 750 per thousand ; the death-rate of 
 the vaccinated was 11 per thousand ; the death-rate of the un- 
 vaccinated was 372 per thousand. 
 
 What was true of the fatahty was found also true as to the 
 virulence or otherwise of the attack. " From the experience of 
 1,741 patients treated in hospitals, Dr. Barry reported 17"2 per 
 cent, of severe and confluent cases of small-pox in patients of all 
 ages who had been vaccinated, and 81-5 per cent, of the same 
 forms of smaU-pox, out of every 100 attacks in people of all ages 
 who had not been vaccinated; for children under 10 the cor- 
 responding figures were 9 and 78. 
 
 " In the hospitals also the familiar immunity of re-vaccinated 
 persons in attendance on the sick was observed. There were 161 
 
374 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 persons employed* in the wards and offices of five hospitals. Of 
 the 161, 18 had had small-pox before their engagement, none of 
 these fell ill ; 62 persons had been vaccinated in infancy only, of 
 these 6 were attacked, 1 died; the remaining 81 persons had 
 been successfully re-vaccinated, not one of these contracted 
 small-pox." 
 
 In the early days of vaccination it was stated to confer full im- 
 munity, we now know that this is not correct. Given that several 
 years have elapsed since the vaccination, and that the person is 
 exposed to a large dose of the poison, the disease may be contracted, 
 and the same remark holds good with regard to first attacks of 
 small-pox ; the author has himself seen a person pitted from a former 
 attack contract a second, and die. There are evidently some so 
 constituted that protection is evanescent, but the majority are 
 absolutely safe after a successful vaccination, from all ordinary in- 
 fection, for an unknown and somewhat uncertain number of years. 
 It is probable that re-vaccination every seven years of the population 
 would extinguish small-pox altogether ; in any case re-vaccination is 
 to be advised by the medical officer of health, if he should ^ have 
 grounds for forecasting an epidemic, and certainly when an epidemic 
 actually exists. It seems indeed monstrous that with this powerful 
 agency at command, there should be any necessity for spending 
 sums of money on small-pox hospitals, when a complete and 
 thorough compulsory re-vaccination of the community would at once 
 stamp it out. Re-vaccination must be considered in the I'ght of a 
 test— if the vaccination should " take," it is a sign that the infection 
 of small-pox would also " take." 
 
 Measles. 
 
 Measles is a febrile exanthem, highly infectious, more especially 
 prevalent in the early years of life, and but occasionally affecting 
 adults ; one attack gives immunity, as a rule, against a second. 
 
 (285) Statistics. 
 
 In this country measles is fatal to from six to fourteen thousand 
 
 1 Re- vaccination would be more sougM by number.s of people were it not for the 
 dread of "bad arms," and it cannot be denied that a largish proportion of re-vaoei- 
 nations are followed by far more redness and unpleasant local sequelse than primary 
 vaccinations. The reason of this might well be a subject for careful inquiry in the 
 laboratory of the bacteriologist. 
 
XXVI.] MEASLES. 375 
 
 children yearly ; the mortality per million of the population of all 
 ages being for successive quinquennial periods as follows : — 
 
 5 years 1861— 65. 5 years 1866— 70. 5 years 1871— 75. 5 years 1876— SO. 5 years 1R81— 85. 
 456-6 428-4 373-2 384-8 410-2 
 
 It is specially a disease of children ; 90 per cent, of the deaths 
 being of children under five years of age : for example, of 12,013 
 deaths registered from this cause in 1886, the folio-wing was the ago 
 distribution : — 
 
 5 per cent. 
 
 Under 5 . 
 
 10,878 
 
 . 90-5 
 
 5 . 
 
 958 . 
 
 7-9 
 
 10 
 
 89 . 
 
 -7 
 
 15 
 
 28 . 
 
 •2 
 
 20 
 
 22 
 
 •2 
 
 25 
 
 25 . 
 
 -2 
 
 35 
 
 12. 
 
 . -1 
 
 45 
 
 1—1 
 
 
 12,013 
 
 Of the 12,013 deaths 6,090 were males, 5,923 females. Of the 
 different ages that make up the children under five years of age, 
 the greatest number occur above the first and below the second 
 year of life. The disease being practically confined to children, it 
 would be a more accurate way of considering the mortality to state 
 per population under five years of age, this for the five years end- 
 ing 1885 is no less than than 2844 per thousand, or 2,844 per 
 million. 
 
 (286) Seasonal Prevaleince. 
 
 Buchan and Mitchell's curve ^ based upon the weekly deaths for 
 the thirty years ending with 1874, shows a double maximum and 
 minimum during the year, the larger maximum occurring in 
 November, December, and January, and the smaller in May and 
 June ; the larger minimum in August, September, and October, 
 and the smaller in February and March. The most rapid fluctua- 
 tion takes place in the fall from Christmas to the middle of 
 February, the weekly deaths falling from 42 to 21. The curve is 
 a very steady one, the maxima and minima being well marked in 
 each of the thirty years. 
 
 ^ Op. dt. 
 
376 A MANUAL OF PUBLIC HEALTH. [ohai'. 
 
 (287) Symjptoms. 
 
 There is a distinct incubation period, which exhibits but few 
 variations, the initial fever commencing on the 12th, and the 
 eruption appearing on the 14th day after infection. In popular 
 language, measles commences as a violent cold, the eyes are con- 
 gested and red, the mucous membranes of the nose inflamed, and 
 there is some cough. Not unfrequently the throat is a little sore. 
 In cases of moderate severity, there is considerable fever, tem- 
 peratures of 104° and 105° being common, while in severe cases 
 the temperature on the 5th day of illness may reach as high as 
 109°. The eruption fully out, the temperature falls rapidly one or 
 two degrees above the normal standard. The eruption comes out 
 in three crops ; it makes its appearance on the third, fourth, and 
 occasionally on the fifth day of the fever ; the first crop attacks the 
 face, twenty-four hours after the facial exanthem, the trunk- is 
 invaded, and the eruption lastly attacks the extremities. As it 
 appears in one part of the body so it fades in the other. On the 
 6th or 7th day, it has vanished entirely, and there is a bran like 
 and not very conspicuous desquamation. The eruption consists of 
 small circular pinkish red or raspberry coloured spots ; on pressing, 
 there is no feeling of induration as in small-pox eruptions ; it 
 disappears on pressure. On looking at the arrangement of the 
 eruption it is very commonly distributed in circinate curves. In 
 very severe cases there may be effusions of blood beneath the 
 skin, as in typhus ; measles again is occasionally papular, and on 
 the neck, arms, and breasts, in very young children, vesicles have 
 been known to form. The organs of the chest are in the majority 
 of cases more or less affected, and death when it occurs is for the 
 most part due to pneumonia. 
 
 In the mildest cases the eruption does not occur or is so evan- 
 escent as to pass unnoticed. Here there are no elements for 
 diagnosis, the symptoms are those of a catarrh. Possibly the 
 " colds " so often seen among adults in times of measles epidemics, 
 are attacks of measles without eruption. To complete the history 
 of measles it must be mentioned that in a few instances there 
 is a well marked eruption but no inflammation of the mucous 
 surfaces. 
 
xxvi.] MEASLES. 377 
 
 (288) Etiologij. 
 
 It may be stated with some confidence that measles is one of 
 the micro-parasitic class dependent on some specific microbe. In 
 the blood, in the capillary vessels of the skin, as well as in the 
 catarrhal exudations, cocci and diplococci have been observed/ 
 but the bacteriology of measles has not been yet systematically 
 investigated, and it is rather from analogy than from experiment 
 that it may be presumed to be dependent on the specific 
 microbe. The materies moQ'hi is in the expectoration, and the 
 cutaneous debris. Whether the other excreta are infectious is 
 not known. 
 
 (289) Measures to he taken in Oiiibreaks of Measles. 
 
 The fact that measles begins as an ordinary cold, and that it is 
 in this stage highly infectious, puts an extraordinary difficulty in 
 the way of the hygienist. Of all diseases measles is most difficult 
 to arrest the spread of in a household. Neither in typhus nor in 
 small-pox, is the disease so intensely infectious in the early days, 
 but in measles we are face to face with a fever which by the time 
 the diagnosis has been formed has already sown its seed in all those 
 who are susceptible of its influence, and who have been brought 
 within striking distance. The striking distance also is probably 
 .considerable, at all events its rapid spread in schools under circum- 
 stances in which actual contact has not taken place, suggests that 
 it travels to a greater distance through the air than the infection 
 of typhus. Although measures of isolation will in nine cases 
 out of ten be too late so far as the family or household is con- 
 cerned, it is right to give such measures a trial, and to isolate 
 the first cases of measles directly the affection is recognised, all 
 excreta, whether from the kidneys, bowels, or from the mouth 
 and nose, should be immediately disinfected or destroyed. The 
 only practical method of dealing with rural epidemics of measles 
 has been found to temporarily close the schools of the area infected ; 
 this it must be confessed has answered far better in country 
 districts where the children live in isolated communities than in 
 large towns. Measles has not hitherto been treated in infectious 
 
 ^ Keating, Phil. Med. Times, 1882. Cornil and Bates, Los Baeteries, 1885. 
 
378 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 hospitals ; to receive measles in hospitals would be a good thing 
 in the interest of most of the patients themselves, but for the 
 reason already given, that is the early development of infection, it 
 is questionable whether the great expense to the community of 
 treating the thousands of cases of measles would be compensated 
 by corresponding advantages. Measles is one of those diseases 
 which requires patient research to elucidate more clearly its nature. 
 If success is attained in this direction, it may be then hoped that 
 some satisfactory scheme of prevention may be formulated. 
 
 Scarlet Fever (syN. Scarlatina). 
 
 (290) General Course of Scarlet Fever. — Incubation. 
 
 Typical scarlet fever of ordinary severity is characterized by the 
 following symptoms : On or about the fourth day ■^ after receiving 
 
 ^ The following remarks as to the incubation period of scarlet fever, by Dr. 
 Clement Cubes, are valuable : — "I think there is no incubation period so variously 
 stated by different authors as that of scarlatina ; I have heard it given from a few 
 hours to twenty-eight days. Yet there is nothing more certain in my opinion than 
 the fact that it never extends beyond a week, and rarely lasts so long. During the 
 time that scarlet fever is prevalent it should be remembered that there is a class of 
 sore throats — to all appearance often only simple acute tonsillitis, while at others 
 having a membranous or sloughy appearance, and with a complete absence of eraption 
 on the skin— occuning in those who have already had scarlatina ; this kind of sore 
 throat, however, is capable of passing on scarlatina to an individual who has not 
 already been affected by it. Scarlatina is often spread extensively by these means ; 
 for if the patient has suffered previously from scarlatina, these sore throats are looked 
 upon as simple non-infectious sore throats, and are consequently not carefully isolated 
 for three or four days, as they should be. Being unrecognized therefore as centres 
 of infection the incubation period of scarlatina is miscalculated accordingly, entailing 
 in consequence, not only a scientific inaccuracy, but sometimes preventible disease 
 and death. Thus A has scarlatina on June 1st, and is carefully isolated on the same 
 day ; but previous to his being isolated he infects or gives off geims which find a 
 nidus in B's throat who has already had scarlatina, with a sore throat which appears 
 on June 5th. B not being isolated for this goes about infecting his school-fellows for 
 a week. Amongst others 0, who has not had scarlatina, is infected by him on the 
 last day of the week, June 12th, and on June 16th C shows symptoms of scarlatina. 
 Here A is regarded as the source of infection of C, and his case accordingly is regarded 
 as one of sixteen days' incubation. Again, B infects many boys, who have hitherto 
 had scarlatina, with sore throat only, on various days, and these again others, until 
 some one becomes infected who has not suffered from scarlatina, and in his case true 
 scarlatina appears, perhaps on the twenty-eighth day from A's isolation. We then 
 hear of a case of twenty -eight days' incubation of- scarlatina. There is also another 
 not sufficiently recognised source of error in estimating the period of incubation of 
 scarlatina, e.g. . . . Some years ago the following episode happened within my 
 experience ; — I had a case of scarlatina, and when a week had passed I assured the 
 master in whose house it had occurred that no more cases would arise from this first 
 case. However, many days after, another occmTed,! and at the end of a week I 
 repeated with confidence my statement that no other cases could arise from the first 
 
XXVI.] SCARLET FEVER. 379 
 
 the infection, there is sore throat, and a scarlet eruption over the 
 face and neck, the eruption seen in its earliest stage consists of 
 very minute spots and may easily be mistaken for measles, 
 especially as there is often some catarrh and congestion of the 
 conjunctivae, but these spots rapidly become confluent and the 
 erythematous blush is diffused over the whole surface of the skin, 
 leaving scarcely any healthy oases. On the first day of the 
 eruption it affects the head, neck, and upper part of the body ; it 
 keeps extending, attacking on the second day the rest of the 
 trunk, and on the third day the extremities. This order is not 
 constant, for cases are continually seen in which the legs are first 
 affected. The colour varies in different cases in intensity of hue, 
 it may be a lobster red or as dark as the colour of beetroot, in 
 severe cases it may take a livid hue, and be mixed with petechise. 
 Bouchut's test is useful in the diagnosis of the eruption. It 
 depends on the fact that the conti-actile power of the small vessels 
 of the skin is much increased in scarlet fever, hence any pressure 
 on the skin occupied by the eruption gives rise to a more or less 
 enduring white stripe. The mucous membrane of the tongue and 
 cheeks are affected. The papiUse of the tongue are enlarged, they 
 stand up, salient and erect, little scarlet protuberances above a 
 thick, creamy white fur ; this appearance of the tongue has sug- 
 gested to some a likeness to a strawberry, to others the prominent 
 papillae of the tongue of the cat, hence the term " strawberry 
 tongue," " cat's tongue." 
 
 There is another rare class of cases in which the sore throat is 
 absent or nearly so, the rash abundant, and evident, and yet the 
 person feels fairly well. A remarkable case of this kind was com- 
 municated to the author by one of the Metropolitan OfiScers of 
 Health ; the case was that of a gentleman who had a perfectly 
 
 or second cases, but that we had not yet heen able to trace the origin of the first case. 
 This was? repeated again several times until we had I think about five cases, all of them 
 with an incubation period of considerably over a week. . . . How to interpret the facts 
 accurately I could not, though I was convinced of the accuracy of my knowledge of 
 the incubation of scarlet fever. However, by and by the unknown quantity was dis- 
 covered. The boys went home for the holidays, and one of the parents wrote to say 
 that he regretted his son had been allowed to come home with his hands peeling from 
 scarlatina. This boy had never been ill for an hour, consequently no one knew any- 
 thing about his having scarlatina ; throughout the whole time he had gone about 
 infecting his school-fellows, and the only wonder is that he did not infect hundreds 
 instead of units. ... I strongly affirm that it is a rare thing for scarlatina to occur 
 after the fifth day from exposure, and never after the eighth day ; I know of no 
 reliable case on record to the contrary." — Health at School. London, 1887. 
 
380 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 typical scarlet fever rash, with no sore throat, and the rash was 
 followed by desquamation ; the gentleman declared himself abso- 
 lutely well, and it was with great incredulity that he received the 
 diagnosis of scarlet fever. The difficulty of secluding the above 
 cases is obvious ; it is the slight ambulatory cases of scarlet fever 
 which baffle diagnosis, obscure effectually the sequence from case 
 to case, and act as insidious carriers of the disease from person to 
 person. So far as is practical, the Medical Officer of Health 
 should consider every case of sore throat in times of scarlet fever 
 epidemic as likely to propagate scarlet fever, in short to be slight 
 cases of the disease. This recommendation must not be taken to 
 mean the exercise of compulsory powers of removal, for such 
 powers must never be exercised unless the diagnosis is clear, but 
 the recommendation refers to measures of isolation undertaken 
 voluntarily on the advice of the health officer, and especially to 
 the management of schools and public institutions. 
 
 (291) Seasonal Prevalence of Scarlet Fever. 
 
 The prevalence of scarlet fever is distinctly governed by season. 
 The curve given in Buchan and Mitchell's paper,^ shows that 
 the death-rate begins to rise in the first week of September, 
 attains its maximum in October, commences to decline in Decem- 
 ber, and is the lowest in March, April, and May. The curve show- 
 ing the admissions of scarlet fever patients to the Asylums Board 
 Hospitals (see Plate, opposite) gives very similar results : during 
 seventeen years the admissions fell to the minimum four times in 
 February, four times in March, five times in April, twice in June, 
 once in September, and once in December. The maximum 
 immber was attained once in January (1888), once in July, three 
 times in September, seven times in October, three times in 
 November, and twice in December. 
 
 (292) Mortality' of Scarlet Fever. 
 
 This varies much in different years. During the seventeen 
 years, from 1855-71, the total number of deaths was returned as 
 321,892, or on an average 18,934 yearly. 67'2 per cent, of these 
 deaths were of children under five years of age. 
 
 ^ Qp cit. see page 369 for methods employed by the authors. 
 
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XXVI.] 
 
 SCAELET FEVER. 
 
 381 
 
 The case and age mortality of scarlet fever can be gathered from 
 the following Table -^ : — 
 
 TABLE XL. 
 
 SCARLET FEVER.— Table showing Mortality at vaeious ages of 25,788 cases 
 
 ADMITTED INTO THE AsYLTTMS BOAED HOSPITALS. 
 
 AGES. 
 
 Male?. 
 
 Females. 
 
 Total. 
 
 Cases 
 Admitted. 
 
 Died. 
 
 Moi-tnlity 
 per cent. 
 
 Cases 
 Admitted. 
 
 Died. 
 
 Mortality 
 per cent. 
 
 Cases 
 Admitted. 
 
 Died. 
 
 Combined 
 Mortality 
 per cent. 
 
 Under 5 ... 
 5 to 10 ... 
 
 10 to 15 ... 
 
 15 to 20 ... 
 
 20 to 25 ... 
 
 25 to 30 ... 
 
 30 to 35 ... 
 
 35 to 40 ... 
 
 40 to 45 ... 
 
 45 to 50 ... 
 
 50 to 55 ... 
 
 55 to 60 ... 
 And upwards 
 
 3,562 
 
 4,973 
 
 2.043 
 
 856 
 
 398 
 
 178 
 
 111 
 
 45 
 
 27 
 
 5 
 
 10 
 
 1 
 
 813 
 
 433 
 
 93 
 
 47 
 
 17 
 
 11 
 
 9 
 
 6 
 
 5 
 
 "l 
 
 1 
 
 22-82 
 8-70 
 4-55 
 5-49 
 4-27 
 6-17 
 8-1 
 13-33 
 18-51 
 
 10-00 
 100-00 
 
 3,525 
 
 5,382 
 
 2,326 
 
 1,131 
 
 608 
 
 308 
 
 155 
 
 86 
 
 29 
 
 16 
 
 10 
 
 1 
 
 2 
 
 733 
 
 433 
 
 106 
 
 37 
 
 22 
 
 13 
 
 12 
 
 5 
 
 1 
 
 1 
 
 "l 
 
 20-79 
 8-04 
 4-55 
 3-27 
 3-61 
 4-22 
 7-74 
 5-81 
 3-44 
 6-25 
 
 50-00 
 
 7,087 
 
 10,355 
 
 4,369 
 
 1,987 
 
 1,006 
 
 486 
 
 266 
 
 131 
 
 56 
 
 21 
 
 20 
 
 2 
 
 2 
 
 1,546 
 
 866 
 
 199 
 
 84 
 
 39 
 
 24 
 
 21 
 
 11 
 
 6 
 
 1 
 
 1 
 
 1 
 
 1 
 
 21-81 
 8-36 
 4-55 
 4-22 
 3-87 
 4-93 
 7-85 
 8-39 
 
 10-71 
 4-76 
 5-00 
 
 50-00 
 
 50-00 
 
 Totals 
 
 12,209 
 
 1,436 
 
 11-76 
 
 13,579 
 
 1,364 
 
 10-04 
 
 25,788 
 
 2,800 
 
 10-85 
 
 N.B.- 
 
 -The above table includes deaths within 48 honrs after admission as well as deaths 
 from intercurrent maladies. 
 
 Hence, if the deaths from scarlet fever be multiplied by 11, there 
 is a fair probability that the number obtained will approximate to 
 the number of cases occurring in a district. 
 
 (293) Sex and Age. 
 
 The following extract from the Forty-ninth Annual Report of the 
 Registrar-General will show the incidence of scarlet fever on sex 
 and age : — 
 
 " In the course of the 27 years, 1859-85, nearly half a million 
 deaths from scarlet fever were registered in England and Wales. 
 These deaths form the basis of the following Table, which gives the 
 mean annual mortality per million living at successive age-periods, 
 for each sex. 
 
 ' Metropolitan Asylums Board. Annual Report of Statistical Committee, 1888. 
 
382 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 Table XLI. 
 
 Mean Annual Mortality from Scarlet Fever pee Million Living at 
 Successive Ase-Periods, 1859-85. 
 
 Age. 
 
 Annual Deatlis per Million living. 
 
 Males. 
 
 Females. 
 
 0—1 . 
 
 1—2 ... 
 
 2-3 . 
 
 3—4 . 
 
 4—5 . ... 
 
 1664 
 4170 
 4676 
 4484 
 3642 
 
 1384 
 3874 
 4491 
 4332 
 3556 
 
 0-5 . . . 
 
 5—10 . . 
 10—15 . . 
 15—20 
 
 20—25 . . . 
 25—35 ... 
 35 and upwards 
 
 3681 
 
 1667 
 
 346 
 
 111 
 
 59 
 
 36 
 
 13 
 
 3482 
 
 1613 
 
 381 
 
 113 
 
 77 
 
 58 
 
 15 
 
 All Ages 
 
 778 
 
 717 
 
 It will be seen that in eacli sex the mortality from scarlet fever 
 rises to a maximum in the third year of life, and then falls, at first 
 slowly, but afterwards rapidly, becoming smaller and smaller with 
 each successive age-period, to the end of life. 
 
 Further it will be noted that from birth to the end of the tenth 
 year of life, that is to say, throughout that portion of life in which 
 by far the greater part of the deaths from scarlet fever occur, the 
 male mortality is considerably higher than the female mortality, 
 but that after this period the reverse is the case, the excess being 
 in each later age-period on the side of the female sex. 
 
 Seeing on what a very large basis these rates have been cal- 
 culated, both as regards number of deaths and number of years 
 over which they were spread,^ we may feel assured that the 
 differences here pointed out between successive age-periods and 
 the two sexes are not accidental or transitory, but fixed and 
 permanent; and the question next to be considered is whether 
 
 ^ The very variable severity of scarlet fever in different outbreaks makes it 
 necessary, for any trustworthy statistics, to take a long series of years into account. 
 
XXVI.] SCAELET FEVEK. 383 
 
 these differences of mortality are due to the disease being more 
 common, or to its being more likely to terminate fatally in one sex 
 than the other, and at some ages than others. Are the differences, 
 that is to say, differences of prevalence or differences of case- 
 mortality ? 
 
 The first step in examining this question is to ascertain the 
 case-mortality, that is to say, the proportion of deaths to cases at 
 each age -period and in each sex. 
 
 The data available for this calculation are neither so abundant 
 nor so complete as could be wished. The particulars, however, as 
 to age, sex, and results have been obtained in 17,795 cases of 
 scarlet fever admitted during the 12 years 1874-85 into the 
 London Fever Hospital and the Metropolitan Asylums Hospitals at 
 Stockwell and Homerton, and the rates given in Table XLII. are 
 calculated from these 17,795 cases. It was necessary, however, to 
 supplement, to a certain extent, the inforination obtained from 
 these London hospitals; for the published reports of these hos- 
 pitals do not distinguish the several years of life in the 0-5 years- 
 period, and, as this is the period of life in which scarlet fever is at 
 its maximum, the separation of these single years from each other 
 is of much importance. This deficiency has been met in the 
 following manner : — The official reports for Christiania in Norway 
 give the full particulars of nearly 5,000 cases of scarlet fever which 
 had occurred there in the years 1870-82. The case-mortality among 
 these attacks for the aggregate 0-5 years age-period differed very 
 slightly from the case-mortality for the corresponding age-period 
 in London, and it was therefore no very great assumption to 
 suppose that there was a corresponding degree of similarity 
 between the case-mortalities in the single years which make up 
 the 0-5 years period. It has been assumed, therefore, that the 
 case-mortality in the 1st, 2nd, 3rd, 4th, and 5th years of life in 
 London differed from the corresponding case-mortalities in Chris- 
 tiania just in the same degree as did the case-mortality in the 
 aggregate age-period, made up of those five years, and the rates 
 given in the table for these first five years are those thus obtained.'^ 
 
 ^ The caaemortality in Christiania for the entire 0-5 age-period was, for males 
 211 per 1,000 cases, while in London it was 241. For females it was 200 in Chris- 
 tiania and 217 in London. The case-mortalities in Christiania for the single years have 
 therefore been raised by 14'22 per cent for males and by 8'5 per cent, for females, to 
 give the mortalities for London. — Gf. Beretning om Folkemmngden og Suiidhedstil- 
 atavden i Christiania, 1882, pp. xiii.-xiv. 
 
384 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [CHAP. 
 
 Table XLIL 
 
 Case-Mortality. — Deaths pee 1,000 Cases of Scarlet Fbvee in Hospitals 
 
 1874-85. 
 
 Age. 
 
 Males. 
 
 Females. 
 
 0—1 
 
 1—2 .... 
 
 2—3 
 
 3—4. 
 
 4—5 . . . 
 
 395 
 384 
 255 
 184 
 130 
 
 442 
 346 
 226 
 174 
 112 
 
 0—5 
 
 5—10 . 
 10—15 . 
 15—20 
 
 20—25 
 
 25—35 
 
 35 and upwards .• 
 
 241 
 106 
 56 
 40 
 39 
 75 
 85 
 
 217 
 97 
 53 
 34 
 32 
 43 
 65 
 
 The figures in this table are very striking, and show beyond 
 dispute how utterly untenable is the statement made, even in 
 some works of high medical authority, that age and sex are 
 without importance as elements in the prognosis of scarlet fever. 
 As regards sex, putting aside the first year of life, when the cases 
 are so few that the accuracy of the calculated case-mortality is 
 doubtful, the danger of an attack of this disease is at every age- 
 period considerably greater if the patient be of the male than if 
 of the female sex. The differences due to sex are, however, as 
 nothing in comparison with those due to age. The chance of a 
 case proving fatal in each sex is highest in the first year of life, 
 and then diminishes rapidly and with unbroken regularity to the 
 end of the twenty-fifth year, after which there is again an increase 
 of risk. 
 
 Having now ascertained, firstly, what is the mortality from 
 scarlet fever at each age-period and in either sex, and secondly, 
 what number of cases correspond to each such death, it is of 
 course a simple matter to combine the two tables and calculate 
 the number of cases at each age-period and in each sex for equal 
 numbers living, it being however important to notice that the 
 cases thus obtained will be cases of equal severity to those which 
 
XXVI.] 
 
 SCARLET FEVER. 
 
 385 
 
 form the basis of Table XLII., that is to say, cases fit for admission 
 into a hospital. The results are given in the following table : — 
 
 Table XLIII. 
 
 Estimated Annual Cases of Scaklet Fever, of Equal Seveeitt to those 
 Admitted into Hospital, peb Million Living, at Successive Age-Periods 
 and in Each Sex. 
 
 Ages. 
 
 Males. 
 
 Females. 
 
 0-1 ... 
 
 1—2 . . . 
 
 2—3 . . 
 
 3—4 . 
 
 4—5 . . 
 
 4,213 
 10,859 
 18,337 
 24,370 
 28,015 
 
 3,131 
 
 11,197 
 19,872 
 24,897 
 31,750 
 
 0—5 .... 
 
 5—10 
 10—15 . . 
 15—20 . . . 
 20—25 . 
 25—35 ... 
 35 and upwards . . 
 
 15,274 
 
 15,726 
 
 6,179 
 
 2,776 
 
 1,613 
 
 480 
 
 1S3 
 
 16,046 
 16,629 
 7,189 
 3,324 
 2,406 
 1,349 
 231 
 
 So far our course has been simple, and the results arrived at 
 may be accepted with much confidence, though it may be admitted 
 that it would be more satisfactory were the basis of the table of 
 case-mortality (Table XLII.) enlarged so as to embrace a greater 
 number of cases and a .longer series of years. But the next stage 
 in the inquiry becomes much more hypothetical, and the result 
 will consequently be less trustworthy. The question to which an 
 answer has to be sought is, whether the diminution of cases of 
 scarlet fever in successive age-periods, shown in Table XLIII., is 
 merely due to the increased proportion, at each successive age- 
 period, of persons who have already been attacked by scarlet 
 fever and are therefore protected against a future attack, or 
 whether it indicates a diminishing susceptibility to the infection 
 with advance of age in those' who are as yet unprotected. It 
 will not be difficult to obtain an answer to this question if the 
 figures in Table XLII. represented the general case-mortality and 
 not merely the mortality of hospital cases ; but, though scarlet fever 
 patients are sent into hospital not only when they are severe cases, 
 but often simply in order to separate an infectious child from the 
 
 c 
 
386 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 rest of the family, it cannot be doubted that on the whole the 
 average of the hospital cases will be of more than average severity, 
 there being notoriously a large number of scarlet fever cases in 
 which the ailment is so slight that it would not occur to the 
 parents to send the child away from home. Consequently the case- 
 mortality as given in TableXLlI. is almost certainly much too high ; 
 it is true for hospital cases, but not for all cases. Now there are 
 some large towns in which returns are made of all known cases of 
 scarlet fever, whether occurring in or out of hospitals, and, though 
 these returns are neither of sufficient magnitude nor of sufficient 
 certainty to afford a very secure basis, yet they afford some assist- 
 ance, and judging by them we shall probably not be very far from 
 the mark if we assume that, for every individual who is protected 
 against future scarlet fever by an attack of equal severity to that 
 of an average hospital case, there is another person protected by 
 an attack of less severity. Let it be assumed then, that this is 
 true, and then the next step can be taken ; the proportion of the 
 population that is protected at each successive age-period in each 
 sex can be calculated, and the proportion between the cases and 
 the unprotected population ascertained. The results of this some- 
 what tedious arithmetical process are given in the following 
 table : — 
 
 Table XLIV. 
 
 Estimated' Annttal Number of Attacks and Deaths bt Scarlet Fever in 
 A Million Unprotected Persons Of each- Sex at Successive Age 
 Periods. 
 
 Age 
 
 Attacks. 
 
 Deaths. 
 
 
 Males 
 
 Females. 
 
 Males. 
 
 Females. 
 
 0—1 
 
 6,779 
 
 4,887 
 
 1,668 
 
 1,386 
 
 1—2 
 
 17,758 
 
 18,723 
 
 4,220 
 
 3,916 
 
 2—3 
 
 33,065 
 
 36,480 
 
 4,832 
 
 4,647 
 
 3—4 
 
 47,385 
 
 48,874 
 
 4,801 
 
 4,657 
 
 4—5 
 
 58,906 
 
 68,036 
 
 4,095 
 
 4,036 
 
 5—10 
 
 37,524 
 
 40,423 
 
 2,100 
 
 2,060 
 
 10—15 
 
 17,332 
 
 20,817 
 
 499 
 
 567 
 
 15—20 
 
 8,365 
 
 10,508 
 
 171 
 
 182 
 
 20—25 
 
 4,714 
 
 7,972 
 
 94 
 
 130 
 
 25—30 
 
 1,491 
 
 4,585 
 
 58 
 
 101 
 
 30—35 
 
 472 
 
 787 
 
 21 
 
 26 
 
 - - ■■ - / 
 
 Estimated on the assumption stated above. 
 
XXVI.] SCARLET FEVER. 387 
 
 The figures in this table cannot of course claim to be more than 
 approximate estimates. More precise results will be hereafter 
 obtainable, when the case-mortality can be based upon a larger 
 accumulation of data than was available for the construction of 
 Table XLII., and which shall include the cases outside as well as 
 those within hospitals. Allowing, fully, however, for this element 
 of uncertainty as to the precise figures, we are nevertheless able 
 to draw with much certainty the following conclusions as to 
 scarlet fever : — 
 
 1. The mortality from this disease is at its maximum in the 
 third year of life, and after this diminishes with age, at first slowly 
 afterwards rapidly. (Table XLIV..) 
 
 2. This diminution is due to three contributory causes : (a) the 
 increased proportion in the population at each successive age- 
 period of persons protected by a previous attack ; (/S) the diminu- 
 tion of liability to infection in successive age-periods of those who 
 are as yet unprotected ; (7) the diminishing risk in successive age- 
 periods of an attack, should it occur, proving fatal. 
 
 3. The liability of the unprotected to infection is small in 
 the first year of life, increases to a maximum in the fifth year or 
 soon after,^ and then becomes rapidly smaller and smaller with 
 advance of years. (Table XLIV. Cols. 1, 2). 
 
 4. The chance that an attack will terminate fatally is highest 
 in infancy, and diminishes rapidly with years to the end of the 
 twenty-fifth year ; after which an attack is again somewhat more 
 dangerous. (Table XLIV.) 
 
 5. The female sex throughout life, the first year possibly 
 excepted, is more liable to scarlet fever than the male sex. 
 (Table XLIV.) 
 
 6. But the attacks in males, though fewer, are more likely to 
 terminate fatally. (Table XLIV.) 
 
 Now it is sometimes said that the separation from its family of 
 
 a child who is attacked by scarlet fever is scarcely worth the 
 
 trouble and expense it involves, seeing that the rest of the 
 
 children, though they may escape on that special occasion, are 
 
 almost certain to contraqt this very common disease at some future 
 
 ^ The Table does not suffice to show whether the fifth year be the year of actual 
 maximum. For as the 6-10 year-period is not broken up into separate years the 
 maximum might possibly be in the sixth or even seventh year. 
 
 c c 2 
 
388 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 time, and may therefore as well, if not preferably, have it at once. 
 The results, however, to which our statistical inquiry has led us, 
 are completely subversive of such a position. They show — in- 
 dependently of the plain fact that a very large proportion of 
 persons go through life without ever contracting this disease — 
 that the longer an attack is deferred, the less likely it is to occur 
 at all; and not only so, but that, even supposing it to occur 
 eventually, the less likely it is to end fatally." 
 
 (294) Sequelce and Complications of Scarlet Fever. 
 
 Of late years the relative frequency of different complications of 
 scarlet fever has been studied on a large scale in the hospitals con- 
 nected with the Asylums Board, and the various reports of the 
 Statistical Committee constitute a veritable mine of information. A 
 curious circumstance about these reports is however the undoubted 
 fact that scarlatina derived from one part of the Metropolitan area 
 does not present the same percentage of complications as another ; 
 for instance, in the 1887 epidemic, in the Eastern Hospital, albu- 
 minuria complicated the cases in the proportion of 4"9 per cent, of 
 the attacks, while in the Western Hospital, in the same year and 
 the same epidemic, albuminuria prevailed in the proportion of 35'6 
 per cent. ; it may be suggested that the staff of the one hospital 
 more diligently examined the urine than of the other, but there 
 are similar differences with other diseases ; take, for example, 
 otorrhea : in 1887 the Eastern Hospital records show, in over 1,000 
 cases, that otorrhea prevailed in the proportion of 4"3 per cent., in 
 the Western ll'O per cent. Hence it is impossible to be dogmatic 
 with regard to the relative frequency of particular complications ; 
 it may however be useful to give the following percentages 
 observed, compiled from 1,115 cases of scarlet fever admitted into 
 the Western Hospital in 1887 : — 
 
 Per cent, of attacks. 
 
 Albuminuria .... . . 35 '6 
 
 Adenitis (inflammation of glands of neck) 25 "4 
 
 Rhinitis .... . 11-3 
 
 Otorrhea ... 11-0 
 
 Nephritis 5 '6 
 
 Abscess (mostly cervical) . 3-8 
 
 Arthritis . . . 3'0 
 
 Stomatitis . 1'9 
 
 Conjunctivitis ..... 7 
 
XXVI.] 
 
 SCARLET FEVER. 
 
 389 
 
 To this may be added a long list of less frequent complications, 
 sucli as hsematuria, pyaemia, convulsions, dropsy, peri and endo- 
 carditis, laryngitis, cystitis, and others. It must be specially 
 noted that the complications mentioned above rarely occur simply, 
 they are for the most part compound, that is, a person will suffer 
 at once from albuminuria, otorrhea, and abscess, or other 
 combinations. 
 
 Dr. Sweeting has observed the remarkable fact that albuminuria 
 has been on the increase in the Western Hospital in successive 
 epidemics, due, as he considers to decreasing cubic space, the 
 wards becoming in successive years more crowded with patients. 
 He gives the following table : — 
 
 Table XLY. 
 
 Albumintima, 1882-1887. 
 
 Teai-. 
 
 Numter 
 
 of completed 
 
 cases. 
 
 Number of these 
 
 which presented 
 
 Albuminuria. 
 
 Rate 
 per cent. 
 
 Remarks. 
 
 1882 
 1883 
 1884 
 
 64 
 
 248 
 
 89 
 
 9 
 61 
 17 
 
 14-0 
 24-6 
 19-1 
 
 Heat and nitric acid used as a 
 
 test for albumen. 
 Picric acid first employed in early 
 
 part of year. 
 Picric acid exclusively employed. 
 
 1885 
 
 180 
 
 39 
 
 21-6 
 
 It j» ti 
 
 1886 
 
 343 
 
 101 
 
 29-4 
 
 )) )) , 11 
 
 1887 
 
 1,115 
 
 397 
 
 35-6 
 
 )> )i », 
 
 The same increase of albuminuria has been noted by Dr. Thorne, 
 late physician to the London Fever Hospital, who says,^ " There 
 have been occasions when, owing to repairs or otherwise, it 
 has been found necessary as a temporary measure to exceed the 
 number of patients properly allotted to one or other ward, and 
 when this has been the case the practice has almost invariably 
 been followed by an increase in the number of patients exhibiting 
 albumen in the urine." 
 
 It may well form the subject of inquiry whether the curious 
 odour given off by lungs and skin in the worst form of scarlet 
 •^ Practitioner, December, 1887. 
 
390 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 fever is Qot some volatile toxic matter producing albuminuria, if 
 so, it would be a reasonable explanation of the above facts. 
 Whatever the cause of the increase, such observations are addi- 
 tional arguments for the amplest cubic space in infectious 
 hospitals. 
 
 (295) Period during which it is necessary to isolate Scarlet 
 Fever Patients. 
 
 It is to be hoped that accurate observations based upon experi- 
 mental data will ere long be forthcoming, so as to enable us to 
 know when a patient ceases to be contagious ; at present we have 
 to rely solely iipon the length of desquamation or discharges. 
 That in the prolonged "peeling" of some cases of scarlet fever 
 the debris contains the scarlatinal infection is more a matter of 
 inference than actual proof, but until the question is settled, 
 it will be safest to take the period of seven weeks from the 
 beginning of the illness as a rule for ordinary cases, provided the 
 desquamation is finished, and this is the opinion of Dr. Gayton,^ 
 the superintendent of the North-Western Hospital, whose observa- 
 tions may be quoted verbatim : — " The variableness of desqua- 
 mation, or peeling, is by all medical men admitted. Occasionally 
 a long period elapses before the whole of the cuticle has separated — 
 six weeks, two months, and longer ; indeed, that on the soles of the 
 feet may often be seen peeling long after the desquamation on the 
 rest of the body has ceased, when the patient is perfectly well, 
 and has been walking about, perhaps, for a long time. Again, it 
 may be so slight as to be perceptible about the roots of the nails 
 only, or so considerable as to cover the whole place with dust every 
 time the patient shakes himself, during the whole of which time, 
 however, it would be utterly wrong — nay, criminal — to sanction 
 any inter-communication with the healthy. Enforced isolation, 
 after a time at least, is no doubt very hard, especially in cases 
 where the disease is slight, where there is no sense of illness, and 
 but slight or no appearance of desquamation, but, nevertheless, 
 it is sound doctrine ; the precaution may appear needlessly exces- 
 sive, but the case is one for great caution. As a matter, therefore, 
 of sanitary precaution against the dissemination of infection, it is, 
 
 ' Metropolitan Asylums Board. Atmual Eeport of Statistical Committee, 1888. 
 
XXVI.] SCARLET FEVER AND MILK. 391 
 
 from my point of view, utterly wrong to permit any scarlet fever 
 patient whatever to mingle with persons susceptible to the disease 
 until the expiration of seven weeks from the beginning of the 
 illnesss, and in those cases where the desquamation is of late 
 appearance, until the process is completed, and for a fortnight 
 afterwards, nor then, unless there is entire absence of discharge 
 from the nose and ears, and the clothes worn on discharge are 
 clean and thoroughly disinfected." 
 
 (296) The ConTiexion of Scarlatina with Disease in Milch Cows. 
 
 That in some way or other milk conveys the cause of scarlet 
 fever has been many times noticed, but it was. not until the inquiry 
 by Mr. Power into an epidemic of scarlet fever (1882) in St. 
 Giles and St. Pancras, that there were sufficient grounds for 
 believing that the cow itself may secrete milk which, independent 
 of human agency, is an infectious fluid, and will give those drinking 
 such milk, who are susceptible of the poison, scarlet fever. To 
 quote Buchanan, in this epidemic " two facts could be affirmed ; 
 the one, that a cow recently come into milk at a particular farm 
 had been suffering from some ailment, seemingly from the time of 
 her calving, of which loss of hair in patches was the most conspi- 
 cuous manifestation ; the other, that there existed no discoverable 
 means by which the milk, which had coincided with scarlatina in its 
 distribution, could have received infective quality from the human 
 subject." The facts, although imperfect, were so far suggestive 
 that, at the instance of the Local Government Board, Dr. Klein 
 made some experimental observations as to the concern of animals 
 with human scarlatina, and it was found that, particularly when a 
 cow was in milk, a definite disease was producible in the animal 
 by means of scarlatina infection, the disease was capable of being 
 communicated from one animal to another by inoculation. 
 
 In 1885 new light was thrown upon the subject, by what is 
 known as the Marylebone epidemic. The author reported to the 
 Local Government Board a sudden and extensive outbreak of 
 scarlet fever that was evidently connected with a particular milk 
 supply. The retailer obtained his supply from two farms, and 
 the coincidence of the retail milk distribution with scarlatina 
 was limited to one portion of the milk, which portion only was 
 
392 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 derived from a certain farm at Hendon. Mr. Power was deputed 
 to investigate the matter, and he found that milk had heen 
 distributed by retail in St. John's Wood, in St. Pancras, in Hamp- 
 stead, and at Hendon, and in these districts only, and from every 
 one of these districts, except from St. John's-Wood, the same general 
 story was forthcoming. " Until the end of November or beginning 
 of December, 1885, the district had been for some months excep- 
 tionally free from scarlatina ; about this date scarlatina had under- 
 gone a sudden and notable increase in the district, and then and 
 thenceforward a strikingly large proportion of the recorded cases 
 had occurred among persons who proved, upon inquiry, to be 
 customers of the milk retailer dealing in the particular Hendou 
 milk." 1 A very strict inquiry at the Hendon farm seemed to put 
 beyond a doubt, that the milk had not been contaminated there 
 by human agency. 
 
 By a series of facts amply detailed in Mr. Power's report, among 
 which the exemption of the St. John's Wood customers occupied 
 an important link in the chain of evidence, the infected milk was 
 traced to a particular cowshed, and to particular cows. In the end 
 it was demonstrated beyond a reasonable doubt that in December 
 these cows suffered from an eruptive disease of the udder and 
 teats, a condition first introduced there in the previous month by 
 some cows newly arrived from Derbyshire. 
 
 Products derived from the affected animals were studied by 
 Dr. Klein, and two of the cows were purchased and conveyed to 
 the Brown Institution. 
 
 Dr. Klein ^ made a series of researches with this material, and 
 the results of which up to the present are as follows : — 
 
 The cow disease is characterised by closely similar anatomical 
 features to the disease in man. From the diseased tissues 
 and organs of man and cow alike a streptococcus can be 
 separated which has the following characters. The streptococcus 
 grows on gelatin in opaque white colonies, and it does not 
 liquify the gelatin. It is slower of growth thaur most micrococci. 
 After a long time (several weeks) it has a fairly distinct but 
 slightly irregular and crenate outline here and there, beset 
 
 1 Fifteenth Annual Report of the Local Government Board {Supplement), 1885-6. 
 
 2 Seventeenth Annual Report of the Local Government Board (Suwlement), 
 1887-8, p. xiii. ^ ^^ 
 
Plate I 
 
 
 
 
 
 i.^rf;',.J«,-7^ 
 
XXYI.] 
 
 SCARLET FEVER AND MILK. 
 
 393 
 
 with dark knobs or linear processes (see Fig. 49, which, shows the 
 appearance of an artificial culture on gelatin x 3). When grown 
 in milk it coagulates the milk. If the inoculated milk be kept for 
 two days in the incubator at 35° this distinguishes it from the 
 streptococcus of foot and mouth disease, to which it has otherwise 
 remarkable resemblance. Some of the elements may be as dip- 
 lococci or as short chains. Cultivated in broth it forms long and 
 
 Fig. 49. 
 
 Fig. 50. 
 
 exquisite chains (see Fig. 50, which is from a photograph of a 
 subculture in broth). The elements of the chain are a little larger 
 than those of foot and mouth disease. 
 
 Subcultures of the micrococci have the property when inoculated 
 into calves of producing in them every manifestation of the Hendon 
 disease, except sores on the teats and udders, and subcultures from 
 human scarlatina inoculated into recently calved cows can produce 
 in those cows, along with other manifestations of the Hendon 
 disease, the characteristic ulcers on the teats — ulcers identical in 
 character with those observed at the Hendon farm. 
 
 The post-mortem appearances of the chief organs affected are 
 represented in Plate I. from Dr. Klein's original drawings. A is 
 a section of the spleen of a cow which had been artificially in- 
 oculated with a culture of the streptococcus derived directly from 
 human scarlatina. The gland was slightly enlarged, of a dark 
 colour, and in the section numerous petechise are observed ; B is a 
 cut bronchial gland showing pigment and extravasated blood in 
 
394 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 the cortical lymph sinuses and in the medulla ; c is a portion of 
 the lung showing numerous petechias. 
 
 The subcultures produce in rodents a disease pathologically 
 similar to cow and human scarlatina. 
 
 Calves fed on subcultures established from human scarlatina 
 obtain the flendon disease. 
 
 Children (as proved by the Marylebone epidemic) fed on milk 
 from cows suffering from the Hendon disease obtain scarlatina. 
 The above, Dr. Buchanan ^ justly remarks, form a mass of evidence 
 that the Hendon disease is a form occurring in the cow of the very 
 disease that we call scarlatina when it occurs in the human subject. 
 
 So far the evidence of the Local Government Board's scientific 
 staff; their conclusions are not, however, accepted in their en- 
 tirety by all bacteriologists. In particular Professor Crookshank 
 maintains that a disease in Wiltshire, apparently identical with 
 the Hendon disease so far as external appearances go, is cow-pox, 
 and infers that the Hendon disease was also cow-pox ; to which 
 Dr. Klein replies that there can be no question that the Wiltshire 
 " is not the disease I saw at Hendon, and now known as cow- 
 scarlatina. Inasmuch as both are ulcerative diseases showing 
 ulcers particularly on teats and udders, the two no doubt resemble 
 each other. In so far as the ulcers have the structure of ulcers, 
 the ulcers (if we may ignore considerations of duration) again have 
 resemblances inter se. In so far as they are communicable from 
 animal to animal, they are both of them infectious diseases. Also 
 they both have micrococci in the . discharges of the ulcers, though 
 the micrococci differ in their characters. But there, it seems to 
 me, the similarity ends." 
 
 Drs. Edington and Jamieson have also investigated scarlatina by 
 biological methods. Edington, from his researches, ascribes the 
 true cause of scarlatina to a motile bacillus. 
 
 It is unfortunate that hitherto no eminent bacteriologist has 
 either confirmed Klein's researches or any of the other rival 
 theories. The last research of Klein, in which he has succeeded 
 in reproducing the Hendon disease by inoculations of human 
 scarlatinal matter in recently calved cows, is most important, and 
 
 1 Report by Dr. Klein on a Disease of Cows. Fifteenth Annual Eeport of the Local 
 Government Board (Supplement), 1885-6. "The Morphology and Biology of 
 Streptococcus," by Dr. Klein. Seventeenth Annual Eeport of the Local Government 
 Board (Supplement), 1887-8. 
 
XXVI.] TYPHUS. 395 
 
 could easily be tested. Taking the whole evidence together, it 
 generally tends to prove that Klein's views are correct, but in 
 such a complicated and difficult subject we must not too hastily 
 accept them. 
 
 Typhus. 
 
 Typhus fever is peculiarly a disease of crowded poor centres of 
 population. Hence it is specially Medical Officers of Health in 
 charge of large towns who are likely to have an opportunity of 
 seeing cases of typhus. 
 
 It is characterised by a high temperature, great muscular pros- 
 tration, a distinctive eruption, is highly infectious, and one attack 
 confers as a rule immunity against a second. 
 
 (297) Statistics. 
 The diminution of the number of deaths from typhus in modern 
 times is remarkable. Before 1869 the Registrar-General included 
 under one heading three classes of continued fever, but since that 
 date there have been separate returns; 4,281 deaths from typhus 
 were returned in 1869; with a few unimportant exceptions the 
 deaths declined year by year to 318 in 1885 ; or, put in another 
 way, the death-rate for typhus has declined from 193 per million 
 in 1869 to 12 per million in 1885. In 1887 there were admitted 
 into the Asylums Hospitals 36 cases ; in 1888 only 1, and in 1889, 
 23 cases. 
 
 (298) Incuhation Period. 
 There seems to be a real variation in the period of so-called 
 latency. In 31 cases carefully observed by Murchison, in 1 case 
 it was not less than 21 days ; in 1 exactly 15 days ; in 1 not less 
 than 14 days; in 1 not less than 13 days ; in 4 exactly 12 days ; 
 in 13 a period of 12 days was within the known limits ; in 2 it was 
 not more than 10 days; in 1 not more than 6 days ; in 1 exactly 
 5 days ; in 1. between 5 and 2 days ; in 2 there was not more than 
 4 days ; in 1 not more than 2 days ; and in 2 there was no latent 
 period, or only one of a few hours. From whence it may be 
 gathered that ] 2 days is the most usual period, and that with 
 regard to the question of quarantine a period of 15 days will take 
 ia nearly all the cases. 
 
396 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (299) Symptoms. 
 
 The advent of typhiis is nearly always sudden. It may be 
 preceded by the usual indefinite slight headache and malaise for 
 one or two days, but oftener the date is sharply defined by rigors, 
 frontal headache, lassitude, pain in the back and limbs (especially 
 in the thighs), and a high temperature. The temperature on the 
 second day is mostly above 102°, by the fifth day above 103°, and 
 may reach 105°. A fever in which by the fifth day the tempera- 
 ture is not higher than 102° is probably not even a mild attack of 
 typhus. In severe cases the temperature is very high — 104° to 
 104'9° on the second or third day. Between the fourth and seventh 
 days, but usually on the fourth or fifth, there is an eruption. The 
 eruption, when it first appears, is specially likely to be confused 
 with the eruption of measles. The spots are small, varying in 
 diameter from a few lines to mere specks, and grouped together 
 in patches with an irregular outline. At first of a dirty pink, and 
 slightly elevated above the surface of the skin, they disappear on 
 pressure, but after the first or second day they become of a darker 
 colour, and on pressure only get paler. 
 
 The best place to look for the eruption is on the back. The 
 eruption is often scanty, and in dark-skinned races difficult to see. 
 There may also be difficulty in detecting the eruption in the lower 
 orders from the presence of dirt, as well as in kitchens and dark 
 rooms from the absence of a good light. The eruption is present 
 in 97'7 per cent, of the cases, when looked for by skilled and 
 experienced observers. As it does not appear until the fourth day, 
 and it may be later, in the first cases of a typhus epidemic, the 
 patients will probably be not moved to hospital before the fifth 
 or sixth day. The eruption does not appear in successive crops ; 
 they all appear as a rule within 24 hours of the commencement 
 of the eruption. About the second week of the disease minute 
 haemorrhages take place subcutaneously, giving rise to purplish 
 spots or petechise. These, of course, do not disappear on pressure. 
 The frequency of petechise has given rise to one of the synonyms 
 of typhus fever, viz., " petechial fever," but petechise in the milder 
 cases may be absent. On the other hand, they are sometimes to 
 be seen at the commencement of the malady. A very good 
 representation of the eruption on the skin in its different 
 
XXVI.], TYPHUS. 397 
 
 stages is given in Murchison's classical work on The Continued 
 Fevers. 
 
 The pefcechise have been confounded with flea-bites and vice-versa. 
 la the author s experience a child, three years old, during an epi- 
 demic of typhus, was sent upon the certificate of a physician to the 
 hospital, but the authorities returned the child two days afterwards, 
 stating the spots were those produced by fleas — a curious error, the 
 more so because the petechise of typhus are not very similar. A close 
 examination with a lens will reveal the fine puncture in the centre 
 of the spot made by the piercing apparatus of the little vampire. 
 
 About the end of the first week delirium sets in. The delirium 
 may be acute, although this is rare. It is, however, important 
 to remember that cases have been known in which the patient 
 has escaped from his attendants and appeared in the street. 
 Fortunately, owing to the rapid manner with which abundance of 
 fresh air dilutes and renders innocuous the typhus poison, this 
 circumstance is not very dangerous to the public, a chance meet- 
 ing of a delirious patient in the open street being probably more 
 alarming than infective. Nevertheless, the possibility of such an 
 occurrence shows the necessity of isolation in a suitable place, and 
 nursing by trained nurses. 
 
 After three or four days of delirium succeed nervous depression 
 and stupor. The muscular prostration is extreme, the patient Kes 
 in bed with vacant stupid countenance, the conjunctivae injected, 
 the eyelids closed, and the pupils contracted, the tongue dark brown 
 and coated with sordes. There may be tremors, subsultus, and 
 picking of the bed-clothes. The pulse is frequent, small, and un- 
 dulating. The bowels nearly always confined. The urine generally 
 copious and either evacuated involuntarily, or having to be drawn 
 away by a catheter. In this state the patient passes many hours 
 or several days with life trembling in the balance ; if the case is to 
 terminate fatally the stupor passes into profound coma, or sudden 
 engorgement of the lungs suffocates the patient, or a combination 
 of syncope and coma supervene. If the case is to terminate in 
 recovery, then on or about the fourteenth day there is a more or less 
 sudden amendment, the patient falls into a quiet sleep from which 
 he wakes another man. Recovery is now rapid. In a week there 
 will be only left great muscular weakness, and often also some 
 cerebral debility, both to be completely recovered from. 
 
398 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (300) Etiology of Typhus. 
 
 It is only by analogy that tjrphus is classed with diseases supposed 
 to be of micro-parasitic origin. The truth must be told that con- 
 cerning its real nature we know extremely little. There are some 
 grounds for believing typhus to be the emasculated plague, in a few 
 cases of typhus there are purulent swellings very similar to the 
 buboes and abscesses of the plague, and it is a circumstance of some 
 significance that Clot Bey, the eminent Egyptian physician, on 
 visiting the London Fever Hospital some years since, saw cases of 
 typhus complicated with swellings in the parotid region, and declared 
 that such cases in Egypt would be called cases of the " Plague." 
 There have only been isolated bacteriological observations on cases 
 of typhus ; for instance, Mott ^ has described active motile dumb-bell 
 cocci in the blood, and plugs of cocci in the lymphatics of the heart, 
 but no elaborate sustained inquiry into the nature of typhus has been 
 made by modern methods. Typhus has in all historic times marked 
 out for its peculiar habitat spots where human beings heaped 
 themselves together in poverty and mental misery. Of all predis- 
 posing causes the most fertile have been overcrowding, mental and 
 bodily depression. It has followed the wake of armies, it has 
 penetrated with the felon into the jail, it has sailed in the slave ship, 
 and become endemic in the lowest and most densely populated 
 parts of large cities. 
 
 " A careful study," says Murchison, " of the histoiy of typhus 
 epidemics demonstrates, in my opinion, the intimate connection 
 between these epidemics and famine or distress. They have 
 appeared during every variety of climate, season, and weather; 
 famine and overcrowding have been the sole conditions common to 
 them all." Murchison even went so far as to believe that under 
 these circumstances typhus might be produced de novo, but this 
 doctrine will not be accepted at the present day. Presuming it to 
 be caused by a micro-parasite, it is known that many of these live 
 under ordinary circumstances as saprophytes on vegetable and other 
 organic matter ; it is therefore more reasonable to suppose that, 
 instead of a creation of the typhus poison, it ever exists, and under 
 certain circumstances attacks human beings. 
 
 Whatever may be the nature of typhus poison there is good 
 1 British Medical Journal, 1883. 
 
XXVI.] TYPHUS. 399 
 
 . evidence to believe that it is lighter than atmospheric air. Haller 
 found that ozone introduced into a typhus ward was most rapidly 
 consumed in the upper part of the room. It has also been observed 
 that if typhus be treated on the second floor of a hospital, patients, 
 on the third or upper floors are likely to catch it, while on the 
 contrary, if the typhus patients are placed at the top, the infection 
 does not descend. The bodies of typhus patients emit a peculiar 
 odour, and the odour is supposed to be connected with the infection ; 
 those patients who have the strongest odour are most apt to com- 
 municate the disease. The typhus poison is most probably thrown 
 off by the skin and lungs, and taken in by breathing. The striking 
 distance of typhus is important ; the oldest observations are those 
 of Haygarth, on the subject. In 1777 he devoted much attention 
 to this matter, and concluded that the infectious matter of small 
 pox does not exceed half a yard, and that the contagion of 
 typhus is confined to a much narower sphere. We, however, 
 now know that this opinion with regard to small pox is en- 
 tirely misleading. Lind, Tweedie, and Murchison all, however, 
 agree that the typhus poison only strikes within a very small 
 distance, probably a fever hospital taking typhus patients may be 
 situated in the centre of a large population without public danger ; 
 at all events no indictment has been laid against the Loudon Fever 
 Hospital, and at no time has typhus fever prevailed in its neigh- 
 bourhood in such a manner as to suspect the hospital as the cause. 
 Murchison says, " From all experience it follows that if a typhus 
 patient be placed in a large, well ventilated apartment the attend- 
 ants incur little risk, and the other residents in the same house 
 none whatever. There are likewise no grounds for the popular 
 belief that typhus may be propagated through the atmosphere 
 from a fever hospital to the houses in its neighbourhood. On the 
 other hand, medical men who auscultate typhus patients, or who 
 inhale their concentrated exhalations from under the bedclothes, run 
 no small danger, and the danger is always increased or diminished in 
 proportion to the supply of fresh air." 
 
 The typhus poison adheres to clothes and woollen or organic sub- 
 stances generally, but if these are exposed to the air it becomes 
 innocuous ; no instance is on record of a medical man carrying typhus 
 home to his family, although some have been in constant attendance 
 on typhus patients. On the other hand, if clothes infected with 
 typhus have been tied up in bundles or put away in boxes or 
 
400 A MANUAL OP PUBLIC HEALTH. [chap. 
 
 drawers, or have been kept under other conditions which have pre- 
 vented full areation, under these circumstances the infection may- 
 be long retained, and in medical literature may be found several 
 instances in which fomites have conveyed the infection after a 
 considerable time has elapsed. 
 
 From available evidence it appears that the first few days of 
 illness are not so infectious as when the fever is at its height and 
 during the period of convalesence. Murchison says, " My opinion is 
 that the disease is really most contagious from the end of the first 
 week up to convalescence, when the peculiar odour from the skin 
 is strongest, and that the bod}' ceases to give off the poison as 
 soon as the fever subsides and the appetite and digestion are re- 
 stored. During the first week of typhus there is little danger, 
 when the patient is removed within this time the disease rarely 
 spreads." If this doctrine be accepted patients should be safe to 
 discharge from hospital a week after the complete cessation of the 
 fever. The evidence as to whether a dead body of a person dying 
 from typhus is contagious or not is far from clear, but it is safest 
 to consider such a corpse contagious, and to take measures 
 accordingly. 
 
 (301) Mortality. 
 
 The mortality calculated from 18,268 cases admitted into the 
 London fever hospital during the years 1848-59 was 18"9 per cent, 
 of the cases, but the mortality from more recent statistics is less ; for 
 instance, in 54 cases of typhus in an outbreak in St. Marylebone 
 in 1881 the mortality was 15'6 per cent, and in 1887 the case 
 mortality of typhus treated at the hospitals of the Asylum Board 
 was only 11'6 per cent. Typhus is not alone less prevalent but 
 less mortal than formerly. 
 
 The mortality is greatly influenced by age, the mortality being 
 lowest among children from 10-14 years of age, highest in adult 
 life; for example, in cases admitted to the London Fever Hospital 
 between the years 1862-70 the following was the age-distribution 
 mortality : — 
 
 Age. Mortality per cent. 
 
 Under 10 years ... 3 '27 
 
 From 10 — 14 years . 1-67 
 
 „ 16—19 „ . . . 3'96 
 
 „ 20—29 „ . . . . 12-34 
 
 ,, 30—39 ,, . . ... 22'63 
 
 ,, 40—49 „ . 35-97 
 
 Above 50 years . .... 57 '03 
 
XXVI.] TYPHUS. 401 
 
 It used to be stated that the predisposition to infection was 
 less in children, more in adults, and the rule laid down was 
 that the bread-winners of the family are first struck down, then 
 the children, but this does not coincide with the more recent 
 experiences, see p. 404. 
 
 Males are a little more liable to die from typhus than females. 
 The cause probably mainly is the greater muscular development. 
 Typhus fever is a fever in which there is disintegration of muscle 
 and poisoning of the system from the products ; hence it is an 
 old observation that patients with strong muscular development 
 bear typhus ill, and that the mortality is greater among such. 
 Besides this males on the whole are more intemperate than 
 females, and are more liable to kidney complications ; intem- 
 perance in itself predisposes. 
 
 (302) Seasonal Prevalence. 
 
 The prevalence of typhus is a little influenced by season. 
 Buchan and Mitchell's^ curve shows that typhus is above the 
 average from January to the beginning of May, and, with the 
 exception of the hot season of July, in which it is very slightly 
 above, it is slightly below the average from the middle of May 
 to the end of September ; it rises decidedly in the first 
 week of October, and decreases in the middle of December 
 to again rise towards the end of the same month. They, how- 
 ever, rightly remark that " it is a curve which calls for clearer 
 definition from future observations, though it has two maxima, 
 the larger in the early months of the year, and the smaller in 
 the height of summer." The mortality curve of Buchan and 
 Mitchell does not altogether agree with the admissions into the 
 London Fever Hospital in the different months of the year ; thus 
 the 18,268 cases admitted from 1848-1870 were distributed through 
 the months as follows : — 
 
 January . . 
 
 10-8 per cent. 
 
 July 
 
 6'8 per cent. 
 
 February 
 
 8-8 „ „ 
 
 August 
 
 6-4 „ „ 
 
 March . 
 
 10-4 „ „ 
 
 September 
 
 6'3 „ ,> 
 
 April 
 
 8-9 „ 
 
 October 
 
 7-8 „ „ 
 
 May . 
 
 8-3 „ „ 
 
 November . 
 
 9-1 ., „ 
 
 June 
 
 71 „ „ 
 
 December 
 
 , . 8-8 „ „ 
 
 ' Journal of the Scottish Meteorological Society, July 1874-75. 
 
 D D 
 
402 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 The general fact that it is more prevalent in cold, less prevalent 
 in mild, weather, has been explained by saying that in the cold 
 months of the year the poor shut their windows and therefore the 
 ventilation being less typhus spreads easier, a very feasible expla- 
 nation, if the December and July portions of Buchan and Mitchell's 
 curve can be explained away ; otherwise not so. 
 
 (303) Race. 
 
 It is not known whether typhus irrespective of personal habit 
 and general environment attacks one race rather than the other, the 
 broad fact that in England typhus is more especially disastrous 
 among the Irish is incontestable, but it is among the Irish that 
 there has been most overcrowding and poverty, a sufficient cause 
 of greater prevalence. In the years 1848-67 there were admitted 
 into the London Fever Hospital : 
 
 1 in every 135 of the Irish inhabitants of London. 
 
 1 „ 223 „ English. 
 
 1 „ 397 ,, Scotch. 
 
 1 -, , 404 , , foreigners resident in London. 
 
 showing a considerable incidence on the Irish race. 
 
 (304) Prevalence of Typhus in 1886. 
 
 In 1886 the Medical Department of the Local Government 
 Board ^ made a special inquiry as to the existence of typhus in 
 the country, and Mr. Spear, to whom was entrusted the investiga- 
 tion, made a most instructive report. For one reason or other 67 
 districts came under suspicion ; in most of these where fever was 
 found it proved to be the ordinary enteric fever of the country, 
 but in no less than 17 important centres of population typhus was 
 found existing ; for example, at Leeds 56 cases in 33 families were 
 reported between October 26th, 1886, and 28th of January, 1887, 
 nearly all occurring "among the Irish, in a locality in which the 
 people were poor and ill-housed. "Unrecognised cases among 
 children had occurred in this infected area before the date 
 assigned to the earliest reported case." 
 
 At Middlesborough a localised outbreak of typhus occurred in 
 
 1 Sixteenth Annual Report of the Local Government Board {Supplement). Report 
 of Medical Officer for 1886. 
 
' XXVI.] TYPHUS. 403 
 
 the latter half of 18S6, at least eighteen cases and four deaths 
 being notified between August 11th and December 4th. The 
 early cases seem to have been mistaken for " scarlatina." In 
 Hartlepool — a town in which the poorer quarters are so crowded 
 together as to render impossible free areation, and the houses 
 described by Mr. Spear, in many cases "so ill- ventilated, damp, 
 and in such bad repair as to be unfit for habitation " — typhus broke 
 out in 1886 ; the first cases were certainly unrecognised, and were 
 confused with "typhoid," there were 141 known cases, but owing 
 to defects in the administration of Hartlepool at that date only 58 
 cases were removed to hospital. The same report gives details of 
 typhus outbreaks in Oldham, Maryport, Sunderland, Liverpool, 
 and other places, and Mr. Spear concludes as follows : " The cir- 
 cumstances related above will show how difficult it has been found 
 in the majority of cases to learn the actual origin of an outbreak of 
 typhus. The frequency with which the early cases are mild in 
 character so as to pass unrecognised, and the constancy with which 
 they appear under circumstances of destitution and squalor, may 
 suggest the possibility of the germination or growth under such 
 conditions of a morbific agent possessed of potential capacity, 
 thereafter progressively developing infectiveness and specificity — 
 a theory which, in relation to apparently simple sore throat and 
 diphtheria, has been brought under notice by Dr. Thorne. I have 
 not found, however, that early, apparently initial, cases among 
 adults are exceptionally mild. It seems that this characteristic 
 of early cases is marked because of the frequency with which 
 children are the first to suffer, and they, although it is somewhat 
 paradoxical considering their greater susceptibility to infection, 
 exhibit first to last during the progress of an epidemic singular 
 immunity from severe and fatal attack. Moreover, although the 
 disease amongst children is comparatively benign, it exhibits, so 
 far as my experience goes, marked specific characters. The 
 characteristic measly eruption is commonly distinguishable, and 
 nervous and nutritive disturbances as shown, for example, by 
 subsequent though transient deafness, and the falling ofi" of the 
 hair, which we should not expect to follow an ordinary febrile 
 attack, are of extremely frequent occurrence." The report next 
 lays stress on the frequency of failure to recognise the early cases, 
 and the lamentable results. " In Leeds, Hartlepool, Carlisle, 
 
 D D 2 
 
404 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Middlesborough, Oldham, Newcastle-oii-T3'ne, and Flint the disease 
 gained a footing through the neglect of unrecognised cases, and in 
 Liverpool this is the common experience with respect to constantly 
 recurring localised outbreaks." . . . The comparative inac- 
 tivity of the typhus of recent years — its slowness of extension — is, 
 it would appear, mainly attributable to the comparative absence of 
 distress ; for, although much harassing poverty has prevailed of 
 late, that form of it has happily been exceptional which amounts 
 to absolute want. That the inherent potency of the infection 
 remains the same may be inferred from the fact that under the 
 more fixed and comparable conditions its behaviour does not vary ; 
 it will still spread with great frequency to the well fed and well 
 housed, as, for example, to hospital nurses, when such persons are 
 much exposed to its influence ; and again, its fatality amongst 
 adults is maintained. On the other hand, the belief indicated 
 above is supported by pbserving its constant predilection for the 
 most indigent of the population, by noticing the manner in which 
 it will single out the most distressed and squalid households, and 
 then spread to all the various members." ^ 
 
 (305) The Nazareth Mouse Outbreak. 
 
 The outbreak of typhus at Nazareth House in 1882-3 is par- 
 ticularly instructive to medical officers of health, for it is a good 
 example of the mild form which modern typhus may assume and 
 the necessity of the accurate diagnosis of the febrile ailments 
 of children. Nazareth House is a home in Hammersmith for the 
 succour of the aged poor and destitute children. Its population in 
 1883 was 53 sisters of charity, 133 old persons, male and female, 
 and 175 children. On October 8th a visit was made by the uncle 
 of one of the children, accompanied by a little child, who had 
 recently recovered from " some illness." The illness of this child, 
 as investigated by Mr. Spear, was probably undiagnosed typhus. 
 The uncle lived in a very bad cellar-dwelling in Hammersmith, he 
 looked himself ill. On the 22nd of October the child E. L., which 
 had been visited, sickened of a feverish disorder, which was 
 thought to be " influenza," the sister who nursed her remembered 
 a measly rash, the child's hair subsequently fell off leaving the 
 
 ' The most recent recorded outbreak of typhus is one which occurred in Sheffield 
 in 1890, and is described by Dr. Thomson. Public Health, vol. iii. p. 17. 
 
XXVI.] TYPHUS. 405 
 
 head almost bald ; five weeks after E. L.'s attack, when the latter 
 had been down in the class room for about a fortnight a second 
 child, C. O., was taken ill. Then a child who had sat at C. O.'s 
 bedside reading to her was stricken, so " the disease continued to 
 spread, tintil on the 9th of January, 1883, eight cases had 
 occurred, all of them, with the exception of the first case, being 
 very sUght it appears, so that the disease was still looked upon as 
 "influenza." On January 9th Christmas day was kept; the 
 children had a Christmas tree and a dramatic performance, and in 
 the evening a large party of friends from the outside, as well as the 
 inmates, including the convalescent children, were assembled in 
 the " Community " Hall. Two priests played much with the 
 children on January 9th, and they both afterwards passed through 
 an attack of fever, which was regarded at the time by different 
 medical attendants as typhoid, but which there is great probability 
 was typhus. One sickened exactly fourteen days after the day of 
 the party ; the other had been ailing for some days, and the com- 
 mencement of his attack is not well determined. On the 9th of 
 January two children were poorly at Nazareth House, and one was 
 confined to bed, and on the following day two sickened. One of 
 these last suffered from a lung complication, and died on January 
 23rd. She was eighteen years of age, and her death was certified as 
 from " influenza, congestion, and convulsions." Meanwhile other 
 cases occurred, so that on February 2nd seven more children were ill. 
 The medical attendant now suspected typhus fever, precautions as 
 to the admission of strangers were prescribed, and a few days later, 
 on February 6th, when a sister who had been nursing the children 
 was attacked, pretty complete isolation measures were adopted.^ 
 
 In all the cases were thirty-one in number. The disease was 
 actually three months prevailing in a mild form before it was 
 recognised, the home itself was neither dirty nor overcrowded, and 
 the sanitary arrangements and regulations were reported by 
 Mr. Spear to be excellent. 
 
 (306) The Isolation aTid Prevention of Typhus. 
 The prevention of typhus is in theory of the simplest : — given 
 good ventilation and ample cubic space typhus disappears. Since 
 
 1 Report of the Medical Officer to the Local Government Board for 1883. Mr. 
 Spear's report upon an outbreak of typhus fever at Nazareth House, Hammersmith. 
 
406 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 the severe application of the Artisans and Labourers' DwelHngs 
 Acts in the parishes of St. Giles and St. Marylebone, and the 
 construction of improved dwellings, typhus has become extinct in 
 those parishes. The improvements in Liverpool have also markedly 
 reduced the disease, and probably in a few years typhus will almost 
 disappear from the mortality records of that city. An outbreak of 
 typhus demands the immediate personal investigation and atten- 
 tion of the health officer. There should be a house-to-house and 
 room-to-room inspection of the affected area, and cases of over- 
 crowding should be rigidly dealt with. Handbills distributed 
 among the people, insisting upon the almost certain prevention 
 of the malady by the windows of sleeping rooms being open at 
 night, may also do good. In such bills it should be specially 
 pointed out that typhus is not so much a children's as an adult's 
 disease, and that therefore individual effort in the way of cleanli- 
 ness, aeration, and sobriety is the more essential. In dealing with 
 Irish populations the hearty co-operation of the priest will make 
 the work of the health officer easier, and should always be obtained 
 if possible. Every case of illness, no matter under what name it 
 is called, should be investigated by the health officer in the 
 affected area. In the first few cases of typhus the diagnosis must 
 be well established ; but . if the outbreak seems to be likely to 
 attain any dimensions, it is not wise to wait for the eruption, but 
 given an adult with headache, high fever, and prostration, he 
 should be removed at once. 
 
 The danger of infection to the medical men and nurses of hospitals 
 in which typhus is treated, as well as to laundresses who wash 
 typhus-infected linen, is considerable : the records of the London 
 Fever Hospital give lamentable evidence of this. No doubt some 
 of the exposure might be rendered less dangerous ; for instance, if 
 a constant current of air could be established in a typhus ward it 
 should not be difficult for nurses and doctors to do all that is 
 necessary in the way of attention and examination on the wind- 
 ward side. Auscultation is specially dangerous, the more so if the 
 clothes are turned down and the physician immediately puts his 
 ear to the usual short stethoscope. It is to be recommended that 
 the chest to be examined remain exposed for some minutes pre- 
 viously to the air, and that the long flexible stethoscope be 
 always used. Nurses should be preferably selected above thirty- 
 
XXVI.] TYPHUS. 407 
 
 five years of age ; they should be sufficient in number so as not 
 to be fatigued, and be carefully instructed as to the danger of 
 breathing too closely the emanations from the patient. The most 
 ample ventilation should be enforced, and the greatest cubic space 
 possible is a necessity in the treatment of typhus patients. It is 
 not known whether the excreta from bowels and kidneys are 
 infectious or not, but it is prudent to consider them so, and, as 
 in typhoid fever, to receive them in disinfecting solutions. 
 
 The ordinary disinfection and aeration of rooms from which 
 typhus patients have been removed is sufficient, for however 
 virulent the typhus poison in its concentrated state may be, there 
 is ample proof of its easy destruction. Fumigation with sulphur 
 or chlorine and afterwards submitting bedding and other things 
 to a heat above the temperature of boiling water for a few hours, 
 will perfectly disinfect. 
 
 Experience derived from Liverpool and other places show the 
 necessity of having " houses of refuge " provided, in which those 
 persons who have been, so to speak, soaking in a typhus atmo- 
 sphere, although not themselves suffering from the disease, can be 
 purified and have their clothes disinfected. 
 
CHAPTER XXVII. 
 
 MICRO-PAEASITIC DISEASES AFFECTING THE NERVOUS SYSTEM. — 
 RABIES. ^TETANUS. — WHOOPING COUGH. 
 
 (307) Babies. 
 
 To this group belong rabies, tetanus, and whooping cough. 
 
 It is unnecessary to treat of rabies in this work, for it is more 
 a matter of veterinary police. It is obvious that, so far as danger 
 to man is concerned, a malady that is implanted only by direct 
 inoculation by the bite of an animal (usually a dog) can be 
 practically suppressed by a general muzzling order throughout 
 the kingdom, carried out with the greatest severity and uniformity 
 for two months. If this were done it is not likely that the order 
 would have to be repeated for several years. This however 
 requires a special Act of Parliament, the present law allowing 
 each county authority to make their own regulations, hence 
 neither uniformity of repression nor permanent good has followed ; 
 the unmuzzled rabid dogs of a county not under order biting the 
 muzzled dogs of another. 
 
 The beautiful researches of M. Pasteur, showing that the 
 microbe is primarily localized in the nervous system, and that it 
 is possible to attenuate the virus and to perform a protective 
 inoculation even after the bite, are matters of notoriety. 
 
 Tetanus. 
 
 (308) Researches on the Bacteriology of Tetanus. 
 
 Tetanus is a disease caused by a micro-parasite ; the micro- 
 parasite most frequently enters the body by means of a wound. 
 
CHAP. XXVII.] TETANUS. 409 
 
 It is only within the last few years that the true nature of 
 tetanus has been manifested ; the following is a brief notice of the 
 more important researches : — 
 
 Carle and Rattone^ were the first to produce typical tetanus 
 in the rabbit. They inoculated an emulsion of the sciatic nerve 
 from a person who had died of tetanus ; infection of a second 
 animal with the sciatic nerve of the first produced the same result, 
 but inoculations of the blood were fruitless. 
 
 Nicolaier,^ under the direction of Flugge, introduced garden 
 earth subcutaneously into rabbits, guinea-pigs, and mice ; clonic 
 spasms of the affected limb were produced, and in the course of 
 twenty-four hours this was followed by general tetanus. At the 
 seat of inoculation fine bristle-shaped bacilli were found ; these 
 were often swollen at one end. If the garden earth was previously 
 sterilized by heating it to 110°, then no effect followed; artificial 
 cultures were not pathogenic. Winiwarter * repeated and confirmed 
 these results. 
 
 Eosenbach was the first who discovered the bacillus in man. 
 He injected under the skin of guinea-pigs and rabbits pieces of 
 tissue taken from the boundary-line between the sound and gan- 
 grenous parts of the thigh of a man dying of tetanus; tetanus 
 was produced in the animals, and it was propagated through a 
 series of animals by inoculation of matters taken from near the 
 inoculated place. The bacillus was recognized in the neighbour- 
 hood of the inoculation, but not in the rest of the organs. 
 
 Brieger * separated a ptomaine from an impure culture of the 
 bacillus; he called this substance tetanin, because it produced, 
 even if injected in minute quantity, tetanus in animals. He 
 separated the same substance from the amputated arm of a 
 tetanic subject. 
 
 Bonome^ in three cases of traumatic tetanus propagated the 
 malady from matter taken from the neighbourhood of the wounds, 
 and recognized the bacillus; his inoculations of the blood, the 
 spinal marrow, and the nervous tissues were negative. He found 
 
 ^ Carle e Eattone, "Studio experimentale sull' eziologia del tetano," Qiornale 
 delta R. Acad, di Med. di Torino, 1884, 3. 
 
 ^ Nicolaier, Deutsche med. Wochenschrift, 1884, 2. 
 
 ' "Wini-warter, AUgemeine chirurg. Pathologie u. Therapie, 1817, 13te auflago. 
 
 * Brieger, Berlin, klin. Wochenschrift, 1887, 15, 17 ; 1888, 17. 
 
 ^ Bonome, Giornale della E. Acad, di Med. di Torino, 1886. Arehiv par. la 
 Seienza Med. 1888, xii. 4. 
 
410 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 that the bacillus when in the spore state was not destroyed at a 
 temperature of 100°. He made the instructive observation that 
 at the storming of the church in Bajaido, out of seventy wounded, 
 nine died of tetanus, and in three he recognized the specific bacillus. 
 He experimented with limestone dust taken from the ruins ; this 
 inoculated into wounds produced tetanus in animals, and he found 
 in the pus taken from the inoculated part the bacillus. The 
 researches of Giordano,^ Ferrari,^ and Hochsinger ^ are also to be 
 mentioned, from all of which the conclusion may be drawn that 
 traumatic tetanus has usually some connection with the contami- 
 nation of wounds by earth. This connection was specially clear in 
 some cases observed by Beumer. One of these cases was that of 
 a man, aged thirty-one, who was attacked with tetanus after a 
 wound by a splinter when playing at skittles, and it was found 
 that small splinters of wood taken from the skittle alley produced 
 tetanus when inserted beneath the skin of animals. In a second 
 case, recorded by the same observer, a boy running barefoot 
 wounded his foot by a stone, and tetanus followed ; small stones 
 taken from the same place introduced into wounds in animals 
 produced tetanus. 
 
 In a later series of experiments,* Beumer excised little bits of 
 tissue from the neighbourhood of the umbilicus of infants dying 
 from tetanus neonatorum, and inoculated these bits of tissue into 
 animals and produced tetanus. 
 
 Beumer also proved, through a highly exact series of researches, 
 that the tetanus-producing bacillus was very widely distributed in 
 the superficial layers of various kinds of soil, on the foul surface of 
 streets, and in the dust of dwellings. He also showed that a 
 wound when actively gra,nulating was not very susceptible of 
 taking the infection. 
 
 Several cases are on record in which tetanus seems to have 
 been conveyed by the hands or instruments of the surgeon. One 
 of the most striking of these is related by Langer, in which the 
 horses castrated by the same icraseur died of tetanus, but after 
 boiling the instrument in oik no others died or were affected from 
 its use. 
 
 •■ Giordano, Giornale dell. Acad, di Med. di Torino, 1887, 3, i. 
 ' Ferrari, Italien. CMrurg. Congress, Genua, April, 1887. 
 ' Hochsinger, Centralblatt f. Bacteriol, 1887, ii. 2, 3. 
 * Beumer, Berlin, Tclin, WooTienschrift, 1887, 30, 31. 
 
XXVII.] TETANUS. 411 
 
 The latest observations and experiments have been made by 
 Eiselsberg.^ He has given details of six cases vfhich he has had 
 the opportunity of investigating. 
 
 The first case was that of a woman with a compound fracture ; 
 the wound had been much contaminated by dirt ; tetanus occurred 
 on the fourteenth day. Cultures were made from the blood, with 
 negative results. Eiselsberg also inoculated the blood into 
 animals, but no effect followed, nor could any bacilli be found 
 therein ; on the other hand, the secretion from the wound con- 
 tained, with other organisms, the specific bacillus, and from this 
 secretion impure cultures were obtained. A culture of the third 
 generation was injected into three rabbits and four mice ; the mice 
 died the following day, one rabbit remained healthy, the second 
 suffered from tetanus and recovered, the third died of tetanus. 
 
 The second case was that of a man who had a mild attack after an 
 injury to his finger ; in this case there was also contamination of 
 the wound by dirt. Experiments gave negative results. 
 
 The third case was that of a man who died from tetanus. Small 
 pieces of skin taken from near the wound produced tetanus in 
 animals. Impure cultures of the wound-secretion produced the 
 same effects. 
 
 A fourth case gave veiy similar results. In this case the man 
 had received his wound in a certain cellar, and experiments were 
 made on the earth of this cellar; tetanus was produced when 
 the wounds of animals were contaminated with it. 
 
 In the fifth case tetanus had been produced by a splinter of 
 wood. The splinter had been carefully preserved by the man's 
 wife for two and a half years. Small pieces of this splinter 
 were inserted beneath the skin of animals, and tetanus followed. 
 The bacillus was recognized in the secretion. 
 
 In the sixth case a servant in scrubbing a floor got a splinter 
 of the wood of the floor under her thumb-nail and died of 
 tetanus. Fourteen months after the same splinter produced tetanus 
 in rabbits. So far as to traumatic tetanus. Idiopathic tetanus is 
 rare, and it is not improbable that in reality it does not exist, but 
 is derived from some slight scratch or wound which has passed 
 unnoticed ; in other words, so-called idiopathic tetanus has a con- 
 cealed traumatic origin. 
 
 ■^ Wiener Tclin. Wochenschrift, 1888. Public Health, vol. i. 117. 
 
412 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (809) The Prevention of Tetanus, 
 
 In view of the modern discovery that tetanus is produced by a 
 micro-organism to be found in dust and dirt and adhering to 
 foreign substances, the surgeon will naturally take the greatest 
 pains not alone to cleanse wounds but to apply to the cut surfaces 
 in cases of foul wounds strong disinfectants, or even where neces- 
 sary cut clean away the bruised and soiled cut surfaces. It is, 
 however, obvious that save in the way of disseminating information 
 on these points among the public at large, tetanus is a malady against 
 which the Health Officer can do little or nothing. He may how- 
 ever point out that the discharges from such wounds, should be 
 collected on clean rags or similar substances, which can be either 
 disinfected or burned. 
 
 WHOOMNG-CotTGH. 
 (310) General Nature of Whoofing-Cough. 
 
 Whooping-cough is believed to be a micro-parasitic disease, the 
 poison of which more especially affects the nervous system. With 
 a few exceptions the sufferers are solely children and persons of 
 tender years. The most prominent symptom is a peculiar expira- 
 tory cough, by which the lungs are pretty well emptied of air ; 
 following this cough there is a prolonged inspiration with a 
 peculiar crowing sound — the so-called " whoop." 
 
 (311) Statistics. 
 
 Whooping-cough kills a large number of children, the mean 
 number of yearly deaths during the twenty-five years ending 1888 
 was 11,964; the maximum number occurred in 1878, when 17,784 
 deaths were ascribed to this cause, the minimum in 1864, 8,570 
 deaths. 
 
 (312) Etiology. 
 
 Fatal and common disease as whooping-cough is, there is very 
 little definite knowledge concerning the laws which govern its 
 diffusion. All that is known is that it is excessively infectious, 
 and that once introduced into a house, it is liable to attack all 
 young children not protected by a previous attack. In its 
 
XXVII.] WHOOPING COUGH. 413 
 
 seasonal distribution it is most fatal in January, February, and 
 March, up to the second week of April. A curve plotted out for 
 a number of years showing the weekly deaths from whooping- 
 cough shows an inverse relation to the scarlet fever curve ; that is 
 to say, the latter curve turned upside down is like that of whoop- 
 ing-cough, the maximum of the one corresponding with the 
 minimum of the other. Whether there is any real antagonism 
 between these two diseases is not known. 
 
 The disease has a stage of latency, which is generally put at 
 between five or six days. 
 
 The infecting distance is great. An instance occurred under the 
 writer's own observation in which a tramp brought a child from 
 some distance into a small town in Somersetshire to the work- 
 house. At the time there was no whooping-cough in town or 
 workhouse. The child had whooping-cough. The woman with 
 her baby was allowed to sit at a table in the open air, at which 
 the workhouse children were having a sort of treat. The woman 
 remained there about an hour. In a few days a third of the 
 workhouse children were simultaneously affected with whooping- 
 cough. 
 
 The well known St. Helena case may also be cited. The captain 
 of a ship in which there was some children suffering from whoop- 
 ing-cough allowed the linen of the sick to be sent ashore, and 
 shortly afterwards the same disease broke out among the inhabit- 
 ants. Burger ^ has stated that elliptical cocci are constantly 
 present in the sputum of persons affected with whooping-cough, 
 but the bacteriology has not been worked out. 
 
 (313) Duty of the Medical Officer of Health. 
 
 In cases of whooping-cough it is certain that on recovery or 
 death the clothing, and the room with its contents, should be pro- 
 perly disinfected. Hitherto it has not been practicable to isolate 
 cases of whooping-cough in special hospitals. 
 
 1 Berl. Uin. Wochen^hrift, 1888. 
 
CHAPTER XXVIII. 
 
 MICBO-PAKASITIC DISEASES MAINLY AFFECTING THE EESPIEATOEY 
 
 ORGANS. 
 
 Pneumonia. 
 
 (814) Epidemic Pneumonia. 
 
 There is abundant evidence that at least the species of pneumonia, 
 known as "croupous or fibrinous pneumonia," is one of the class 
 of maladies produced by a micro-parasite. It is infectious, and 
 not unfrequently prevails in an epidemic form. This is the view- 
 generally adopted by hygienists, and one which the writer has 
 held and taught for the last twelve or thirteen years ; the pro- 
 fession at large have not yet fully adopted this view, hence few, 
 if any, precautions are taken to prevent the spread of the disease. 
 
 (315) Evidence of the Infectious Character of Pneumonia. 
 
 It may be well here to adduce some evidence of the infectious 
 character of pneumonia. 
 
 In the Akerhus prison ^ two outbreaks occurred, one in 1847, 
 another in 1866. In the last epidemic no less than sixty-two cases 
 occurred in six months amongst 360 prisoners. 
 
 Thoresen, of Eidswold,^ records an epidemic of croupous pneu- 
 monia almost confined to a single row of cottages. The epidemic 
 lasted a month. 
 
 An epidemic broke out in 1860 in the Mediterranean fleet. Its 
 infective character was very evident, and Dr. Bryson,^ who recorded 
 
 '' Norsk. 3£ag f. Laegevidenskaben, vol. xxii., p. 345. 
 
 2 Ibid. 3rd ser., vol. i., p. 65, 1871. ' Lancet, January 9, 1862. 
 
CHAP. XXVIII.] PNEUMONIA. 415 
 
 it, pointed out several characters common to it, and the pleuro- 
 pneumonia of cattle. 
 
 Five cases of pneumonia ^ occurred almost simultaneously, March 
 
 1874, at a school at East Sheen, Mortlake. The time- of attack 
 coincided with a large escape of sewer gas into the school, and 
 the boy first attacked slept in one of the rooms most exposed to 
 the efiluvium. 
 
 Mr. Alfred Mayo ^ communicated cases of infectious pneumonia 
 to the author as follows. The first case was that of a bricklayer, 
 aged thirty-five, who was taken ill with pleuro-pneumonia. His 
 mother nursed him and caught the malady and died. A neighbour 
 nursed this last case. She, in her turn, caught the disease and 
 died. Lastly, her child took it but recovered. 
 
 In the writer's Dictionary of Hygiene, the following additional 
 cases are recorded : — 
 
 A farmer at Bow, Devon, suffered from pneumonia ; his niece 
 nursed him ; she soon became affected with the same disorder, 
 and, going home, infected her husband. 
 
 A Dolton farmer became ill with pneumonia on April 16th, 
 
 1875, and died on the 18th. The servant girl who nursed him 
 suffered from the same malady, the first symptoms appearing a 
 week after the death. She went whilst ill to her married sister's 
 home, who also contracted the same malady. 
 
 Another man became ill of pneumonia in April of the same 
 year, and died after ten days' illness. His wife contracted the 
 disease, her first symptoms appearing immediately after his death. 
 
 About the same date, a farmer's daughter, a mile from the 
 house of the former patient, became ill of pneumonia; five other 
 cases followed, all in the same parish (population, 470), consisting 
 of a small village and a few scattered houses. 
 
 A clergyman became ill with acute pneumonia. The woman 
 who nursed him in about seven days contracted the same disease. 
 The clergyman's sister, taking the place of the nurse was, in her 
 turn, also seized with pneumonia. A brother of the clergyman 
 now took the place of the last ; he, in his turn, also was laid up 
 with the same disease. The nurse and sister both died, the two 
 brothers recovered. 
 
 1 "Sewer Gas Pneumonia." Irish Eospital Gazette, Nov. 1, 1874. 
 
 2 Article " 7n&u-mom.3," in Dictioimry of Hygiene, London, 1876. 
 
416 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (316) The Middlcsbormogh Epidemic. 
 
 To these examples may be added the Middlesborough epidemic,^ 
 investigated by Dr. Ballard. Middlesborough itself has a population 
 of about 69,000, and the adjacent sanitary districts of Ormesby, 
 Normanby, and Eston, are something in the aggregate about 
 28,000. The epidemic period extended over twenty-four weeks from 
 January 20th to July 14th, 1888, during which time there were 
 369 fatal cases of pneumonia; this, probably, represented some 
 1,000 cases, for the mortality of 762 known cases was 23'1 per 
 cent. There was an exceptional mortality among males, and an 
 exceptional incidence on certain age periods. On each 10,000 
 males the incidence was 64, on each 10,000 females, 16. The 
 rate of mortality in the group under 15 years of age was about 
 the average, but above 1 5 about 5 times that of the mean annual 
 mortality for corresponding periods. In the age group, 15 to 45 
 years, the rate of the mortality was 4"6 times that of the mean 
 of eight years, and at ages above 45 it was 5'4 times that of the 
 mean. Dr. Ballard gives a clear account of the symptoms, and 
 also of the post-mortem appearances, these differ but little from 
 the acute pleuro-pneumonia that anyone who has practised in 
 rural districts is quite familiar with. There was ample evidence 
 of its infective character. 
 
 (317) Etiology of Pneumonia. GamaUiaJs Vievjs. 
 
 Gamal^ia^ has carefully worked out the bacteriology of pneumonia, 
 and his views are as follows : — ■ 
 
 He considers that the streptococcus lanceolatus is the cause of 
 pneumonia. This same micro-organism under the name of the 
 diplococcus lanceolatus is, according to Professor Pio Poa and Dr. 
 Guido Bordoni TJfferduzzi, the cause of epidemic cerebro-spinal 
 meningitis (see PiMic Health, vol. i. p. 85). Its presence is 
 constant in pneumonia. This is proved not alone from the clinical 
 experience of others, but from his own observations on twelve 
 autopsies. " I have studied," says Gamaleia, " these post mortems 
 
 ' Supplement to Eighteenth Annual Report of the Local Government Board, 
 1888-8S. 
 
 2 " The Etiology of Fibrinous Pneumonia in Man." by N. M. Gamaleia. {Annales 
 de VInstitut Pasteur. No. 8, August, 1888.) Public Health, vol. ii. 
 
XXVIII,] PNEUMONIA. 4lV 
 
 without choice, and in the order in which they presented them- 
 selves on the dissecting table. Some cases had been erroneously 
 diagnosed as those of typhoid fever or mdiary tuberculosis, but 
 I only accepted the diagnosis revealed by the corpse. Thus I 
 have collected varied forms of pneumonia — simple pneumonia 
 of a single lobe, double pneumonia, pneumonia complicated with 
 cerebro-spinal meningitis and endocarditis. The duration of the 
 malady was also variable, and I had under observation the different 
 anatomical forms of the sick lung, the initial hyperaemia, the red 
 hepatisation, grey hepatisation, and abscess. Each case has served 
 me — ■ 
 
 " (a) To make cultures on gelatin. 
 
 "(h) To make stained microscopical preparations of the juice of 
 different organs. 
 ■ " (c) To inoculate animals sensible to the pneumonic virus. 
 
 " The first method rarely succeeded, because the autopsies were 
 made long after death, and the culture of our microbe on solid 
 ■media is very difficult. A small number of foreign germs prevents 
 the specific culture. The second process has on the contrairy 
 always given me positive results, and I have always been able to 
 recognize as cause of the evil the streptococcus lanceolatus, that is to 
 say the double lanceolate coccus surrounded by a clear or coloured 
 coccus, retaining the violet coloration of Gram. But on this 
 subject there are important remarks to make. The lanceolate 
 tjoccus has not always its typical form and aspect. It sometimes 
 happens that in a rabbit or mouse dead of septic pneumonia that 
 the microbes in the blood and even in the spleen present them- 
 selves under the form of simple cocci without capsule, whilst the 
 liver and kidneys are full of typical diplococci. Nevertheless, it 
 has only happened to me in three lungs out of the twelve not to 
 find typical forms, but even in these the specific microbe appeared 
 with all its distinctive characters in other parts of the same body 
 (fibrinous pleuritic exudation, spleen, dura mater of spinal cord). 
 Besides, in the human lung (likewise in the sheep), the pneumonic 
 coccus has often its capsule coloured, and as this coloured capsule 
 may be elongated and tortuous, it singularly disfigures the appear- 
 ance of the microbe. On the contrary, the cocci absorbed by the 
 leucocytes, as is the rule in the first period of the pneumonic 
 affection in the man and the dog . often remain as colourless as their 
 
 E E 
 
418 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 capsules, and are only distinguished as little regular vacuoles in 
 the bodies of cells. Lastly, the same thing may happen which has 
 been observed in the spleen in anthrax, and especially in the 
 oedema of anthrax — that is, the soluble products excreted by the 
 virulent microbes render every preparation too confused to allow 
 the typical form of the microbe to be distinguished. This may be 
 remedied by washing the preparation with alcohol after passing it 
 through the flame. 
 
 " These reserves made, I affirm I have always seen the microbe 
 of Pasteur in the pneumonic corpse." 
 
 Gamaldia next speaks of the success of his inoculations. He finds 
 the mouse more sensitive than the rabbit. The mouse " inoculated 
 under the skin with an emulsion of pneumonic sputa, dies in twenty- 
 two hours, and presents at the autopsy a mass of typical microbes 
 in the blood and organs." He next deals with the objection made 
 against the etiological unity of fibrinous pneumonia, especially on 
 behalf of Friedlander's microbe. This last microbe is found nor- 
 mally in saliva. It is a good saprophyte, and invades sometimes 
 the diseased or dead lung. Weichselbaum found it in 70 per cent, 
 of his cases, but, with the exception of three cases, always mixed 
 with other microbes. As to the researches of authors preceding 
 Frankel, it is certain the microbe they called Friedlander, which 
 they found, was no other than that of Pasteur, since it was stained 
 by the method of Gram which decolourises the bacillus of Fried- 
 lander. As to the experimental production of pneumonia by cul- 
 tures of Friedlander's njicrobe, there is no doubt several bacteria 
 will produce pneumonia. Such for instance which determine at 
 the seat of inoculation a sero-fibrinous exudation, as the microbe of 
 fowl cholera, and the bacteria of charbon, 
 
 (318) Pathogenic Bole of the Streptococcus Zanceolatus. 
 
 Contrary to general belief, this microbe does produce typical 
 pneumonia in the dog and sheep. The experiments which follow 
 were made with virulent pneumonic virus, that.is with the Pasteur 
 microbe taken from the human corpse, or isolated from pneumonic 
 sputa, and its virulence increased by several passages through 
 rabbits. The successive passages through the organism of the 
 labbit, especially if the inoculation has been intravenous, augments 
 
XXVII.] PNEUMONIA. 419 
 
 manifestly the virulence of the pneumonic streptococcus. The 
 time elapsing between infection and death becomes progressively 
 shorter from twenty-four hours to twelve, and even to five hours. 
 The character of the disease is also changed ; instead of the pro- 
 longed febrile affection with meningitic complications, produced by 
 the ordinary virus, a sort of poisoning appears, which commences 
 with the infection, and leads to a tranquil death, preceded by a 
 progressive and continuous loss of strength. This excessively 
 virulent matter no longer leaves in the body the hyperaemia and 
 hypertrophy of the spleen typical of the ordinary virus — the 
 animal succumbs without resisting. The blood of the heart is full 
 of streptococci which have in this case often coloured capsules. It 
 is this blood, or cultures from it, with which the experiments were 
 made. 
 
 Animals may be placed in relation to their resistance to the 
 pneumonic virus, on a scale, the bottom of which is occupied by 
 the pigeon with its absolute resistance, and the successive stages 
 by the dog, the sheep, and the rat ; the rabbit and the mouse are 
 at the top of the scale. The mouse is the animal most sensitive to 
 pneumonia, it always dies after a subcutaneous injection of a few 
 drops of a virulent culture within an interval of from twelve to 
 twenty-four hours, with all the symptoms of subacute septicaemia. 
 At the autopsy is found a slight gelatinous oedema at the seat of 
 inoculation, the spleen more or less hypersemic, and an enormous 
 quantity of microbes in the blood and in all the organs. The 
 virulence of the microbe increases in its passage through the body 
 of the animal. M. Gamaldia's experiments were made on thirty 
 mice. The disease in the rabbit has the same characters. The 
 attenuated virus produces a fibrin o-granulous infiltration at the seat 
 of inoculation, a pneumonia, a sero-fibrinous pleurisy with fibrinous 
 peritonitis. The virus sterilized by heat (120° C), produces a per- 
 sistent granular tumour which has no tendency to be absorbed. 
 The same tumour is produced by the virulent virus in the rabbit 
 rendered refractory to the virus. The virulence is considerably in- 
 creased by passing through the rabbit ; GamaMia has made as 
 many as twenty-four transmissions from animal to animal, and has 
 caused pneumonia in 200 rabbits. 
 
 The white and grey rat are also very sensitive, and similar 
 lesions are found, but the local effect is greater. The sheep is 
 
 E E 2 
 
420 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 more refractory, and requires large doses; here again, the local 
 symptoms are considerable. Death takes place in from the third to 
 the fifth day of the disease. Gamal^ia has experimented on twelve 
 dogs. The dog is still more refractory, he is cured generally in 
 from ten to fifteen days, after having passed through all the stages 
 of red and grey hepatisation as in man. The squirrel and the cat 
 occupy in the scale of susceptibility an intermediate place between 
 the rabbit and the. rat. All these facts lead to the following con- 
 clusion : — 
 
 (1) There exists variable degrees of receptivity for the pneu- 
 monic virus. These degrees may be measured by the abundance 
 of the microbes of the blood and by the extent of the local reaction. 
 The less an animal resists, the less the inflammatory pneumonia at 
 the place of inoculation, the greater the abundance of microbes in 
 the blood of the corpse. The type of the local reaction varies 
 according to the degree of receptivity. The local reaction absent 
 in the mouse, becomes a restricted haemorrhagic oedema in the 
 rabbit ; the rat presents an extended oedema of a yellow amber 
 tint, and gelatinous consistence ; in the sheep and the dog, the 
 oedema is greater, and is composed of sero-fibrinous parts mixed 
 with harder granulations having a grey tint constituted by an 
 abundant cellular infiltration. 
 
 (2) The animals little sensitive to the pneumonic virus offer a 
 very pronounced local resistance, followed by a typical fibrinous 
 pneumonia. Pneumonia, then, is not a general infection localizing 
 itself in the lung as its place of predilection, but the local reaction 
 has the place of the virulent inoculation. The animals extremely 
 susceptible, as the rabbit, and mouse, have no pneumonia because 
 there is no local action, and the virus generalizes itself within them 
 and slays them by acute septicaemia. 
 
 (3) Man belongs, in relation to the pneumonic virus, to the 
 category of resistant animals. Hence the feeble mortahty from 
 pneumonia (10'8 per cent.) — hence the extended local reaction 
 in the form of inflammation of the lungs, and the paucity of 
 microbes in his blood. It is clear that the results obtained 
 in the dog and sheep, animals little susceptible, are specially 
 applicable to the elucidation of human pathology. It may be 
 affirmed that an inoculation into the pulmonary tissue of animals 
 partially refractory (e.g., dogs, sheep) of the streptococcus lanceolatus, 
 
XXVIII.] PNEUMONIA. 421 
 
 gives rise to a typical fibrinous pneumonia. Thus the chief 
 objection advanced against the etiological role of this microbe 
 falls to the ground. 
 
 (319) Streptococcus Zanceolatus in Healthy Persons. 
 
 How is the fact to be explained that the streptococcus lanceo- 
 latus is found in the saliva of healthy persons ? It is necessary to 
 at once admit its frequent presence in normal saliva. Two cases 
 in which GamaMia found it most abundant were in the saliva of 
 persons not suffering from pneumonia. Goldenberg has found the 
 microbe in more than half the mouth secretions of healthy 
 persons. 
 
 M. Pasteur has, a long time ago, shown that a disease of silk- 
 worms is caused by a common microbe which is found everywhere in 
 the food of the worms, remaining inoffensive for those who have 
 good digestion, and slaying those in feeble health or with weak 
 digestive organs. M. Pasteur has also shown that the septic vibrio, a 
 very virulent microbe, always exists in the intestines of the 
 mammalia without troubling their health. 
 
 Gamaleia himself has found that the microbe of fowl cholera, so 
 terrible for birds, is constantly found, although in small numbers, 
 in their intestines, and that a poisoning by non-pathogenic bacteria 
 suffices to open for them a portal into the blood. 
 
 It may, then, be believed that among healthy persons the strep- 
 tococcus laiiceolatus finds conditions opposed to its hurtful action. 
 These conditions are only realised among animals little suscep- 
 tible, as man, the sheep, and the dog ; for the others, like rabbits 
 and mice, succumb to the inhalation of the virus. Gamaleia has 
 instituted direct experiments on this point. Whilst the virulent 
 streptococcus introduced into the lung parenchyma of sheep 
 always develops there a fatal fibrinous pneumonia, the same virus 
 injected by the trachea does not kill. Thus, on more than 
 twenty sheep, virulent pneumonic virus, injected into the trachea 
 in quantities of 10 c.c, did not kill one. Hence it must be con- 
 cluded that a lesion of the lung parenchyma, and an introduction 
 of the virus into this wounded parenchyma, are necessary con- 
 ditions for the production of pneumonia in sheep. It was in- 
 teresting to know the more intimate Jfccts which pass after 
 
422 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 intrabronchial injection. Gamaleia made the following experi- 
 ment to elucidate this : — 
 
 On May 11th, at nine a.m., three sheep were inoculated by 
 intrabronchial injection with the virulent streptococcus. Body 
 temperature before infection 40° — 40'5 C, at seven p.m. 40'2 to 
 40 '5. The first was killed in the evening. Autopsy, spleen soft 
 and hypersemic ; in both lungs and particularly at the apex of the 
 right lung, regions very hypereemic. The microscopical examina- 
 tion of this region revealed the presence of the streptococcus as 
 well as an infiltration of mononuclear and polynuclear cells. These 
 two varieties of " phagocytes " contained masses of Pasteur's 
 microbe. Free streptococci were rare. A mouse inoculated by 
 the juice of the hypersemic lung succumbed the next day to 
 septicsemic pneumonia ; some streptococci were found in the spleen, 
 and in the disintegrated state (d I'Mat digiH), in the liver, and 
 particularly in the kidneys. 
 
 On May 12th, at three p.m., the surviving sheep had a tempera- 
 ture of 39'6° and 39'2°. One was killed. The autopsy showed 
 catarrh of the bronchial tubes ; the walls of the tubes were 
 hypersemic and covered with rusty-coloured mucus (the injection 
 was made from the blood of a lapin de passage). There were 
 hypersemic spots on the right lung. A microscopical examination 
 showed the absence of the typical streptococcus in the lung. A 
 squirrel inoculated by the pulmonary juice did not take pneumonia. 
 The streptococcus, on the contrary, was abundant in the bronchial 
 mucus, mixed, however, with other microbes, one of which was 
 similar to that of Friedlander's microbe. 
 
 It is thus seen that the pneumonic virus, introduced into the 
 trachea, does not determine the lesions of pneumonia in the 
 healthy lung. It provokes a pulmonary hypersemia and afiEux of 
 phagocytes which destroy the streptococcus. A few microbes pass 
 into the blood, from whence they are eliminated in the ordinary 
 way. But neither in the pulmonary alveoli nor in the capillaries 
 are conditions found sufficient for the production of the pneumonic 
 exudation. Microbes which are disintegrated or digested in the 
 pulmonary alveoli and in the blood remain living in the bronchial 
 mucus, and may, under favourable conditions, conduce to the 
 development of pneumonia. 
 
 This is what happened indeed to the third sheep of the preceding 
 
XXVIII.] PNEUMONIA. 423 
 
 experiment. After remaining quite well during the experiment, it 
 was inoculated in the eye by the virus of rabies, and succumbed on 
 June 4th. The autopsy showed typical lesions of croupous pneu- 
 monia. The left lung was covered with a thick fibrinous layer of 
 a gray colour, and was augmented in volume, and had all the other 
 signs of pneumonia with fibrinous exudation, the pneumonic 
 streptococcus was found in great number; the streptococcus was 
 less numerous in the hepatised red and gray lung tissue, and was 
 infrequent in the spleen and liver. 
 
 To better study the mechanism of immunity of healthy lungs, a 
 microscopical analysis was made of the sputa of a subject who 
 suffered from fibrinous pneumonia, and afterwards from chronic 
 bronchitis ; this subject expectorated masses of microbes, virulent 
 to rabbits. 
 
 The sputum was tenacious, and adhered to the vessel; under 
 the microscope it showed itself as a nearly pure culture of the 
 specific streptococcus, with polynuclear globules, and endothelial 
 cells, having a large nucleus and very granular. An attentive 
 examination of these last cells, which have all the character of 
 " macrophages," showed that they contained enormous numbers of 
 the streptococcus of Pasteur in different phases of degradation. In 
 the same cell with the typical form of the diplococcus may be 
 found attenuated and angular forms which comparison alone con- 
 nects with the specific microbe. One may in this way be 
 convinced that the debris contained in the " macrophages " are the 
 remnants of pneumonic microbes. The polynuclear leucocytes 
 also contain the streptococcus but in much smaller quantity. 
 
 These phenomena give us the sought-for explanation of the 
 immunity of the pulmonary tissue ; the pathogenic microbes, even 
 when they exist in very great quantity in the bronchial mucus, 
 and arrive at the pulmonary alveoli, are stopped in their develop- 
 ment by the macrophages who seize and devour them. In this 
 strife the endothelial cells may themselves die and be rejected in 
 the sputum. It is then clear that the production of pneumonia, 
 or the maintenance of health, depends on the relative activity of 
 the two orders of combatants. It may be also comprehended how 
 the issue of the strife rnay be determined by slight predisposing 
 causes, as cold, bronchitis, a fall, contusion of the chest, inhalation 
 of irritating vapours and others. 
 
424 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 In this way is explicable why the etiology of fibrinous pneumonia 
 is composed of two factors — contagion, and the influence of the 
 seasons with their action on the pulmonary cells. 
 
 To verify this GamaMia has experimented on the pneumonic 
 infection by first injecting substances capable of slaying the 
 pulmonary " macrophages." Into the tracheas of six sheep was 
 injected a solution of tartar emetic, four of them being inoculated, 
 also by the trachea, with the pneumonic virus. One died the next 
 morning from the inoculation, and the autopsy presented ' red 
 hepatisation of the right lung in several places ; a second had 
 typical pneumonia, the third and fourth suffered from fever; 
 " the control animals " remained healthy. 
 
 Hence we may conclude that influences injurious to the pulmonary 
 cells predispose to the development of the streptococcus in the 
 lung. 
 
 The conclusions that Gamaleia finally draws are : — That the 
 streptococms lanceolatus Pasteuri is- always found in human fibrin- 
 ous pneumonia. That this streptococcus produces in partially 
 refractory animals fibrinous inflammation of the lungs. That its 
 pathogenic influence is held in check in healthy men by the 
 activity of the pulmonary phagocytes. He believes he has shown 
 that human fibrous pneumonia is always caused by Pasteur's 
 microbe. 
 
 (320) Bacteriology of the Middlesborough Pneumonia Cases. 
 
 Dr. Klein 1 has made a careful research by the aid of modern 
 methods on the micro-organisms in the cases of pneumonia in the 
 outbreak recorded by Dr. Ballard (p. 416), and he draws the follow- 
 ing conclusions : — 
 
 (1) In the diseased lung of the Middlesborough pneumonia cases 
 there were present in large numbers short bacilli, that are not 
 Friedlander's bacillus nor the Diplococcus pne%omonicB of Frankel and 
 Weichselbaum, but which upon cultivation and inoculation into 
 rodents appear to be a definite species, distinctly different from 
 either : he therefore calls this bacillus the Bacillus Pneumonice. 
 
 (2) Neither Friedlander's bacillus nor the Diplococcus pneumonice 
 
 1 Supplement to the Eighteenth Anmial Report of the Local Government Board, 
 1888-89, 323. 
 
xxviii.] PNEUMONIA. 425 
 
 of Frankel and Weichselbaum was obtainable from tbis buman pneu- 
 monic lung by cultivation. 
 
 (3) Tbe lung-juice of tbis pneumonia wben inoculated into 
 guinea-pigs, and especially wben inoculated into mice, produced an 
 acute disease, of wbicb tbe cbief and constant anatomical lesion was 
 severe inflammation of tbe lungs. Mice were more susceptible 
 tban guinea-pigs. 
 
 (4) Artificial cultures of tbe Bacillus pnetimonice from tbe buman 
 lung or from tbe blood of an experimental mouse proved very viru- 
 lent to mice — less so to guinea-pigs. In mice tbese bacilli produced 
 tbe same fatal disease as mentioned above, with conspicuous 
 pneumonia. 
 
 (5) Tbe blood and lung juice of mice and of guinea-pigs dead of 
 tbe disease experimentally induced by the materials from tbe 
 severally above recorded sources, produced on inoculation into other 
 mice and guinea-pigs severe fatal pneumonia. 
 
 (6) In all experimental animals dead of the induced disease, the 
 lung-juice (in mice also as a rule the heart's blood and the spleen), 
 contained the bacillus pneumonice. 
 
 (7) By feeding mice vsdtb artificial cultures of tbe bacillus, the 
 same pneumonia was produced, but not in so large a proportion of 
 experimental animals as by inoculation. 
 
 (321) Preve7itive Measures. 
 
 Whether Gamal^ia's views on pneumonia are correct or whether 
 they will be modified by future research, there is good reason to 
 class epidemic pneumonia as dependent upon sanitary state, and 
 intimately connected with foul sewers, collections of filth and general 
 air and soil pollution. It will be tbe duty of tbe health officer to 
 inquire into cases of pneumonia as be would into any other septic 
 disease, to enforce isolation where be can, and also to cause disin- 
 fection of the room, bedding and clothing after the termination of 
 each case. 
 
CHAPTER XXIX. 
 
 septicemic maladies. 
 
 Erysipelas. 
 
 Erysipelas is a septic disease closely allied to some forms of 
 diphtheria, to puerperal fever, and to pyaemia. It has also an 
 analogy to scarlet fever. 
 
 Erysipelas is a contagious and infectious disease, the common 
 external sign of which is an inflammation of the integument, ex- 
 tending in some cases to the areolar tissue, and tending to spread 
 indefinitely. 
 
 (322) Mortality from Erysipelas. 
 
 During the twenty-five years ending 1886, 51,582 deaths in 
 England and Wales are ascribed to this cause ; the maximum 
 number of deaths was in 1874, when 3,358 deaths were registered ," 
 the minimum number was in 1886, when 1,523 deaths were caused 
 by erysipelas ; the mean number of the whole being 2,063. 
 
 Erysipelas is one of the diseases to be certified by the medical 
 man or notified by the householder in places like the metropolis, 
 where the Infectious Disease Notification Act is in force, so that 
 in a few years there will be valuable statistical evidence as to the 
 frequency of illness from this malady. 
 
 Erysipelas attacks more males than females, the cause is pro- 
 bably because males have more frequently external wounds and 
 abrasions than females. 
 
CHAP, sxix.] ERYSIPELAS. 427 
 
 (323) Mortality as Influenced by Season. 
 
 The deaths from erysipelas are above the average from the 
 middle of September to the end of March, and below the average 
 for the rest of the year. The deaths rise rapidly from the last 
 week in October to the third week of November, wiien the absolute 
 maximum for the year is attained. The minimum period is from 
 the middle of June to that of September (Mitchell and Bnchan). 
 If the deaths from erysipelas and those from puerperal fever be 
 plotted out for a sufficient number of years in a curve according to 
 season, the curves very fairly coincide. 
 
 (324) Bacteriology. 
 
 Erysipelas is without doubt caused by a micro-organism. This 
 has been named the streptococcus erysipelatosus ; it is found at 
 the edge of the inflamed skin, occupying the lymphatic channels 
 and spreading along them as the disease advances. The cocci are 
 from "3 /i to "4 /a in diameter ; they have been cultivated outside 
 the body and from the artificial cultures ; true erysipelas in such 
 animals as the rabbit has been induced by inoculation. 
 
 Fehleisen^ carefully examined thirteen cases of erysipelas, he 
 found identical changes in all. The lymph vessels of the skin as 
 well as those of the subcutaneous cellular tissue, but more 
 especially those of the most superficial layer of the corium were 
 found packed with chain micrococci. In those places in which a 
 particularly great development of the cocci had taken place they 
 were found lying in the lymph spaces and channels of the skin. 
 They never entered the blood-vessels. 
 
 (32,5) Etiology. 
 
 By far the most usual means of infection is by a wound, and it 
 may be that many cases of idiopathic erysipelas are also due to an 
 entry of the microbe by means of some superficial and unnoticed 
 abrasion. 
 
 All the older hospitals have their histories of erysipelas. In 
 1760, for example, erysipelas spread so extensively through the 
 
 ' Fehleisen On Erysipelas, translated by L. Ogilvie, M.B., B^Sc, London, 1886. 
 
428 A MANCJAL OF PUBLIC HEALTH. [chap. 
 
 ■wards of St. Thomas's Hospital, as to excite the greatest alarm. No 
 modern surgeon would allow a case of erysipelas to be in the same 
 ward as other patients who have either undergone or are about to 
 undergo operations. 
 
 In the winter of 1851 erysipelas broke out in one of the wards 
 of University College Hospital, and is thus described by Mr. 
 Erichsen : " The hospital had been free from any cases of this 
 kind for a considerable time, when on the 15th of January, at 
 about noon, a man was admitted under my care and placed in 
 Brundrett Ward. On my visit, two hours after his admission, I 
 ordered him to be removed to a separate room, and directed the 
 chlorides to be freely used in the ward from which he had been 
 taken. Notwithstanding these precautions, two days after this 
 a patient from whom a necrosed portion of ilium had been re- 
 moved a few weeks previously, and who was lying in the 
 adjoining bed to that in which the patient with the erysipelas 
 had been temporarily placed, was seized with erysipelas of which 
 he speedily died. The disease then spread to almost every case 
 in the ward, and proved fatal to several persons who had been 
 recently operated upon." 
 
 Quite independent of wounds there are a number of cases on 
 record in which persons in contact with cases of erysipelas have 
 been affected, and the inference seems a fair one that they took 
 the disease through the lungs. 
 
 The incubation period when erysipelas is inoculated varies from 
 ^fteen to sixty hours. 
 
 (326) Disinfection after Erysipelas. 
 
 It has been found very difficult in certain cases to destroy the 
 contagion of erysipelas. For example, the old Dreadnought was 
 so saturated with it, that it was found necessary to cease using 
 it as a hospital ship. Hence a hospital ward which has had 
 cases of erysipelas should be treated in a most rigorous manner. 
 After a thorough and complete cleansing, it should be well fumigated 
 with chlorine, and then every part wetted with a solution of 
 corrosive sublimate 1 per 1,000. Erysipelas is, however, 
 thanks to the new antiseptic surgery, becoming rare in hospitals. 
 When the disease occurs in private houses the ordinary means of 
 
XXIX.] DIPHTHERIA. 429 
 
 disinfection will suffice. In investigating an epidemic of erysipelas 
 particular attention should be paid to the drainage and to the 
 abatement of nuisances, for it is ever to be remembered that 
 erysipelas is a septic disease and is intimately connected with 
 uncleanliness. 
 
 DiPHTHEKIA. 
 
 Diphtheria is a micro-parasitic disease, affecting primarily the 
 mucous membrane of the fauces and larynx, but it may also 
 develop on other mucous surfaces, or even in wounds. The micro- 
 organism develops a poison at the seat of the infection, one of the 
 most striking effects of which is paralysis — but the latter is not 
 constant. 
 
 (327) Mortality from Diphtheria. 
 
 From 1855-80, a period of twenty-six years, there have been 
 registered 89,603 deaths from diphtheria in England and Wales, 
 which gives for those years an average death-toll of 3,446 annually. 
 More females die than males ; this excess is real, and not to be 
 accounted for by the excess of female population. The deaths 
 from diphtheria among the female population are 12 per cent, 
 above the male population, whereas the number of females living 
 exceeds that of males by 5 per cent., leaving an excess of 7 per 
 cent, which cannot be attributed to the disparity of the sexes. 
 
 (328) Geographical Distribution of Diphtheria in England 
 and Wales. 
 
 This has been carefuUy studied by Dr. Longstaff {Vlth Annual 
 Report Local Government Board. Supplement.) He has taken his 
 facts from the abundant statistics of the twenty-six years end- 
 ing 1880, and has graphically displayed in a shaded map the 
 local mortality ; the depth of tint being proportional to the 
 degree. The small fatality of diphtheria in Devonshire, Cornwall, 
 and the Midland counties, contrasts in a striking manner with the 
 blackness of Norfolk, the eastern counties, and the dark tint of 
 Wales. He shows that diphtheria has always displayed a tendency 
 
430 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 to prevail in sparsely-populated districts rather than' in centres of 
 population ; as years have gone on, this tendency has become less 
 and less marked, so that there has been a progressive tendency to 
 equalize the special mortality in urban and rural districts. To sum 
 up in nearly his own words the result of this inquiry : — Whatever 
 units of area are taken in the examination of the geographical dis- 
 tribution of diphtheria in England and "Wales, the same general 
 results are arrived at. The distribution of diphtheria is apparently 
 sui generis, the mortality from the disease clearly is not regulated 
 by the same causes as influence the general mortality, certainly 
 density of population does not favour it. This disease appears 
 rather to have a preference for special districts, the great majority 
 of which may be described as rural, and which have but a small 
 proportion of their people living in towns ; indeed several of 
 these districts, notably Eothbury, Solihull, Hailsham, Petersfield, 
 Ledburj^ and Tenterden, have such a very low general death-rate 
 (varying from 15'3 to 177 per 1,000), that they fairly claim to 
 be amongst the healthiest areas in England. On the other hand, 
 whilst among those districts which have to a great degree 
 escaped the ravages of diphtheria there are some notably healthy 
 areas, such as Farnham and Andover (with death-rates of 16'7 
 and 17'7), there are also a number of towns of medium or large 
 size, some of which, such as Leigh, Bolton, and Wigan, have high 
 general death-rates, ranging from 23'5 to 27'1. 
 
 The geographical distribution of the other diseases is totally 
 dififerent to that of diphtheria. That summer diarrhoea is espe- 
 cially a disease of towns is a familiar fact to which attention 
 has repeatedly been called by the Eegistrar-General. Measles is 
 especially fatal in London ; scarlet fever is most common in the 
 mining and manufacturing counties — Durham, Yorkshire, North- 
 umberland, Staffordshire, Warwickshire, Cheshire, Lancashire, 
 Monmouthshire, and South Wales. 
 
 Fifty-seven per cent, of the deaths of males and 51 per cent, 
 of the deaths of females occur in the first five years of life; in 
 the next five years 25 and 29 per cent, respectively, while after 
 the forty-fifth year is reached only 2'5 per cent, of the deaths 
 of males, and 2 per cent, of the deaths of females takes place 
 (Longstaff). The average deaths per 1,000,000 during the 
 twenty-six years mentioned were for males 157, for females 168. 
 
XXIX.] DIPHTHERIA. 431 
 
 (329) Researches on the Bacteriology and Pathology of Diphtheria, 
 
 A number of competent observers have, during the last ten or 
 twelve years, devoted themselves to researches on the nature of 
 diphtheria. The student will find an excellent study of these 
 researches up to 1884 in Loefiler's classical paper published in 
 •the Mittheilungen des Kaiserhchen Gesundheitsamte, Berlin, 1884. 
 
 Especial value attaches to the researches of OerteV Loeffler,^ 
 and Klebs.^ 
 
 Loeffler, Klebs and Oertel agree in finding on the diphtheritic 
 surface a large number of micrococci and various non-pathogenic 
 forms of micro-organisms ; some of the micrococci seem to agree 
 with the characters of the septic kinds and penetrate more or less 
 into the mucous tissue. These, when isolated by cultivation, may 
 produce in animals abscesses or a kind of pyaemia and death, but do 
 not produce diphtheria. On the other hand, a micro-organism first 
 carefully described by Klebs, may be considered the bacillus of 
 diphtheria. These bacilli are 6'4 fi long and l"! /jl broad, they 
 have one or both ends swollen. They have no power of self- 
 movement. They are intensely stained by methylene blue. Spores 
 have not been definitely observed, and since it is found that when 
 exposed for half-an-hour at 60° C. the life of the bacilli is destroyed, 
 this behaviour to heat is not consistent with the presence of spores. 
 To propagate the bacilli by artificial means in cultures, a temperature 
 a little above 20° is necessary. Loeffler considers them capable of 
 retaining their vitality for three months. 
 
 Inoculated in various ways into mice or rats, both species are 
 found to possess immunity. On the other hand, small birds, guinea- 
 pigs, fowls and pigeons may all be successfully inoculated ; fowls 
 are less sensitive than small birds. 
 
 Loeffler made one experiment on a long-tailed Java monkey, the 
 result was negative. Possibly diphtheria may be communicated to 
 the anthropoid apes, for there is a case on record of a chimpanzee 
 dying from true diphtheria in the Hamburg Zoological Gardens.* 
 The geneTal efiect of inoculating an artificial cultivation of the 
 
 ^ See M. J. Oertel. Die Pathogenese der epideTiiischen Diphtheric. Leipzig, 1887. 
 " Op. cit. 
 
 ° Klebs. Archivf. experimentelle Fathclogie u. Pharmakologie. Bd. I. iv. 
 ' Hilgender and Paulicki in Gentralblatt fur die medicinischen Wissengchaften, 
 1«69, No. 47. 
 
432 A MANUAL OF PUBLIC HEALTH. [chae. 
 
 bacillus subcutaneously or into the mucous membrane of the trachea 
 of a guinea-pig is somewhat as follows : — at the place of inoculation 
 there is rapidly formed a fibrinous exudation, and death follows 
 about the second or third day. The post-mortem characters are 
 haemorrhages and inflammatory points in the muscular structure, 
 capillary extravasations and bleeding in the internal organs, 
 swelling of the glands and of the spleen. The specific bacilli are 
 confined to the affected mucous membrane or to the seat of 
 inoculation. 
 
 Loeffler summarises the results of his experiments on guinea- 
 pigs in the following words : — " The facts illustrate in a convincing 
 way, that the death of the animal was not caused by a spread of 
 the organism generally throughout the body, but through a different 
 kind of action developing locally. The hsemorrhagic oedema, the 
 fluid in the pleura, the lobular brown consolidation of the lungs, 
 which, without the presence of bacilli, develop in these organs, 
 definitely prove that a poison produced at the seat of infection 
 circulated through the blood stream, which was capable of causing 
 profound changes in the walls of the vessels." Very instructive 
 were also the experiments of Loefiler on inoculations of the vaginae 
 of young guinea-pigs. The vaginae of the guinea-pig is closed by 
 a fold of skin ; a disturbance of this fold causes a superficial, and 
 to the naked eye, invisible erosion of the epithelium, yet this is a 
 sufficient lesion for the penetration of the bacillus and the produc- 
 tion of a fatal diphtheritic vaginitis. With old guinea-pigs the 
 epithelial layer is thicker, and a great proportion of such experiments 
 fail. 
 
 Reverting now to the observations of Loeffler on the patho- 
 logical appearances in the human subject, a typical case may be 
 quoted. In a boy five years old who died of true diphtheria on the 
 seventh day of the disease, the post-mortem appearances were as 
 follows: — pseudomembrane in the throat, larynx and trachea, 
 hsemorrhagic broncho-pneumonia. No noticeable change in the 
 other organs. Sections were made of the uvula, tonsils, lungs and 
 spleen. The extreme tip of the u\Tila was destitute of epithelium, 
 in place of which it was covered by a closely adherent broad 
 pseudo-membrane. In the most superficial layer of this were 
 numerous micrococci and rods, beneath this was a layer with many 
 nuclei, then followed the typical bacilli ;' where these ceased, the 
 
XXIX.] DIPHTHERIA. 433 
 
 broad zone of colourless exudation, in which numerous blood cor- 
 puscle's and a few nuclei appeared. This zone passed into tissue 
 full of leucocytes, escaped blood corpuscles and nuclei in which ran 
 fuU blood-vessels enormously dilated. In the follicles of the 
 tonsils the epithelium was wanting, in its place was a fibrinous 
 nuclear exudation but which contained no bacilli. In the trachea 
 the exudation was in several layers, in the upper part of which 
 there were bacilli of various kinds, whilst in the deeper parts as well 
 as in the tissue no bacilli were found. In the sections of the lunss 
 the capillaries were filled with blood corpuscles and colourless cells. 
 In the interstitial tissue there were numerous leucocytes, in the 
 alveola a fibrinous and cellular exudation but no bacteria. There 
 were also no bacteria in the spleen. 
 
 Thirty cases of diphtheria investigated by Oertel gave somewhat 
 similar results. The general conclusions which may be fairly 
 drawn from the observations of Oertel and of Loeffler is that the 
 disease known under the term diphtheria, consists of at least three 
 forms. In the one the septic infection predominates, and whether 
 Klebs's bacillus was originally present or not, the sufferer is affected 
 with a disease closely analogous, if not identical, with septicaemia ; 
 in such a case there will be no membranous exudation, and the 
 sequelse of paralysis will not be observed. In a second class of 
 cases there is a more or less copious exudation, and in this form 
 Klebs's bacillus will be found, and paralysis may occur as a sequela, 
 but it is not essential. A third form appears to be a mixture of 
 septic and true diphtheritic infection. 
 
 (330) The Nature of the Diphtheritic Poison. 
 
 According to Roux and Yersin i the diphtheritic poison resembles 
 the diastases in some of its properties. A filtered liquid capable 
 of killing guinea-pigs in subcutaneous doses of one-eighth of a c.c.y 
 when heated to 38° for two hours, only produces oedema at the 
 seat of inoculation when injected in doses of a c.c. The same 
 liquid, boiled for twenty minutes, may be introduced into the veins 
 of a rabbit in a dose of 35 c.c. without causing immediate illness, 
 whilst, before boiling, one-half c.c. would have produced certain 
 death. Animals which receive in the veins or under the skin 
 
 ^ Annales de I'Instituf Fastener, July, 1889 ; Public Health, vol. ii , p. 112. 
 
 F F 
 
434 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 large quantities of liquids which have been thus heated, although 
 at first presenting no symptoms, nearly always die after a longer or 
 shorter time. They emaciate, although eating as usual, and show 
 symptoms of paralysis, chiefly in the posterior limbs, a few days 
 before death. 
 
 Roux and Yersin have sought to discover in the bodies of persons 
 dead from diphtheria the same poison. The spleen of an infant 
 dead from infectious diphtheria was macerated in sterilized water, 
 and the liquid filtered through porcelain ; 35 c.c. were injected into 
 the veins of a rabbit, and 8 c.c. subcutaneously into a guinea-pig. 
 The latter died five days after the injection. The rabbit survived 
 for two months ; at first well, it emaciated little by little, and died 
 paralyzed in the hinder extremities. 
 
 In another case of diphtheria the urine was collected when the 
 prostration was very marked, filtered fresh, and injected into the 
 veins of a rabbit and under the skin of a guinea-pig. Eleven days 
 after, the guinea-pig, much emaciated, was dead. The rabbit was 
 paralyzed in the hind extremities on the 45th and died on the 
 51st day. If these animals be compared with those which have 
 been treated with cultures boiled and filtered, the cause of death 
 in both cases will be seen to be the same. Heat destroys a great 
 part of the poison, or induces a modification similar to that which 
 it undergoes in the organism. 
 
 Kept in close vessels, preserved from air and light, filtered cul- 
 tures of diphtheria long preserve toxic properties. A filtered liquid 
 was found after five months to be as poisonous as the day in which 
 it was sealed up in tubes. Exposed to the air its toxic properties 
 gradually diminish. This action of the air is slow in the dark, 
 rapid in the solar light. After two hours of insolation 1 c.c. of a 
 liquid exposed to the air killed guinea-pigs ; the same dose after 
 five hours caused only local oedema. But when not exposed to 
 the air, ten hours of sunshine had but little effect. 
 
 Cultures of the diphtheritic bacillus have only energetic toxic 
 properties when they become alkaline ; when acid, large doses of 
 the filtered liquid are required to affect animals. 
 
 Evaporated in a vacuum at 25°, a residue is left which, when 
 dissolved in a little water, is very toxic, because it contains in small 
 volume the active matter of a large quantity of the culture. An 
 alcoholic extract is innocuous, therefore alcohol does not dissolve 
 
XXIX.] DIPHTHEEIA. 435 
 
 the poison. The active matter may be precipitated by absolute 
 alcohol in the form of white greyish flocculi, exactly in the same 
 way as an aqueous solution of diastase is precipitated by alcohol. 
 
 When a diphtheritic culture is submitted to dialysis, the outer 
 liquid is found to be lethal. Like the diastases, it also has the 
 property of adhering to certain precipitates. 
 
 The best precipitate is phosphate of lime. By fractional pre- 
 cipitation with calcic chloride, and essaying after each precipitation 
 the eflfect of the liquid, it was found that in general the second 
 precipitate was the most active. The dried precipitate is not so 
 active as the moist, but it retains its properties a long time. Even 
 after being heated for twenty minutes in the water-bath at 100°, it 
 will kiU guinea-pigs. This is, therefore, a convenient method of 
 preservation of the diphtheritic poison. 
 
 An attempt was made by Eoux and Yersin to ascertain the 
 quantity of the dry organic matter which must contain the toxic 
 material requisite to cause death in guinea-pigs or rabbits. 
 A c.c. of active liquid gives a centigramme of dry residue; on 
 subtraction of the ash and the portion soluble in alcohol which 
 have no toxic action, there remain two-fifths of a mgrm. of organic 
 matter ; but it is certain the greater part of these two-fifths are 
 formed of other substances than the diphtheritic poison. This 
 weak dose is yet sufficient to kill at least eight guinea-pigs weigh- 
 ing 410 grammes, or two rabbits of 3 kilos each ; a dog weighing 
 9 kilos, should he receive these two-fifths of a mgrm. in his blood, 
 if he does not die, will remain very ill for a long time. 
 
 Hence it follows that if the real poison could be separated in a 
 state of absolute purity, it would be lethal to guinea-pigs in a less 
 dose than 075 mgrm. per kilo (-^-^^ gr. per lb.), to rabbits in a less 
 dose than 013 mgrm. per kilo. 
 
 (331) Klein's ^ letter Researches on Diphtheria. 
 
 While these sheets were passing through the press Klein has 
 published researches, which, if confirmed, throw considerable light 
 on the etiology, and in some points modify the foregoing account. 
 In the first place he found that cultures of Klebs's bacillus were 
 
 1 Report of Medical OflBcer in Supplement to Mghteenth Annual Report of Local 
 Government Board, 1888—1890. Proceedings of the Royal Society, 1890. 
 
 F F 2 
 
436 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 virulent to guinea-pigs on subcutaneous injection, but that the 
 disease thus produced could not be considered diphtheritic. The 
 same cultures were inactive when tested on fowls, pigeons, and 
 rabbits. He next experimented with human diphtheritic mem- 
 brane and found that pigeons, fowls, and rabbits were resistant to 
 its action, but that guinea-pigs when inoculated with the membrane 
 died of a septic infection, and he could not consider that the re- 
 action was of a diphtheritic nature. 
 
 The true bacillus of diphtheria according to Klein is not that 
 discovered by Klebs, but one which is shorter, and its most striking 
 difference to that of Klebs is that it grows on gelatin at 20° C, 
 whereas the bacillus of Klebs does not grow at all below 22° and 
 flourishes best at 35°-37°. The bacillus of Klein seems to be 
 readily obtained in a state of purity by inoculation of a cat's 
 cornea with human diphtheritic membrane, as in the experiments 
 to be mentioned. 
 
 Experiments upon cats vfith human diphtheritic membrane gave 
 some striking results. On various occasions during the last few 
 years there have been obsei-vations of some relation between 
 human diphtheria and a malady in cats ; instances such as e.g., 
 that a cat or cats were taken ill with a pulmonary disease, and 
 when ill were nursed by children, and then these latter sickened 
 with well marked diphtheria. Or reversely, children were taken 
 ill with diphtheria and either at the same time or afterwards the 
 cat or cats sickened. The disease in the cat was described as an 
 acute lung trouble ; the animals were quiet, did not feed and 
 seemed unable to swallow. In some cases they recovered ; in 
 others they became emaciated, while the lUng trouble increased, 
 aiid they ultimately died. In one instance the cat malady occur- 
 ring where children were soon after attacked by diphtheria was of 
 a wide-spread nature ; and post-mortem examination of the animals 
 affected showed severe lung disease, broncho-pneumonia, and large 
 white kidneys due to fatty degeneration of the entire cortex ; a 
 similar condition being also met with in the human subject as an 
 effect of diphtheria. 
 
 Subcutaneous inoculations into cats were carried out with par- 
 ticles of fresh human diphtheritic membrane and with cultures of 
 the diphtheritic bacillus, producing a local diphtheritic swelling at 
 the seat of inoculation and general visceral disease. In the cases 
 
XXIX.] DIPHTHERIA. 437 
 
 in which death followed after a few days the lungs were found 
 much congested, and when death followed after one or more weeks 
 the lungs showed broncho-pneumonia, and the kidneys were 
 enlarged and white, the cortex being in a state of fatty degenera- 
 tion. If the disease lasted beyond from five or seven days, both 
 kidneys were found uniformly white in the cortex ; if of shorter 
 duration, the fatty degeneration was sometimes only in patches, 
 although in these experiments the bacillus was recoverable by 
 cultivation from the swelling at the seat of inoculation. No bacilli 
 were found in the lungs, the blood, or the kidneys, and hence the 
 conclusion is justified that, as in human diphtheria and in that 
 produced by the inoculation of guinea-pigs, so in these experi- 
 mental facts the visceral disease was the result of the action of a 
 chemical poison produced by the growth of the bacillus at the seat 
 of inoculation. From this it is seen the similarity between the 
 natural and the artificial disease in the cat is very great, and the 
 question arises as to the manner in which the cat either receives 
 or imparts the diphtheritic contagion in the natural disease. 
 This natural disease is in its symptoms and pathology a lung 
 disease, and it is reasonable to suppose from analogy that the lung 
 is the organ in which the diphtheritic process in the cat has its 
 seat. The microscopic examination of the diseased lungs of a cat 
 dying from the natural disease bears out this supposition, the 
 correctness of which has also been proved by direct experiment. 
 Broth culture of the special bacillus was introduced into the wind- 
 pipe of cats without injury to the mucous membrane. The animals 
 became ill with acute pneumonia, and on post-mortem examination 
 from two to seven days later there was found extensive pneumonia 
 and fatty degeneration of the kidneys. The air passages contained 
 an exudation like that of human diphtheria aTnd the bacilli were 
 present in large numbers. During the last ten or twelve years 
 several epidemics of diphtheria have been traced to milk, but the 
 way in which the milk became contaminated with the diphtheritic 
 virus was not ascertained, although the evidence was very strong 
 that it had not been from a case of disease in the human subject. 
 The eows which yielded the milk were not reported to be un- 
 healthy, except for having sores or chaps on their teats. Klein 
 inoculated a broth culture of the diphtheritic bacillus into two cows. 
 On the second or third day there was a soft tender swelling at the 
 
438 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 place of inoculation which reached its maximum at the end of a 
 week and then gradually became smaller and firmer. The animals 
 had a raised temperature and left off feeding on the second or 
 third day, then to all appearances recovered ; but on the eighth or 
 tenth day, they were attacked by a slight cough which gradually 
 increased ; both became emaciated ; one died on the fifteenth day, 
 the other was killed (being very ill) on the twenty-fifth day. 
 During the illness both animals had an eruption on the teats and 
 skin of the udder. From one of the cows on the fifth day milk 
 was. drawn from the healthy teat, the outside of the teat and the 
 milker's hand having been first thoroughly disinfected from this milk 
 cultivations were made, and it was found that thirty-two colonies 
 of diphtheria bacillus without any contamination were obtained 
 from a single cubic centimetre. Contrary therefore to what happens 
 in the guinea-pig and in the cat ; the diphtheria bacillus passes 
 from the seat of inoculation into the system of the cow and makes 
 its appearance in the milk. The presence of the bacillus in the 
 eruption on the udder was also demonstrated both by microscopic 
 examination and experiment. Two calves were inoculated with 
 matter from this eruption and both developed a similar eruption, 
 besides becoming affected with severe broncho-pneumonia and 
 fatty degeneration of the kidney. It therefore appears that a 
 definite disease can be produced in the cow by the diphtheria 
 bacillus and the contamination of the milk shows that the bacillus 
 contaminates the general system. 
 
 At the beginning of the month of April, two cats died at the 
 Brown Institute after having been ill for several days with symp- 
 toms like those of natural cat diphtheria between the beginning 
 of April and the beginning of May ; fourteen cats became similarly 
 affected, some more -severely than others, and some died with the 
 characteristic morbid changes. This epidemic, as it may be called, 
 commenced with the illness of the first two cats about the end of 
 March ; and the question arises as to how the disease originated 
 in these two animals ; no cats had been ill in their shed and the 
 two affected ones were healthy when received at their institution 
 some weeks later. But during the latter half of March there were 
 in the stables of the institution two milch cows ill with diphtheria 
 induced by inoculation with the human diphtheria bacillus — in 
 fact the two cows already referred to. The diphtheria bacillus 
 
XXIX.] DIPHTHERIA. 439 
 
 was found in the milk of one of these animals on the fifth day 
 after inoculation, and ordei-s were given to the attendant that the 
 milk of both cows was to be thrown away. This order was not 
 obeyed, for part of the milk was given to the two cats above men- 
 tioned, and they sickened as described within a day or two after- 
 wards. It ought to be mentioned that the man in attendance on 
 the cows had also charge of the cats, but in view of the fact that he 
 himself was free from the disease the possibility of his having con- 
 veyed it to the cats may be dismissed. 
 
 (332) The Prevention of Di-phtheria. 
 
 A common source of infection is actual contact with persons 
 suffering from diphtheria. It is not unfrequently produced from 
 the unnecessary and very dangerous plan of sucking a tracheotomy 
 tube in order to clear it.-* There are epidemics on record distinctly 
 connected with milk. Nevertheless a large proportion of the cases 
 are obscure in origin. It is noteworthy that in LoefHer's investi- 
 gation into the organisms of the healthy mouth and throat he 
 found in one case Klebs's bacillus, so that it may be presumed it 
 gets access to persons' throats without necessarily causing illness. 
 Persons with large tonsils and relaxed throats are probably more 
 liable to be attacked than those whose mucous membranes are in a 
 healthy state, for the micro-organism has then opportunities to 
 attach itself to the interior of a follicle, and unless destroyed by 
 other saprophytic bacteria, or by the secretions of the mucous 
 membrane, to divide and multiply, and get access ultimately to the 
 deeper layers of the tissue. One important factor in prevention of 
 diphtheria is, therefore, when diphtheria is epidemic for persons 
 with weak throats to apply local applications under advice so as to 
 get the mucous membrane into a healthy and therefore resistant 
 condition. 
 
 If the view is correct that a large proportion of the cases are 
 septic, such are likely to be caused by bad drainage, and foulness 
 
 ' It is obvious that a wash-bottle arrangement containing at the bottom of the 
 flask a solution of corrosive sublimate or else strong carbolic acid, and from the glass 
 tube which dips beneath the liquid a rubber tube carrying a little nozzle fitting in 
 the silver canula, would make a most effective apparatus to clear the tracheotomy 
 tube, and the operator could not be directly infected, for the sucked out matter 
 would pass into the disinfectant. By drawing air through the shorter tube a very 
 considerable vacuum will be produced. 
 
440 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 of all kinds. The possibility of infection from cats in the light 
 of Klein's recent research must also be remembered. Diphtheria 
 actually present in a house, the patient should be isolated, and 
 those in attendance should spray the throat with a half or one 
 per cent, solution of carbolic acid two or three times a day. The 
 writer has known families which have taken this precaution and 
 escaped, although for days in hourly contact with bad cases of 
 diphtheria. So far as is known, the diphtheritic poison is easily 
 destroyed, and therefore the disinfecting measures described at 
 page 358 should be successful. 
 
 Puerperal Fever — Septicemia — Pyemia— Blood-Poisoning. 
 
 (333) Influence of Season on Se^ptic Diseases. 
 
 The above names are given to diseases which have so much in 
 common that, in a public health sense, they may be considered 
 almost identical save in relation to sex, and as to whether they 
 arise from external wound or otherwise. 
 
 Puerperal fever and septic diseases generally are also closely 
 allied to erysipelas, for when erysipelas is frequent, puer- 
 peral fever and the other septic class are also frequent in their 
 incidence ; whereas when erysipelas is not frequent, there are also 
 fewer cases of the septic class than usual. For example, take the 
 twenty-five years ending 1888 : the maximum number of puer- 
 peral fever deaths occurred in 1874 (3,108), in the same year 
 the maximum number of deaths from erysipelas (8,358) were regis- 
 tered ; in 1867 occurred the minimum number of puerperal deaths 
 (1,066), in the same year the minimum number of deaths from 
 erysipelas (1,446). The two curves also given by Buchan and 
 Mitchell, showing graphically the seasonal mortality variations for 
 each week of the year, based upon the mortality records for thirty 
 years ending 1874, show the same general fluctuations for ery- 
 sipelas and for puerperal fever. The minimum of each falls in the 
 latter end of August, the mortality rising gradually, to attain the 
 maximum in the last week of November, to decline somewhat 
 throughout December, but to be still above the average, to rise 
 again in January, and then to gradually decline through the suc- 
 ceeding months to the lowest point in August. 
 
XXIX.] PUERPERAL FEVER. 441 
 
 (334) Statistics of Puerperal Mortality. 
 
 The actual number of deaths from puerperal fever in the twenty- 
 five years ending in 1888 was 46,162, the number of births (living) 
 was 19,746,768, which would give a rate per birth of 2-3 per 1000. 
 The rate is not quite so high as this, because the number of births 
 (living) is less than the number of confinements. The mean yearly 
 number of puerperal deaths is 1,846 ; the maximum, as before 
 stated, fell in 1874 (3,018), the minimum in 1867 (1,066). These 
 maxima and minima do not coincide with the maximum or mini- 
 mum of birth: the greatest number of births took place in 1884 
 (906,750), the least number in 1864 (740,275). 
 
 During the three years ending 1888 (the full returns have 
 been published for the last three) there has been an increase of 
 death from puerperal fever in relation to the number of births, the 
 rate per thousand births being for those three years 2'6 per thousand. 
 This increase occurs in confinements treated at the woman's own 
 home by medical practitioners, midwives, &c., and not in the lying- 
 in hospitals. 
 
 The use of disinfectants has caused a complete and happy 
 change in the mortality of lying-in institutions. In the largest 
 childbed institution of the world, viz. the Vienna Lying-in Hospital 
 the mortality previous to 1862 was 28 per 1,000 ; then by hygienic 
 reforms it was reduced by 1880 to 16 per 1,000 ; lastly, during the 
 period since 1880 it has fallen to 7 per 1,000. At Dresden the 
 mortality has been reduced from 50 per 1,000 to 10 per 1,000. 
 The mortality at the Maternity in Paris has been reduced by the 
 same agencies from nearly 10 per cent, to 11 per 1,000. In our 
 own institutions, such as Queen Charlotte's Hospital, and the 
 General Lying-in Hospital, York Road, puerperal fever is almost 
 unknown. It is therefore evident that midwives and a large pro- 
 portion of the profession can either not use antiseptics, or are not 
 able to enforce their use in the subsequent nursing. As Dr. 
 Cullingworth ^ has already stated, in pleading for the more general 
 use of antiseptics in obstetric practice : — " The lying-in hospitals 
 have very properly led the way, and it now rests with those en^ 
 gaged in private practice to take the matter up. It was obvious 
 that the 2,078 deaths certified as having occurred in England and 
 ^ Public Health, vol. i., p. 210. 
 
442 • A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Wales from puerperal fever in 1886 could not have all taken place 
 in hospitals. Indeed, two-thirds of them occurred in counties 
 where not a single lying-in hospital existed. It was not, therefore, 
 a disease of hospitals alone. The only way to avoid this terrible 
 mortality, and to avoid also the enormous amount of puerperal 
 disease which, because it was not fatal, remained unrecorded, was 
 for every practitioner to recognize his responsibiUty in the matter. 
 The use of antiseptic precautions in midwifery practice in Ger- 
 many was made compulsory by the State. The tendency of public 
 opinion in this country was not in the direction of compulsory 
 legislation in such matters. The use of antiseptics in Great 
 Britain was, and was likely to remain, a question of individual 
 responsibility, not of penal enactment. Surely it ought not on 
 that account to be considered the less binding." 
 
 (335) Bacteriology of the Septic Diseases. 
 
 In the septic diseases generally, there have been various micro- 
 organisms, such as bacilli and cocci, found, which, when isolated 
 by cultivation, and the cultures injected subcutaneously, cause 
 abscess, or purulent foci, or gangrene, or erysipelatous inflammations 
 in the lower animals. It is pretty certain that in puerperal fever 
 and septicaemia one or more pathogenic micro-organisms cause 
 the illness. In the puerperal state, the raw surface of the uterine 
 mucous membrane, and any laceration of the peritoneum or other 
 parts, afford an excellent soil for pathogenic microbes ; in other cases 
 a wound or abrasion of the skin is the portal through which the 
 mischief enters ; in others again there is a direct infection or inocu- 
 lation, such, for example, as the pysemia which so often ensues after 
 wounds occurring in dissection. There is another class of cases, 
 which seem to depend upon bad drainage or foul emanations ; this 
 class of blood-poisoning, which often runs its course similar to trau- 
 matic pysemia, is obscure, and requires farther investigation. 
 
 (33G) The Buty of the Health Officer in relation to Fvsrperal 
 
 Fever. 
 
 Under the Notification Act, cases of puerperal fever must be 
 certified by the medical man, notified by the householder. It 
 
xxis.] DISINFECTANTS IN THE PUERPERAL CONDITION. 443 
 
 should certainly be the duty of the health officer to make inquiry 
 into each case ; he should specially direct his investigation as to 
 the previous confinements which either doctor or nurse has 
 attended, and as to whether the medical attendants used disin- 
 fectants in washing their hands, or as to whether antiseptic vaginal 
 injections had been used. The drainage and sanitary condition of 
 the house should also be strictly investigated. 
 
 Since these maladies are not easily communicated unless by 
 direct inoculation, or unless persons in the vicinity of the sick have 
 abrasions of the skin, cuts, or wounds, it is not absolutely 
 necessary to remove the patient to hospital on public grounds ; 
 but if the lodging is itself insanitary or overcrowded, it may then 
 be advisable to urge such removal. 
 
 (337) Disinfectants in the Puerperal Condition. 
 
 A 1 per 1,000 solution of corrosive sublimate for general use — that 
 is, both for washing the hands and as a vaginal injection — or a 5 per 
 cent, solution of carbolic acid, will be found the best. (Eeference may 
 be also made to the trichloride of iodine, see page 345.) After an ob- 
 stetric physician has attended a case of puerperal fever, it has been 
 found most difficult to get free from infection. The main trouble 
 probably is to disinfect the recess between the nail and the finger. 
 From experiment it has, however, been shown that, if the hands are 
 washed with as hot water as can be borne, then with strong alcohol, 
 and then with a strong disinfectant, such as a solution of iodine 
 trichloride, the hands may be made to yield sterile scrapings even 
 when such scrapings are derived from under the nail. This, with 
 two or three Turkish baths, followed by sponging the whole body 
 over with a 1 per 1,000 solution of corrosive sublimate and absolutely 
 fresh clothing, the clothing taken off being sent to the disinfecting 
 chamber, will, if carried out honestly and intelligently, most cer- 
 tainly free the physician's body from any infective particles. 
 
CHAPTER XXX. 
 
 tubercular maladies. 
 
 Tuberculosis. 
 
 Tuberculosis is an infectious malady, caused by a micro-organism 
 to which has been given the name of the Bacillus tiiberculosis. 
 The bacillus once planted in the tissues may give rise to a mere 
 local lesion, as for instance when it is inoculated into the skin ; or 
 may affect one particular organ, such as the lung, far more than 
 any other part ; or may be generally diffused. 
 
 (338) Statistics of Tubercular Mortality. 
 
 Hitherto we have had no trustworthy guide as to the number of 
 cases of tuberculosis, save that of the death returns. In the 
 Registrar-General's returns tuberculosis is divided into phthisis, 
 tabes mesenterica, tubercular meningitis, and " other forms of tuber- 
 cular disease and scrofula." Some of the latter are probably not 
 correctly diagnosed, but on the other hand it may be safely affirmed 
 that a number of cases escape diagnosis, and that the mortality is 
 rather likely to be under- than over-stated. 
 
 During the twenty-five years ending 1886, the average total 
 deaths from phthisis have been 50,000 yearly in England, and 
 those from other tubercular affections 17,700 — in all, nearly 
 68,000. 
 
 An interesting summary is given by the Registrar-General of the 
 deaths from tubercular diseases of children under five years of 
 age for the three decades from 1871 to 1880 : — " The death-rate 
 from phthisis in the years 1851-60 was 1,305 per million: from 
 
CHAP. XXX.] TUBERCULOSIS. 445 
 
 tabes mesenterica and scrofula, 1,920. In 1861-70 the figures are 
 968 for phthisis, 2,213 for hydrocephalus and tubercular meningitis, 
 and 2,267 for tabes mesenterica and scrofula; whilst in 1871-80 
 the figures are 767, 1,800, and 2,550." 
 
 In relation to these Dr. Sims Woodhead^ remarks : — " The differ- 
 ences in the proportions between these figures in the various years 
 might be due in part to more accurate diagnosis, but in part they are 
 to be accounted for by the increase in the death-rate from tabes. In- 
 cluding, as these cases do, the diagnoses of physicians both skilled 
 and unskilled, it would appear from the results of post-mortem ex- 
 amination of the cases described th^t the last group might safely be 
 multiplied by five to give the actual number of cases in which the 
 mesenteric glands were affected, giving no less than 12'75 per 1,000 
 as the rate of disease. If,> in addition, those cases are taken in 
 which the tubercular is followed by a repairative process, the 
 number must be enormously greater." 
 
 (339) The Influence of Age and Sex. 
 
 Females are more Uable to tubercle than men:, in the propor- 
 tion of about 0'2 per 1,000 of the population. It may be stated 
 generally that the mortality is gi'eatest at birth, diminishes rapidly 
 till the fifth year, more gradually till about the fifteenth, and then 
 begins to rise, ait first slowly, then rapidly to the end. In the early 
 years taken as a whole, the mortality is low, but from fifteen to 
 twenty-five it is high ; after this age the mortality somewhat 
 declines. It must howevfer be rernembered thsit during the first five 
 years of life errors in diagnosis are most common, and it is probable 
 that many children die from tubercular meningitis and from tabes, 
 the deaths being returned as from convulsions, teething, diarrhoea, 
 and so forth. 
 
 Different organs are affected £tt very different periods of life. 
 Thus Dr. Woodhead remarks that tubercular meningitis occurs 
 much more frequently between the third and the eighth years than 
 it does at any other period of life. Rilliet and Barthez give the 
 results of the examination of 98 cases of this condition. They 
 state that during the first year there were only two cases ; be- 
 
 ^ " Abstract of the Kesearches of Dr. G. Sims 'Woodhead," Piiblic EealCh, vol. i., 
 1888. 
 
446 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 tween one and two years and a half, 17; from three to five years 
 and a half, 34 ; from six to seven years and a half, 23 ; from eight 
 to ten years, 15 ; and from eleven to fifteen years, 7 cases. 
 
 Of 54 cases of tubercular meningitis examined by Dr. Wood- 
 head, not one was under one year (adopting the same classification) ; 
 between one and two years and a half there were 15 ; from three to 
 five years and a half, 21 ; from six to seven years and a half, 8 ; 
 from eight to ten years, 8 ; and from eleven to fifteen years, 2. 
 These figures correspond fairly closely, and might serve as a basis 
 for comparison. In these 54 cases, tuberculosis was in 39 so widely 
 disseminated that it might fairly be said to be general ; in only 2 
 cases could no primary centre of infection be found. In 6 the 
 only foci that could be primary were to be found in the lymphatic 
 glands of the mediastinum alone or along with those of the 
 mesentery ; in 8 the lungs were the only other organs affected ; 
 and in 1 the lungs and mediastinal glands contained the older 
 tubercle nodules. 
 
 In the brain or in its membranes, the embolic tuberculosis must 
 be looked upon as part of a general process. Intestinal tubercle 
 is most common in the years following childhood from twelve 
 upwards for six or seven years. From an analysis of 127 cases of 
 tuberculosis in children it was found that in 43 instances there 
 was tubercular ulceration of the intestine. During the first yeai- 
 after birth there was only 1 ; between one and two years and a 
 half, 14 ; from three to five years and a half, 10 ; from six to seven 
 years and a half, 7 ; from eight to ten j'ears, 5 ; and from eleven 
 to fifteen years there were 6. So that in this series of cases the 
 intestines arc frequently affected during very early life as well as 
 in somewhat later years. Although the intestines are directly 
 affected by tubercle in such a small proportion of cases, the mesen- 
 teric glands are found to be in some stage or other of tubercular 
 degeneration in no less than 100 instances, or in nearly 79 per 
 cent, of the whole. The age at which these tubercular glands in 
 the mesentery were found is also significant. During the first 
 year of life there were 4 cases ; from one to two years and a half, 
 33 ; from three to five years and a half, 29 ; from six to seven 
 years and a half, 12 ; from eight to ten years, 13 ; and from eleven 
 to fifteen years, 9 cases. Here again the figures are higher during 
 the earlier periods than during later years, but the maximum is 
 
XXX.] TUBERCULOSIS. 447 
 
 reached (as with ulceration of the intestine) at a distinctly earlier 
 period than in the case of tubercular meningitis. In 14 cases the 
 glands only were affected — i.e., there was no tubercle found in any 
 other part of the body. In these cases the glands had become 
 calcified, but in the others the structure and degeneration of the 
 glands were tubercular, bacilli were very few in number and in 
 some cases could not be demonstrated, and the nature of the mass 
 could only be determined by inoculation experiments. Here, 
 again, the second and third periods account for more than all the 
 others put together, 5 and 4 from one to two and a half years and 
 from three to five and a half years, against 5 for the other four 
 periods (1 under one year ; 1 between six and seven and a half 
 years ; 2 from eight to ten years ; and 1 from eleven to fifteen 
 years). These 14 cases were accompanied by neither ulceration 
 nor cicatrisation of the intestine ; there was no peritonitis, and 
 secondary tubercle could be found in no other parts of the body, so 
 that the tuberculosis of the mesenteric glands must be looked upon 
 as the primaiy lesion. Continuing the analysis, it was found that 
 in this 100 cases the glands at the root of the lung were simul- 
 taneously affected in 69 cases, and in 62 the lungs were also 
 affected ; in 13 there was tubercular peritonitis, and in 18 ulcera- 
 tion of the intestine was also found. Of the remaining cases, 4 had 
 tubercular peritonitis and 4 ulceration of the intestine. In 12 cases 
 the mesenteric and mediastinal glands, the peritoneum, the intes- 
 tine, and the lungs were all affected; whilst in no fewer than 53 
 of the 100 cases there was evidence of localised peritonitis, recent 
 or old, occurring between the spleen or liver and the diaphragm. 
 Of the whole 100 cases, only 20 were diagnosed as having abdominal 
 tubercle, and this 20 would be considerably reduced were the 
 doubtful diagnoses eliminated. In these cases, then, the symptoms 
 associated with tubercle in other organs are so predominant that 
 the tubercle in the abdomen was practically overlooked. Dr. 
 Goodhart, speaking of this condition, says : " Caseous or tubercular 
 disease of the mesenteric glands is not uncommon ; nevertheless, it 
 is rare indeed in comparison with the consumption of the bowels 
 which is so often heard of in the dwellings of the poor. From a 
 large out-patient department of the Evelina Hospital during 
 several years, and when at least 6,000 or 7,000 children must have 
 come under observation, and probably considerably more, I have 
 
448 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 only note of 46 cases, and half of these were but of doubtful nature. 
 Some few others are to be associated with phthisis, but as a sub- 
 stantive ailment we might have supposed it to be more common 
 than it is." And Professor Gairdner, in his Lectures to Practitioners, 
 draws attention to the fact that as pathological descriptions can 
 deal with fatal cases only, a far too grave prognosis is arrived at 
 in case of tabes, and that consequently many cases of tubercular 
 disease, not only of the mesenteric glands, but also of the peri- 
 toneum, recover, only the more grave cases succumbing. It is 
 evident from all this that tubercular conditions of the abdomen ' 
 are much more common than can be inferred even from the figures 
 above quoted, where only one-fifth of the real number are stated 
 in the diagnosis charts to be suffering from abdominal tubercle. 
 That there is a great tendency towards calcification and cicatrisation, 
 especially where the tissues have a high resistant power, is well 
 known to all pathologists, who constantly find cicatrices which are 
 to be recognised as of tubercular origin (by the presence of small 
 caseous or calcareous nodules, etc.), in which, however, the tubercle 
 has become quiescent. These are the result of local tubercular 
 changes, the localisation being due to the activity of the tissues. 
 
 (SiO) Prdbahility of a Person Dying from Consumption. 
 
 The late Dr. Farr from his life table calculated that 114,417 
 out of 1,000,000 children born would die of phthisis ; at some or 
 other period of their lives these might therefore be considered 
 predisposed, or in other words they had less resistant power than 
 other people. He then constructed a hypothetical life table of the 
 class dying or to die of consumption, by picking out the survivors 
 of the 114,417 at any age and putting them into a class apart. 
 Such a table illustrates well the effect of age, e.g. : — 
 
 Numbers to Die of Consumption at and after each Age out of 
 1,000,000 Children Born. 
 
 Age X. To die. Age x. To die. 
 
 . . . 114,417 35 54,290 
 
 5 . . . 109,948 45 31,886 
 
 10 . 107,809 55 . . . . . . 15 418 
 
 15 . 104,283 65 . . . . 4,973 
 
 30 95,209 75 . . 679 
 
 25 . 81,424 85 . . . ... 52 
 
XXX.] 
 
 TUBERCULOSIS. 
 
 449 
 
 (341) Influence of Occupation on Tubercle Infection. 
 
 Out-door occupations are less liable to tubercular maladies than 
 in-door; a rural population is therefore less liable than an urban 
 population. Those who are well housed and have ample cubic 
 space are less liable than those living in the reverse conditions. 
 The spread of tuberculosis in this respect strictly follows the law 
 governing the spread of zymotic diseases generally. The one- 
 roomed population of towns have a much higher mortality than 
 those who can afford more than one room. Two causes tend to 
 produce this result — the one is the low state of health breathing 
 an impure atmosphere produces, and hence a less resisting power ; 
 the other is that the nearer the infected and the healthy are, the 
 more prone is infection to be conveyed. 
 
 Dusty trades or occupations are especially liable to produce 
 tubercular lung disease. C. Lombard (Becherches Anatomiqices sur 
 I' Emphys&me pulmonaire) found the order of fatality to be (1) mineral 
 dust ; (2) animal ; (3) vegetable. In 1,000 deaths from consump- 
 tion of adults he found they could be classed according to their 
 occupations as follows : — 
 
 Occupations with mineral and vegetable emanations 
 Occupations with various dusts . 
 Sedentary life . .... 
 
 "Workshop 
 
 Hot and dry air 
 
 Stooping posture 
 
 Sudden movements of the arms . 
 Muscular exercise and active life 
 Exercise of the voice ..... 
 
 Living in open air 
 
 Animal emanations 
 
 Occupations in which watery vapour was breathed 
 
 176 
 
 145 
 
 140 
 
 138 
 
 127 
 
 122 
 
 116 
 
 89 
 
 75 
 
 73 
 
 60 
 
 53 
 
 This result is conformable to the micro-parasitic theory of 
 tuberculosis. The researches of Greenleaf Tucker ^ and others 
 have clearly proved that the number of bacteria in the atmosphere 
 of a room or place is dependent upon the greater or less amount 
 of dust. In a quiet room, such for example as a hospital ward 
 early in the morning, before any dusting, sweeping, or bed-making 
 has been done, the bacteria are very small in numbers because 
 they have settled down with the dust on the floor, the walls, and 
 1 Massachusetts State Board of Health Report, 1888. 
 
 G G 
 
450 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 other objects ; the bacteria attain their maximum number when 
 there is the maximum amount of dust in the air. It is therefore 
 no wonder that a disease hke tuberculosis, so widespread and 
 against which no precautions are taken, infects the dust of work- 
 shops and living rooms, and the bacilli, dust-borne, are breathed ; 
 nor is it a matter of surprise that metallic dust — that is, dust 
 having sharp angles and spiculse — should be more likely to wound 
 the mucous epithelium and open a door as it were for the bacilli 
 to enter, while the softer vegetable fibre has not so great an 
 effect. 
 
 (342) Influence of Soil. 
 
 Drs. Bowditch and Buchanan, working independently, success- 
 fully established the fact that there is a relation between dampness 
 of soil and tubercular affections. It is therefore probable that 
 dampness of a house is also a predisposing cause, although the 
 area in which the particular house stands may be dry. Sir John 
 Simon and others have shown that the draining of soils diminish 
 the death-rate from consumption. Dr. Andrews, of the Chicago 
 Medical College, has studied the geographical distribution of con- 
 sumption in the States, and has shown that there it is most 
 abundant near the sea and diminishes as we recede from it. At 
 equal distances from the sea it prevails at the north and diminishes 
 towards the south. For example, beginning at Massachusetts and 
 going westward, the proportion of deaths from consumption to 
 deaths from all causes regularly diminishes as we recede from the 
 Atlantic. Thus deaths from Massachusetts, 25 per cent. ; New 
 York, 20 per cent. ; Ohio, 16 per cent. ; Indiana, 14 per cent. ; 
 Illinois, 11 per cent.; Missouri, 9 per cent. ; Kansas, 8 per cent.; 
 Colorado, 8 per cent. ; Utah, 6 per cent. ; and then in California 
 it increases again to 14 per cent, on account, according to Andrews, 
 ot the proximity of the Pacific Ocean. A similar decrease is 
 observed in going from north to south — viz., Michigan, 16 per 
 cent.; Indiana, 14 per cent.; Tennessee, 12 per cent.; Alabama, 
 6 per cent. 
 
 Hence tubercular disease seems to follow closely the moisture 
 and temperature of localities. Massachusetts is ten times as 
 fatal to consumptives as Georgia, and Minnesota is twice as fatal 
 as Georgia. The combinations of damp soil, an atmosphere laden 
 
XXX.] TUBEECULOSIS. 451 
 
 with moisture, and variable weather, are the most favourable, aad 
 the reverse of these the least favourable, for the dissemiuation 
 of the malady. 
 
 (343) Influence of Season on Tubercular Fatality. 
 
 This has been worked out in Buchan and Mitchell's research.^ 
 It would of course be more interesting to know at what season of 
 the year the tubercular process commenced than when it termi- 
 nated, but this is not possible until tuberculosis in all its forms is 
 " notified " under the Infectious Diseases Notification Act. 
 
 Buchan and Mitchell have shown that the mortality from tabes 
 follows very closely the temperature, the maximum being from the 
 middle of July to the middle of September similar to the maximum 
 of diarrhoea mortality, and in point of fact the deaths from tabes 
 are mostly hastened by diarrhoea ; the absolute minimum is from 
 the end of December to the beginning of February. 
 
 The relation of phthisis to weather they have also delineated 
 in a curve, and remark : " The absolute minimum occurs in 
 the last week of September, after which it begins steadily to 
 rise ; in the middle of November it rises still more quickly ; 
 during the last three weeks of December it falls a little ; rises 
 again in the beginning of the year, and remains steady until the 
 second week of March, when it rises to the annual maximum 
 during March, April, and May. From the middle of July to the 
 middle of November it is below the average. This is one of the 
 most constant curves in its main features from year to year." 
 
 (344) Bacteriology and Pathology of Tuberculosis. 
 
 Those works are alone noticed which relate to the parasitic nature of the tuber- 
 culous virus. Other works on the etiology of tuberculosis are summarized in great 
 ])art by Waldenburgh (Die Tuberculose. die LungenshwindsucM u. Skrophulose. 
 Berlin, 1869) and by Johne (Deutsche Zeit. f. Thiermedicin. IX Bd.). 
 
 It is known that Villemin, from his experiments on animals, 
 expressed the view that tuberculosis could only be produced by a 
 specific virus. This opinion was at first much contested, but 
 shortly gained ground. Individual authors then maintained not 
 
 1 Jmbrnal of the Scottish Meteorological Society, July 1874, 1875. 
 
 G G 2 
 
452 
 
 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 only the specific nature of tuberculosis, but that it was also pro- 
 bable the tubercular virus was parasitic, e.g., Chauveau,i Baum- 
 garten,^ Ziegler,^ and others. There was no want also of researches 
 recognizing the supposed parasite. Thus Zurn,* had already found 
 in the year 1872 in the tubercle of the cow, and in the inoculated 
 tubercle of the rabbit, small punctiform molecules which he de- 
 scribed as micro-cocci. Buhl ^ likewise maintained that in the 
 cheesy masses and giant cells of tubercle, spherical and rod-shaped 
 bacteria were present. Klebs ** resorted to cultures, and by means 
 of " fractional cultivation " obtained cocci-like organisms, through 
 the inoculation of which he produced tubercles in animals, which 
 tubercles contained similar organisms. Schiller "^ and Reinstadler ^ 
 obtained the same results. Toussaint^ also obtained from his 
 cultures small cocci, mostly in pairs, the virulence of which in- 
 creased with the number of successive generations. Aufrecht^" 
 found in tuberculosis short bacilli, the length of which were half 
 as much again as the breadth ; there were also two different kinds 
 of micrococci. Deutschmann ^^ lastly maintained that the cocci, 
 present in tuberculous pus, which indeed showed throughout the 
 characters of the " monas tuberculosum " (Klebs), were not all of 
 equal activity, only those contained in the deeper, more tenacious 
 layers of the pus, containing cocci which could produce tubercle. 
 
 The researches quoted above, made by very imperfect methods, 
 could not be confirmed, and still the nature of the tubercular virus 
 remained unknown until at last Koch succeeded by his perfected 
 method in discovering the parasite of tuberculosis, and established 
 its etiological significance in a convincing manner. 
 
 In the first communication of Koch ^^ on this subject a method 
 of colouring the bacilli in sputum on microscopic glass covers, and 
 in sections of hardened organs is described : — the preparation was 
 
 ^ Rec. de Med. vet. 1872. 2 Berliner kli%. Woehenserift. 1880. 
 
 ^ Lehrhiich der allg. u. spec. Patholoq. Aimtomie. 1881. 
 
 ■• Zoopathologisehe u. ZoophysiologiscJie Untersuchimgen. 1872. 
 
 ^ Lungenentzundung, Tuhe.rcvJose u. SchwindfucM. 2 Aufl. 1873. 
 
 ^ Tageblatt d. Versammlung Deutsch Naturforscher u. Aertze in Miinchen. 1877 ; 
 Prager Medic. IVochenschrifi. Nos. 42 and 43. 1877. 
 
 ' Archiv f. exper. Pathol. 1 1. Band ; Experimentelle w. histologische Unter- 
 sucTiungen iiher Entstehung u. Ursache der Skroph. u. tuber. Oelenksleiden. Stuttgart, 
 1880. 8 J^rchiv. f. exper. Pathol. II. Bd. 
 
 " Comptes Fiend. 1880. ^ Pathologisdie Mittheilungcn. Magdeburg, 1881. 
 
 " Genlralblattf. d. Medic. Wissenschaft. No. 18, 1881. 
 12 Berliner lelin. JVochenschrift. No. 16, 1882. 
 
Plate n 
 
 *S) 
 
 1^ 
 
 f fS^^^W * ^ 
 
 '%^ 
 
 
 '7^^ 
 
 
 © 
 
 '^, 
 
 y ^'. 
 
XXX.] TUBERCULOSIS. 453 
 
 first placed in a solution which contained in 200 c.c. of water 1 c.c. 
 of a concentrated solution of methylene blue ; to this was added 
 2 c.c. of a 10 p.c. solution of potash. The preparation remained in 
 the solution 20 — 24 hours (or with warming to 40° only half an 
 hour), afterwards it was placed in a concentrated solution of vesuvin 
 for 15 — 20 minutes in the case of sections, and for but 1 — 2 minutes 
 in the case of dried sputum. In this way the tubercle bacilli were 
 coloured blue, the rest brown. 
 
 Two years later Koch^ published a more complete and detailed 
 account of his researches on the etiology of phthisis. Koch recom- 
 mended in this treatise a modification of Ehrlich's staining method, 
 which consists in placing the preparation in a solution composed 
 of 100 c.c. aniline water, 11 c.c. alcoholic solution of methyl violet 
 or fuschin, and 10 c.c. absolute alcohol. The preparation remains 
 in this solution at least twelve hours, but the time can be shortened 
 by warming; it is then transferred to dilute nitric acid (1:3), then 
 washed for a few minutes with absolute alcohol (covering glass 
 preparations only a few seconds) and finally coloured by soaking 
 for a few minutes in aqueous solution of vesuvin or methylene- 
 blue. 
 
 (345) Characteristics of the Tubercle Bacilli. 
 
 Koch 2 described the general characteristics of the micro-organ- 
 isms as follows : — " They always appear in the form of rods the 
 length of which is equal to that of half a red blood corpuscle 
 (about 'OOlSmm. ■0035mm.). Though the length of the bacilli 
 may vary somewhat, the diameter is constant so long as the same 
 staining method is employed ; the alkaline methylene blue pro- 
 cess causes them to appear more slender than when stained with 
 the process of Ehrlich. The bacilli are commonly not quite 
 straight rods but there are found among them slight curves and 
 often also slight twistings, in the longest examples, these may even 
 suggest the notion of the commencement of a spiral. The bacilli 
 are separated from other bacilli which come nearest to them in 
 size and appearance by this tendency to curve." 
 
 See Plates II. and III. Plate II. a represents a giant cell 
 containing numerous bacilli arranged in a radiating form x 700 
 
 ' Mitiheilungen d. Kaiser. Gesundheitsamte. 2 Band. 
 
 2 Mittheilungen mis dem Kaiscrlich GesmidJieiisamte. Berlin, 1884. 
 
454 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (after Koch) ; b represents a few colonies derived from the arti- 
 ficial culture represented in Plate III. 6 x 700. Plate III. a is 
 the naked eye appearance of an artificial culture of the tubercle 
 bacilli on coagulated blood serum ; 6 is a portion of the same 
 culture X 80 (after Koch). 
 
 The tubercle bacilli are frequently beaded ; they may occur 
 singly, or in pairs, or in bundles. The bacilli are always rounded at 
 
 /the ends (see Fig. 51). They are non-motile, do 
 not liquefy the culture medium, and form spores 
 ja both within the body and in artificial cultures. 
 H^ With regard to the latter Crookshank^ remarks 
 wig that "the tubercle bacillus, when examined by 
 ^ _ such powers as Powell and Lealands -^^ in 
 
 Horn. imm. is frequently seen to consist of a very 
 delicate sheath, holding together a number of deeply stained 
 granules, for the most part round or cylindrical, with irregular 
 contour and differing considerably in size, while the light inter- 
 spaces are seen to vary in form according to the shape of the 
 granules. In some preparations more distinct and clearly ovoid 
 granules may be observed which are sometimes terminal. It is 
 not impossible that these ovoid granules are spores which in their 
 behaviour to staining reagents thus form an exception to the 
 general rule. Bat there can be little doubt that a tubercle bacillus 
 consists for the most part of a very delicate sheath, with proto- 
 plasmic contents which have a great tendency to be broken up or 
 coagulated into little segments or roundish granules, owing, 
 possibly, to the treatment they are subjected to in making 
 a microscopical examination. This, however, does not always 
 occur, for the bacilli at times are not beaded, but are stained 
 in their entirety." 
 
 (346) Artificial Cultivation of Tubercle Bacilli. 
 
 Koch found the most suitable medium in which to cultivate the 
 bacilli was blood serum coagulated at a temperature of 65° ; it 
 remains transparent if this heat is not exceeded. He sterilises 
 it by heating for five alternate days for one hour each day, 
 
 ^ Manual of Bacteriology. 2nd edition. 
 
Plate in 
 
 -^ V 
 
 '' %ti i 
 
 Ji.^i:R.OLa.r-l^.Edzr^bui-^li. 
 
xxx.J TUBERCULOSIS. 455 
 
 this treatment always gives sterile serum ; he then coagulates 
 at 65°. 
 
 The bacilli infected into such a soil show no change when the 
 culture is maintained at 37° (which is the best temperature) for 
 many days, it is not indeed until from the tenth to the fifteenth 
 day that changes are evident to the naked eye. The first sign is 
 little whitish points, these increase and are wholly made up of 
 colonies of the bacilli ; the bacilli are arranged more or less with 
 their long axis corresponding with that of the colony itself, with a 
 space between the individual bacilli. But the most characteristic 
 appearance is that of the arrangement of the colonies — when 
 examined by a low power, they are either in S shapes or in such 
 curious curves as to recall the flourishes of fancy letter writing. 
 In old growths these appearances are lost from the blending and 
 massing of the colonies together. 
 
 Baumgarten^ proposed to inoculate, with antiseptic precautions, 
 tubercle containing bacilli into the anterior chamber of the eye of 
 a rabbit ; after from six to eight days the affected part of this 
 anterior chamber is to be inoculated into a second rabbit. By 
 a repetition of this process several times, an absolutely pure 
 cultivation free from all admixture of foreign germ.s can be 
 obtained. 
 
 Nocard and Roux ^ recommend the addition of 6 to 8 per cent. 
 of glycerin to blood serum or agar-agar as very suitable for the 
 growth of the tubercle bacillus. Tubercle bacilli are also said to 
 grow well in broth containing equal parts of glycerin and peptone. 
 Hueppe ^ gives a process by means of which the tubercle bacilli 
 may be cultivated in blood serum, and isolated by the method of 
 plate cultivation. Fluid blood serum, either sterilised or collected 
 germ free, is warmed to 37° C. in the ordinary way, and then equal 
 ' parts of agar-agar solution is added (2 per cent, agar broth with 
 5 to 10 per cent, grape sugar), the whole is mixed by shaking, poured 
 on to a plate, and incubated. 
 
 Pawlowsky* has succeeded in cultivating the tubercle bacillus 
 on potatoes. Koch had declared that the bacillus only developed 
 on animal substances and had failed to raise it on potatoes. 
 
 1 Centrl. f. d. med. Wissen, ^ 884. 
 
 2 Annates de I'Institut Pasteur, 1887. 
 
 * Central, f. Bale. u. Parasit. Bd. I. , No. 20. 
 
 * Annates de I'Institut Pasteur, No. 6, 1888 ; and Public Health, vol. i. 
 
456 A MANUAL -OF PUBLIC HEALTH. [chap. 
 
 (347) The Universal Presence of the Bacilli in True Tulercle. 
 
 Baumgarten,! almost contemporaneously with Koch, succeeded 
 by treating sections of tubercle with very dilute soda solution or 
 potash, in demonstrating bacilli. The identity of these with 
 Koch's bacilli was at a later date established. Baumgarten drew 
 the conclusion from his researches that bovine tuberculosis, human 
 tuberculosis, phthisis, and scrofula belonged to a single species of 
 disease. 
 
 Weichelsbaum (Archivf. exper. Pathol. Bd. XVII.) also tested 
 the views of Koch as to the presence of the tubercle bacilli in 
 human tubercle and as to their pure cultivation, as well as the 
 opposite views of Spina ; he obtained the same results as Koch. 
 At the same time he recognised the difference between the small 
 nodules excited by indifferent bodies and those caused by infection 
 from tuberculous products or pure cultivations. 
 
 Koch pursued his researches with such ardour and so thoroughly 
 that there has been little left for others to discover save in matters 
 of detail. He found the bacilli most numerous in miliary tubercle ; 
 in cheesy bronchitis and cheesy pneumonia ; they were extra- 
 ordinarily numerous in the contents of cavities, shreds from which 
 were almost wholly composed of them. He also found them 
 several times in scrofulous glands, in the fungus granulations of 
 joints ; he also recognised them in bovine tuberculosis as well as 
 in the spontaneous tubercle of pigs, fowls, monkeys, rabbits, and 
 guinea-pigs ; they were likewise constant in a number of cases in 
 the inoculated tubercle of rabbits, guinea-pigs, and cats. He also 
 found the bacillus in lupus and was able to cultivate it from thence 
 artificially. The constant presence of the tubercle bacilli in tuber- 
 culous organs having been ascertained, he turned his attention to 
 their culture and to the production of tuberculosis through the 
 inoculation of the cultures. This requirement was also fully 
 attained ; out of these products new cultures were made which had 
 the same action on animals. Since the tubercle bacillus only 
 grows between 30° and 40°, Koch declared it a true parasite which 
 obtained entrance into the animal organism mostly through 
 breathed air adhering to particles of dust. In phthisical sputa 
 
 ^ Central./, d. Med. WissensAaft, No. 15, 1882. Deutsche Med. Woche^isiihrift, 
 No. 22, 1882, 
 
XXX.] TUBERCULOSIS. 457 
 
 Koch found great numbers of tubercle bacilli, and since, after 
 several weeks' drying, the sputa still retained its infectious 
 character, it was the most common source of the infection, but the 
 flesh and milk of tuberculous animals also played a part. 
 
 (348) Experimental and Clinical Proofs of the Contagious Nature 
 of Tuberculosis. 
 
 A number of physicians have collected evidence from their 
 clinical experience to prove the contagiousness of tuberculosis, e.g., 
 Meyerhoff,"- T. Demuth,^ Faisan,^ Lindmaun* (tubercular infection 
 from the operation of circumcision), Herterich,^ Dehove,^ Ogston,'^ 
 Alison,^ Potain,^ L. Langer,^*" Krasker,^^ Bonyer,^^ Webb,^^ Martin,^* 
 Ganett,^^ Wahl,^* Leser,^^ Schmidt^® (tuberculosis infection from 
 a kiss), and others. To these also belong cases of the so-called 
 infectious tuberculosis of men, in Finger's^^ comprehensive de- 
 scription of lupus and tuberculosis. 
 
 De Lamalleree ^^ cites acasein which a person became infected 
 through eating a half-cooked fowl which had itself become tuber- 
 culous through consuming with its food phthisical sputum. 
 
 Among pathologists, Koch's doctrine found more ready accept- 
 ance, most of them repeated his experiments either in single points 
 or generally, and were convinced of their accuracy. Many of these 
 researches do not appear in literature because, being isimply con- 
 firmatory of Koch's results, their communication was considered 
 unnecessary. Of the published works confirming Koch's results 
 the following may be mentioned : — 
 
 Watson Cheyne,^^ who had worked partly under Koch's instruc- 
 
 ^ Zeit.f. Min. Medicin. Bd. VII. ^ Bairisches artzl. Intelligenzblatt. 1883. 
 
 3 Progris mid. 1883, Nos. 34 and 38. 
 
 * Deutsche med. Woche-nschrifi. 1883, No. 30. 
 
 5 Bairisches artzl. Intelligenzblatt. 1883, No. 23. 
 
 ^ Public du Progris mid. Paris. 1884. 
 
 7 B. Med. Journal. 1884. « ^„^_ ^^^^ (^^ jft(^_ p^ris^ ig84_ 
 
 » Met}, de Mid. 1885. ^^ Wiener mxd. Wochen. 1885, Nos. 15 and 16. 
 
 " Centralblattf. Chirnrgie. 1885, No. 47. 
 12 L'Union mid. 1885, No. 71. 
 ^^ Philadelphia Med. and Surgical Beporter. 1885. 
 ^* Bevue d'Hygiine. Bd. VIII. '° Boston Med. and Surgical Journal. 1886. 
 
 16 ArehiAi. f. Min. Ghirurg. Bd. XXXIV. 
 
 17 Fortschritte diir Medicin. 1887, No. 16. 
 
 18 Ein Fall v. localer Impfiuberculose. Dissert. Leipzig, 1887. 
 
 1^ Central./. Bakteriologie u. Parasitev. Bd. II., Nos. 13 and 14. 
 
 2» Gazette mid de Paris. 1886, No. 32. "' Practitioner, 1883. 
 
458 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 tion, confirmed in all details the work of the latter ; whilst he 
 never failed to excite tuberculosis in animals with a pure culture 
 of Koch's bacillus, he could never succeed with Toussaint's microbe. 
 The manifold appearances which are seen in the lung in tuber- 
 culous infection, he sought to explain by the differences of growth 
 of the bacillus when inhaled into the lung ; a strong development 
 giving rise to a cheesy, a weak to a fibrous pneumonia. 
 
 Raymond and Arthaud,i on testing Koch's discovery as well as 
 Pasteur and Koch's method of culture, came to the conclusion that 
 Koch's bacillus was actually the cause of tuberculosis, they also 
 found that the tubercle bacillus throve well in rabbit broth and 
 meat extract at 25°, but the growth was slow. Colli and Guarineri ^ 
 confirmed on the one hand the presence of tubercle bacilli in 
 phthisical sputum and in several tubercular organs, on the other 
 they obtained, by inoculating the anterior chamber of the eye of 
 rabbits with tuberculous products (such as phthisical sputum, 
 cheesy masses from a tuberculous pleuritis and scrofulous glands), 
 processes in which the}' could recognise tubercle. 
 
 Baumgarten,^ to prove the pathological significance of tuber- 
 culosis, placed in the anterior chamber of the eyes of rabbits pieces 
 of tuberculous tissue. After a few days he could recognise the 
 growth of the bacilli in the cornea and iris ; by the tenth and 
 eleventh day a tubercle visible to the naked eye could be seen 
 in the iris. In the fifth week the kidneys were affected, and 
 in the neighbourhood of the glomeruli there were colonies of 
 bacilli. 
 
 Poten* met the objection that experimental tuberculosis was 
 confined to miliary tuberculosis and not to phthisis, by success- 
 fully exciting in animals processes closely resembling cheesy 
 pneumonia and human phthisis from the introduction into the 
 trachea of particles of tubercle and the products of artificial 
 cultivations. 
 
 Weichelsbaum ^ also by means of powdered dried tuberculous 
 sputum made inhalation experiments on dogs. The experiments 
 showed that whether the inhalation was made once or many times 
 
 1 Arch. gin. de Med. Bd. I. = Gnz. d'ffospit. 1883, Nos. 37 and 40. 
 
 3 Central, f. die med. Wissen. 1883, No. 42. 
 
 * Ex,iKr. Untersiuihii-ngcn uber Lungcnschwindsuehi u.- Tubcrculuse, Dissertation, 
 Gottingen. 1883. * Wiener med. JahrUbeher. 1883. 
 
sxx.] TUBERCULOSIS. 459 
 
 there was constantly, after one or two weeks' incubation, a copious 
 formation of tubercles in the lungs, frequently also tubercle in 
 the bronchial glands and in the kidneys, which through their 
 histological structure and the presence of the bacilli proved to be 
 true tubercle, whilst with the inhalation of non-tuberculous sub- 
 stances only occasionally, or quite singly, small nodules appeared 
 without the tubercle bacilli. In order to make the experiments 
 more decisive, injections were made into the abdominal cavity of 
 dogs of phthisical sputum, this was followed by an extraordinary 
 development of tubercles, whilst after similarly injecting emul- 
 sions of cheese or boiled tuberculous sputum no change took 
 place. 
 
 Before the discovery of the tubercle bacilli, Veraguth^ had made 
 inhalation experiments with tuberculous sputum, and he later 
 extended them ; half of the animals experimented on showed 
 tuberculosis, whilst after inhalation of non-tuberculous sputum no 
 microscopical change in the lungs could be discovered. 
 
 Kussner ^ introduced through an opening in the trachea of 
 rabbits, tuberculous and non-tuberculous sputa ; in the first case 
 tubercle occurred in a gelatinous zone containing bacilli, in the 
 latter no effect at all followed. Sternberg ^ opposed the contention 
 of Formad and others, that through the injection of finely-divided 
 inorganic substances tubercle could be excited. One to two 
 months after the injection of coloured substances or pounded 
 glass, he found the foreign substances rolled into balls and en- 
 capsuled, but never tubercle, Formad could himself be convinced 
 .of this. 
 
 Schmidt * and Bollinger ^ attempted a pure cutaneous infection 
 by rubbing into erosions of the skin of the guinea-pig, substances 
 containing tubercle bacilli. In this way no tubercle could be 
 excited, but only by inoculation into the sub-cellular tissue or into 
 the abdominal cavity, hence they concluded that tubercular infec- 
 tion through vaccination was improbable. On the other hand, 
 Baumgarten * alleged that he had repeatedly succeeded in exciting 
 
 ^ Mittheilungen d. Wiener med. Doct.-Eolleg. 1883. 
 ^ Deutsche med. Wochewchrift, 188.3, No. 36. 
 ' American Journal of Medical Science. 1883. 
 * Bairisches drtzl. Intelligen. 1883. 
 " Zur Aeiiologie der Tuberculose. Miinchen, 1883. 
 
 ' Jahresbericht uber die Forlschritte in der Lehre r. d. pathogen Mihro-organismen. 
 1886. 
 
460 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 tuberculosis by rubbing ia cultivations of the tubercle bacillus into 
 cutaneous wounds. Cases of true cutaneous infection have been 
 recorded in the human subject, for instance, Lesser ^ relates the 
 case of a washerwoman who frequently washed the linen of her 
 husband, who died of a tubercular affection of the lungs as proved 
 by post-mortem examination. The woman presented herself at the 
 same hospital in which her husband had died with a small tumour 
 the size of a cherry growing on the wrist, this was extirpated and 
 found to contain tubercle bacilli. Eight days after the operation 
 the patient showed herself with a perionychia hiberculosa of the 
 terminal phalanx of the left ring-finger. The skin appeared at 
 different places as if it were worm-eaten and undermined by cheesy 
 masses. After removal there was good recovery, but some slight 
 rales could be detected at the apex of the right lung. 
 
 A similar case is described by Steinthal (Deutsch. med. Wochen. 
 No. 10, 1888), and also one is described by Merklen {Gaz. hebdom. de 
 Med. et Ghir. 1885, 27). In the latter case a woman, 26 yearr of 
 age, had nursed her phthisical husband for six months. She used 
 to wash his linen and clean the spittoon. Two months after his 
 death there formed on the back of her second finger a tubercular 
 nodule. This, in four weeks, affected the lymphatics of the arm, 
 and an abscess formed in which tubercular bacilli were discovered. 
 The apices of the lungs also became affected. M. B. Schmidt 
 {Arbeiten aus der Chirurg. Polildinik, Zeijp. 1888) relates the case of 
 a woman aged 44, who nursed her husband dying of phthisis. 
 Before his death he bit her, as she was about to kiss him, on the 
 upper lip. On the bitten part a tuberculous swelling developed. 
 She also had, on the ulnar side of the little finger and the wrist, 
 three characteristic tuberculous nodules in which, after excision, 
 were found giant cells and tubercle bacilli. There are also cases 
 in which medical men seem to have been infected in making 
 post-mortem examinations of tuberculous subjects. 
 
 The tuberculous nodules which are sometimes to be met with in 
 the face, more especially of children, are considered by Lesser as 
 the seat of tubercle inoculation. He relates two cases. The first 
 was a child three years of age which was brought to him with a 
 red livid tubercle of a doughy consistence, situated on the point of 
 
 • Deutsche med. Wochensehrift. No. 29, July 19, 1888 ; PMic Health, vol. i. 
 155. 
 
XXX.] TUBERCULOSIS. 461 
 
 the nose. This was removed ; the wound quickly healed. Eight 
 or nine months later the child suffered from caries of the tarsi.- In 
 the second case a nodule appeared on a hoy's chin, and a few weeks 
 later a tuberculous caries of one of the vertebrae followed. In cases 
 of skin inoculation there is as a rule strong hereditary predisposi- 
 tion — that is, great susceptibility to take the infection. 
 
 Von Wehde^ tested the infectious character of the air of rooms 
 inhabited by the phthisical, by exposing plates wetted with 
 glycerin, and then inoculating guinea-pigs with the dust obtained ; 
 but the latter remained free from tuberculosis, hence he concluded, 
 the expelled air of the tubercular could not infect, and that also 
 tuberculous sputum so long as it was moist released no spores. 
 Celli and Guarnieri,^ Sirena and Pernice,^ and Nicolas,* obtained 
 similar results. On the other hand, Theodore Williams,^ by 
 placing a glass smeared with glycerin for five days in a ventilat- 
 ing-shaft, at Brompton Hospital, was able to recognise the tubercle 
 bacillus. 
 
 Sirena and Pernice^ placed guinea-pigs in a flask in which 
 powdered sputum was shaken up frequently, but neither by inhala- 
 tion nor by injection into the trachea could they ever excite 
 tubercle ; inoculation alone was active. Celli and Guarnieri ^ could 
 but exceptionally excite tubercle by inhalation experiments, only 
 when the mucous membranes were previously irritated by breathing 
 irritating gases. 
 
 The -researches of Muller,^ Truomi,^ are also to be mentioned ; 
 
 both succeeded through the injection of tuberculous pus in tbe 
 
 arteria nutritia tibise of goats, or by the introduction of tuberculous 
 
 matter into the joints of rabbits, in causing typical tuberculosis of 
 
 the bones and articulations. There are also to be remembered the 
 
 researches of Spillmann and Haushalter,!" and E. Hoffmann," who 
 
 succeeded in proving that the abdomen and the excrements of flies 
 
 which suck the sputum of the phthisical, contain the tubercle 
 
 bacilli, so that, therefore, flies may be the medium of tuberculous 
 
 infection. 
 
 ^ Bollinger, ztir Aetiologie der Tuhenulose. Miinchen, 1883. 
 2 Gazzette d. ospit. 1883. 
 
 ' Arch. f. Scienz. Med. Bd. IX. ; Gazz. d. ospit. 1885. 
 * Union Med. 1886, No. 80. ^ The Lancet. 188S. 
 
 6 Ihid. ' Estr. d. Atti. Acad. Med. di Soma. 1886, 
 
 8 Zeit.f. Chirurgie. Bd. XIV. " Giorn. internaiion. d. Scienz. Med. 1886. 
 i» Compt. Bend. T. CV. " Public Health, vol. i. 220. 
 
462 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 E. Hofl'man artificially fed flies ■with phthisical sputum with a 
 positive result ; they became feeble, with iacrease of the excreta, 
 and soon died. The intestinal contents of infected flies inoculated 
 into the anterior chamber of the eyes of nine guinea-pigs gave 
 positive results in five cases. 
 
 (349) The Production of Ttihercles in Animals by Feeding them 
 with Tuberculoiis Products. 
 
 Wesener ^ made a number of researches on the production of 
 tubercle in rabbits from food ; for this purpose he used sputum 
 fresh or putrid, or after treatment with various digestive fluids. 
 The feeding was exclusively milk with the addition of alkali. The 
 result was always positive with simple feeding by fresh tubercu- 
 lous sputum, so also with dry and putrid sputum, tuberculosis of 
 the mesenteric glands being first produced, and next that of the 
 intestine liver and spleen. Direct injection into the intestine 
 much accentuated the process. Treatment of the sputum with 
 different digestive fluids, drying, and putrefaction, did not destroy 
 the infectious matter. Wesener thought that the spores pre- 
 served their characters when the bacilli were destroyed in the 
 stomach. If the number of spores is so small that the lymph 
 apparatus can get rid of them before they multiply, no infection 
 occurs; if a larger number remain in the mesenteric glands, an 
 inflammatory centre at first forms without bacilli, later these 
 farther develop, but if the bacillary material is injected direct into 
 the intestine, very soon tuberculosis of the intestine is produced. 
 Tuberculosis of the mesenteric glands he refers also to the ingestion 
 of milk with few spores. 
 
 Fischer ^ and Baumgarten ^ partly arrived at other results than 
 Wesener, they could by once feeding with milk to which had been 
 added tuberculous juice, excite tuberculosis of the intestine, the 
 mesenteric glands and liver of rabbits. They farther assert that 
 the tubercle bacilli when spore free withstands the action of the 
 digestive juices. In opposition to Wesener's results they found 
 
 ^ Kritische u. expar. Bcitrdgs zur Lehre v. d. Futtenmgs- Tuierculose, Freiburg, 
 1885. ■' ArcJdv.f. exper. -Pathol. Bd. XX. 
 
 3 Centralbl.f. klin. Med. 1884, No. 2. 
 
XXX.] TUBERCULOSIS. 463 
 
 that the intestine was first affected with tuberculosis, and subse- 
 quently the mesenteric glands. The unwounded mucous membrane 
 of the mouth and throat could absorb tubercle bacilli in the food 
 by means of the lymphatic apparatus. 
 
 Professor Straus placed, during from one hour to forty-eight 
 hours, spore cultures of the bacillus of Koch in contact with the 
 pure gastric juice of a dog. After six hours the bacilli had lost 
 none of their virulent action. After twenty-four hours this action 
 was destroyed. It may thence be seen that the tubercle bacilli 
 are not rendered inoffensive by their sojourn in the stomach. 
 Nevertheless, the gallinacese appear to be rarely infected with 
 tuberculosis through the intestinal canal. M, Straus had given 
 daily to fowls during several months, enormous quantities of the 
 sputa of phthisical subjects. In none of the fowls was there any 
 trace of tuberculosis, not even in those which in one year had 
 swallowed as much as fifty kilogrammes of tuberculous sputa. 
 
 Bollinger ^ observed tuberculosis of the intestine, liver and spleen 
 in three fowls which had fed on tuberculous sputa in the court of 
 an hospital. 
 
 (350) Unequal Susceptibility of Different Animals to the Tubercular 
 
 Infection. 
 
 In the numerous experiments on animals which have been made 
 it has been found, as might be expected, that some are more pre- 
 disposed to the infection than others, for instance Daremberg ^ draws 
 from his researches the conclusion that in animals the tuberculosis 
 produced by inoculation depends as to its character on the kind and 
 age of the animal, as well as on the activity and quantity of the tuber- 
 cle bacillus. If the tubercle baciUi are cultivated at 38° C, and in- 
 troduced by trepannation into rabbits and guinea-pigs, the animals 
 are killed in from twenty to thirty days by miliary tuberculosis ; 
 but in a cock and a dove treated in the same way, the first died 
 in six or seven months. A culture at 50° excited in a rabbit only 
 an indolent abscess, the pus of which killed young rabbits in 
 several weeks, whilst old rabbits after some months showed no 
 
 change. 
 
 ^ BayrischB.1 artzl. Intelligenzblatt. 1883, No. 16. 
 ^ Compt. licnd., T. CY. 
 
464 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 It has yet to be proved that any ■warm-blooded animal is exempt 
 from tuberculosis ; some, like the horse, rarely suffer from this 
 malady, but even in the horse spontaneous tuberculosis is not 
 extremely rare, and cases have been described by Johne, Coker, 
 Nocard, M'Fadyean, Campbell, and Freer. 
 
 (351) Giant Cells. 
 
 Koch was of opinion that the beginning of tubercle was the 
 entry of a bacillus into an epithelial cell, which cell may wander 
 from its original seat. The pathogenetic action of the bacillus 
 causes changes in the surrounding cells. The epithelial cell 
 itself is converted into a " giant cell." This account of the origin 
 of giant cells is much disputed, some see in the giant cell a lymph 
 space with proliferating endothelial cells. In some cases Weigert 
 has proved that the giant cell is a collection of cells in which 
 bacilli are causing proliferation at the margin and fusion and 
 degeneration in the centre, the end result being a mass of 
 caseous material in the centre and at the margin proliferating 
 cells with bacilli between them. Klein has seen giant cells pro- 
 duced by the fusion of the epithelial cells of the air vesicles. 
 Small blood vessels, the seminiferous and the lacteal tubules have 
 all been described as developing into giant cells. " The presence 
 of these giant cells affords evidence that the cells are making a 
 determined resistance against the advances of the bacilli, are 
 giving way slowly, and so limiting the area of caseation. In 
 many cases where the giant cells with their rings of nuclei are 
 best marked, very few bacilli are to be found, as they have been 
 destroyed by the phagocytes at the margin — i.e., the active cells 
 with deeply stained nuclei. In other cases, however, the bacilli 
 have taken the place of the nuclei at the margin of the giant cell, 
 the boundary line in such cases being determined for a time 
 by the basement membrane of the tube in which the mass is 
 formed." 
 
 Once the tubercle bacillus gains access to the deeper tissues, it 
 depends on two things whether the bacilli will infect or no, viz. 
 (1) on the numbers of the bacilli themselves, and (2) on the tissue 
 resistance. Should they arrive in large numbers, few tissues will 
 resist the invasion ; should they arrive in moderate numbers the 
 
Plate W 
 
 i» p 
 
 Ji ^R.Clo.7'Jr,.Ed,inb-urqL'' 
 
XXX.] TUBEEOULOSIS. 465 
 
 so-called susceptible individuals will be affected, while those with 
 healthy tissues with normal or a high resistance will be able to 
 destroy or to localize the invading host. 
 
 (352) Pathology of Tuierculosis. 
 
 Some of the naked eye appearances of tubercle and tuberculous 
 ulceration are represented in plates II, III, IV — 
 
 Plate II (c) represents the spleen of a guinea-pig affected with 
 general tuberculosis from the injection of a culture into the 
 anterior chamber of the eye (after Koch). 
 
 Plate III (c) represents the lungs of a guinea-pig infected by 
 inhaling dried tuberculous sputum (after Koch). 
 
 Plate IV (b) is a portion of the small intestine from a Cariama 
 (Oariama cristata), the blood-vessels of which have been minutely 
 injected. It exhibits very small masses of tuberculous matter 
 raised a little above the surface of the mucous membrane. The 
 paleness of the tuberculous matter contrasts strongly with the bright 
 redness of the mucous membrane (Royal College of Surgeons 
 Museum. No. in Catalogue 2,-546). (c) represents a tuberculous 
 ulcer in the human ileum. The surfaces are but little indurated 
 though very vascular, and the floor of the ulcer presents a yellow 
 caseous appearance. There are also several small tubercles (Royal 
 College of Surgeons Museum. No. in Catalogue 2,547). 
 
 Both these ulcers may be compared with («■), which represents a 
 portion of the human ileum affected with a typhoid ulceration of 
 one of Peyer's patches (Royal College of Surgeons Museum. No. 
 in Catalogue 2,499). 
 
 The pathology may be studied conveniently under two divisions, 
 viz., that of pulmonary tuberculosis and that of miliary tuber- 
 culosis. The most recent contribution to and summary of the 
 pathology of the disease is the research of Dr. Sims Woodhead, 
 and the following account is an abstract of Dr. Woodhead's paper 
 on the subject. 
 
 (353) The Pathology of Pulmonary Tuberculosis. 
 
 It is now generally accepted that all cases of rapid infective 
 phthisis are the result of the action of the tubercle bacillus, 
 
 H H 
 
466 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 although it cannot be denied that certain lesions may be produced 
 as the result of the action of other non-specific irritants. In 
 these conditions, however, tubercle is very frequently associated 
 with some other lesions, and it is often extremely difficult to 
 say what changes are due to the one and which to the other. For 
 instance, it has long been held that in stonemasons' phthisis all 
 the characteristic lesions met with in chronic tubercular phthisis 
 are present, but Dr. Woodhead's experience of stonemasons' lung 
 has been that along with the chronic interstitial and arterial 
 changes, set up by the stone particles, there are structural 
 alterations which can be accounted for only on the assumption 
 that they are of tubercular origin, and in some few cases, in con- 
 firmation of this, the presence of tubercle bacilli has been 
 demonstrated in certain of the new growths. In the first instance 
 we should expect under given conditions the mucous surface of 
 the bronchus to be attacked. Such an assumption might most 
 fairly be made after a consideration of Julius Arnold's observa- 
 tions on the course taken by dust when inhaled into the res- 
 piratory passages, Arnold pointing out the important part played 
 by the walls of the small bronchi and their terminal passages 
 in the disposal of inhaled dust particles. Secondly, there is the 
 alveolar epithelium, which under the influence of any irritant 
 material undergoes proliferation more or less rapid, this in certain 
 cases terminating in what we know as catarrhal pneumonia. 
 Here, again, in proof of the statement, take what may be seen 
 under the microscope, when particles of coloured dust have been 
 inhaled into the lung. The cells lining the alveoli are seen to be 
 in an active state of division ; some are still adherent to the walls 
 of the air vesicle, and in these small particles of the pigment may 
 be seen embedded in the protoplasm. The epithelium in this 
 position is a structure which may be attacked by tubercle bacilli, 
 just as in it coal or other particles may be found. Passing still 
 further, and following the course taken by the pigment granules, 
 the lymph spaces around the air vesicles are reached, then the 
 lymphatics in the interstitial and interlobular tissue, the peribron- 
 chial and perivascular lymphatics, and lastly the glands at the root 
 of the lung, either directly or by deep layer of the pleura, over the 
 surface of the lung, and so to the root. As may be seen on re- 
 ference to a section of coalminer's lung, the pigment (in this 
 
XXX.] TUBERCULOSIS. 467 
 
 instance a material which gives rise to little irritation) is carried to 
 every part of the lymphatic system, and is seen to have accumu- 
 lated in very considerahle quantities along the lines of the septa, 
 around the bronchi and bloodvessels, and in the deep layer of the 
 pleura. On microscopic examination, the pigment acting as an 
 irritant, and so giving rise to a slight excess of iibrous tissue 
 in all these various positions, may also be seen. Lastly, the small 
 points of lympathic tissue which occur at intervals along the lymph 
 channels, first described by Burdon Sanderson, then by ELlein, 
 Arnold, and others, are the seats of pigmentation. Tubercle 
 formation may also be met with in any of these positions. It 
 would seem at first sight to be an easy matter to determine at 
 once in what tissue the tubercle has originated in any special 
 case. In the lung, however, where the tissues are so delicate 
 and so complicated, and where in consequence the changes are 
 so rapid, this is not the case; and it is only in exceptionally 
 favourable cases that the mode of origin and spread can be at all 
 satisfactorily demonstrated. Further, the variety in the life 
 histories of individual tubercular growths at one time rendered it 
 a matter of considerable difficulty to arrive at any definite under- 
 standing of tuberculous processes, especially of those associated with 
 pulmonary phthisis. The anatomical structure in the various 
 forms being so absolutely defined in the earlier stages of the growth, 
 it was difi&cult to bring into a common group forms which differed 
 so widely from one another, not only in naked eye but in micro- 
 scopic appearances. 
 
 There is now, however, sufficient evidence to justify pathologists 
 in stating that many of those forms which dififerent clinical 
 observers have from time to time described as tuberculous are un- 
 doubtedly tubercular in character, from the small grey, gelatinous, 
 or fibroid nodule, to the large caseous masses, leading to cavity 
 formation ; and the presence of the specific bacillus has time after 
 time been demonstrated in all these forms, both by staining and 
 by inoculation. There can be little doubt that these forms are 
 essentially the same, and that the differences observed are due first 
 to the resisting power of the tissue attacked, and secondly, to the 
 numbers and activity of the attacking bacilli. If the behaviour of 
 other tissues under the action of mechanical or micro-organismal 
 irritants be borne in mind, there will be little cause for wonder 
 
 H H 2 
 
468 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 that there should be these numerous varieties of manifestation of 
 the action of the specific irritant in tuberculous lungs. In connec- 
 tion with this statement, a matter may be insisted upon to which, as 
 a rule, far too little importance is assigned — viz., the intercurrence 
 of suppurative changes, which are evidently set up by the activity 
 of a different micro-organism. 
 
 Both Dr. Woodhead and Mr. Hare were much struck by the 
 fact " that after one micro-organism has completed its task another 
 may step in and continue the process of breaking down. How fre-, 
 quently a pysemic condition supervenes on a tubercular. How 
 often has a patient suffering from tubercular abscess of the kidney 
 or of the lungs succumbed at last (if not carried off by acute tuber- 
 cular disease) to pyaemia, and pysemia in which the symptoms are 
 extremely well defined." ^ How frequently localized suppuration 
 steps in to aid in the breaking-down process, more frequently in 
 the lungs and in the intestines than in other positions, because of 
 the greater ease with which organisms giving rise to the irritant 
 material can arrive at and remain on the tubercular surfaces in 
 these organs. Writing on this subject. Coats, in his Lectures to 
 Post-graduates, points out that tubercle is essentially a disease of 
 surfaces and channels, and this is so far true that bacilli can reach 
 the tissues only by such surfaces and channels, and that in these 
 channels there are irritant secretions often containing numerous 
 micro-organisms and other products which assist in completing and 
 hastening the breaking-down process commenced and partially 
 continued by the tubercle bacilli. The actions and interactions in 
 these cases are extremely complicated, and but for the occurrence 
 of more simple cases now and again the observer would be com- 
 pletely lost amongst it all. Of 100 eases, in which there was 
 tubercle of the mesenteric glands, the mediastinal glands, or the 
 glands at the root of the lung, were also distinctly affected in 69 
 cases, whilst in 62 cases the lungs themselves were affected. Of 
 these 62, 59 were included under the 69 in which the glands at 
 the root were tubercular, the other three having developed first 
 simple catarrhal pneumonia, which had later become tubercular in 
 character (in two of these bacilli were found). There were also, as 
 the figures show, seven cases in which, although the glands at the 
 root were affected, there was no tuberculous process in the lungs 
 ^ Pathological Mycology, p. 13. 
 
XXX.] TUBERCULOSIS. 469 
 
 This is important, for when the lung cases as a -whole are con- 
 sidered, the figures are slightly different. Of 110 cases of tubercle 
 of the lung, the glands at the root were not affected in every case 
 this was especially noticeable in cases of miliary tubercle, and in 
 several cases of catarrhal pneumonia. There were distinct tubercle 
 nodules, and caseation in the glands, except in those cases where 
 there had been adhesion of the lung at any point, or where 
 there had been collapse of the lung. Where these conditions were 
 present — i.e., adhesion, collapse, etc. — the tubercle in the glands at 
 the root was, in a much larger proportion of cases, of more recent 
 date. In the 110 cases there were cavities in 32, caseous masses 
 but no large cavities in 39, racemose tubercle with a tendency to 
 fibroid change in 25, and tubercular catarrhal pneumonia in 15, in 
 each case the character of the predominant lesion only being re- 
 corded. The cavities and caseous masses were not, as in the adult, 
 usually confined to the apex, but were, as in monkeys and other 
 animals, scattered throughout the lung — a fact which might be ex- 
 plained on the supposition that in such cases the general pre- 
 disposing causes of tuberculosis are acting quite apart from those 
 of local origin. Where these local predisposing causes do come 
 into play, the seat of election in children is not at the apex, but at 
 the root of the lung, very frequently posteriorly, and at the base. 
 
 The general tuberculous affection of the lung in children appears 
 almost invariably to have associated with it one of three antecedent 
 conditions : — 
 
 (a) Simple capillary bronchitis and catarrhal pneumonia, such as 
 very frequently follow or are associated with measles, diphtheria, 
 scarlatina, whooping-cough, and other similar conditions, in which 
 there is a weakened condition and impaired power of resistance of 
 the epithelial cells lining the capillary bronchi, the alveolar pas- 
 sages, and the air vesicles ; further, there are those interstitial 
 changes in connection with the lymphatic network mentioned pre- 
 viously ; and, lastly, there is the irritable (speaking now of the 
 proliferating tissues of the gland) and weakened condition of the 
 glands, both the small collections of the glandular tissue along the 
 lines of the lymphatic channels and the larger glands at the root 
 of the lung. Not only is the resisting power less in these condi- 
 tions, but owing to the large amount of work they have been 
 called upon to do in connection with the absorption of the catarrhal 
 
470 A MANUAL OP PUBLIC HEALTH. [chap. 
 
 products, the glands, though enlarged and swollen and evidently 
 acting most vigorously, are unable to respond to any increased de- 
 mand for work, either in taking up or destroying fresh materies 
 morbi. In a case of tubercular catarrhal pneumonia, following 
 typhoid fever, the greater part of the lung, especially the lower 
 lobe and the lower part of the upper lobe, was consolidated ; it 
 was grey in colour throughout, was not firmly consolidated as in 
 croupous pneumonia, but was slightly more spongy in texture. 
 From the cut surface a large quantity of purulent fluid could be 
 squeezed, in which were present very large numbers of tubercle 
 bacilli. On section the air vesicles throughout, but especially 
 around the terminal bronchi, were filled with large proliferating 
 epithelial and catarrhal cells, some in an advanced stage of de- 
 generation, but others containing well-marked bacilli in and around 
 them. Although in this case the interstitial changes were not 
 very prominent, there were nevertheless numerous bacilli in the 
 lymphatics, some free, but many contained in the small round 
 corpuscles found there ; and, again, a few bacilli were to be dis- 
 tinguished in the lymph sinuses in the cortex of the glands. In 
 the medullary portion of the gland there was evidently rapid cell 
 proliferation, but little or no caseation. In several other cases of 
 catarrhal pneumonia following diphtheria, scarlet fever, and measles, 
 an earlier stage could be observed. In these conditions the lobular 
 catarrhal pneumonia is frequently preceded by collapse in certain 
 small areas, the result probably of closure of the bronchus with 
 catarrhal products of the bronchus itself. In these plugs, and in 
 such cases as these only, large numbers of tubercle bacilli were 
 found ; they were so numerous that the idea of their having all 
 come originally from some other definite tubercular focus was put 
 out of court entirely, and their presence in such large numbers 
 could only be accounted for on the supposition that a few had first 
 been introduced into the catarrhal mass, which had formed such an 
 excellent cultivation medium that an almost pure culture of the 
 bacilli in the small bronchi had resulted. In the air vesicles in the 
 immediate neighbourhood, a few bacilli may also occasionally be 
 seen, but in the larger proportion of these cases the bacilli are con- 
 fined to the lumen of the bronchus. It may be readily understood- 
 how in such cases, had the patients lived long enough, the bacilli 
 and their products would have made their way into the lymphatics. 
 
XXX.] TUBERCULOSIS. 471 
 
 and so to the glands ; but the process is here extremely rapid, and 
 caseation very speedily supervenes, this apparently being in great 
 measure due to the lowered vitality of the tissues. 
 
 (b) Another form of this general tuberculosis of the lung is 
 where there is inhalation of the specific virus from some localized 
 nodule or mass. In adults the most common termination of a 
 case of apical phthisis is brought about by a form of acute 
 tubercular pneumonia in the dependent parts of the lung. The 
 extreme consolidation and rapid caseation in such cases are here 
 also well-marked features of the process. In like manner it is 
 found that in children the general dispersion of the virus often 
 takes place from a small cavity which eventually opens into a 
 bronchus. In three cases Dr. Woodhead observed a second form 
 of primary focus, one not very commonly recognized, but one of 
 which a case is recorded by Dr. Coats in his Lectures to Prac- 
 titioners, page 170. In two of the cases under consideration the 
 glands at the bifurcation of the trachea were enormously enlarged 
 and distinctly caseous, and at one point they weremuch softened ; 
 just above this softening there had been ulceration into the left 
 bronchus near the bifurcation, and the contents of the softened 
 glands had been practically emptied into the bronchus. As a re- 
 sult of this there were well-marked recent tubercular catarrhal 
 pneumonic patches, swarming with bacilli, throughout the lung, 
 but accompanied by interstitial tubercular changes, although bacilli 
 could be demonstrated as present in the lymphatics. In these 
 cases the catarrhal condition is evidently tuberculous from the 
 first, and the process goes on with extreme rapidity. In the third 
 case, one of the smaller glands at the root of the lung was the infec- 
 tive focus, the ulceration having taken place in one of the larger 
 branches of the left bronchus. A third form of ulceration met 
 with and giving rise to a disseminated catarrhal tubercular process, 
 is that where the wall of the bronchus itself is tubercular, and 
 where in consequence there is ulceration and setting free of the 
 infective material in smaller or larger quantities. This form is 
 very frequently met with, and is a cause of tubercular catarrhal 
 pneumonia in a very large number of cases. 
 
 (c) The third of the antecedent conditions of general catarrhal 
 tubercular pneumonia is that condition in which the lymphatic 
 glands at the root of the lung and the mediastinal glands are 
 
472 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 practically inactive. This occurs specially when the tubercular 
 glands are caseous, but it may also occur in other conditions, where 
 the glands are either altered in structure or are choked (if such 
 a term could be used) by the presence of foreign particles. In 
 these cases, where the nutrition of the tissues is greatly impaired, 
 general catarrhal tubercle is frequently met with, but it is then 
 almost invariably associated with chronic or more recent interstitial 
 tubercle. 
 
 In localized tubercle the lymphatics seem to play a much moi'e 
 prominent part than they do in the general form, though here, 
 again, the two forms, lymphatic and catarrhal, are so closely 
 associated that it is difficult to say where the one ends and the 
 other begins. The seat of election of tubercle in children is not 
 at the apex, but near the root of the lung, posteriorly, at the free 
 margins (in patches) or at the base. In those cases of tubercle at 
 the root, the predisposing cause is, as has been pointed out, the 
 tuberculous condition of the gland. The lymph stream in the 
 lung cannot be looked upon as going constantly in any one 
 direction, on account of the very free lymphatic anastomosis 
 in various parts of the lung, and through this free anastomosis 
 an area may be drained by another set of lymphatic vessels, 
 even though its own proper vessels are occluded. Thus when 
 a gland at the root of the lung becomes functionally inactive 
 from its conversion into caseous tubercle, the lymphatics going 
 directly to it from an area in the immediate neighbourhood are 
 obstructed, and there are both impaired nutrition in and diminished 
 excretion from this part. Although, however, the tissues in this 
 area immediately around the gland have their lymph supply 
 altered, the tissues outside the localized area are drained into 
 the lymphatics (1) of the glands corresponding to these areas, and 
 (2) into those which eventually find their way into the deep layer 
 of the pleura, and so to the root of the lung ; and it appears 
 probable that in consequence of this " backward flow " the affected 
 area may in certain cases give rise to a further extension out- 
 wards. Tubercle at the posterior part of the lung and at the free 
 margins is to be associated with obstruction and collapse, conditions 
 so frequently met with in children and so common a cause of 
 simple catarrhal pneumonia. The essential conditions necessary 
 for tubercular catarrh and impaired lymph discharge are present. 
 
XXX.] TUBERCULOSIS. 473 
 
 and the bacilli, left at rest, develop very rapidly in the air vesicles, 
 or more slowly in the lymph spaces in the interstitial tissue. 
 Tubercle at the base of the lung is found especially in those 
 cases where there is pleurisy, or in cases of peritonitis, tubercular 
 or not. Of the cases analysed (127) the liver or spleen, or both, 
 were adherent to the under surface of the diaphragm in sixty-five 
 cases, most frequently as the result of old peritonitis, now without 
 a trace of tuberculous structure remaining; but in seventeen, 
 recent tubercular peritonitis was well marked. In a very con- 
 siderable number of cases where old pleurisy was present, the 
 base of the lung was markedly tubercular. In four instances the 
 lower part of the lower lobe was transformed into a solid caseous 
 mass, whilst in the fibrous tissue of which the adhesion was com- 
 posed there were well-marked tubercular nodules, some quite young, 
 but others in an advanced stage of caseation. In these cases the 
 extension is, in the first instance, by the lymphatics, and then 
 perhaps to the epithelium ; but the pi-edisposing cause appears 
 to be the state of rest induced by the adhesions of the organs of 
 the abdomen and thorax to the opposite surfaces of the diaphragm, 
 leading to imperfect lymphatic circulation and exchange. 
 
 In the case of tubercular peritonitis, in which caseation occurs 
 at an early stage, it might reasonably be expected that tubercular 
 pleurisy and mediastinal tubercle would be rapidly developed. 
 Professor Klein and Dr. Hunter have both laid great stress upon 
 the fact that foreign materials which find their way into the 
 abdomen are soon passed on to the under surface of the diaphragm ; 
 and Dr. Hunter, in his experiments on the absorption of injected 
 blood from the abdomen, demonstrated most clearly the presence 
 of blood corpuscles, comparatively little altered, first between the 
 liver and the diaphragm, and secondly in the lymphatics of the 
 diaphragm. The bearing of this on the adhesions of the liver 
 to the diaphragm are exceedingly important, as are also Klein's 
 observations on the paths taken by foreign particles after passing 
 from the abdomen. Bearing these facts in mind, it may be easily 
 understood how it is that tuberculosis of the mediastinal glands 
 and tubercular pleurisy of the costal pleura are both so frequently 
 associated with tubercular peritonitis. The glands, too, at the 
 root of the lung frequently (as seen in so many specimens) 
 become caseous before the lung itself is affected ; in some cases. 
 
474 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 no doubt, this is due to a process similar to that described as 
 occurring in the mesenteric glands, where it is accompanied by no 
 permanent lesion in the intestine ; but in other cases it seems 
 to be equally beyond question that the specific virus has passed 
 (a) from the mesenteric and retro-peritoneal glands, and (b) from 
 the peritoneal cavity through the central part of the diaphragm 
 and the broad ligament of the lung, or (c) by a more or less 
 circuitous route along the lymphatics of the parietal pleura to the 
 root of the lung. It is worthy of note that until pleurisy is set up 
 in these cases there is no transmission from pleura to pleura, 
 but that as soon as the slightest adhesion takes place there may 
 be continuation of the process on the two surfaces. It should 
 be observed, however, that in addition to this affection of the 
 costal pleura the visceral pleura may also be the seat of tubercular 
 nodules, the virus in this case having come probably from the 
 abdominal cavity by the diaphragm and the broad ligament. In 
 all these forms there is abundant evidence of the transmission 
 from point to point of the virus by way of the lymphatic channels, 
 especially where the tissues generally are highly resistant, and 
 where the epithelial cells, though they do not arrest the passage 
 of the bacilli into the lymph spaces, have still sufficient vitality 
 to continue to grow in a more or less regular manner. In such 
 cases the connective tissue resistance is also great, and though 
 the bacilli may still continue to grow and to attack the cells in 
 their immediate neighbourhood, those cells outside the immediate 
 sphere of action of the irritant are stimulated into proliferation 
 and fibrous tissue formation, so that a fibroid capsule is formed 
 around the cellular or caseating centre. When the epithelium 
 itself is attacked caseation rapidly ensues, and absorption from 
 this point may take place for some distance along the lymphatics. 
 In consequence of this method of spreading by the lymphatics of 
 the lung, nodules may be sought in those positions in which coal 
 pigment is found to accumulate, the only difference observable 
 being that in tubercle the nodules are usually somewhat limited 
 in their area of distribution, the pigment, on the other hand, being 
 disseminated over the whole lymphatic area. The changes around 
 the vessels and in the bronchi are marked by no special features ; 
 the tubercles are formed in connection with the peri-bronchial 
 and peri-vascular lymphatics, and in some cases, as has been 
 
sxx.] TUBERCULOSIS. 475 
 
 observed, they appear to be formed in the small lymphoid nodules 
 which may be seen in the walls of the lymphatic vessels. 
 
 In the intima of the vessels, as Cornil and Eanvier, Hiibner 
 Greenfield, Hamilton, and others have insisted, the changes are 
 extremely well marked, and quite recently attention has been 
 called to the fact that even some of the systemic arteries may be 
 deeply affected with arteritis obliterans in cases of chronic phthisis. 
 How far the changes in the intima are associated with those in the 
 adventitia is as yet not fully decided, but there seems every reason 
 to hold with Arnold, that wherever the lymphatic circulation in the 
 adventitia is disturbed — especially where there is irritation and 
 proliferation of the endothelial cells of the lymph spaces — corre- 
 sponding changes are met with in the intima, particularly where 
 the process is chronic in character. 
 
 (354) Tlu Pathology of Acute Miliary Tiiberculosis. 
 
 Acute miliary tuberculosis must be looked upon as the result of 
 spreading of the infective material directly by the blood channels. 
 The demonstration of this fact was first accomplished by Weigert, 
 who, in a series of several cases of acute miliary tuberculosis, was 
 able to determine the presence of ulceration of the pulmonary 
 vein. The process being similar to that in or near the wall of a 
 bronchus in the cases mentioned, Ponfick had first supposed that 
 the bacilli might pass from a tubercular thoracic duct into the 
 venous trunks, and thus to the general circulation. It is probable 
 that both observers were correct, and that both forms may occur. 
 Coats further points out that a limited distribution of tubercle by 
 the blood may be due to the passage of bacilli into the minute 
 venous radicles in the glands in which tuberculous changes are 
 occurring. That bacilli are found in the blood has been now 
 frequently demonstrated, and quite recently several cases have 
 been recorded, in which general tuberculosis has come on after 
 haemorrhages in patients suffering from apical phthisis. This is a 
 matter of all the greater interest when it is borne in mind that all 
 these cases of acute tuberculosis were developed in from seventeen 
 to twenty-five days, just the period given by Koch as that required 
 for the development of tuberculosis when produced experimentally. 
 The importance of this can scarcely be over-estimated from a 
 
476 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 surgical point of view, indicating as it does the methods of pro- 
 cedure to be adopted in operating on any tuberculous part. The 
 bacilli, though found in the blood in such cases, do not become 
 active until they come to some part of the circulation at which 
 they can make their way into the surrounding tissues. In some 
 cases bacilli are present in the emboli, or they may be actually 
 distributed in the embolic area, in many cases appearing to make 
 their way from the capillary vessels into the lymph spaces, and only 
 then giving rise to the characteristic series of changes. 
 
 (355) The, Relations of Scrofula, Lupus, and Tuberculosis. 
 
 The recent research of Dr. Alfred Lingard ^ shows the precise 
 relationship of these affections. They must all be classed as tuber- 
 culous. Scrofulous material injected into a guinea-pig produces a 
 general tuberculosis ; lupus material does the same thing, but 
 slower. In fact, given tubercle, scrofula, and lupus, there is a 
 regular gradation of virulence, as tested by subcutaneous inocula- 
 tion into guinea-pigs; with tubercle, in six or seven days the 
 glands enlarge ; with scrofula, the enlargement of the glands just 
 above the inoculated point is not observed for two or three weeks ; 
 and with lupus, 28 days is the earliest time within which this 
 has been noticed. Tubercle kills a guinea-pig in an average 
 period of 80 days ; scrofula, 206 days ; lupus, 331"5 days. It is 
 pretty certain that scrofula and lupus may be considered as the 
 expression of different stages of attenuation of the tubercle bacillus, 
 but by successive removes the bacillus acquires its pristine energy ; 
 thus, according to Lingard's experiments, if a guinea-pig be in- 
 oculated with scrofulous material, and the period in which it lives 
 be reckoned as 100 days, products from this guinea-pig, injected 
 into a second, kill in 63 days ; inoculation from the second into a 
 third guinea-pig kills in 38 days ; and inoculation from the 
 third into a fourth kills in 29 days. 
 
 (356) Propagation of Tubercle through the Agency of Milk derived 
 from a Diseased Goiu. 
 
 There have been numerous researches upon this important 
 
 ^ Supplement, containing Report of Medical Officers, to Eighteenth Annual 
 Report of the Local Government Board. 
 
XXX.] TUBERCULOSIS. 477 
 
 subject. Johme ^ maintained that the milk of tuberculous animals 
 should not be given to sucklings, and should not be consumed by 
 any one when the teats were affected. The flesh of tuberculous 
 animals may be eaten if the tuberculosis is not general, but the 
 internal organs affected and the lymphatic glands are to be put 
 on one side. In general tuberculosis the flesh also was not to be 
 eaten. Lydtin ^ made experiments with the raw and boiled milk 
 of tuberculous cows with and without udder affection on guinea- 
 pigs, and obtained only once with raw milk a positive result, hence 
 he thinks that the danger of infection through milk cannot be 
 great, and through boiling can be quite avoided. 
 
 Martin^ has experimented with Paris milk, derived from thirteen 
 different dairy farms, by injection into the peritoneum of guinea- 
 pigs. In one case general tuberculosis supervened. Stein * obtained 
 a positive result in several instances by injecting the milk of 
 tuberculous cows into the abdominal cavity of guinea-pigs, 
 although in one only of his cases was the udder affected. 
 The Commission^ appointed in Victoria to inquire as to the 
 extent of tuberculosis gave an opinion that the meat of animals 
 strongly affected with tuberculosis should be forbidden, but in 
 less severe cases could be consumed. On the other hand, tuber- 
 culous cows should be rigorously excluded from supplying milk 
 for consumption. 
 
 Quittel^ declared the use of flesh actually tuberculous, not fully 
 boiled or cooked, injurious, but the meat of a tuberculous animal 
 only injurious if the animal has become thin, and more than one 
 organ is affected. 
 
 Bang ^ found the milk in cases of tubercle of the udder always 
 to contain the specific bacillus, and it constantly produced tuber- 
 culosis. The milk of tuberculous cows with healthy udders some- 
 times contained tubercle bacilli, and then could produce tubercu- 
 losis ; sometimes it was free from bacilli, and then inoculations 
 were fruitless. In bacilli holding milk submitted to the centri- 
 fugal apparatus, for the most part bacilli could be recognised in the 
 
 ^ DeutscTie Zeitschrift f. Thier. Medicin. Bd. IX. 
 
 2 Archiv. f. Thierheilkmide. 1884. * Revue de Midecin. 1884, No. 2. 
 
 * Experimentelle BeUrage mr Infectiositat perlsiicMiger Kiihe. Dissertation. Berlin, 
 1885. = Report, 1884-5. 
 
 5 Deutsche Vierteljahr. f. offentl. Geswndheit. Bd. XIX. 
 ' Tidsh. f. Landmkonomi. 1886. 
 
478 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 scum at the periphery of the apparatus, the cream also contained 
 single bacilli. Cream raised by standing was infectious, and the 
 same must be said of the butter. Heating bacilli holding milk to 
 70 deg. C. destroyed mostly the infection, but not always. Boiling 
 was constantly successful in destroying the infection. 
 
 Galtier ' concluded from his researches that not only the raw or 
 coagulated milk from tuberculous cows could infect, but also the 
 cheese or whey prepared from it. He also calls attention to the 
 fact that fowls or pigs could be infected from feeding on such 
 substances. 
 
 At the International Medical Congress in Copenhagen, Bang 
 gave the results of an examination of no fewer than twenty-seven 
 cases of tubercular mammitis, and he was able to demonstrate the 
 presence of tubercle bacilli in the milk or in the sediment, and 
 with this milk or sediment he was able to produce tuberculosis 
 both by inoculation and by ingestion. Nocard was able to 
 demonstrate the presence of the specific bacillus in milk in eleven 
 cases. 
 
 Dr. Woodhead has made a most careful and systematic examina- 
 tion of over 600 cows in the Edinburgh dairies with Professor 
 MacFadyean. Of the whole, they found thirty-seven beasts in 
 which there was mammitis, but only six, or 16 per cent., in the 
 milk of which they could demonstrate the presence of tubercle 
 bacilli, and then only in small numbers. In one of the six cases, 
 and subsequently in five other cases, they made sure of the exist- 
 ence of the bacilli in enormous numbers in the udder by micro- 
 scopic examination. They find that new tubercular tissue is 
 disseminated in patches of various sizes throughout a portion of 
 the gland, and that all the more minute elements of tubercle may 
 be distinguished — the small round cells in which the nuclei are 
 comparatively large, and the epithelioid cells, between or amongst 
 which is a fairly well developed reticulum. The giant cells are 
 very numerous, but are not so well defined as one sees them in the 
 human subject ; they are scattered throughout the new tissue. 
 The tendency to caseation of tubercle in the udder is not nearly so 
 well marked as in other parts of the body, but it does undoubtedly 
 occur at points. The new growth of tuberculous tissue gradually 
 invades the lobules of the gland, passing in along the lines of the 
 1 Compt. Bend. T. CIV. 
 
XXX.] TUBERCULOSIS. 479 
 
 lymphatics of the interlobular septa, so that a gradual transition 
 from the healthy gland substance to the dense tubercular mass 
 may be seen. In the mass itself the characteristic bacilli are 
 present in almost inconceivable numbers. They are seen first as 
 small stained rings (masses of bacilli) around a slightly granular or 
 homogeneous mass — in fact, the giant cells seem to consist of the 
 debris of cells, the result of the activity of the bacilli. In the 
 smaller cells bacilli may also be seen, and others may be demon- 
 strated lying in the spaces between the cells. On careful exami- 
 nation of the more healthy parts of the gland, especially at the 
 margin of the new growth, ulceration into the ducts may be made 
 out. In consequence of the interference with the nutrition of the 
 tissues immediately around the ducts or acini, the basement mem- 
 brane has given way and a small mass of tubercular granulation 
 may be seen projecting into the lumen; the epithelium is also 
 proliferating. In the granulation tissue, in the epithelial cells, and 
 even lying free in the lumen, there are frequently numerous bacilli, 
 aad it can be easily understood how, once in this position, they 
 find their way into the milk. This ulceration is not, however, of 
 such frequent occurrence as might be expected, for in the greater 
 part of the gland substance left there is little or no catarrhal pro- 
 liferation, and the ducts and acini appear to be obliterated in great 
 measure by compression. In addition to these positions, bacilli 
 could be demonstrated in epithelial cells still attached, and also in 
 rare cases in those lying free in the apparently healthy milk ducts, 
 in which position Professor MacFadyean had first demonstrated 
 them. These facts, when considered along with the occurrence of 
 bacilli in milk, with the feeding experiments recorded by so many 
 observers, and the great prevalence of tubercle in certain classes of 
 animals, go far to prove that milk is a source of tubercular infec- 
 tion, especially to young children. Cases are constantly cropping 
 up in which pigs on dairy farms are affected with tuberculosis of a 
 most typical character. Dr. Woodhead has recorded an outbreak 
 (amongst pigs) on a dairy farm which could be distinctly traced to 
 the milk of three cows in which the udders were markedly affected. 
 All veterinary authorities concur in stating that cattle and swine 
 are the two species in which genuine tuberculosis most frequently 
 occurs. When it is remembered that on dairy farms, and even on 
 farms where pedigree cattle (cattle which are very frequently 
 
480 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 highly tubercular) are reared, the milk, especially that of cows 
 suspected of disease, is given to the pigs, which often become 
 tuberculous, it will appear in the light of recent researches that the 
 disease is propter hoc rather than, as so many still hold, merely 
 post hoc. It has often been objected, of course, that if all tuber- 
 culous cattle gave tubercular milk, the human race would run a 
 risk of being rapidly exterminated ; but it might now be main- 
 tained, as the result of most careful clinical observation, that it is 
 only when the functions of the intestine are interfered with, and 
 when, in consequence, there are temporary or permanent alterations 
 in structure and in the chemical constituents of the fluids and gas 
 in the alimentary canal, that tubercle bacilli can make their way 
 unaltered through the epithelial barrier. The importance of Koch's 
 experiments on anthrax and cholera bacilli, when ingested, cannot 
 be over-estimated, and most of those who have followed him in this 
 line of experimentation have come to the same conclusions on this 
 point, however widely they may differ on others. It is not only 
 the intestine itself, however, that is affected by these functional 
 disorders. The mesenteric glands are also placed at a great dis- 
 advantage. This may be easily understood when it is remembered 
 how the slightest irritation in any position is almost immediately 
 followed by changes in the lymphatic channels and glands. 
 Every one is familiar with the peculiar condition of enlargement, 
 congestion, and succulence that is found in such glands. This 
 condition must be looked upon as the result of stimulation ; the 
 cells are roused into greater activity, they proliferate more rapidly, 
 and take up the foreign matter ; the gland as a whole acting as a 
 kind of vital sieve. In this process, however, the store of resistant 
 energy is gradually diminished, and should tubercle bacilli find 
 their way into the gland during or shortly after this extra stimu- 
 lation, they run less risk of being destroyed by active epithelioid 
 and lymph cells than when these cells are not already partially 
 exhausted. 
 
 (857) Propagation of Tuberculosis from consuming the Flesh of 
 Tuberculoics Animals. 
 
 In the first place it is still disputed whether bovine tuber- 
 culosis is identical with human tuberculosis ; if not the same, 
 
XXX.] TUBERCULOSIS. 481 
 
 the probability of Gontracting tbe disease would be much less than 
 if the two diseases are identical. The balance of evidence is de- 
 cidedly on the side of those who agree with Dr. Woodhead, viz., 
 that the tubercle bacilli are identical although they may present 
 some feeble difference of form from being cultivated in the tissues of 
 animals, the temperature of which exceeds that of the human body, 
 for instance the temperature of the pig and cow is from 38°'3 to 
 38°-8 ; in the calf, SQ^-S ; in the horse, 38°-3 ; and in the hen, 40°-0 
 to 40°'o, and it may well be that a slight rise of temperature in 
 these animals varies considerably the powers of propagation, and 
 also indirectly the virulence of the bacilli, as indeed Klein's ex- 
 periments have shown. 
 
 M. Nocard read at the Congress on Tuberculosis a paper on the 
 dangers to which one is exposed by the use of the flesh of tuber- 
 culous animals. It would appear to result, from his very ingenious 
 experiments, that the muscles destroy or digest, as expressed by 
 M. Nocard, the bacilli in such a way that the meat of animals 
 affected with generalised tuberculosis presents but very little 
 danger. Thus, four cats ate with impunity the flesh of a tuberculous 
 cow, whilst a fifth cat that had eaten a lymphatic gland of the cow 
 succumbed in a very short time to experimental tuberculosis. M. 
 Nocard, therefore, thinks that it is not necessary to exaggerate the 
 precautions, or to hold Koch's bacillus in great dread, adding that 
 one can eat without fear the flesh of tuberculous animals, the 
 tubercles of which are limited to the viscera and to the different 
 lymphatics ; even that of animals, the tuberculosis of which is 
 generalised would be but exceptionally to be dreaded. 
 
 W. Kastner also has made a research as to whether the muscles 
 of an animal affected with tubercle of the lung may be eaten 
 with impunity. He made infusions of meat from animals thus 
 affected and injected the infusions into the peritoneal cavities of 
 guinea-pigs. Out of 16 animals thus treated 12 remained healthy. 
 Kastner concludes that special dangers from infection are not to 
 be feared save in the rare cases in which tubercles are to be 
 found in the muscles. 
 
 On the other hand Professor Jeannel, of Toulouse, has studied 
 the generalisation of tuberculosis by the inoculation of rabbits. 
 Extirpation on the fourth day of the glands above the point in- 
 oculated did not prevent the success of the inoculation, which is 
 
 I I 
 
482 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 a proof that the bacilli had not been arrested in the lymphatic 
 -system. Moreover the blood of a rabbit inoculated by sub- 
 cutaneous grafting behaves like a virulent dilution from the 
 second day, perhaps earlier. Injected en masse in the peritoneum, 
 this blood determines an experimental tuberculosis. Hence M. 
 Jeannel does not believe in local tuberculosis ; for him the malady 
 is generalised in all the organism before manifesting its existence 
 by visceral localisation. 
 
 The question as to whether tubercle is ever localised in animals, 
 whether it is confined to the lung, brain, kidney, or liver is one 
 which bears directly upon the practice of a medical officer of 
 health. If in the opinion of those best able to judge ; an animal 
 with a small portion of lung alone showing signs of disease, the 
 rest of the viscera being healthy, and the flesh even when submitted 
 to a strict microscopical examination showing no bacilli — yet contains 
 invisible spores which when placed under suitable conditions may 
 develope into tubercle ; then it is the duty of the health officer 
 to condemn the whole animal for the least speck of undoubted 
 tuberculous taint. This is the view taken by the Congress on 
 Tuberculosis which met at Paris in 1889, and this is the view 
 taken by Dr. Russell, of Glasgow, as shown by the leading 
 case of prosecution relative to diseased meat in that city fully 
 reported in Public Health, Vol. II., p, 75, and also published as 
 an official sort of blue book by the Glasgow Sanitary Authority. 
 The question cannot be said to be entirely set at rest but the evidence 
 certainly goes so far as to show that this drastic course is the safest, 
 and that such meat does in fact generally contain a few of the 
 bacilli or their spores, and that such meat when eaten in a 
 half-cooked state by young children who inherit some weakness of 
 tissue resistance or are at the time in a state of imperfect health 
 may, and does, produce a certain amount of tubercular infection. 
 
 (358) Disinfection of Tuberculous Products. 
 
 It is in the first place important to know in what excreta the 
 tubercle bacilli are likely to be found. 
 
 In the sputum of the phthisical, it is a matter of common 
 knowledge and utilised daily in clinical work that myriads of the 
 
XXX.] TUBEKCULOSIS. 483 
 
 specific micro-organisms are to be found. With regard to the urine 
 the following researches may be mentioned : Lichtheim ^ found in 
 the contents of the renal pelvis of a corpse, tubercle bacilli; 
 Rosenstein ^ also succeeded, in the urine of a person suffering from 
 tuberculosis, in recognising the tubercle bacilli, and thus confirm- 
 ing the diagnosis of tuberculosis of the urogenital apparatus ; 
 Babes ^ claimed priority, since he had a few days earlier communi- 
 cated a similar discovery to the Anatomical Society of Paris. A 
 number of researches followed, recording successful attempts in 
 finding tubercle bacilli in the urine of patients suffering from 
 tuberculosis of the genito-urinary tract. Such observations were 
 by Smith,* Irsai,^ and Probstiug * ; Philipowiez,' who not only in 
 chronic tuberculosis of the kidney, but also in acute miliary 
 tuberculosis, found in the urine of the corpse tubercle bacilli ; 
 farther, by Kerstein,^ who found tubercle bacilli easily by allowing 
 the urine to subside in a conical glass, and filtering off the sediment ; 
 lastly, by Morpurgo and Krecke. 
 
 The solid excreta from the tuberculous have seldom been in- 
 vestigated. Cramer ^^ was the first who recognised in them tubercle 
 bacilli ; he also avers that he has several times found bacilli in 
 stools of the healthy, which were not to be distinguished from 
 tubercle bacilli. Lichtheim ^^ and de Giacomo^^ found tubercle 
 bacilli in the loose evacuations of patients suffering from tubercu- 
 losis of the intestines ; and, in the non-tuberculous, large cocci and 
 spore-like forms which gave the same colouration as tubercle 
 bacilli. Koch and Gaffky " could only recognise tubercle bacilli in 
 the dejecta of the phthisical with marked symptoms of intestinal 
 tuberculosis ; they also confirmed the other researches of Lichtheim 
 and de Giacomi on the presence of spores, which could be coloured 
 like tubercle baciUi. Lastly, Wolfram '^ is to be mentioned, who 
 
 1 The Zancet. 1886. = Central, f. d. Med. Wissemchaft. 1883. No. 5. 
 
 ^ Central./, d. Med. Wissmschuft. 1883. No. 9. '^ The Lancet. 1883. 
 
 ^ Wiener med. I'resse. 1884. No. 37. 
 
 ^ Berliner klin. Wochensehrift. 1884. No. 37. 
 
 7 JViener mtd. Blatter. 1885. 22. 
 
 " Anthiel d. Tuberc. a. d. Aetiol. App. Dissert,. Berlin, 1885. DeiitscJie med. 
 Wochenschrift. 1886. No. 15. 
 
 ^ Archiv. p. I. Scienz Med. Vol. X. No. 19. 
 
 '" Miinchner med. Wochenschrift. 1887. ^'- Ibid. 
 
 \*Ibid. " FortschritU der Med. 1883. No. 5. 
 
 ^' Mittheihmgen aus dem Kaiserlich. Gesundheit, Bd. II. 
 15 Praeglad.lek. 1884. 
 
 I I 2 
 
484 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 found tubercle bacilli in the stools of persons affected with tuber- 
 culosis of the intestines. 
 
 In purulent discharges from the ear of the phthisical, tubercle ba- 
 cilli have been frequently found, e.g., by Eschle,^ VoltoHni ^ (in two of 
 his cases caries of the petrous bone was also present), Eitzefeld,* and 
 Nathan * (in three of his cases there was also caries of the mastoid 
 process, or of the smaller bones of the ear). Lastly, Habermann ^ 
 was able to recognise tubercle bacilli in a number of corpses, who in 
 life had been affected with tuberculous changes in the middle ear. 
 
 To these must be added various scrofulous discharges ; Holtz ® 
 for instance has found tubercle bacilli in the glandular swellings of 
 scrofulous affections, in certain kinds of eczema and subcutaneous 
 abscesses ; Volckman ^ has even found bacilli in the scrapings of 
 the epidermis of scrofula. 
 
 There have been several exact researches as to the disinfection 
 of tubercle, the leading one being that of Dr. Fischer,* who dis- 
 covered the remarka,ble power of aniline water as a disinfectant 
 for tuberculous sputum. If sputum be treated with ten times its 
 bulk of aailine water and allowed to remain in contact 24 hours, 
 it is fully disinfected, but he at the same time points out that 
 considering the relative price of aniline water and that of carbolic 
 acid, the latter is preferable ; he found that 5 per cent, carbolic acid 
 added in equal bulk to the sputum and acting for 25 hours fully 
 disinfected. 
 
 Corrosive sublimate did not give so favourable a result : 1 to 
 600 solution added to sputum in the proportion of one part of 
 sputum and one of the sublimate solution failed to disinfect. In 
 all the above the result of the disinfection was ascertained by 
 subcutaneous injection of the disinfected and undisinfected sputum 
 into animals. 
 
 A heat of 100° when dry sometimes failed to disinfect, although 
 it acted during 60 minutes. Boiling for 10 minutes, or a steam 
 heat acting for 15 minutes disinfected perfectly. 
 
 Yersin^ has made some experiments by the "thread" method 
 
 1 Deutsche med. Wochemchrift. 1883. No. 30. > Ibid. No. 31. 
 
 ^ Ueber d. Tuberc. des Ohres. Dissert. Bonn. 1884. 
 
 ^ Deutsche Arch. f. Min. Med. Bd. XXXV. 
 
 ^Pragermed. Wochenschrift. 1885. No. 6. Zeit- f. Heilkunde. Bd. VL 
 
 « Klin. Arbog. 1885. ' Arehiv. f. klin. Chirurgie. Bd. XXXifl, 
 
 8 Mittheil. aus dem. Kaiser. Gesundheitsamte. 1884. 
 
 8 Annates de VInstitut Pasteur. No. 2, 1888. Public Eealth, vol. i. 1889. 
 
XXX.] TUBERCULOSIS. 485 
 
 described at page 315. This method is of course inferior to that 
 of direct inoculation, but it has its value. He gives the following 
 as the result of his experiments with the bacillus of tubercle : — 
 
 Substance Used. Time. 
 
 Phenol 5 per cent 30 sees. 
 
 ., 10 „ „ 1 min. 
 
 Absolute Alcohol 5 ,, 
 
 Iodoform in Ether 1 per cent 10 ,, 
 
 Ether 10 „ 
 
 Mercuric Chloride 1 per cent. . 10 ,, 
 
 Thymol 2 hrs. 
 
 Sallcylie Acid 6 ,, 
 
 He also studied the action of heat, and declares that at a tempera- 
 ture of above 70° sterilization is effected. 
 
 (359) The Prevention of Tuberculosis. 
 
 The Medical Officer of Health at present is neither aided by 
 pubUc opinion nor by statute in any attempt he may make to 
 directly stop the propagation of tuberculosis. The only way open 
 to him is to direct his attention to dampness of habitation, to 
 overcrowding, to tuberculous meat and to diseased milch cows ; in 
 all these points he has a certain amount of power, but to isolate 
 the affected person, to disinfect articles infected with tubercle 
 bacilli, he has no power, imless he can get his authority to consider 
 tuberculosis as " an infectious disease " under the 120—122 sections 
 of the Public Health Act. This will no doubt come in time, but 
 the knowledge that the medical and scientific world possess is 
 distinctly in advance of the knowledge of the people at present. 
 The people will have to be educated on this matter, and once the 
 danger of " catching " consumption is fully recognized, there will be 
 no difficulty in the first place of obtaining power to isolate those 
 cases where there is likely to be danger to the healthy, and in the 
 second place to have each case notified to the sanitary authority. 
 From the large number of victims to tuberculosis in this country, 
 it is a far more important malady to have notified than such 
 purely infantile complaints as measles. 
 
 Phthisis and miliary tuberculosis should be treated in a public 
 health sense exactly as an infectious fever, the sufferer should be 
 isolated, the liquid and solid excreta disinfected, preferably with 
 
486 A MANUAL OF PUBLIC HEALTH. [chap. xxx. 
 
 10 per cent, carbolic acid and the sputum of the phthisical received 
 on rags or paper and burned. The propagation of tuberculosis by 
 milk is to be met by a more rigid inspection of milch cows than 
 has heretofore been made, and when proper abbatoirs are estab- 
 lished throughout the country a strict meat inspection will then be 
 possible, but until that is done a very large amount of the meat 
 consumed must be derived from tuberculous animals. 
 
CHAPTER XXXI. 
 
 MALARIA — MALARIOUS DISEASES. 
 
 (360) The Effects of Malaria. 
 
 Under the somewhat indefinite term of malarious diseases is 
 meant those maladies which experience has shown to be intimately 
 connected with a particular condition of soil. 
 
 Malarious soils are all more or less marshy, or are tracts in the 
 vicinity of marshes ; places which are well drained or dry, and those 
 which are covered with water are not malarious. The diseases 
 are thus intimately connected with some particular kind of vege- 
 table decomposition. 
 
 The effects of malaria in their lightest form express themselves 
 as neuralgias of an intermittent type, or as epidemic jaundice ; the 
 author, for instance, has noticed that in a malarious tract from time 
 to time occur a number of almost simultaneous cases of more or 
 less pronounced jaundice without fever or other symptom ; but the 
 most typical malady of all connected with malaria is that of ague 
 or intermittent fever. In the hotter parts of the world there is 
 also yellow fever ; this has several analogies to the intermittents. 
 
 (361) Bacteriology of Malarious Diseases. 
 
 Probably there are several kinds of micro-organisms which pro- 
 duce as many varieties of intermittent fever. Klebs and Crudeli^ 
 have, however, isolated from cases of intermittent fever a bacillus 
 from 2 to 7 /A long, which is capable of growth into twisted 
 threads. Spore formation takes place at the centre or at either 
 end. Marchiafava ^ has also discovered in the blood of persons 
 ' Archill, f. Experimental Pathol. 1879. ^ Ihid. 
 
488 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 suffering from intermittent fever similar bacilli with end spores. 
 These kinds, if indeed they are not identical, have been found 
 in the soil of the Roman Campagna. Inoculated into rabbits they 
 produce an intermittent fever, and in the spleen and marrow the 
 threads and spores are found in abundance. There have also been 
 found in the blood in cases of malaria amoeboid bodies and motile 
 filaments. 
 
 The modem theory, therefore, is that these bacilli or analogous 
 micro-organisms are produced in vast numbers in malarious soils, 
 that the spores are raised by evaporation or by the agency of wind, 
 that they float in the atmosphere, fall with the night dews, and are 
 breathed into the lungs or swallowed with the food or saliva and 
 produce the maladies enumerated. 
 
 (362) Geographical Distribution of Malarious Tracts. 
 
 In this country the fens of Norfoli and Lincolnshire used to be 
 noted haunts of malaria, but the drainage of both these counties 
 has reduced the number of cases greatly, and fatal ague is quite an 
 insignificant cause of death in the Registrar-General's returns. It 
 is in the deltas, the marshy banks, and the embouchures of rivers 
 that agues are to be looked for. In Europe the Italian maremma} 
 the plains of Walcheren and of Rosendaal, the lines of detached 
 pools along the Guadiano in Spain, impress their malarious 
 character on the memory as a cause of great mortality of armies 
 in the historical campaigns. In India the stations of Calcutta, 
 Chinsurah, and Berhampore are highly malarious. In America 
 malaria hangs about the Orinoco, the Amazon, and other great 
 rivers ; in short, there is scarcely a country in the temperate and 
 torrid zones which have not portions of moist and swampy land 
 dedicated to malaria. 
 
 (363) Malaria from Local Causes. 
 
 Malaria may spring from essentially local and removable causes. 
 The Medical Officer of Health may find from careful inquiry that in 
 a particular group of houses or in a particular house from time to 
 
 1 A good account of tlie Italian maremma and the history of intermittent fever 
 in Italy is given in Luttres ecrites d'ltalie en 1812 et 1813, par F. Sullin de Chateau- 
 vreux. Paris, 1816. 
 
XXXI.] MALARIA. 489 
 
 time cases arise which have a more or less malarious character ; in 
 such instances, the height of the ground water and the nature of 
 the soil will have to be carefully investigated. Nor must it be 
 lost sight of that there are cases on record which show that heaps 
 of decaying or drying vegetable substances will cause intermittent 
 fever; for instance, it is an accepted fact in the Netherlands, France, 
 and Italy that the steeping of flax in stagnant water and spreading 
 it out to dry has been followed by paludal fever. In India large 
 masses of exhausted indigo plants put in heaps has caused inter- 
 mittent fever, when in a state of putrefaction, to families to 
 leeward of the heaps. 
 
 (364) Prevention of Malaria. 
 
 The preventive measures are good drainage, the removal of 
 stagnant ponds, of decaying masses of vegetation or heaps of 
 vegetable matter. Travellers having to pass through a malarious 
 country may to a certain extent protect themselves from malaria 
 by dosing with quinine ; it has been repeatedly shown that 
 provided the doses are large quinine has a real preventive 
 quality. The doses of the sulphate should be 5 grains at first 
 twice a day, and then gradually increased up to any dose which 
 can be borne without singing in the ears or other symptoms of 
 " quinism." 
 
CHAPTER XXXII. 
 
 miceo-parasitig maladies primaeily attacking the 
 intestine. 
 
 Enteric or Typhoid Fever. 
 
 Enteric or typhoid fever is a malady produced by a micro- 
 organism which attacks the intestine in the first place, and after- 
 wards other organs ; it is attended with fever, and mostly diarrhcea, 
 and other systems of constitutional disturbance. 
 
 (365) Statistics of Mortality from Enteric Fever. 
 
 The average deaths from enteric fever in England during the 
 eighteen years from 1869 to 1886 inclusive reaches the mean 
 number of 7,203, the extreme yearly numbers being 5,061 and 
 8,913 ; the mortality per million from typhoid fever is given for 
 the same number of years in rates varying from a minimum of 173 
 to a maximum of 371. 
 
 Typhoid fever is especially a disease of the young adult, and is 
 more prevalent in country places than in well-drained towns. Dif- 
 fused generally throughout the civUized world it is particularly, 
 prevalent in warm climates such as India. It is the most fatal of 
 all the diseases to which the British soldier in India is liable, and 
 it occurs in all parts of India from the Eastern to the Western 
 frontiers ; on the hills and mountains as on the plains there is no 
 station and cantonment which is exempt.^ This great prevalence 
 in India is more due to sanitary than to climatic conditions. 
 
 ' Twmty-fourik Annual Bep. San. Com. India. 1887. 
 
CHAP. XXXII.] TYPHOID FEVER. 491 
 
 During the eight years ending 1887, the following are the ad- 
 mission and death-rates of the army in the three Presidencies. 
 
 
 Admissions of Typhoid 
 eases to Hospital 
 per 1,000 strength. 
 
 Death-rate 
 per 1,000 strength 
 from Typhoid. 
 
 Bengal 
 Madras 
 
 7-1 
 
 3-53 
 
 2-17 
 
 Bombay 
 
 80 
 
 3-02 
 
 (366) Case-Mortality of Enteric Fever. 
 
 The case-mortality of enteric fever in England is somewhat less 
 now than formerly; during the three years 1886-8 the case- 
 mortality of the hospitals of the Asylum Board varied from 14'59 
 to 14"85 per cent. Murchison's statistics derived from the London 
 Fever Hospital, 1848-1859, give an average of 17'2 per cent., and 
 the average mortality of 28,051 cases treated at various hospitals 
 at home and abroad in various years up to 1870 is given as 17'45 
 per cent. 
 
 The liability to attack is influenced enormously by age, but the 
 death-rate is not influenced in anything like the same proportion — 
 in which it contrasts with typhus, for instance Murchison gives the 
 following figures derived from London fever hospital experience : — 
 
 
 Typhus Mortality 
 
 Enteric Mortality 
 
 
 per cent, of the cases. 
 
 percent, of the cases. 
 
 Uiider 10 years 
 
 . . . 1-65 
 
 11-36 
 
 )) )) ii 
 
 3-27 
 
 
 From 10 to 14 
 
 1-65 
 
 12-86 
 
 „ 15 to 19 
 
 3-96 
 
 . . . 15-48 
 
 „ 20 to 29 
 
 12-34 
 
 20-46 
 
 „ 30 to 39 
 
 22-63 
 
 25-90 
 
 „ 40 to 49 
 
 35-97 
 
 25-00 
 
 Above 50 
 
 57-03 
 
 34-94 
 
 From whence it appears that the death-rate increases with advanc- 
 ing age to much less extent than typhus. 
 
 (367) Incubation Period. 
 
 If the modem view is correct, viz., that typhoid depends upon 
 the invasion of the intestine by a micro-organism, there ought 
 not to be a very definite incubation period. For in experiments 
 with anthrax (a micro-organism of something the same nature), 
 in which the bacillus anthracis has been introduced into the system 
 
492 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 of animals by dosing the natural food passages, the incubation 
 period has been variable. For instance Koch, Gafiky and Loeffler ^ 
 fed sheep, some with large doses of anthrax, others with small, the 
 feeding being done in such a manner as to avoid all wounding of 
 the mouth. In the first case in which sheep were fed with large 
 doses, they died without exception in a few days from anthrax 
 infection ; on the other hand, out of ten sheep who daily took a 
 small dose of anthrax, those that were affected at all died re- 
 spectively the 5th, 6th, 11th and 19th day after the beginning of 
 the feeding. In all the mortal cases a post-mortem examination 
 made it clear that the anthrax had infected the intestine, the seat 
 of infection being as in typhoid the lymph follicles and Peyer's 
 patches. 
 
 After these experiments it will cause no surprise to find cases 
 like those cited by Murchison in which it appears clear the in- 
 cubative period was only two days. In most of the cases recorded 
 the incubation period has been about two weeks, but it may be 
 much shorter and it may be longer. 
 
 (368) Seasonal Prevalence. 
 
 Enteric fever is markedly influenced by season, by far the 
 greater number of cases in Europe and America occurring in the 
 autumn, hence one of its synonyms " autumnal fever " ; the least 
 number of cases occur in April and May. 
 
 5,988 cases admitted into the London Fever Hospitals during 
 the twenty-three years from 1848 to 1870 were distributed 
 throughout the months of the years as follows : — 
 
 
 Cases. 
 
 Per cent. 
 
 January . . 
 
 . . 433 . . 
 
 7-2 
 
 Febmaiy . 
 
 306 . 
 
 4'9 
 
 March 
 
 318 
 
 5-3 
 
 April 
 
 209 
 
 3-5 
 
 May . . . 
 
 . 232 
 
 . 3-9 
 
 June . 
 
 335 . 
 
 5-6 
 
 July . 
 
 434 
 
 7-2 
 
 August . 
 
 . 721 . . 
 
 12-0 
 
 September . 
 
 803 . 
 
 13-4 
 
 October . . 
 
 839 ... . 
 
 . 14-0 
 
 November . 
 
 819 
 
 13-7 
 
 December 
 
 539 . 
 
 9-0 
 
 ^ Mittheilungen aus 
 
 dem Kaiserlichen Gesundheitsamte. 
 
 Berlin, 1884. 
 
XXXII.] TYPHOID FEVER. 493 
 
 The experience of the Metropolitan Asylums Board is very 
 similar (see Chart opposite). In the fifteen years ending December, 
 1888jthe maximum occurred eleven times in October, three times 
 in November, once in December, once in January; in 1880 the 
 cases were few, and it was equally prevalent in August, September, 
 and October, there being no marked difference in each of the 
 three months, the curve being here continued, or to speak more 
 accurately interrupted, by a straight line. 
 
 Buchan and Mitchell's curve ^ of the mortality mapped out by 
 Bloxam's method for the deaths in London during the thirty years, 
 1845 — 74, places the maximum in the last week of October, which 
 would well coincide with hospital experience. They point out its 
 great similarity with the scarlatina mortality curve, differing from 
 it though in the duration and phases of the minimum period. 
 " Scarlatina falls below its average in the beginning of January, 
 typhoid fever not until the last week of February ; scarlet fever 
 has its absolute minimum period from the middle of March to the 
 middle of May, typhoid fever from the middle of May to the end 
 of June ; scarlet fever begins steadily to rise in the second week 
 of May, typhoid not until the beginning of July, when the heat of 
 summer has fairly set in." 
 
 (369) Bacteriology of Enteric Fever. 
 
 Eecklinghausen^ in 1871 found in a case of abscess of the kidney 
 which had complicated typhoid, colonies of micrococci ; he did not 
 consider these a factor in the production of typhoid, but an acci- 
 dental complication. In the following year Eberth ^ also found 
 micro-organisms in the corpses of typhoid cases. 
 
 In 1875 Klein* found in a case of fatal typhoid, in the mucous 
 membrane of the intestine, a fungus with copious mycelium and 
 numerous macro and micro-gonidia ; in a later communication 
 Klein recognised micro-organisms in the spleen and noted the 
 presence of micrococci in the mucous membrane of the intestine 
 and the lymph follicles. Browicz, in 1875, discovered in the 
 kidneys, the spleen, the muscular structure of the heart, and in the 
 
 ^ Op. cit. 
 
 2 Verhandlung der physicaliscJi-mediein GesellscTiaft in Wurzhurg, 1871. 
 
 ^ Zur Xemntniss dir lacteritischen Mykosen. Leipzig, 1872. 
 
 * Reports Medical Officer L. G. Board. 1875 
 
494 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 intestine of a patient who had died of typhoid, bacilli. Socoloff,^ 
 in 1876, investigated the spleens of nine cases of typhoid and found 
 micrococci in three of them. Fischel,^ in twenty-nine cases, found 
 micrococci in the spleen, in the remainder he could discover no 
 micro-organism. 
 
 In 1880 Eberth made a noteworthy research. He very carefully 
 investigated twenty-three cases of typhoid, paying special attention 
 to the spleen and the lymph glands. The sections he cleared up 
 with concentrated acetic acid. Out of the twenty-three cases 
 twelve presented organisms ; in each of the twelve these were found 
 in the lymph glands, in six cases they were in the spleen. The 
 colonies looked at first like heaps of cocci, but where they were 
 less crowded could be seen to consist of bacilli. The rods were 
 short with gently rounded ends ; they had a soft outline and con- 
 tained frequently very small, highly refractive, spore-like bodies. 
 They were not easily stained with colouring agents. In 1881 
 Eberth * returned with new experience to the subject, and by that 
 date had altogether investigated forty cases of typhoid. Out of these 
 he had found the above described bacillus eighteen times ; in 
 twenty-two the result was negative. Klebs* published a few 
 months after Eberth's first paper an account of a bacillus which he 
 and his assistants had found in typhoid cases. Klebs devoted 
 much time to the study of this bacillus and described it at length ; 
 he considered it a constant micro-organism in cases of typhoid. It 
 is a matter of doubt whether Eberth's bacillus is the same as that 
 of Klebs. Koch,^ it appears, independent of Eberth and Klebs, 
 and about or before the same time, had discovered a special bacillus 
 in typhoid, which did not agree with any other known micro- 
 organism. 
 
 Other researches followed, such as those of Meyer,^ Coats,'' and 
 Crooke, these generally confirmed Eberth.* 
 
 The last noteworthy research is that of Gaffky.^ Gaffky made 
 a most painstaking research on the bodies of twenty-eight patients 
 
 1 Virch Archiv. Bd. 66. 1876. ^ Pragcr med. Wochenschrift. 1878. 
 
 3 Firch Archiv. Bd. 83. 1881. 
 
 * Arch.f. exper. Pathol, u. Pharmak. Bd. 12, Heft 2 u. 3. 
 
 ^ Mitlheilungen am dem Kaiserl. Gcsundheitsamte. Berlin, 1884. 
 
 ^ Untersuchtingen iiber den Bacillus des Abdominaliyphiis. Inaug.-Diss. Berlin, 
 1881. 
 
 !■ B. Med. Journal. 1882. » ^ jjf^^i Jourrial. 1882. 
 
 ' Mitthcilungen aus dem Kaiserl. Gesimdheitsamte. Berlin, 1884. 
 
XXXII.] TYPHOID FEVER. 495 
 
 who had died of typhoid; he hardened the internal organs in 
 alcohol, then cut hundreds of fine sections, these sections were 
 treated as follows. They remained for from twenty to twenty-four 
 hours in a methylene blue solution, made by adding a saturated 
 alcoholic solution of methylene blue to distilled water until a very 
 deeply coloured, non-transparent staining liquid was obtained, this 
 was prepared fresh each time. The sections were nest washed 
 with water, dehydrated by absolute alcohol, cleared up by turpen- 
 tine, and mounted in Canada balsam. Of the twenty-eight cases 
 in one alone he failed to find Eberth's bacillus ; this might be 
 explained from the fact that the death took place at the end of 
 the fourth week from peritonitis arising from a perforation. In 
 twenty-two instances the colonies were found in the spleen ; in 
 thirteen cases in which the liver was examined, colonies were found 
 in them all ; in seven cases in which special attention was turned 
 to the kidney, in three the bacilli were found ; in four cases in 
 which the mesenteric glands were investigated, in three the bacilli 
 were found. Probably tlie failure to find the bacilli in other cases 
 by other observers arises from the technical difficulty of the 
 research, and also because the colonies are scattered in some cases 
 at wide intervals ; in such it is only by making a number of 
 sections that success will be attained. In one of the twenty-eight 
 cases Gaffky found micrococci, he follows Recklingbausen, Eberth, 
 Koch, and others in considering their presence as secondary and 
 not an essential of the disease. Gaffky was able to cultivate the 
 colonies by the following process : — The spleen from the corpse of 
 a typhoid patient, showing no trace of decomposition, was washed 
 carefully with a one per thousand solution of corrosive sublimate, 
 and then by means of a knife previously held in the flame to 
 effectually sterilise it, cut into two halves. 
 
 Other slices were made by freshly sterilised knives, and platinum 
 wires, which had been the moment before made red-hot so as to 
 destroy any kind of organism infected from these surfaces. The 
 platinum wires were then drawn over nutrient gelatin so as to 
 make a streak. The cultivation of this miniature-sown furrow 
 took plp,ce in a moist glass chamber at the ordinary temperature 
 of the room. After twenty-four hours the streak showed a white 
 cloudiness which, after another twenty-four hours, had increased in 
 intensity, but was still confined to the streak. The gelatin did 
 
496 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 not become fluid. On examining with a low power the streak was 
 found to consist of a large number of roundish, granular colonies 
 of a light brown colour. On now taking minute portions from the 
 streak and examining the colony thus removed in a drop of 
 distilled water and highly magnifying the bacilli were found to be 
 motile. 
 
 Pursuing his researches, Gaffky found that the bacillus grew in 
 quite a characteristic way on slices of potato ; the potato was pre- 
 pared in the way familiar to bacteriologists and the surface 
 " seeded " with the bacillus. The slices were cultivated in the 
 moist glass chamber at the ordinary room temperature. In forty- 
 eight hours, if a particle of the surface be taken for microscopical 
 examination, it seems as though the whole surface is covered with 
 a connected resistant skin, and from whatever part a tiny sample 
 is taken it is found to consist of incredible numbers of the motile 
 bacillus ; these are most of them of the ordinary size, but others 
 are in the form of long glittering threads. There is no other 
 baciUus known that is motile, does not liquefy the gelatin, and 
 which grows on gelatin in the way described. The motile property 
 is due as usual to motile threads at the ends of the rods. At the 
 ordinary temperature of rooms no spore formation takes place, but 
 it was found that spores could easily be produced by cultivating at 
 from 30° to 40°. The spores are as usual long lived and resistant. 
 Fig. 52 (a), represents the appearance of a stab culture in gelatin 
 of the bacillus. Fig. 52 (h), is probably the same bacillus found by 
 Klein in a fatal case of diarrhoea.^ Gaffky failed to raise the same 
 bacillus from typhoid stools, because other organisms liquefied the 
 gelatin. Chantemesse and Widal^ have been more successful. 
 They found that trichloride of iodine added to gelatin in the pro- 
 portion of 1 to 500 prevented the growth of all ordinary micro- 
 organisms, but the typhoid bacillus was an exception. Using this 
 medicated nutrient gelatin, the authors affirm that they have 
 separated Eberth's bacillus from typhoid excretions. Gaffky was 
 similarly unsuccessful in attempting to raise the bacillus from 
 blood. 
 
 Recently there have been published improved methods; M. Rodet^ 
 
 ^ Supplement, Seventeenth Annual Report, Local Government Board. 
 
 2 Gaz. hebd. et de Med. CUr. 1887. No. 9, 146. 
 
 ' Comptes rendiis de la Societi de Biologie, T. ii.. No. 8. Public ffealth, ii., 382. 
 
XXXII.] 
 
 TYPHOID FEVER. 
 
 497 
 
 has taken advantage of the fact that most micro-organisms 
 will not grow at a high temperature, e.g. 44'5° C, but this tem- 
 perature is not destructive of the typhoid bacillus. M. H. Vincent ^ 
 modifies this process by sterilizing broth, and to every 2 c.c. adding 
 a drop of carbolic acid and then testing, say drinking water, by 
 
 •■< ] 
 
 Fig. 52. 
 
 adding from five to fifteen drops to the broth. On now cultivat- 
 ing at 42° if the broth remains clear for twelve hours, the 
 typhoid bacillus is not present ; on the other hand, if it clouds 
 the turbidity is probably due to the bacillus, and by successive 
 removes, that is, by taking minute quantities of the already 
 clouded broth and transplanting into a fresh tube, and so on, an 
 
 1 Comptes rendus de la SocieU de Biologie, T. ii., No. 5. Public Health, ii,, 381. 
 
 K K 
 
498 A MANUAL OF PUBLIC HEALTH. [chap 
 
 absolutely pure cultivation may be obtained and the characters 
 of the suspected microbe studied. Rodet and Roux ^ believe that 
 there is an intimate relation between the bacillus coli communis 
 and the bacillus of typhoid fever, the latter being indeed the 
 bacilli in a state of attenuation or degeneration. 
 
 Eberth's bacillus has rather frequently been found in water 
 which has produced typhoid. Beumer, for instance, found it at 
 Greifswald, Rodet at Sous-Ville-Charmoux, Arloing at Cluny, 
 Widal at Paris, and Chantemesse at Clermont-Ferrand and Pierre- 
 fonds. In the latter case Chantemesse found no less than 25,000 
 bacilli to the litre in a well — the water of which apparently com- 
 municated typhoid fever to twenty persons — chemical analysis in 
 this case indicated no great pollution. To these examples may be 
 added several in the United States. Dr. Prudden,^ of New York, 
 found Eberth's bacillus in a filter in a household, some of the 
 members of which suffered from typhoid, and filters from affected 
 houses during the same outbreak were examined by Dr. Ernest 
 of Boston and by Dr. Swartz, in a few cases with a positive 
 result. 
 
 Numerous experiments by Klein, Murchison, Birch-Hirschfeld, 
 Klebs, Gaffky, and many others, have been made as to . the possi- 
 bility of infecting animals with true typhoid. For this purpose 
 monkeys, guinea-pigs and various other animals have been fed with 
 typhoid stools or artificial cultivations of Eberth's bacillus, pro- 
 ducts have been also injected subcutaneously or into the veins. 
 Birch-Hirschfeld appears to have given a rabbit some disease 
 similar to typhoid by feeding it for a long time with food infected 
 with typhoid excreta. But considered as a whole the experiments 
 are not altogether conclusive.^ 
 
 (370) Symptoms. 
 
 In a few cases which are specially dangerous to the public the 
 only deviation from health is an almost painless looseness of the 
 
 ^ Oomptes nndus de la Societi de Biologie, T. ii., No. 7. 
 
 ^ Fourth Annual Report of the State of Maine. 
 
 ' It is stated that Vaughan has inoculated successfully dogs and cats with Eberth's 
 bacUlus found in the Iron Mountain drinking water. — Sixteenth Report of the 
 Michigan Board of Health. 
 
XXXII.] TYPHOID EEVER. 499 
 
 bowels, with a little fever at night, a general loss of appetite and 
 slight weakness. Such cases often from first to last go about their 
 ordinary avocations, seek no medical advice, and must be infective 
 centres, without doubt doing occasionally much damage. The 
 author has seen three of these cases in which one had suffered for 
 at least a fortnight, in the second some nine days, and in the other 
 a long time which could not be definitely fixed, but was probably 
 seventeen or eighteen days. The ordiuary typical mild case pre^ 
 sents the following symptoms : — The commencement is insidious, 
 it may be marked by diarrhoea or by rigors, fever of a remittent 
 character sets in, the temperature rising the first evening to 100° to 
 go down half a degree or more the following morning. The second 
 evening the temperature will be higher, say 101°, rising as a rule 
 each night up to the fifth or sixth day when it will attain 105° or 
 106°, keeping for a week or more at or about this evening tempera- 
 ture, and going down each morning a degree or a degree and a 
 half About the twelfth or thirteenth day comes a change. The 
 temperature, although nearly as high as before in the evening, be- 
 comes much less in the morning, going down three or foui* degrees 
 at the end of the third week, sometimes before ; the fever markedly 
 declines and the morning temperature becomes nearly normal, and 
 in the fourth week convalescence sets in. The tongue during this 
 time is mostly red and fissured or becomes dry and brownish. 
 The abdomen is tender, there is gurgling in the iliac fossa upon 
 pressure, the spleen on careful percussion is found to be larger than 
 natural. Between the seventh and fourteenth days there are 
 successive crops of isolated elevated rose-coloured spots, each spot 
 lasts about two or three days. There is nearly always diarrhoea, 
 in a few cases hsemon-hage from the bowels. In many cases bleed- 
 ing from the nose. Prostration comes on rather late, patients 
 keeping up to the seventh or tenth days. The termination of the 
 disease in mild cases may be as early as the twenty-fourth day, in 
 severe it is protracted to the thirtieth or longer. Sometimes 
 even a mild case is carried off by perforation of the intestine or by 
 profuse haemorrhage. The prognosis on this account must always 
 be guarded ; with typhoid until complete convalescence no one can 
 tell what will happen even when all fever has passed, in a few 
 instances relapses take place. Coma is occasionally present and 
 sometimes active delirium. 
 
 K K 2 
 
500 A MANUAL OF PUBLIC HEALTH. [cHAr. 
 
 (371) Predisposition. 
 
 With the exception of a previous attack of typhoid, which to 
 some extent renders a person not liable to contract the same dis- 
 ease a second time, there is only one marked difference in indivi- 
 dual susceptibility, and this one depends on age. The disease is 
 almost entirely confined to children and adolescence, a point to be 
 borne in mind in the selection of nurses for typhoid cases. " The 
 mean age of 1,772 cases admitted into the London Fever Hospital 
 during ten years, 1848-57 was 21'25 ; that for males being 21'45, 
 and for females 21*06. These averages are more than five years 
 under those of the entire population " (Murchison). Persons under 
 thirty are more than four times as liable to enteric fever than 
 persons over thirty. This is remarkably different to typhus. At 
 one time it was thought that owing to anatomical reasons it was 
 not possible for the aged to develop typhoid, but the cases of 
 people over fifty, and even a few over seventy, which have been 
 proved by post-mortem examination to have suffered from fatal 
 typhoid are sufficient in number to disprove this view. All that 
 can be said is that the liability to contract typhoid after thirty 
 years of age, progressively diminishes, and that cases over fifty are 
 rare. 
 
 (372) Pathological Appearances after Death. 
 
 In the works of Louis,^ Chomel,^ Rokitansky,' Jenner,* Hoffman, 
 Murchison ^ and W. Budd ® will be found the most minute details 
 of the anatomical lesions observed in cases of death from typhoid 
 fever. These storehouses of information contain a vast amount 
 of minute details as to the appearances of every organ and tissue. 
 The morbid changes however which are always present in this 
 disease and never present^ in any other are mainly in the intestines. 
 As Dr. Budd truly reinarked in his classical monograph, " Take the 
 diseased intestine away and it becomes impossible, in a common out- 
 
 ' Louis, Eecherches sur la Fiivre Typhoid. 1841. 
 2 Chomel, Lemons de OUnique Mid. Tom. L Paris, 1834. 
 ^ Eokitansky, Path. Anatmnie. 
 
 * "W. Jenner, Med. Ghir. Transact. Vol. xxxiii, Ed. Monthly Journal of Med 
 Science, 1849-50. 
 
 ^ The Continued Fevers of Great Britain. 
 
 « Typlwid Fever, by W. Budd, M.D., F.R.S. London, 1873. 
 
Plate y 
 
 ."TA 
 
 v'.JJ 
 
XXXII.] TYPHOID FEVEE. 501 
 
 ward survey, at least, to distinguish the body of a man dead of 
 typhoid fever from that of a man killed by many another septic 
 poison ; take away the body but leave the intestine, by the marks 
 upon it death from this fever is at once distinguished from death from 
 every other cause." The greatest interest is in those cases which 
 have died at a sufiSciently early istage to show the commencement of 
 the process. Death so rarely takes place before the end of the second 
 or third week of the fever that there have been comparatively few 
 opportunities of investigating this stage. An exquisite example is 
 however figured in Dr. Budd's work of the appearance of the intes- 
 tine probable before the seventh day (see Plate V., Fig. 1, which 
 has been produced from the original drawing) ; in this the ileum 
 presents its mucous membrane covered with raised roundish bodies 
 so strikingly like an eruption, that Dr. Budd considered it analogous 
 to an internal exanthem. More particularly in the earliest stage 
 which has been witnessed a certain number of Beyer's patches, or 
 of the isolated follicles, as the case may be, acquire a considerable 
 increase of thickness, and stand out in relief on the internal sur- 
 face of the gut. Chomel says that the intestine feels as if a solid 
 and elastic substance had been inserted between the coats. On 
 cutting through a patch thus affected a cheesy yellow substance 
 exudes. The mucous membrane at this stage may be perfectly 
 healthy, exhibiting no traces of ulceration. In a case in which 
 Meyer ' had an opportunity of observing the post-moriem appearances 
 on the second day of the illness there was found simply swelling 
 of the solitary follicles and Beyer's patches, without the slightest 
 sign of ulceration ; the mesenteric glands were not swollen. In this 
 perfectly recent case a microscopical examination revealed an ex- 
 traordinary number of Eberth's bacillus in the cells in the sub- 
 mucosa and between the muscular layers or coats of the intestine. 
 The second stage is that of ulceration. This commences in two ways ; 
 to the one the French observers have given the name oi plaques molles, 
 to the othev plaques dures. In the first the mucous membrane be- 
 comes softened, and one or more superficial abrasions appear on 
 the surface of the diseased patch, extending and uniting to one 
 large ulcer which proceeds at various depths through the bowel 
 coats and may go on to perforation. In the case of the more 
 common plaques dures the mucous membrane and sub-mucous 
 ^ Mittheihingen wus dem Kais&rliohen Gesundheitsamtc. 
 
502 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 tissue become detached in the form of a slough, leaving behind an 
 ulcer. See for example Plate IV. {a), which has been drawn from 
 a preparation in the Museum of the Koyal College of Surgeons 
 (No. in Catalogue, 2499). It is a portion of the ileum injected 
 and everted. The large ulcer occupies the site of one of Peyer's 
 patches. There are also several smaller circular ulcers formed 
 by ulceration of the solitaiy glands. The time of the ulceration 
 is so variable that no inference as to the age of the disease can 
 be drawn from its presence. Ulcers have been met with as early 
 as the second day, Louis, Hoffman, Murchison, Chomel, each record 
 a case in which ulceration had not commenced on the twelfth 
 day, in the majority of cases however ulceration will be found 
 after the tenth day. The next stage is the separation of the 
 sloughs and the cicatrization, a kind of interim period within 
 which death often takes place. Seen at this stage Murchison 
 gives the following characteristic marks by which the ulcers are 
 to be distinguished from other ulcers. 
 
 (1) They have their seat in the lower third of the small in- 
 testine, and their number and size increase towards the ileocascal 
 valve. 
 
 (2) They vary in diameter from a line to an inch and a half. 
 Close to the caecum a number of ulcers often unite to form a mass 
 of ulceration several inches in extent. 
 
 (3) Their form is elliptical, circular, or irregular ; they are ellip- 
 tical when they correspond to an entire Peyer's patch ; circular 
 when they correspond to a solitary gland ; and irregular when they 
 con-espond to a portion of a Peyer's patch, or when several unite 
 to form one. 
 
 (4) The elliptical ulcers are always opposite to the attachment of 
 the mesentery. They do not form a zone encircling the gut (as 
 may be observed in the tubercular ulcer), but their long diameter 
 corresponds to its longitudinal axis. An elongated ulcer, however, 
 running transversely may result from the confluence .of several 
 ulcers originating in the solitary glands, especially in the larger 
 bowel. See Plate V., Fig. 2, and Plate IV". (a). 
 
 (5) Their margin is formed by a well-defined fringe of mucous 
 membrane detached from the submucous tissue, a line or more 
 in width and of a purple or slaty blue colour : this is best seen 
 when the bowel is floated in water. After the separation of 
 
XXXII.] TYPHOID FEVBE. 503 
 
 the sloughs, there is no thickening or induration of the edge as in 
 the tubercular ulcer. 
 
 (6) Their base is formed by a layer of submucous tissue, by the 
 muscular coat or by the peritoneum. There is no deposit of morbid 
 tissue at the base of the ulcer, although sometimes fragments of the 
 yellow sloughs may be seen adhering both to the base and edges. 
 
 The last stage is cicatrization. Usually in the fourth week the 
 alcers nearest the caecum commence to cicatrize and the rest 
 gradually follow, but they may become chronic, and then the con- 
 valescence is much delayed. The cicatrices are slightly depressed, 
 less vascular, smoother, and the intestine is at that spot thinner 
 than elsewhere. According to Chomel all traces of the ulcer in a 
 short time disappear. The mesenteric glands are always en- 
 larged, save perhaps at the very first commencement of the disease 
 as in Meyer's case, and they become infiltrated with the same 
 yellow matter as the glands of the bowels, the spleen is invariably 
 enlarged, the liver and kidneys occasionally hypersemic. 
 
 (373) Diagnosis of Typhoid. 
 
 There may be difficulty in the diagnosis of typhoid during life, 
 there can be none after death ; the essential anatomical signs in 
 the intestines, aided by a bacteriological examination of the spleen 
 will in all cases give reliable results. It should also be noted that 
 Gaffky found that in a case where he failed to demonstrate in the 
 spleen micro-organisms, yet the bacillus could be raised by cultivat- 
 ing small portions of the tissue. 
 
 During life typhoid has been confounded with typhus, remittent 
 fever, pysemia, influenza and various forms of tuberculosis, all of 
 which occasionally closely simulate typhoid fever, besides which 
 trichinosis has been mistaken for typhoid. Cases of the above have 
 puzzled physicians of great experience, but as a rule, provided 
 accurate thermometric observations are taken for a few days and 
 the patient closely watched, the diagnosis of typhoid presents no 
 difficulty. 
 
 (374) Theory of the Propagation of the Disease. 
 
 The modern theory is that the specific microbe, which according 
 to Koch, Eberth, and Gaffky, is a bacillus,, forms within the body 
 
504 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 spores, and these spore-holding bacilli are expelled in myriads with 
 the stools ; like all spore-bearing micro-organisms they are very 
 resistant, and may be preserved for an unknown long period. The 
 stools infect drains, cesspits, sewers, or the soil itself; if the ex- 
 cretal matter obtain access to food of any kind there is a liability 
 to infect those taking such food ; water of course may also be 
 infected either directly or indirectly from the spring passing through 
 already polluted earth. There can be no typhoid without the 
 bacillus, but on the other hand we have no evidence to prove that 
 the spore-holding bacillus must have passed through the intestine 
 of a man before it infects a second ; on the contrary, there is every 
 probability that it has something of the same history as the bacillus 
 anthracis, and that it can under appropriate conditions thrive as 
 easily as it does in the incubator of the bacteriologist. 
 
 Enteric fever has many a time attacked the traveller in tracts 
 of country in the tropics which are not known to be inhabited, and 
 in numbers of cases in this country the most exhaustive inquiry 
 has failed to show traces of a pre-existent case. Typhoid fever 
 does not arise de novo, for no cunning concoction of filth aided by 
 warmth and moisture will create an Eberth's bacillus, the bacillus 
 has sprung from some pre-existent colony, that colony from a pre- 
 vious one, and so on : but to say that an infective colony must 
 have descended from micro-organisms flourishing in a human body 
 is going beyond existing evidence, the balance of which points in 
 the other direction. The most reasonable theory is that the cause 
 of typhoid is a vegetable parasite capable of having an independent 
 existence and propagating its kind, and completing its cycle of 
 existence quite independent of the body ; probably its normal 
 existence is that of a saprophyte. Hence its endemic prevalence 
 in certain parts, hence the impossibility of always tracing typhoid 
 from one person to another, and hence the mysterious isolated out- 
 breaks which from time to time occur. 
 
 (375) The Ground Water Theory. 
 
 Pettenkofer has laid great stress on the connection with the 
 height of the ground water and the prevalence of typhoid. It is 
 true that when typhoid- most prevails the ground water is sinking 
 or at its lowest, and when typhoid least prevails the ground water 
 
XXXII.] TYPHOID FEVEE. 505 
 
 is rising or at its highest, but this may possibly be explained by 
 the fact that in the one case the springs are more dilute and con- 
 tain in a given bulk the least impurity, so that presuming a specific 
 infection when the ground water is highest the infective colonies 
 will be farther apart than in autumn, when the springs are low and 
 any impurity concentrated. Whatever the explanation the fact 
 remains, which whether essential or merely coincident, is too con- 
 stant for the student to neglect. 
 
 (376) Propagation of Typhoid. 
 
 Occasionally typhoid excreta may be dried and blown about in 
 dust, become breathed, and thus getting access to the mouth, be 
 swallowed with the saliva ; while admitting this as possible, there 
 is no instance on record, in which this mode of transmission has 
 been rendered more probable than other ways. The whole patho- 
 logy of the malady points to the cause gaining access to the 
 alimentary canal by drink or food. It is undoubtedly in some way 
 or other swallowed, the chief agent being water. That water 
 specifically polluted with typhoid excreta is liable to produce 
 typhoid, is so well established by a mass of evidence that only a 
 few examples need be cited. 
 
 The outbreak of typhoid described by Dr. W. Budd,^ in 1847, 
 may be referred to, at Richmond Terrace, Clifton, in which 
 the inhabitants of thirteen contiguous houses drinking a com- 
 mon polluted water supply were nearly all struck down at 
 the same time with typhoid. Other families in the terrace 
 under precisely the same conditions, but not drinking this par- 
 ticular water, escaped. There is again the particularly instructive 
 outbreak detailed by Mr. Spear,^ in the Mountain Ash district, in 
 which a portion of the water mains were found to be carried 
 through an excessively foul sewage deposit, and the main being 
 leaky, at times actually drew sewage matter into the pipes. The 
 typhoid area in Mountain Ash strikingly coincided with the distri- 
 bution of water by the particular branches supplied by this portion 
 of the main, whereas the other portions of the village supplied with 
 
 ' Op. cit. 
 
 2 Publie Health, vol. i. p. 183 ; L. G. B. Med. Off. Rep. 1887. 
 
506 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 the same water, but unpolluted, escaped.^ There is also the remark- 
 able outbreak detailed by Gaffky,^ which will always hold a place 
 in the literature of this disease, on account of the great minuteness 
 and thoroughness with which the epidemic was investigated. The 
 outbreak occurred in the summer of 1882 in the garrison at 
 Wittenberg. It was practically confined to those who drank from 
 a particular well, which well was polluted by a neighbouring cess- 
 pool. Into this cesspool in March and also in May the dejections of 
 two isolated and successive cases of typhoid for several days had 
 been cast ; there followed in June and July no less than ninety cases. 
 The interesting part of the history is that others drinking a 
 spring not very far away, but considerably polluted, although not by 
 this particular cesspit, did not suffer from typhoid. Gaffky was 
 able to disprove infection carried by the atmosphere, or by the 
 food, the specifically polluted water could alone be inculpated. 
 Such cases as the foregoing, and they might be multiplied by 
 some hundreds, are in the light of exact experiment, two neigh- 
 bouring communities taking exactly the same food, the same 
 milk supply, and breathing the same atmosphere, but differing 
 in this one thing, that the one drink a specifically polluted water- 
 supply, the other a water-supply which may be pure or impure, 
 but is not specifically polluted ; the one " the control," do not 
 suffer from typhoid, the others are attacked. 
 
 Among epidemics of enteric fever which are particularly in- 
 structive is the one at Bangor in 1882, which was investigated by 
 Dr. Barry.* The epidemic caused 548 cases of sickness, and 42 
 deaths. There was strong circumstantial evidence that the public 
 water supply had on a particular occasion become polluted by river 
 water flowing over the filter beds and carrying with it the accu- 
 mulated dirt from the filtering surface, and also excrements which 
 had been discharged into the river ; some of these there was reason 
 for believing were discharges from certain enteric fever cases. As 
 another instance of the propagation of enteric fever by a public 
 water supply, reference may be made to the Hitchin outbreak in 
 1883, which was investigated by Mr. H. Power.* Here the water 
 
 ^ Precisely the same kind of infection oooiirred recently in Alma Square, St. 
 Marylebone. The epidemic is described by the author in the St. Manjlebone Sanitary 
 Chronicles, February, 1890. 
 
 2 Mittheilungen aus dem, Kaiserlichen Geswndheitsamte. Berlin, 1884. 
 
 3 L. a. B. Med. Off. Rep. for 1882. * Ibid. 1883. 
 
xxxn.J TYPHOID FEVEE. 507 
 
 ■was contaminated in various ways, but especially from an overflow 
 pipe at the water works which permitted the occasional reflux of 
 the water of the much polluted river Hiz into the tank.^ 
 
 There are also instances in which the infection has been con- 
 veyed by milk, and in a few of these it has been demonstrated 
 that the cans have been washed or the milk adulterated with 
 polluted water. 
 
 (377) Prevention of Typhoid. 
 
 The doctrine is now firmly established that the infection is alone 
 carried in the discharges from the bowels, hence there is no danger 
 whatever in nursing cases of typhoid, nor in treating them at home, 
 always provided that the nursing is skilled and efficient, and this 
 cardinal fact is borne in mind. The motions themselves should 
 always be passed into a strong disinfectant ; and remembering that 
 the typhoid bacillus on expulsion from the body is in the spore 
 state, it is doubtful whether the sulphate of iron recommended by 
 Dr. W. Budd is sufficiently trustworthy, for after all, ferrous sul- 
 phate is not a disinfectant of the highest rank, and it is preferable 
 to use a 2 per cent, solution of corrosive sublimate, dissolved by 
 means of ammonium chloride in water; this should always be 
 placed in the bed-pan or receptacle, nor is it wise to cast im- 
 mediately the discharges thus disinfected into drains, cesspits or 
 sewers. All disinfection requires time, and at least two hours should 
 elapse before the dejecta are thrown away. A supply of the 
 usual weak corrosive sublimate solution 1 per 1,000 should be 
 kept for the nurses to wash their hands in, if soiled ; it is specially 
 necessaxy that the hands before meals should be washed in this 
 solution. It would naturally be far more efficacious to burn all 
 excreta by receiving it in sawdust and cremating it in a special 
 furnace, but this can only be done in hospitals or where special 
 facilities are at hand. All bed-linen and bedding soiled by dis- 
 charges should be thoroughly disinfected ; the linen may be boiled 
 
 ^ The student may also peruse with profit the following Reports : — Beport by 
 Mr. Power on an Outbreak of Fever at Norwood, L. G. B. Med. Off. Sep. for 1882 ; 
 Report by Dr. Blaxall on Enteric Fever at Sherborne, ibid. ; Report by Dr. Airy on 
 an Outbreak of Fever at Melton Mowbray, L. ff. B. Med. Off. Rep. /or 1881 ; Report 
 by Dr. Page on Enteric Fever at Beverley, L. G. B. Med. Off. Mep.for 1884 ; Report 
 by Mr. Shirley Murphy on the Outbreak of Enteric Fever at St. Albans. (In this 
 case there was good evidence of specific contamination of the milk supply. ) L. G. B. . 
 Med. Off. Bep. for 1884 . 
 
508 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 the bedding should go to the hot air or steam apparatus, and be 
 exposed at least four hours to a heat of 115° to 120° F. 
 
 In country villages, where typhoid breaks out again and again 
 every autumn, and no special sanitary defect is discovered, the 
 whole area of the soil is probably infected, and the only way to 
 deal with such places in the absence of obvious causes is, I believe, 
 to close existing water supplies, no matter how pure they may 
 seem to be, and to change them altogether, if this can be done. 
 How far in these cases the application round each household of a 
 powerful disinfectant to the soil itself, as well as to the drains may 
 be of service has yet to be proved. A constant series of cases 
 occurring regularly in the autumn among children, would point 
 to the probability of the soil itself being infected, for as is 
 well known children sit about on the ground, continually have 
 earth-soiled hands, and in this way contaminate their food. In 
 any case the presence or absence of typhoid in rural communities 
 is an excellent test of sanitation. If present, it is the duty of the 
 Medical Officer of Health to study very closely the water supply, 
 the sewerage disposal, and the earth contamination of the area, 
 and to remedy any defects which he may discover. 
 
 ASIATIC CHOLEEA. 
 
 (378) History of Cholera in England. 
 
 The first description of cholera is generally held to have been 
 given by Garcia del Huerto, a physician of Goa, about 1560. 
 As a disease attacking a number of people, and when introduced 
 into a community rapidly spreading, it is without doubt a modern 
 disease. Had it prevailed in ancient times, there would certainly 
 have been a record of its ravages. The date at which it appeared in 
 India is put at 1777, but at this time it was not generally diffused. 
 In 1817, cholera was more or less prevalent through the whole of 
 India, and from this date India may be considered the home of 
 cholera, and from this date onwards India has exported its cholera 
 infection at irregular intervals to Europe. 
 
 The history of cholera is complicated and confusing, and its 
 literature voluminous ; in this work written for English readers, 
 it will be best to confine the attention entirely to our own island. 
 
xsxii.] CHOLERA. 509 
 
 Cholera has visited England four times, the dates being 1831, 1849, 
 1854, 1866. In 1831 it first appeared in October; at that time 
 there was no registration of the causes of death, but the deaths of 
 52,547 persons from cholera were reported through various channels 
 to the Board of Health. The important practical observation was 
 made that cholera was usually preceded by preliminary diarrhoea ; 
 and house to house visitation with the early administration of medi- 
 cine, seemed to arrest the farther development of the disease in not 
 a few instances. 
 
 (379) E;pidemic of 1848-9. 
 
 In the ] 848-9 epidemic, the disease was studied by a number 
 of observers well qualified to trace out cause and effect. This 
 epidemic taught us to look closely on the water and the soil as 
 the chief factors that had to do with diffusion. For in- 
 stance, in London, the districts supplied with water taken from 
 the Thames above Battersea, had a mortality of 15 per 1,000 ; 
 districts supplied with water from the New River, the Lea, and 
 the Ravensboume, 48 per 1,000 ; districts supplied with Thames 
 water taken below Battersea Bi-idge (between Battersea a.nd 
 Waterloo Bridge), 123 per 1,000 ; in other words, the populations 
 drinking different portions of the same river, suffered from cholera 
 in proportion to its pollution, for it is scarcely necessary to observe 
 that the water of the Thames above Battersea was much 
 purer than below Battersea. Another discovery made in the 
 1849 epidemic with regard to London was the relationship ol 
 cholera mortality to elevation. Dr. Farre, writing his report of the 
 epidemic said, " The elevation of the soil in London has a more 
 constant relation with the mortality from cholera than any known 
 element. The mortality of the nineteen highest districts was at 
 the rate of 33 per 10,000, and of the nineteen lowest districts 100 
 in 10,000. The elevation in the two groups above the high- 
 water mark of the Thames was as 71 to 10 feet (7"1). While the 
 mortality was as 1"3 or in the inverse ratio . . . Cholera was ex- 
 cessively fatal in all the four districts which lie on a level with or 
 below the Trinity high-water mark ; it destroyed 144, 164, and 505 
 in 10,000 inhabitants. Notwithstanding the disturbance produced 
 by the operation of other causes, the mortality from cholera in 
 London bore a certain constant relation to the elevation of the 
 
510 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 soil, as is evident when the districts are arranged in the order of 
 their altitude. We place the districts together which are not on 
 an average 20 feet above the Thames, and find on these bottoms 
 of the London basin the mortality was at the average rate of 102 
 per 10,000 ; in the 2nd group at 20 and under 40 feet elevation, or 
 on the second terrace, the mortality from cholera was at the ra.te 
 of 65 in 10,000 ; in the 3rd group, or on the third terrace, 40-30 
 feet high, the mortality from cholera was at the rate of 34 in 
 10,000 ; in the 4th group 60-80 feet high, the mortality from 
 cholera was at the rate of 27 per 10,000 ; in the 5th group 80 to 
 100 feet high, the mortality was at the rate of 22 per 10,000 ; in 
 a district 100 feet high, the mortality was 17 per 10,000; in 
 Hampstead, about 350 feet high, it was 7 in 10,000." 
 
 The system of registration had been in force since 1837, hence 
 for the first time an accurate computation of the mortality was 
 made. According to the official returns 53,293 died of cholera and 
 18,887 of diarrhoja. 
 
 (380) Upidemic of 1854!. 
 
 In 1854, Sir Benjamin Hall was President of the Board of 
 Health ; he obtained the assistance of a medical council, aided by 
 others well versed in chemistry and microscopy. This medical 
 council or "scientific committee," studied more particularly and 
 closely the distribution of cholera in the metropolis, and the result 
 of their inquiries was summarised and expounded in a masterly 
 report by Mr. Simon. " As often," said Simon, " as Asiatic cholera 
 had been epidemic in London, it had been observed to prevail with 
 especial severity in certain registration-districts on the south side 
 of the river ; viz., in St. Saviour's, St. Olave's, and St. George's, 
 Southwark, in Bermondsey, Newington, Lambeth, Wandsworth, 
 Camberwell, and Rotherhithe." He next proceeds to show that 
 the conditions of these populations were precisely the same save 
 in the quality of the water consumed in different households. 
 " For throughout, those southern districts of London, two great 
 competing water companies had in past times canvassed house by 
 house for their customers ; their rival mains were still branching 
 in the same area, often running parallel in the same streets ; and 
 during the late invasion of cholera, these two systems of pipes 
 were respectively charged with very different waters. 
 
XXXII.] CHOLERA. 511 
 
 " If, during tte epidemic prevalence of cholera persons consuming 
 pure water are less liable to suffer the disease than persons consum- 
 ing foul water, surely there might be expected some striking differ- 
 ence between the death-rates of two populations respectively drinking 
 from the Thames at Ditton and from the Thames at Battersea. 
 
 "And such were the sources of supply of the two companies 
 referred to; the Lambeth Company pumping from the higher 
 part of the river, the Southwark and Vauxhall Company from 
 the lower; the former furnishing as good a water as any dis- 
 tributed in London, while the latter was purveying perhaps the 
 filthiest stuff ever drunk by a civilized community. . . In the 
 24,854 houses supplied by the Lambeth Company, comprising a 
 population of about 166,906 persons, there occurred 611 cholera 
 deaths, being at the rate of 37 to every 10,000 living. In the 
 39,726 houses supplied by the Southwark and VauxhaU Company, 
 comprising a population of about 208,171 persons, there occurred 
 3,476 deaths, being at the rate of 130 to every 10,000 living. 
 
 " The population drinking dirty water accordingly appears to have 
 suffered three times as much mortality as the population drinking 
 other water."^ 
 
 (381) The Broad Street Pum;p. 
 
 It was also in the epidemic of 1854 that the report of the water 
 supply of the Broad Street pump exercised much influence on 
 popular and scientific opinion. The water in the well, which was 
 undoubtedly contaminated with sewage, was said to have been 
 specifically polluted by the cholera excreta of a child who suffered 
 from cholera from August 28th to the 30th. The cases of sickness 
 and deaths among the consumers of this pump water are given as 
 follows : — 
 
 1854. 
 
 Attacks. 
 
 Deaths. 
 
 August 28. 
 
 . Child attacked. 
 
 
 29. . . . 
 
 . . . 1 
 
 ... 1 
 
 30. . . 
 
 8 
 
 . . 2 
 
 31. . 
 
 . . . 56 
 
 3 
 
 September 1. ... 
 
 . . 143 
 
 . . 70 
 
 2. . . . 
 
 . . . . 116 
 
 . . 127 
 
 3. . . . 
 
 54 . . 
 
 ... 76 
 
 4. . . . 
 
 . . . . 46 
 
 . . 71 
 
 5. . . 
 
 . . 36 
 
 ... 45 
 
 6. . . 
 
 .... 20 
 
 37 
 
 7. . . 
 
 . . . 28 
 
 ... 32 
 
 8. . 
 
 . . . . 12 
 
 30 
 
 1 Report oil Cholera Outbreak, St. James's, Westminster. 
 
512 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (382) Lessons Learnt from the 1849 and 1854 Ejaidemics. 
 
 The total advance in knowledge of the etiology of cholera 
 derived from the 1849 and 1854 epidemics may be summed up 
 in the words of Dr. Farre, " The final report of the scientific 
 committee proved conclusively the extensive influence of water 
 as a medium for the diffusion of the disease in its fatal forms. 
 The zymotic theory was established, and Dr. Snow's view that 
 the cholera stuff was distributed in all its activity through water 
 was confirmed." 
 
 (383) The Cholera of 1866. 
 
 In 1866 cholera was again epidemic in England. It had hovered 
 over Europe the previous year. In the autumn of that year, 
 indeed, a few victims of the disease iTad died in England, and it 
 had been imported into Portsmouth and Southampton. "At 
 Epping in Essex, the Groombridge family, the medical attendant, 
 and a woman who laid out their servant, were killed by cholera 
 in the last days of September and the first days of October." 
 Nevertheless, it was not until July, 1866, that the disease burst in 
 a limited part of the metropolis. Beginning on July 11th, it 
 reached its maximum severity on July 31st, and then its intensity 
 declined ; the number of deaths registered in London from 
 cholera was 6,973, from diarrhcsa 3,197, and the total number 
 of deaths from cholera in England was 14,378 (1,842 per million), 
 and 17,170 from diarrhoea (1,036 per million). This epidemic 
 was studied with the greatest care by Radcliffe, Parkes, and a 
 number of other well qualified observers, and the reports of Dr. 
 Farre, of Sir John Simon, of Dr. Netten Radcliffe and others on 
 the medical staff of the Local Government Board, are some of 
 the most valuable which have ever appeared upon the subject 
 and will repay perusal. 
 
 (384) The East London Water Company and the Cholera of 
 
 London. 
 
 Dr. Radcliffe proved that the area of greatest cholera incidence 
 in London almost exactly coincided with the area supplied by the 
 East London Water Company. The map in which the districts are 
 
XXXII.] CHOLERA. 513 
 
 shaded according to cholera mortality, of the original report, is 
 very striking, and it would be difficult to convince any reasonable 
 person that so close a coincidence was due to chance ; still less so, 
 when the description of the condition of the water-works at that 
 time and other facts are known. 
 
 The East London Water Works drew their supply from the 
 river Lea, near Tottenham Mills, certainly not at that point a pure 
 stream, and below it nothing but a sewer receiving the sewage of 
 a large mass of the London population. After depositing in sub- 
 sidence beds, the water went to a series of filtering beds at Lea 
 Bridge, and from Lea Bridge the water was led by a closed iron 
 conduit to two covered reservoirs on the west bank of the Lea at 
 Old Ford. On the opposite bank were two immense reservoirs, 
 the water of which was when required for use sent along an open 
 foul conduit to the filtering beds at Lea Bridge, but it was possible 
 to turn the water unfiltered from the northern uncovered reservoir 
 into the service covered reservoirs. A careful examination also 
 proved that all these reservoirs were liable to soakage from the 
 filthy waters of the Lea. The engineer of the Company confessed 
 that at the close of June, or at the beginning of July, unfiltered water 
 was drawn from the northern uncovered reservoir into the covered 
 reservoir to the depth of three inches to supplement a defective 
 supply from the filter beds. It was also proved that the first 
 known cases occurring, in one household June 12th, in another 
 June 26th, got rid of their cholera dejecta undisinfected into 
 drains which went direct into the Lea a little way above the 
 reservoirs. In other words, there was direct evidence of the Lea 
 having been placed under conditions of specific contamination, 
 that this river water could gain access by soakage into the 
 reservoirs, and that one of the reservoirs containing unfiltered Lea 
 water had communicated with the covered service reservoir, and 
 that this water had been drunk by a large population. 
 
 It is true there were outbreaks in the same area which did not 
 fit in with this theory, but with regard to these there were possi- 
 bilities of infection by contact with the discharges of patients 
 either immediately or otherwise, or there was a more or less 
 plausible explanation. On the whole, the water carriage theory 
 was held at that time and is still held to sufficiently explain the 
 epidemic of cholera in 1866 so far as the Metropolis is con- 
 
 L L 
 
514 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 cerned. This belief was strengthened by the strictly parallel 
 case of Newcastle-on-Tyne. The ordinary death-toll in that 
 city was 11 daily from all causes, but in the height of the cholera 
 epidemic, people were dying from cholera alone at the rate of 
 from 100 to 146 per day. The Tyne Company, running short of 
 water, had pumped in the sewage laden river, polluting their purer 
 supply. The colour of the water is said to have resembled porter. 
 On stopping the drinking of this liquid, and substituting a proper 
 supply, the cholera was stayed. 
 
 (385) The Relation of Altitude to Cholera Mortality. 
 
 The mathematical relation of altitude of cholera mortality had 
 been deduced by Dr. Farr from the lessons of the epidemic, both 
 of 1849 and 1854, in the following terse rule : — " The mortality of 
 cholera is inversely as the elevation of th^ people assailed above the sea 
 level," but the deviation from Farr's rule in the 1866 epidemic 
 was very wide if applied to the whole metropolis. The mortality 
 from cholera in the lowest lying districts (under three feet above 
 high water mark) was less than in districts at an elevation of from 
 3 to 10 feet; the greatest mortality occurred at an altitude of 
 from 10 to 20 feet ; the next greatest at from 20 to 40 feet ; and 
 the number following in order after this at from 40 to 60 feet." 
 Although the rule did not hold good when applied to the whole 
 Metropolis, it did so in the most affected locality. The numbers 
 in the East and North-East districts being 107, 89, 88, 76, 17, 4, 
 from the lowest elevation up to 60 to 80 feet. Mr. Radcliffe re- 
 marked upon this that " it would seem as if a certain degree of 
 intensity of prevalence of cholera in the metropolis is requisite 
 before the mortality follows the law as to elevation unfolded by 
 Dr. Farr." 
 
 (386) Mwtality of Cholera in Relation to Age and Sex. 
 
 According to Farr, the mean mortality in the last three 
 English epidemics was of males 18-0, of females 17'8 to 10,000 
 living of all ages. 
 
 " The mean mortality from all causes in the three cholera years 
 was, for males, 19'3 in excess, for females, 17'9 in excess of the 
 
XXXII.] CHOLERA. 515 
 
 average mortality to 10,000 living ; so females suffered less tlian 
 males. 
 
 The mortality is higher in boys than in girls at all the ages 
 under 15 ; at the ages of reproduction, 25 — 45, the mortality of 
 women, many of them pregnant, exceeds the mortality of men ; 
 but at the ages after 65 the mortality of men exceeds the mortality 
 of women. 
 
 There is evidently a law of mortality involved in the age in- 
 dependently of sex; thus in the three first lustres of life the 
 deaths of boys to 10,000 living were 31-8, 13-2 and 7-6; of girls 
 28'4, 12'6, 6'4 ; and the mean mortalities of the two sexes at the 
 same ages were 30-1, 12'9, and 70, which differ little from the 
 series 30"1. 14'5, and 7"0, where the numbers are obtained by 
 assuming that the mortality is inversely as the age, and decreases 
 about 14 per cent, for every year of age, or is less than half at 
 5-10, and less than a fourth at 10-15, what it was in the first 
 five years of life. 
 
 After the age of puberty, or from the age of 15 to 25, the 
 mortality also increases very little ; it is 8*1 for males and 7'8 
 for females; and at the six decennial ages extending from 25 to 
 85, the mortality increases from 15'4 to 43'6, at a very constant 
 rate, as is seen on comparing the calculated series with that 
 observed in both sexes.-*^ 
 
 The Deaths Obseeved in Thebb Epidemics by Choleea to 10,000 Living 
 
 AT BACH Age. 
 
 Aces, Men. Women. 
 
 25—35 . 
 
 . 15-2 . 
 
 . 15-6 
 
 35—45 . 
 
 . 19-5 . 
 
 . 20-2 
 
 45—55 . 
 
 . 23-5 . 
 
 . 23-1 
 
 55—65 . 
 
 . 28-4 . 
 
 . 31-4 
 
 65—75 . 
 
 . 35-9 . 
 
 . 35-4 
 
 75—85 . 
 
 . 42-2 . 
 
 . . 44-9 
 
 85—95 
 
 . 46-0 . 
 
 . 41-4 
 
 95 and up 
 
 . 82-4 . 
 
 , . . 82-8 
 
 
 series. 
 
 . 15-4 . 
 
 15-4 
 
 . 19-8 . 
 
 19-0 
 
 . 23-3 . 
 
 23-4 
 
 . 29-9 . 
 
 . 28-9 
 
 35-7 
 
 . 35-7 
 
 43-6 
 
 . 44-0 
 
 .43-7 
 
 . 54-0 
 
 57-6 . 
 
 . 67-0 
 
 ' Let mx = mortality by cholera at age x, then r'^x = Mx+n = mortality at 
 age X + n. In the series given the logarithm of r is taken as 1 '93665. This applies 
 only to the ages under 15. At the ages from 25 to 85, and even upwards, the loga- 
 rithm of »• is 0-00911. 
 
 r = (^ll^f= C?l™) = r0212 
 
 and logarithm r = 0-00911. 
 
 L L 2 
 
516 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Thus to 10,000 men living of the age of 25 and under 35 the 
 deaths by cholera and choleraic diarrhcea, as above defined, were 
 15"2; to 10,000 women the deaths were 15'6; and the mean mor- 
 tality of the two sexes in equal numbers is expressed by 15'4. The 
 mean deaths by cholera at the next age (35-45) were 19'8 to 
 10,000 living, and so on. The calculated series approximates very 
 closely to the observed facts : it is a series in geometrical pro- 
 gression and may be conceived as representing this principle that 
 human life loses the power of resisting the zymotic life of the- 
 cholera epidemic year by year after the age of puberty, or what is 
 equivalent, that the lethal power of the epidemic on the organism 
 increases at the rate of 2'12 per cent. Thus for instance, 1,000,000 
 persons of the age of 30 are exposed to cholera, and 1,540 of them 
 die ; then of the same number of the age 31 exposed to the same 
 epidemic under exactly the same circumstances 1,573 will die, and 
 to 1,000,000 persons of one year of age older, or age 32, the deaths 
 will be 1,606. So some force is taken away from the organism 
 every year of life, every second we may conceive, by which its 
 constituents become less able to resist the action of the cholera 
 leaven. And the diminution of resisting force obeys a law which 
 is of this nature ; the loss is an accumulating quantity, and in the 
 end becomes so great as to leave the life at the mercy of other 
 forms of life or of other forces. 
 
 Thus the mortality at one age being given, the mortality at any 
 other age within certain limits can be calculated.^ 
 
 (387) Syin;pto'nis. 
 
 Cholera has without doubt a period of incubation, but the 
 difficulty in knowing when the infection first occurred in but a 
 comparatively small number of cases has caused this period to be 
 variously estimated by different writers. The most probable state- 
 ment is that of Niemeyer, who fixed it at not less than thirty-six 
 hours and not more than three days.^ The symptoms of cholera 
 vary according to severity, the most severe of all killing at once 
 without intestinal discharge — the so-called " cholera sicca " ; a less 
 
 1 mgo = ?-3»m3„ = 28-89 15-40r3» = 15-40 x (1-0212)3<'. By logarithms 
 A.15-40 + SOXr = Km^o = A28-89. 
 
 2 Farr, Report on the Cholera Epidemic in England, Supplement to Twenty-ninih 
 Annual Report of the Registrar-General. London, 1868. 
 
XXXII.J CHOLEEA. 617 
 
 severe form but yet one in which the symptoms are of the most 
 serious character and a mild form. 
 
 There have been many descriptions of the clinical aspects of 
 cholera, but for our purpose the report of Dr. Sutton ^ on the 
 characters of cholera in 1860 will suffice, the more so, as the 
 symptoms of 250 cases were very carefully analyzed, and all these 
 cases occurred in England. Sutton's description is therefore that 
 of Asiatic cholera as seen when imported into England. 
 
 In the one case of cholera sicca described by Sutton, the history 
 was shortly as foUows : A man about 40 to 50 years of age, was 
 seen walking in the public street ; he suddenly cried out, put his 
 hand to his belly and fell down. He was conveyed to the hospital 
 without loss of time but died on the way. 
 
 The organs were generally healthy. But the duodenum was 
 full of an opaque pale canary-coloured liquid ; on following the 
 intestine down the fluid got thinner, until when the ileum was reached 
 it had all the characters of the so-called rice-water discharges. 
 The small intestine was full of fluid. In the large intestine was a 
 large quantity of semi-solid and solid faeces. 
 
 In other words in cholera sicca the person seems to faint to death 
 without previous diarrhoea or other symptoms, and the only 
 evidence of the cause of death being cholera is the state of the 
 intestines. 
 
 Preliminary Diarrhoea. — In a good many cases of cholera there 
 is what has been called " preliminary diarrhoea." Of 41 cases in 
 which diarrhoea preceded the choleraic symptoms, in 12 the 
 diarrhoea had been present from periods varying from 12 hours to 
 24. In 13 the diarrhoea had preceded from 33 hours to 2 days ; in 
 the rest the periods were from 3 days up to 8 weeks. It is highly 
 improbable that the longer periods (anything indeed over 3 days) 
 had a direct connection with true cholera ; cases in which diarrhoea, 
 for instance, preceded the cholera symptoms for several weeks must 
 have been ordinary diarrhoea on which the cholera grafted itself ; 
 it is reasonable to suppose that in cholera epidemics persons with 
 disordered intestines are more likely to be infected than those who 
 are in health ; it is even a question whether even the shorter 
 periods all belong to cholera. This supposition also affords a 
 plausible explanation of the undoubted good that the early treat- 
 1 Ninth Eeport of the Medical Officer of the Privy Gouneil. 
 
518 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 ment of so-called preliminary diarrhoea does in the prevention of 
 cholera extension. It may well be that a congested intestine 
 affords the best soil for the cause of cholera, and by curing the 
 congestion, the healthier secretions are able to destroy any con- 
 tagium which may be swallowed. 
 
 The symptoms more particularly referable to cholera usually 
 commence with great suddenness and are generally divided into a 
 cold and a hot stage ; the cold stage being that in which there is 
 more or less collapse. The hot stage is the stage in which reaction 
 sets in. The average duration of the cold stage in Sutton's cases 
 was from 20 to 80 hours. The disease commences with frequent 
 vomiting and violent purging, and the poison elaborated in the 
 intestines is conveyed by the circulation throughout the muscular 
 system, and fearful cramps and spasms result. The cold stage 
 fully established, the eyes are sunken, the lips vivid, the tongue 
 blanched, and the pulse may with difficulty be felt at the wrist. 
 The voice is a whisper, but intelligence remains. The temperature 
 (external) is always below normal, falling rapidly from 5 to 7 
 degrees below the standard, and in the reaction the temperature 
 then is with few exceptions either normal or a little above. It 
 hence follows that the so-called hot stage, is only a stage in which 
 the surface temperature of the body is again approximately that of 
 health, the term is a bad one, suggesting fever which does not 
 exist. From first to last cholera is a depressor of vital function ; 
 but when the maximum temperature during the whole time is 
 steadily below normal, such cases are likely to be fatal. The 
 cold stage passes rapidly either to death or recovery. If the 
 latter, either the patient sinks into a quiet sleep, or the count- 
 enance begins to look more natural, the pulse more perceptible, 
 the skin warmer, the cramps and sickness with the purging 
 stop, and gradually the functions are again resumed. 
 
 (388) Post-mortem Appearances. 
 
 The post-mortem appearances of cholera are seen in then* 
 most characteristic form in rapid cases which have died during 
 the cold stage. The chief signs of cholera are to be found in the 
 condition of the lungs and intestines. The ultimate tissue of the 
 lungs is remarkably dry and light; the lungs weigh less than 
 
XXXII.] CHOLERA. 519 
 
 normal, the right side of the heart is gorged with blood, and of 
 course the vena cava, and the pulmonary arteries are also dis- 
 tended, the left or systemic side and the aorta and its branches 
 are on the contrary comparatively empty. 
 
 The mucous membrane of the ileum, especially that of the 
 lower part, is congested ; there is loosening and detachment of 
 the epithelium of the surface and of that lining the glands of 
 Lieberkiihn. There is a special congestion around Peyer's lymph 
 glands. These alterations according to Koch are the effect of 
 the comma bacillus which secretes a special chemical ferment. 
 The changes are most pronounced in the lower part of the ileum, 
 higher up the changes diminish in intensity and finally disappear 
 in the upper part of the small intestine. 
 
 (389) Bacteriology of Asiatic Cholera. 
 
 In 1848 Pacini had described " vibrios " in the intestinal dis- 
 charges of cholera patients. Klob also, in 1867, appears to have 
 laid great stress on certain small organisms that he described, but 
 whether these minute bodies described by Pacini and by Klob were 
 identical with the comma bacillus of Koch is uncertain; the 
 microscopes of that time were inferior in definition and in power 
 to those now used, and the knowledge of bacteria of the crudest ; 
 however this may be, and whether the organisms described by 
 Koch, have been previously discovered or not, to Koch and the 
 German cholera commission belong the entire credit of discovering 
 that a particular micro-organism is always associated with Asiatic 
 cholera, and with no other disease. This discovery was the out- 
 come of the work done by the commission in the years 1883-4 
 in their extensive inquiry into cholera in Egypt, Calcutta, and 
 France. 
 
 During the acute stage of cholera there are to be found in the 
 rice water discharges minute bodies, which Koch calls, on account 
 of their shape, " comma bacilli ; " these by some are regarded as a 
 spirillum {spirillum cholerce Asiaticce), by others as vibrios. In 
 size they are of the same thickness as the tubercle bacillus but 
 only half their length ; they present the appearance of little curved 
 rods, and so far resemble a comma that the latter is a good name. 
 They are actively motile and liquefy the gelatin as most of the 
 
520 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 moving micro-organisms do. The commas multiply by transverse 
 division and after division -the two offsprings may remain joined 
 end to end in the shape of an S; ^^^ by further division they may 
 grow into a spiral or wavy form. " It grows in and liquefies slightly 
 alkaline gelatin ; more slowly in neutral, scarcely at all in slightly 
 and not at all in markedly acid gelatin. On a gelatin plate cultiva- 
 tion the individual colonies are round, lie in a funnel-shaped cavity, 
 when viewed by transmitted light and magnified, they look like 
 ground glass ; the edge of the colony is finely notched. In a 
 gelatin tube a funnel-shaped cavity forms at the top of the punc- 
 ture made by the inoculating wire and lying in this cavity there is 
 what looks like an inverted air bubble, with its top on a level with 
 the surface of the jelly, and open to the air, along the puncture the 
 gelatin liquefies, and in this may be seen with the naked eye the 
 whitish mass of colonies more particularly at the lowest part ; in 
 from three to four weeks liquefaction spreads to the whole mass, 
 the bacilli falling to the bottom as a greyish white sediment having 
 a faint orange tint in certain lights, and if undisturbed, a perfectly 
 transparent liquid separates a whitish scum on the top from the 
 sediment below."^ In gelatin cultures growth is most rapid at from 
 80° to 100° Fahr. ; it grows slowly at 60°, and even at 50°, but below 
 60° it does not grow ; it is not destroyed at a freezing temperature. 
 If kept moist it will live for months ; drying always destroys it,^ 
 for hitherto no spore or resisting forms have been discovered. 
 Milles and Macleod have, it is true, seen an appearance like endo- 
 spores, and such bacilli bore forty-eight hours drying and yet 
 recovered, but with longer drying death of the commas always 
 resulted. In the absence of air, growth on gelatin ceases. The 
 " commas " also grow well on agar-agar, on mucus flakes taken from 
 the intestine, on potato, and in broth. 
 
 The opponents of the theory of the part which Koch and the 
 German school assign to the comma spirillum in relation to cholera 
 
 ^ An Enquiry into the Causatioil of Asiatic Cholera, by Neil Macleod, M.D., and 
 Walter J. Milles, P.R.C.S., Fublic Health, vol. i. p. 322. 
 
 2 In Berekholtz's elaborate research {ArbeiUn aus dem Kaserl. GesujidheUsamte. 
 Bd. V. 1) on the effect of drying the cholera bacillus, he found cultures containing 
 exclusively commas and S forms somewhat more resistant than cultures which con- 
 tained no S forms. He considers it very probable that in natiu'e the slimy mass of 
 a culture may form a sort of protective capsule, and thus prevent the full drying 
 and preserve the life of some of the commas. This he deduces from the different 
 behaviour of the bacillus when dried on silk threads and on glass. 
 
XXXII.] CHOLERA. 521 
 
 make the most of tlie easy destructibility of this micro-organism ; 
 not alone does drying destroy, but it falls a victim to feeble disin- 
 fectants, and, as before mentioned, even the acids of the guinea- 
 pig's stomach effectually dissolve it. Surgeon-Major Cunningham ^ 
 has shown that when cultivations of commas are added to water or 
 to soil, the schizomytes attack the commas, and they tend to rapidly 
 disappear. For example, Cunningham added to a pretty good 
 drinking water cultivations of the comma bacillus ; in one experi- 
 ment none were found at the end of four days, in another all had 
 disappeared at the end of five days. In yet another series of 
 experiments excreta-polluted water was used, and all commas disap- 
 peared in a period varying from four to nine days, but when the 
 water had been previously boiled the commas added could be found 
 up to the twenty-fifth day.^ In ordinary garden soil the commas 
 could be discovered from ten to twenty-six days after contamination. 
 Garden soil previously polluted with faeces and then contaminated 
 with commas, was more destructive, and the commas were not found 
 in periods from six to nine days, a few afterwards, but if the same 
 garden soil polluted with excrement was first sterilized by heat 
 and then the comma cultivations added they were still present 
 after forty-seven days. Kitasayo^ also found that ordinary fresh 
 unsterilized faeces infected with the bacillus retain but for a short 
 time living comma bacilli, but if the fseces are sterilized by steam 
 or other means, the destruction is far less. 
 
 In other words, under ordinary conditions the agency of 
 destruction is so powerful that it would seem impossible, if the 
 cause is the comma spirillum cholerae, for cholera to be truly en- 
 demic in a country. Dejections cast into soil or water fall a prey to 
 other micro-organisms, and contrary to the teachings of so many 
 observers, Cunrdngham's experiments would tend to prove that the 
 fouler the soil, the more chance of inimical schizomytes. 
 
 But on the other hand, Nicati and Rietsch have shown that the 
 commas could live in the water at the port of Marseilles for 
 eighty-one days, and in the absence of other organisms the life of 
 
 ^ Scientific Memoirs by the Medical Officers of fhc Army of India. Edited by Sir 
 Benj. Simpson. Part iv. 1889. 
 
 2 Macnamara arrived at very similar conclusions. He considered water polluted 
 witli cholera excreta ceased to become dangerous when after successive generations 
 of animalcules, confervse appeared ; this in India happened about the third day. 
 
 3 Zeitsehrift f Eygiene. Bd. V. heft 3. 
 
522 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 the comma may, according to Koch, be prolonged for more than 
 144 days. It is a question whether the observations of Cunning- 
 ham are really so much against the comma bacillus as a cause of 
 endemic cholera as that observer appears to think, the life history 
 of the organism is not yet fully worked out, it is known to have 
 more than one form, and it has not yet been studied under all 
 possible conditions. 
 
 The observations of Ferd. Hueppe,^ recently published, show that 
 the "commas" when first expelled from the body, having de- 
 veloped under anaerobic conditions, are tender and easily destroyed, 
 but when exposed to air or oxygen they become more resistant 
 and act more energetically. The practical importance of these facts 
 relative to early disinfection is obvious. Hueppe at the same time 
 points out that this difference of vigour in the anaerobic and 
 aerobic condition satisfactorily explains the infrequency of direct 
 infection. 
 
 (390) Tlw Bacillus of Finhler and Prior. 
 
 A bacillus was discovered by Finkler and Prior ^ in cholera 
 nostra which bears a superficial resemblance to the spirillum of 
 cholera, but it may be readily distinguished by its method of 
 growth in gelatin, the comma bacillus, when inoculated by the stab 
 method shows at the end of twenty-four hours a white track along 
 the course of the stab ; on the other hand, under the same condi- 
 tions, the Finkler-Prior bacillus liquefies the gelatin much quicker, 
 and throughout the whole extent, while the comma only shows 
 a little liquefied well on the top exposed to the air. Hovorka and 
 F. Winkler,^ by using the albumen of plovers' eggs coagulated at 
 90° C. and sterilized by exposure to a heat of from 60° to 70° 
 for twenty minutes on three successive days have obtained a 
 culture medium by the aid of which they believe they have a 
 new distinction between the organisms mentioned. A stab culture 
 of Koch's bacillus in this medium soon shows a surrounding layer 
 which reflects light stronger than the rest of the albumen, and 
 hence appears clearer ; on observation with a lens are seen greyish 
 
 ^ Prdger mcd. Wochenschrifi, March 19, 1890. Public Health, vol. iii. p. 87. 
 2 Ergdnzungshifte zum Central./. Allgemeine OesuTidheitspflege. Bd. I. 1865. 
 2 Allgemeine Wiener med. Zeitung. XXXIV. Jahr. No. 23. Public Health, 
 vol. ii., \j. 114. 
 
XXXII.] CHOLERA. 523 
 
 crowds of colonies, which on the third day occupy the whole 
 breadth of the needle track. There is no real liquefaction although 
 there may be here and there incipient signs of it. The Finkler- 
 Prior baciUus shows a liquefaction around the colonies by the 
 second day. This becomes so decided that on the third day the 
 mass of the albumen is detached from the walls of the test 
 tube. By the sixth or seventh day the albumen is coloured yellow 
 ^the colour increases in depth until the whole is changed into 
 yellow brown— then the albumen becomes again solid. It is this 
 rapid liquefaction, the yellow colour and subsequent " setting " 
 again of the albumen which forms the distinguishing mark be- 
 tween the two micro-organisms, 
 
 (391) The Becogniiimi of the Comma Bacillus hy Chemical Tests. 
 
 Chemical tests have also been proposed for the recognition of 
 the comma bacillus. Otto Bujwid^ states that when the cholera 
 comma colonies have grown to white points, and beef broth is 
 inoculated with one of them and cultivated for twelve hours at 37° 
 C. the liquid takes a rose colour on the addition of hydrochloric 
 acid. M. J. R. Petrin ^ has also shown that the comma bacillus 
 reduces nitrates to nitrites ; but these chemical effects can only be 
 used practically when further research has shown that they are 
 peculiar to this bacillus ; in the meantime they must be considered 
 as only confirmatory of the other characters. There is a spirillum 
 {spirillum sputigenum) to be found in saliva and carious teeth, 
 which is morphologically similar to Koch's bacillus, but it is diffi- 
 cult to cultivate, and is apparently a distinct form ; there is also 
 another spirillum which is something like Koch's commas which 
 has been isolated from cheese ; this spirillum is smaller than the 
 cholera spirillum and has a different method of growth. 
 
 (392) Klein's Objections to the " Comma " Theory. 
 
 It remains to be added that Klein ^ has criticized the comma 
 theory, and has also repeated Koch's experiments without confirm- 
 ing them. One of the arguments against Koch's theory, according 
 
 1 Zeitschrift f. analytisohe Chemie, vol. xxvi. j Public HeaWi, vol. i. p. 93. 
 ^ Centralblatt f. Bakteriol in Parasitenkunde. Bd. V. 18 ; Public JJcalih, vol. ii , 
 p. 56. 
 
 "^ Fifteenth Annual Beport of the Local Government Board. Svpplement, 1886. 
 
524 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 to Klein, is that in all infectious diseases produced by a micro- 
 organism, the micro-organism is found in the blood or tissues ; this 
 no longer holds good, that is if the observations on diphtheria by 
 the French school and by Loeffler are correct ; in that disease a 
 micro-organism grows on and within the mucous tissue, is entirely 
 local, and yet affects profoundly the system. Klein views the comma 
 bacillus as accidental, probably being always present in small numbers 
 in the intestines, and then under favouring conditions multiplying ; 
 he acknowledges, however, the almost constant presence of the 
 commas in cases of true cholera. Neither the experiments nor the 
 arguments of Klein are sufficiently conclusive, and on the whole 
 the current of scientific opinion leans to the side of Koch. 
 
 (393) Experiments on the Communicability of Cholera before the Dis- 
 covery of the Comma Bacillus. 
 
 1. Injections of cholera blood into the veins. 
 
 In 1831 Magendie ^ injected an ounce of cholera blood into the 
 veins of a dog without effect. When eight ounces were employed 
 the dog became affected with cholera-like symptoms and died ; the 
 post-mortem appearances had some similitude to those found in 
 cholera. In 1836, a Venetian physician. Dr. Giacinto Namias, and 
 afterwards Semmola,^ inserted blood coagula taken from the hearts 
 of persons dead from cholera, beneath the skin of rabbits; the 
 effects as might be expected were uncertain and contradictory. 
 Marshall,* in 1849, made seven experiments with cholera blood. 
 He injected the blood into the veins of animals ; the effects pro- 
 duced were in every instance considered by the experimenter as 
 sufficiently explained by the assumption that dead blood had 
 been introduced charged " with the products of its own decomposi- 
 tion." A more important experiment was made subsequently by 
 the same observer : blood was taken from six living patients, and 
 after being defibrinated and slightly diluted with water, was in- 
 jected from 20 to 30 minutes after abstraction into the veins of 
 animals ; the quantity injected was from four to six drachms when 
 dogs were employed, and about three drachms for cats and rabbits. 
 
 ^ Ze<;ons sur le ChoUra Morbus, 8vo. Paris, 1837. 
 
 ^ Annali Universali de Medicina, compilaii da A. Omodel, t. 77-78. 
 
 ^ Brit, and For. Med.-Ohir. Mev. vol. xi. 398 
 
XXXII.] CHOLERA. 525 
 
 Into the veins of two dogs were injected larger quantities of blood 
 taken from patients affected with other diseases to serve as a 
 control. One only of the dogs exhibited any very decided 
 symptoms. This dog was prostrated for many hours, the bowels 
 were slightly relaxed and there was loss of appetite. The following 
 day the animal was well, the other animals suffered very slightly. 
 Injections of fresh living cholera blood by Namias, Carl Schmidt,^ 
 and by Jos. Meyer ^ into the veins of dogs, rabbits, and cats, all 
 gave negative results. 
 
 The general result of all the experiments is that although large 
 quantities of blood may produce symptoms, yet that the cause of 
 cholera is not in the blood, or if in the blood cannot affect 
 animals. 
 
 II. — Injections of the intestinal discharges of cholera. 
 
 Mr. Marshall injected into the jugular veins of cats and dogs 
 filtered rice water discharges. The animals were languid and dis- 
 tressed and had slight purging for two days. 
 
 III. — Introduction of the intestinal discharges into the stomach 
 of animals. 
 
 By far the best class of these cases are those of unintentional 
 experiment as when dogs have devoured human cholera vomit or 
 excreta. A well authenticated case is recorded by Meyer.^ A 
 large house-dog ate portions of his master's cholera stools. 10 
 hours after, the dog vomited a pale-coloured liquid and discharged 
 a yellowish, offensive, watery dejection. In seven hours he was 
 dead. Hertwig made the post-mortem. A rice-water looking 
 liquid flowed from the mouth, and was contained in large quantity 
 in the alimentary canal. The intestines were congested and the 
 lining membrane covered with white flaky mucous; Peyer's 
 patches were reticulated and surrounded by areolae of injection. 
 Von. Hildenbrandt* has collected a large number of instances in 
 which domestic animals suffered from a disease resembling cholera 
 in places where cholera was epidemic. Marshall made nine 
 experiments in which vomited or dejected matters were intro- 
 duced into the stomachs of animals. The experiments were made 
 
 ^ C. Sohmidt, Gharakteristik der epidemischen Cholera gegeniiier verwandten 
 Transiidations-anomalien. Leipzig, 1850, p. 79. 
 
 2 Virchows' Archiv. f. Pathol. Anat. Bd. iv. ^ Op. cit. 
 
 * Oesler. med. Jahrhncher. Bd. xvii., xviii. Vienna, KSS, 1839. 
 
526 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 on dogs, cats, guinea-pigs, and rabbits. Two of the three dogs 
 died, one recovered, the symptoms and the post-mortem appear- 
 ances bore some likeness to cholera. 
 
 In 1850 Jos Mej'er^ made a similar series of experiments on 
 dogs. Out of six dogs, one only yielded negative results. The 
 five remaining suffered from diarrhoea, three died, the post-mortem 
 appearances were not dissimilar from those of cholera. 
 
 In 1853 Dr. Lauder Lindsay,^ then resident physician to the 
 cholera hospital, Edinburgh, induced a fatal diarrhoea among dogs 
 by confining them for a length of time in a small room having a 
 capacity of 1,050 feet, on the floor of which the ejections, excreta, 
 and urine of cholera patients were strewed ; the animals were also 
 fed with the blood, urine, and other fluids and solids obtained from 
 the bodies of persons who had died of cholera. 
 
 IV. — Administration of small quantities of dried excreta. 
 
 Thiersch ^ made a careful series of experiments on white mice. 
 He soaked filter-paper in rice-water cholera discharges, allowed 
 the paper to dry, and fed white mice with paper thus prepared. 
 The experiments were made in several series, the discharges were 
 taken from different parts of the intestine, and allowed to stand 
 and decompose during different periods of time. He found that 
 the mice were not affected by eating filter-paper soaked with the 
 fresh discharges ; but that if the discharge was allowed to de- 
 compose for from two to six days, it induced a fatal diarrhoea. 
 
 Dr. Burdon Sanderson* made a very exact series of similar 
 experiments to those of Thiersch. He found that the rice-water 
 discharges allowed to stand for from three to four days produced 
 a cholera-like disease among mice, and that the disease could be 
 communicated from one affected animal to another of the same 
 species. 
 
 It has been the custom of late years to pass by these experi- 
 ments of Thiersch and Burdon Sanderson, but the results were 
 remarkable, and they deserve repetition aided by bacteriological 
 investigation. There are also reasons to consider the celebrated 
 instance of infection from water described by Macnamara ^ in the 
 
 ^ Virchows' Archiv.f. Path. ATiat. Bd. iv. 31. 
 ^ Ed. Med,, and Surg. Journal. Vol. Ixxxi. 
 
 * Saupt Bericht uher die Cholera-Epidemie des Jahres, 1854. Munich, 1857 
 ■• Ninth Bep. Med. Officer to the Privy Council. 
 
 * Macnamara, A Treatise on Asiatic Cholera, 1870, p. 381 
 
XXXII.] CHOLERA. 527 
 
 light of an experiment. " A small quantity of the dejecta of a cholera 
 patient was known to have been washed into a vessel containing 
 water, the mixture after being exposed to the heat of the sun for 
 one day, was swallowed by 19 men on the following morning; 
 within three days five of these were affected with cholera." 
 
 (394) Modern Experiments on Animals with Cultivations of the 
 Comma Bacillus, &c. 
 
 Nicati and Rietsch, injected directly into the duodenum of 
 dogs and guinea-pigs cultivations of the comma bacillus, they 
 induced a disease very much like cholera. This experiment was 
 repeated by Babes, Flugge, and Watson Cheyne, and the results 
 confirmed. At first Nicati and Rietsch ligatured the bile duct, but 
 subsequently this was not found necessary. Koch also repeated 
 this experiment and declared that out of 18 guinea-pigs into which 
 he had injected the comma bacillus into the duodenum, 13 had 
 died of cholera. At the same time control experiments were not 
 omitted, and cultivations of a number of other pathogenic 
 organism were injected into the duodenum of guinea-pigs ; all the 
 control animals lived. In 1885 Koch announced that he had 
 succeeded in reproducing the disease in the guinea-pig without 
 opening the animal's abdomen. He had studied the digestive pro- 
 cess in the guinea-pig and found that the stomach reaction was 
 always acid ; this acidity had probably destroyed the commas when 
 the latter were given by the mouth. To overcome this, he had 
 injected into the stomach a solution of soda; in this way the 
 commas were made to pass along into the small intestine, neverthe- 
 less, there was mostly failure. This he ascribed to the rapid 
 peristalsis of the first portion of the rabbits' intestines, the commas 
 were hurried on, before they had time to multiply. He found that 
 coloured foods passed from stomach to coecum in a few minutes. 
 To overcome this, he dosed the animals with opium (the opium 
 being injected into the peritoneal cavity). " I apply," says Koch, 
 "opium in the form of tincture, in the dose of 1 c.c. to every 200 
 grms. weight of the animal. After this dose there follows in a 
 very short time deep narcosis, after which the animal is as lively as 
 before. With a combination of soda solution and cholera broth, 
 
528 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 and after injection of opium tincture, experiments were made on 
 35 guinea-pigs ; of these 30 died of cholera. The symptoms during 
 life and the appearances after death were identical with those 
 foimd in guinea-pigs which had received duodenal injections." ^ 
 
 Dr. Neil Macleod ^ has repeated and extended these experiments 
 of Koch. In thirty-four experiments on guinea-pigs with cultiva- 
 tions of comma bacilli, all were successful in producing a cholera- 
 like disease ; in twenty-one of the animals the result was fatal. 
 Eleven control animals treated exactly in the same way, but 
 receiving sterilized broth, recovered, and showed no symptoms, 
 Tbj-ee animals also receiving soda solution alone, were in no way 
 affected. 
 
 From one of the animals that died after a dose of cholera 
 material the small gut contents were collected in a sterilized vessel 
 and injected in doses of 2 c.c. into the stomachs of two other 
 animals. These two animals died and the contents of their small 
 intestines were used in the same way, and so on through ten 
 generations. Of twenty-one animals thus treated two recovered, 
 nineteen died. The dose varied from -5 to 2'5 c.c. 
 
 The post-mortem appearances in the guinea-pigs experimented 
 on by Macleod are thus described : — " The blood was fluid, thicker 
 and darker than natural ; the tissues of the thoracic and abdominal 
 walls were markedly dry ; the small intestine was throughout dis- 
 tended, congested, and paralyzed-looking, and occupied a much 
 larger proportion of the abdominal cavity than usual. The coecum 
 was distended with fluid or semi-fluid contents. If the animal 
 had died early the fluid was not quite clear in the small gut, there 
 being present traces of food, still the watery character was very 
 manifest and mucous flakes were abundant. If the animal had died 
 on the second or third day, no food remains were to be seen, and 
 the fluid in the small gut was the counterpart of the typical 
 cholera stool in man. In either case the comma bacilli were 
 demonstrated microscopically and by cultivation as in man. While 
 the organism in the broth injected could be frequently counted in 
 a microscopic field, in a drop of the small bowel contents from an 
 animal having received such broth, the bacilli might be so nu- 
 merous that counting them without dilution of the fluid examined 
 
 1 Ber. Klinische Wocheiischrift, Sept. 21, 1885. 
 
 2 Public Health, 1888, vol. i. p. 322. 
 
XXXII.] CHOLERA. 529 
 
 was an impossibility. On floating the bowel on water the stripping 
 of the epithelium could be well demonstrated." 
 
 The conclusions arrived at by Dr. Neil Macleod and Walter J. 
 Milles, F.K.C.S. Eng., in their able research, are as follows : — 1st, 
 the comma bacillus of Koch is invariably present and associated 
 with certain changes in the small intestine, in cases of Asiatic 
 cholera ; 2nd, there is no evidence to show that it is a normal 
 inhabitant of the human alimentary canal, and therefore no proof 
 for the assertion that it is a result of the disease. 3rd, the means 
 used to introduce the comma bacillus into, and those used to lessen 
 the peristalsis of, the small intestine of the guinea-pig cannot be 
 regarded as causing appearances like those of Asiatic cholera, or 
 as causing the death of the animal, far less a mortality of over 
 60 per cent. ; 4th, pure cultivations of the comma bacillus intro- 
 duced into the stomach under the precautions described, are 
 pathogenic to the guinea-pig; 5th, injected with similar precau- 
 tions, the contents of the ileum from those animals killed by 
 injections of pure cultivations of the bacilli, act in the same 
 manner as pure cultivations of that organism ; 6th, the organism 
 multiplies in the small intestine of the animal, and there are 
 associated therewith changes similar to those in man in Asiatic 
 cholera." 
 
 (395) Propagation of Cholera hy Water and Otherwise. 
 
 In the brief history of cholera in England, sufficient examples 
 have been given as to the propagation of cholera by water. Koch 
 considers that the cholera contagium is in all cases swallowed, the 
 commas may be in the water or may be in food, but it must be 
 swallowed ; he would consider the possibility of it being propagated 
 by sewer gas problematical, and that it can be blown about as dust 
 and breathed in that form, would be negatived by the experimen- 
 tally ascertained fact that drying is fatal to the bacillus. In respect 
 therefore to the propagation of cholera in other ways than by 
 swallowing the contagium in food and drink, the history of the 
 introduction of cholera into Southampton as described by the late 
 Dr. Parkes in 1866 is full of interest.^ On the 10th of June, 1866, 
 the P. and 0. steamship Poonah arrived from Alexandria, Malta, 
 ^ Ninth Sep, of the Med. Offlcer of the Privy Gouncil. 
 
 M M 
 
530 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 and Gibraltar, having on the preceding day lost a man from cholera ; 
 the cause of the outbreak was attributed to foul water taken in at 
 Gibraltar ; the history clearly shows that the severe diarrhoea pre- 
 vailing on board the steamship was confined to a certain section 
 of the crew who drank the water from a particular tank, and this 
 water was found on analysis to be much polluted. However this 
 may be, it is certain tliat eight or ten people suffering from 
 " choleraic diarrhcea were landed in the town and dispersed in 
 various quarters, and that their dejections passed into the sewers." 
 
 There were doubtful cases of cholera on June 12th, June 15th, 
 and July 6th in Southampton, but the disease definitely and 
 unmistakably broke out from July 6th to the 13th : up to the 
 evening of the I7th no less than thirty-five to thirty-seven deaths 
 had occurred. By the 4th or 5th of August the epidemic was 
 virtually over. 
 
 Dr. Parkes considered that the outbreak probably introduced by 
 the Poonah had no connection with the water supply of South- 
 ampton. " The whole of Southampton is supplied from a town 
 reservoir ; the supply is continuous ; there are no cisterns. If the 
 water was the cause it must have affected the town generally ; 
 there are nearly 60,000 people in Southampton, and there' were 
 only 320 cases of cholera scattered over nearly three months. It 
 is impossible to suppose that 49,700 people who used the water 
 could have escaped had the water been bad." ..." The disease 
 was certainly worst in the most unhygienic parts of the town, but 
 was not confined to these, for good houses in airy situations in the 
 low part of the town suffered and some of the worst localities 
 remained free." 
 
 After a very careful consideration of all the possible causes, 
 Dr. Parkes was inclined to accuse the sewer system. " Almost all 
 the town is sewered, but unfortunately on a bad principle, a very 
 large network of sewers being provided towards the outlet in order 
 to act as a reservoir during certain periods of the tide. There is 
 thus a great stagnancy during several hours of the day, and indeed 
 at some periods it is probable that there is very little flow even 
 for long periods. The ventilation is very imperfect, beiag pro- 
 vided for by gratings in the road, and as these give ofif offensive 
 effluvia, they are continually stopped up with pieces of wood by 
 the inhabitants of the neighbouring houses. The consequence is 
 
xxxii.] CHOLERA. 531 
 
 that the gases are thrown back upon the houses and force their 
 way through the very imperfect traps." 
 
 From causes detailed in the original report, the sewers at the 
 time of the Poonah's arrival were in a particularly clogged and 
 offensive state, and the sewage pumping at the western station had 
 been discontinued. " In the beginning of July the pumping of 
 the western shore sewer into the outlet sewer was recommenced." 
 ..." All the immense mass of sewage from the western sewers 
 was raised and then poured down an open conduit into the outlet 
 sewer. Tons and tons of sewage were thus daily pumped up, and 
 frothing and agitated by this churning were poured like a cataract 
 down the open channel for some 8 or 9 feet. The effluvia dis- 
 engaged from this quantity of seething sewage was overpowering. 
 It spread all over the neighbourhood, and was bitterly complained 
 of in the adjacent houses. The effect, however, would not be con- 
 fined to them ; the cloud of effluvia thus thrown up must have 
 extended far beyond the point where it was detectable by smell. 
 The occiirrence of some early cases of cholera in clean, airy houses 
 near tliis pumping station was the first thing that called attention 
 to it, and it was then found that diarrhcea was beginning to prevail 
 in several of the adjacent houses. There was no local cause to 
 account for these attacks except the great effluvia thus disengaged." 
 But the most striking point in the history is when a closed iron 
 pipe was substituted for the open conduit and carbolic acid largely 
 used as a disinfectant, there was an immediate diminution in the 
 cholera outbreak ; the alteration took place on the 19th of July, 
 and Dr. Parkes says, " On the 24th of July the worst was 
 over." 
 
 It is therefore only reasonable to believe that the incidences as 
 to time and place were not accidental, but that the state of the 
 sewers and the cloud of spray and effluvia at the pumping station 
 had a very definite connection with the Southampton cholera 
 epidemic of 1866. 
 
 (396) Propagation of Cholera by Clothes Soiled with the Discharges^ 
 
 There are also numerous cases on record in which those who 
 have washed the undisinfected linen of cholera patients have 
 been attacked with cholera, and the following incidents are types 
 
 M M 2 
 
532 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 scattered in literature of cases in which cholera has been con- 
 veyed to distances by undisinfected clothes. 
 
 In 1854 cholera broke out in a village in Bedfordshire, two fatal 
 cases occurred. The first case was that of a man whose son had 
 died in London a week or two before of cholera, and whose clothes 
 (undisinfected) were sent down to the country. The man un- 
 wrapped the clothes himself, was seized with the disease, and died 
 in a short time. This case was the nucleus from whence the 
 others took their infection.^ At Leistheim, near Munich, the first 
 case of cholera was in the house of a labourer, one of whose 
 daughters was in service at Munich, the latter sent her parents 
 clothes belonging to a family some member of which had died 
 of cholera. These old clothes were at once appropriated and 
 worn. Three days afterwards (September 21st) the father and 
 mother were seized with cholera, and died on the 22nd and 23rd ; 
 other members of the family took the disease.^ 
 
 (397) Pettenkofer's Themj. 
 
 Pettenkofer's theory of the spread of cholera is that it is in- 
 timately connected with the composition of the soil. The essential 
 elements as to season and locality are : — (1) The physical composi- 
 tion of the earth and subsoil of the dwelling. (2) The moisture 
 of the soil and its changes ; this moisture he designates by the 
 collective term " ground water ; " to these must be added the 
 presence of nourishing substances in the soil suitable for the 
 nourishment of the lower organisms. (3) The specific germ ; he 
 is also inclined to lay stress upon individual predisposition. The 
 rise and fall of the ground water is but an index of the moisture 
 of the earth ; the most dangerous time for cholera, according 
 to Pettenkofer, is when the ground water, having risen above its 
 usual level, sinks or is sinking. The later epidemics and the out- 
 breaks on vessels at sea, give but moderate support to this theory. 
 
 (398) Preventive Measures as formulated hy Koch. 
 In the conference on cholera at Berlin, 1885, Koch sketched the 
 following scheme as to preventive measures.^ The preventive 
 
 1 On Malaria and Miasmata, by Dr. Barker, F. R. S. Macnamara, p. 162. 
 
 ' Quoted by Macnamara. 
 
 ^ Berliner klinische Wochen., Sept. 21, 1885, No. 37, a. u. b. 
 
xxxii.] CHOLERA. 533 
 
 measures against cholera must ia the first place be referred to the 
 fact that the infection is produced in man, and is contained in the 
 evacuations. In order therefore to make the infectious matter 
 harmless, the dejecta are to be mixed with suitable disinfectants. 
 Carbolic acid is the most suitable, a five per cent, solution, mixed 
 with an equal bulk of either the dejecta or the vomited matters is 
 sufficient to destroy fully the cholera bacillus. 
 
 If it were possible to collect all the excreta of the sick in vessels 
 and to immediately treat them with disinfectants, then the destnac- 
 tion of the infectious matter would be simple and certain, and 
 better results would be obtained with disinfectants than now, but 
 any one who has to do with cholera patients knows that only a 
 portion of the excreta actually goes into the vessel, the rest is on 
 the bed, the earth, the clothing, and the hands of the sick and his 
 attendants. Hence all things which either can be soiled or are 
 soiled by the dejecta must be disinfected. 
 
 The soiled linen must be put into a solution of 5 per cent, 
 carbolic acid or other disinfecting fluid. Where clothes need not 
 be immediately sent to the wash but may remain several days in 
 the disinfecting fluid, weaker solutions may be used. Clothing, 
 bedding, and mattresses, which cannot well be disinfected by fluid 
 disinfectants, should be submitted to steam in a disinfecting 
 apparatus. Things, as ambulances and the like, which can neither 
 be disinfected with fluid disinfectants nor by steam should not be 
 used for some time, but well aerated, for if the bacillus is dried it 
 is destroyed. Where disinfecting apparatus and appliances are 
 not at hand, things of little value may be burnt, those of more 
 value simply exposed to the air for a long time. 
 
 The aeration and drying through heat is the most suitable for 
 the disinfection of the sick room. Disinfection with gaseous 
 reagents especially with sulphurous acid gas, later researches have 
 shown to be uncertain and therefore not desirable. The nurses are 
 to wash their hands often, never to touch the mouth with the hands, 
 and if the hands become soiled with the discharges they must be 
 disinfected with carbolic acid or corrosive sublimate solution. 
 Eating in the same room in which are persons sick of cholera 
 must be specially avoided, as in the dwellings of the poor so often 
 happens. 
 
 But with all the above-named precautions complete success may 
 
534 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 not be attained because these precautions can only be taken in the 
 serious cases which are recognized as cholera. The numerous 
 slighter attacks which are not recognized as cholera, and which seek 
 no medical aid, are not amenable to these regulations. Like the 
 ambulatory form of scarlet fever, measles, &c., these are probably 
 still more dangerous to the public health than the pronounced cases 
 of cholera, since the dejections of these cases have been ascer- 
 tained to contain the comma bacilli, yet the sick are enabled to go 
 about their occupations, and to carry from place to place their 
 infection unsuspected. 
 
 If we turn now to the accepted English method of prevention 
 as drawn out by the present medical officer to the Local Govern- 
 ment Board, the directions only differ as to detail, irrespective of 
 whether Asiatic cholera is produced by " commas " or not ; stress is 
 laid by both the English and German school on the special danger 
 of the excreta, the importance of cleanliness, of disinfection, and 
 of general hygiene. 
 
 (399) Official Memorandum as to Prevention of Cholera. 
 Peeoatitions Against the Infection of Choleea. 
 
 1. The Order of the Local Government Board of July 12th, 1883, now in force, 
 gives certain special powers to the Sanitary Authorities of the sea-coasts, enabling 
 them to deal with any cases of cholera brought into port, so as to prevent as far 
 possible the spread of disease into this country ; but as cases of choleraic infection have 
 widely different degrees of severity it is possible that some such cases slightly aifected 
 will notwithstanding the vigilance of local authorities be landed without particular 
 notice in English sea-board towns, whence they may advance to other and perhaps 
 inland places. 
 
 2. Former experience of cholera in England justifies the belief that the presence 
 of imported cases of the disease at various spots in the country will not be capable 
 of causing much injury to the population if the places receiving the infection have 
 had the advantage of proper sanitary administration, and in order that all local 
 populations may make their self defence as effective as they can, it wUl be well for 
 them to have regard to the present state of knowledge concerning the mode with 
 which epidemics of cholera at least in this country are produced. 
 
 3. Cholera in England shows itself so little contagious in the sense in which small- 
 pox and scarlet fever are commonly called contagious, that if reasonable care be 
 taken where it is present there is almost no risk that the disease will spread to 
 persons that nurse and otherwise attend closely on the sick ; but cholera has a certain 
 peculiar infectiveness of its own, which where local conditions assist, can operate 
 with terrible force and at considerable distances from the sick. It is characteristic of 
 ■cholera (and as much so of the slight cases where diarrhoea is the only symptom, as 
 of the disease in its more developed and alarming forms) that all matters which the 
 patient discharges from his stomach or bowels are or can become infective. Pro- 
 bably, under ordinary circumstances, the .patient has no power of infecting other 
 persons except by means of these discharges ; nor any power of infecting even by 
 them except in so far as particles of them are enabled to taint the food, water, or 
 air, which people consume. Thus, when a case of cholera is imported into any place, 
 
XXXII.] CHOLERA. 535 
 
 the disease is not likely to spread unless in proportion as it finds, locally open to it, 
 certain facilities for spreading by indirect infection. 
 
 4. In order rightly to appreciate what these facilities mitst mean, the following 
 conditions have to be borne in mind — first, that any choleraic discharge, cast without 
 previous thorough disinfection, into any cesspool or drain or other depositary or 
 conduit for filth, has a faculty of infecting the excremental matters with which it 
 there mingles, and probably, more or less, the eflBuvia which those matters evolve ; 
 secondly, that the infective power of choleraic discharges attaches to whatever bed- 
 ding, clothing, towels, and like things, have been imbued with them, and renders 
 these things, if not thoroughly disinfected, as capable of spreading the disease in 
 places to whioh they are sent (for washing or other purposes) as, in like cii'cum- 
 stances, the patient himself would be ; thirdly, that if, by leakage or soakage from 
 cesspools or drains, or through reckless casting out of slops and wash -water any taint 
 (however small) of the infective material gets access to wells or other sources of 
 drinking water, it imparts to enormous volumes of water the power of propagating 
 the disease. When due regard is had to these possibilities of indirect infection, there 
 will be no difficulty in understanding that even a single case of cholera, perhaps of 
 the slightest degree, and perhaps quite unsuspected in his neighbourhood, may, if 
 local circumstances co-operate, exert a terrilily infective power on considerable masses 
 of population. 
 
 5. The dangers which have to be guarded against as favouring the spread of cholera 
 infection, are, particularly, two. First, and above all, there is the danger of water 
 supplies which are in any (even the slightest) degree tainted by house refuse or other 
 like kinds of filth : as where there is outflow, leakage, or filtration from sewers, 
 house drains, privies, cesspools, foul ditches, or the like, into springs, streams, wells, 
 or reservoirs from which the supply is drawn, or into the soil in which the wells are 
 situated : a danger which may exist on a small scale (but perhaps, often repeated in 
 the same district) at the pump or dip well of a private house, or, on a large or even 
 vast scale in the source of public water works, and secondly there is the danger of 
 breathing air which is fouled with ef&uvia from the same source of impurity. 
 
 6. Information as to the high degree in which those two dangers affect the public 
 health in ordinary times, and as to the special importance which attaches to them at 
 times when diarrhceal infection is likely to be introduced, has now for so many years 
 been before the public that the improved systems of refuse removal and water supply 
 by which those dangers are permanently obviated for large populations, and also the 
 minor structural improvements by which separate households are secured against 
 them ought long ago to have come into universal use. 
 
 So far, however, as this wiser course has not been adopted in any sanitary district, 
 security must, as far as practicable, be sought in measures of a temporary and pallia- 
 tive kind, (a) Immediate searching examination of sources of water supply should 
 be made in all cases where the source is in any degree open to the suspicion of 
 impurity ; and the water both from private and public sources should be examined. 
 Where pollution is discovered, everything practicable should be done to prevent the 
 pollution from continuing, or, if this object cannot be obtained, to prevent the water 
 from being drunk. Cisterns should be cleansed and any connections of waste pipes 
 with drains should be severed. (J) Simultaneously, there should be immediate 
 thorough removal of every sort of house refuse and other filth which has accumulated 
 in neglected places ; future accumulations of the same sort should he prevented : 
 attention should be given to all defects of house drains and sinks through which 
 offensive smells are let into houses ; thorough washing and lime washing of uncleanly 
 premises, especially of such as are densely occupied, should be practised again and 
 again. 
 
 7. It may fairly be believed that, in considerable parts of the country conditions 
 favourable to the spread of cholera are now less abundant than at any former time ; 
 and in this connection, the gratifying fact deserves to he recorded that during recent 
 years, enteric fever, the disease that in its method of extension bears the nearest 
 resemblance to cholera, has continuously and notably declined in England. But it 
 is certain that in many places such conditions are present as would, if cholera were 
 introduced, assist in the spread of that disease. It is to be hoped that in all these 
 
536 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 cases tlie local sanitary authorities will at once do everything that can be done to 
 put their districts into a wholesome state. Measures of cleanliness taken beforehand 
 are of far more importance for the protection of a district against cholera than 
 removal or disinfection of filth after the disease has actually made its appearance. 
 
 8. It is important for the public very distinctly to remember that pains taken and 
 costs incurred for the purposes to which this memorandum refers cannot in any event 
 be regarded as wasted. The local conditions which would enable cholera, if imported, 
 to spread its infection in this country, are conditions which, day by day, in the 
 absence of cholera, create and spread other diseases ; diseases which, being never 
 absent from the country, are in the long run, far more destructive than cholera, and 
 the sanitary improvements which would justify a sense of security against any appre- 
 hended importation of cholera, would to their extent, though cholera should never 
 re-appear in England, give ample remunerative results in the prevention of other 
 
 GEORGE BUCHANAN, 
 Local Government Board, July 21, 1885. Medical Officer of the Board. 
 
 General Cholera Order. 
 
 To all Port Sanitary Authorities, except the Port Sanitary Authorities of the Port 
 
 of London ; to all Urban and Rural Sanitary Authorities, whose districts 
 
 include or abut on any part of a customs port, which port is not within the 
 
 jurisdiction of any Port Sanitary Authority ; to all Officers of Customs ; to 
 
 all Medical Officers of Health of the Sanitary Authorities aforesaid ; to all 
 
 masters of ships ; and to all others whom it may concern. 
 
 Whereas "We, the Local Government Board, by an Order bearing date the 17th 
 
 da}' of July, 1873, made certain rules and regulations with a view to the treatment 
 
 of persons affected with cholera, and for preventing the spread of the disease ; and 
 
 whereas cholera is now ^ prevalent in certain parts of Egypt with which this country 
 
 has communication, and it is expedient that in place of the rules and regulations 
 
 made by the said Order, other rules and regulations as hereinafter contained should 
 
 be made : 
 
 Now therefore We, the Local Government Board, do hereby rescind the said 
 Order, except in so far as it may apply to any proceedings now pending, and We 
 do, by this our Order, and iu exercise of the power conferred on us by section 130 of 
 the Public Health Act 1875, and every other power enabling us in this behalf, make 
 the following rules and regulations, and declare that they shall be enforced and 
 executed by the authorities hereinafter named : — 
 
 Definitions. 
 
 Article 1. In this Order — The term "ship" includes vessel or boat ; the term 
 "officer of customs" includes any person acting under the authority of the Com- 
 missioners of Customs ; the term " master " includes the officer or person for the 
 time being iu charge or command of a ship ; the term ' ' cholera " includes choleraic 
 diarrhoea; the term "Sanitary Authority" means every Port Sanitary Authority 
 except the Port Sanitary Authority for the Port of London, and every Urban or 
 Rural Sanitary Authority whose district includes or abuts on any part of a customs 
 port, which port is not within the jurisdiction of a Port Sanitary Authority ; the 
 term "Medical Officer of Health" includes any duly qualified medical practitioner 
 appointed by a Sanitary Authority to act in the execution of this Order. 
 
 For the purposes of this Order — 
 
 (1) So much of a customs port abutting on an Urban or Rural Sanitary District 
 as is nearer to such district than to any other, and is not included within the juris- 
 diction of any Port Sanitary Authority, shall be deemed to be within such district. 
 
 (2) Every ship shall be deemed infected with cholera in which there is or has 
 been during the voyage, or during the stay of such ship in a port in the course of 
 such voyage, any case of cholera. 
 
 1 1883. 
 
XXXII.] CHOLERA. 53T 
 
 I. Regulations as to Detention by Offiobes of Customs. 
 
 Article 2. If any officer of customs, on the arrival of any ship, ascertain from the- 
 master of such ship or otherwise, or have reason to suspect, that the ship is infected 
 with cholera, he shall detain such ship, and order the master forthwith to moor or 
 anchor the same in such position as such officer of customs shall direct, and there- 
 upon the master shall moor or anchor the ship accordingly. 
 
 Article 3. "While such ship shall be so detained no person shall leave the same. 
 
 Article 4. Such detention by the officer of customs shall cease as soon as the ship- 
 has been duly visited and examined by the Medical Officer of Health ; or if the ship 
 ?hall, upon such examination, he found to be infected with cholera, as soon as the' 
 same shall be moored or anchored in pursuance of Article 10 of this Order. Provided 
 that if the examination be not commenced within twelve hours after notice given as- 
 aforesaid, the ship shall, on the expiration of the twelve hours, be released from 
 detention. 
 
 II. Kequlations as to Sanitary Authorities. 
 
 Article 6. Every Port Sanitary Authority, except as aforesaid, and every other 
 Sanitary Authority within whose district persons are likely to be landed from any 
 ship coming foreign, shall as speedily as practicable, with the approval of the chief 
 officer of customs of the port, & some place within the jurisdiction or district of the 
 Sanitary Authority where any ship may be moored or anchored, for the purpose of 
 Article 10 ; and shall make provision for the reception of cholera patients and 
 persons suffering from illness removed under Articles 13 and 14. 
 
 Article 7. The Sanitary Authority, on notice being given to them by an officer of 
 customs, under this Order, shall forthwith cause the ship, in regard to which such 
 notice shall have been given, to be visited and examined by their Medical Officer of 
 Health for the purpose of ascertaining whether she is infected with cholera. 
 
 Article 8. The Medical Officer of Health, if he has reason to believe that any 
 ship within the jurisdiction or district of a Sanitary Authority, whether examined, 
 by the officer of customs or not, is infected with cholera, shall, or if she have come 
 from a place infected with cholera, may visit and examine such ship for the purpose 
 of ascertaining whether she is so infected, and the master of such ship shall permit 
 the same to be so visited and examined. 
 
 Article 9. If the Medical Officer of Health, making such examination as afore- 
 said (whether under Article 7 or 8), shall be of opinion that the ship is infected, 
 he shall give a certificate in duplicate in the following form or to the like effect, and, 
 shall deUver one copy to the master and retain the other or transmit it to the 
 Sanitary Authority. 
 
 Ceetificate. 
 
 day of , 188 , 
 
 . Sanitary Authority of - 
 
 I hereby certify that I have examined the ship of 
 
 now lying in the port of — 
 
 (or detained at ), and that I find that she la 
 
 infected with cholera. 
 
 Medical Officer of Eealth (or medical practitioner appointed by the- 
 Sanitary Authority). 
 
 Article 10. The master of every ship so certified to be infected with cholera shall 
 thereupon moor or anchor her at the place fixed for that purpose under Article 6,. 
 and she shall remain there until the requirements of this Order have been duly 
 
 fulfilled. , ,. ., , . ^. -,. . , 
 
 Article 11. No person shall leave any such ship until the examination hereinafter 
 
 mentioned shall have been made. 
 
 Article 12. The Medical Officer of Health shall, as soon as possible after any such 
 
 ship has been certified to be infected with cholera, examine all persons on board the 
 
538 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 same, and all persons who shall not be certified by him as hereafter mentioned shall 
 be permitted to land immediately on their giving their names and the places of their 
 destination. 
 
 Article 13. Every person certified by the Medical Officer of Health to be suffering 
 from cholera, shall be dealt with under any regulations that may have been made by 
 the Sanitary Authority under Section 125 of the Public Health Act 1875 ; or where 
 no such regulations shall have been made shall be removed, if the condition of the 
 patient admit of it, to some hospital or place previously appointed for that purpose 
 by the said authority ; and no person so removed shall leave such hospital or place 
 until the Medical Officer of Health shall have certified that such person is free from 
 the said disease. If any person suffering from cholera cannot be removed the ship 
 shall remain subject, for the purposes of this order, to the control of the Medical 
 ■■Officer of Health ; and the infected person shall not be removed from or leave the 
 ship, except with the consent in writing of the Medical Officer of Health. 
 
 Article 14. Any person certified by the Medical Officer of Health to be suffering 
 from any illness which such officer suspects may prove to be cholera, may either be 
 detained on board the ship for any period not exceeding two days, or be taken to 
 some hospital or other place previously appointed by the Sanitary Authority, and 
 detained there for a like period, in order that it may be ascertained whether the 
 illness is or is not cholera. Any such person who while so detained shall be certified 
 by the Medical Officer of Health to be suffering from cholera shall be dealt with as 
 provided by Article 13 of this Order. 
 
 Article 15. The Medical Officer of Health shall, in the case of every ship certified 
 to be infected, give directions, and take such steps as appear to him necessary, for 
 preventing the spread of infection, and the master of the said ship shall forthwith 
 carry into execution such directions as shall be so given to him. 
 
 Article 16. In the event of any death from cholera taking place on board of such 
 ship while so detained, the master shall, as directed by the Sanitary Authority or the 
 Medical Officer of Health, either cause the dead body to be taken out to sea and 
 committed to the deep, properly loaded to prevent its rising, or shall deliver it into 
 the charge of the said authority for interment, and the authority shall thereupon 
 have the same interred. 
 
 Article 17. The master shall cause any articles that may have been soiled with 
 cholera discharges to be destroyed, and the clothing and bedding and other articles 
 of personal use likely to retain infection which has been used by any person who may 
 have suffered from cholera on board such ship, or who having left such ship shall have 
 suffered from cholera during the stay of such ship in any port, to be disinfected or if 
 necessary destroyed ; and if the master shall have neglected to do so before the ship 
 arrives in port, he shall forthwith, or upon the direction of the Sanitary Authority 
 or the Medical Officer of Health, cause the same to be disinfected or destroyed, as the 
 case may require ; and if the said master neglect to comply with such direction 
 within a reasonable time, the authority shall cause the same to be carried iuto 
 execution. 
 
 Article 18. The master shall cause the ship to be disinfected, and every article 
 therein, other than those last described, which may probably be infected with 
 cholera, to be disinfected or destroyed, according to the directions of the Medical 
 Officer of Health. 
 
 Given under the seal of office of the Local Government Board, this 
 twelfth day of July in the year one thousand eight hundred 
 and eighty-three. 
 
 OHAELES W. DILKE, Presidmt. 
 HUGH O'WEN, Secretary. 
 
 Notice. — The Public Health Act 1875 provides by section 130, that any person 
 wilfully neglecting or refusing to obey or carry out, or obstructing the execution of 
 any regulation made under that section shall be liable to a penalty not exceeding 
 fifty pounds. 
 
 Date of publication in the London Gazette, 13th July, 1883. 
 
XXXII.] DIAERHCEA— ENGLISH CHOLEEA. 539 
 
 (400) Order Prohibiting Importation of Bags. 
 
 The Order at the time of cholera apprehension in 1885 against the importation of 
 rags from Spain, was to the following effect : — 
 
 Article 2. From and after the date of this Order, and until the 1st day of 
 November, 1885, no rags from Spain shall be delivered overside nor landed in any 
 port or place in England or Wales. 
 
 Article 3. If any rags shall be delivered overside or landed in contravention of 
 this Order, they shall, unless forthwith exported, be destroyed by the person having 
 control over the same, with such precautions as may be directed by the Medical 
 Officer of Health of the Sanitary Authority within whose jurisdiction or district the 
 same may be found. 
 
 Article 4. All masters of vessels, consignees, and other persons having control of 
 any rags prohibited under this Order from being delivered overside, except for the 
 purpose of export, or landed, are required to obey these regulations. 
 
 Article 5. All officers of customs are empowered to prevent the delivery overside 
 or landing of rags in contravention of this Order. 
 
 Article 6. It shall be the duty of the Sanitary Authority to take proceedings 
 against masters of ships, consignees, or other persons having control over any rags 
 who shall wilfully neglect or refuse to obey or carry out, or shall obstruct the 
 execution of any of these regulations. 
 
 DiAEEHCEA — English Cholera. 
 
 DiarrhcEa is a general disease, the leading symptom of which is 
 frequent purging ; at present it is not possible to differentiate 
 between acute diarrhoea and English cholera, nor is it possible to 
 definitely state whether two or more essentially different diseases 
 are included under the term " diarrhoea," the latter name being as 
 a matter of fact given to any disease attendant with frequent 
 purgation, and for which there does not appear any local lesion or 
 any specific fever such as typhoid to account for it. 
 
 (401) Mortality and Sickness from Diarrhcea. 
 
 The amount of illness from diarrhoea it is impossible to state, but 
 Dr. Ballard i gives as the result of his Islington statistics that out 
 of 272,409 cases of sickness treated in charitable institutions 16,479, 
 or 60'5 per cent., were due to diarrhoea. The amount of sickness 
 varies very much in different years, and also the mortality. 
 
 During the ten years 1861 to 1870, out of 4,794,500 deaths 
 registered from all causes, 207,256 were ascribed to diarrhoea, and 
 during the ten years 1871 to 1880 out of 5,178,311 deaths 
 
 ' "Biarrhcea and Diphtheria," i/cd. Officers' Supplement, Rep. Local Government 
 Board, 1887. 
 
540 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 221,652 were ascribed to diarrhoea. This is equal to 432 per 1,000 
 of all deaths in the first period of ten years, and to 42'7 per 1,000 
 of all the deaths in the second period (Ballard). 
 
 Dr. Ballard suggests that this may not be all the mortality, but 
 only that which is immediate ; diarrhoea, like scarlatina, specially 
 interferes with the kidney function, and hence it may lay the 
 foundation of kidney diseases which may at a long period after- 
 wards prove fatal. 
 
 (402) SymptoTris. 
 
 Dr. Ballard summarizes briefly the symptoms as follows : — 
 Diarrhoea, vomiting, convulsive phenomena, a bodily temperature 
 at certain periods above, at other periods below what is normal, 
 reduction in quantity or actual suppression of urine, embarrassed 
 breathing, and where looked for commonly physical indications of 
 pulmonary hypersemia or inflammation, pallor of the surface of the 
 body, loss of bulk and flesh, and exhaustion with its various well- 
 known clinical features. Occasionally there is jaundice. In two 
 of Dr. Ballard's cases there was a fugitive rash. The diarrhoea may 
 be very slight, there is nothiug characteristic about the stools, but 
 as a rule they are at one stage or another of the malady horribly 
 offensive. Convulsions Dr. Ballard views as the most important 
 phenomena of the malady, and when convulsions occur late they 
 indicate a ursemic condition of the blood. The temperature in 
 its course is peculiar and much like that of cholera. At the com- 
 mencement there appears to be some little febrile disturbance, but 
 sooner or later in the cases about to become fatal, the temperature 
 falls more or less below the normal range, being lower in the 
 morning than in the evening, aud even then it mostly fails to 
 attain a normal standard. Towards the end of a fatal case the 
 temperature is apt to rise. 
 
 (403) Seasonal Influences. 
 
 Dr. Ballard has carefully studied the effect of season. The 
 malady he concludes is not only present among the population 
 every year but in all seasons and at all times of every year ; but 
 not in all seasons and times alike. 
 
 For example, taking his Islington experience, and dividing the 
 
XXXII.] DIARRHCEA— ENGLISH CHOLERA. 541 
 
 year into thirteen periods of four weeks each, from the first to the 
 twentieth week he considers a pre-epidemic period, the next five 
 periods belong to the epidemic period, and the last three to the 
 post-epidemic period ; or the seasonal influence may be considered 
 in quarters. Of the 15,478 Islington cases, in the first quarter 
 there occurred 8"7 per cent, of all the cases, in the second 16'8 per 
 cent., in the third 60"7 per cent., and in the fourth 13'8 per 
 cent. 
 
 In yearly variations of prevalence by far the greatest occur in 
 the "epidemic period." From eleven years of the Islington 
 statistics, Ballard thinks that a higher prevalence than usual in 
 the " post-epidemic period " may be connected with a deficiency of 
 customary prevalence in the preceding " epidemic period," and he 
 gives tables illustrative of this and- other points both with regard to 
 diarrhoea observed in Islington and diarrhoea observed in Eedditch ; 
 finally concluding that the lateness or earliness of attainment of 
 maximum prevalence in the " epidemic period " has more to do with 
 the "post-epidemic" prevalence than the degree of prevalence in 
 the " epidemic period " has to do with it. 
 
 In Buchan and Mitchell's paper i the general seasonal distribu- 
 tion of deaths is well brought out, and Ballard's conclusions are 
 confirmatory. Buchan's diagram looks like a section of an Alpine 
 mountain, the peak of culminating point being attained in the 
 first week in August, the deaths rapidly running up from zero in 
 May, through June and July to as rapidly diminish down to 
 Ballard's post-epidemic period, but still a little above the average 
 through October, November and December. 
 
 The most instructive part of Ballard's study on seasonal in- 
 fluences is that in which he traces the influence on the different 
 ages. Taking the six years 1857 to 1862, 40-6 per 10,000 of all 
 ages were known to be attacked in the pre-epidemic period, 230'5 
 in the epidemic, and 37'5 in the post-epidemic period. In the pre- 
 epidemic period 135'2 per 10,000 of the age period under five, were 
 attacked, and 26'0 of the population over five, hence the propor- 
 tion was as 62 to 10 during the epidemic period, 816'4 per 10,000 
 under five, and 140'3 over five, that is in the proportion of 58 to 
 10 ; while during the post-epidemic period the relation is as 65 is 
 to 10. 
 
 ' Joum. of the Scottish Met. Soe., July, 1875. 
 
542 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (404) Predispositimi. 
 
 From Dr. Ballard's exhaustive inquiry it seems that contrary 
 to general belief the healthiest children suffer most from diarrhoea ; 
 on the other hand, as might be expected, it is most fatal among 
 weakly children. Presuming that diarrhoea is excited by a chemical 
 poison like Vaughan's tyrotoxine, it may be argued that the 
 healthiest children are the greatest feeders, and therefore would 
 be likely to take a greater dose of the poison in milk or other 
 substances; hence this fact may be scored on the side of the 
 chemical theory. 
 
 (405) Bacteriology of Diarrhoea. 
 
 Dr. Tomkins of Leicester has investigated the micro-organisms 
 found in the air of diarrhoeal affected locahties. Dr. Klein and 
 others have investigated the bacteria found in the intestine and' 
 the discharges, but it cannot be said that any very definite result 
 has yet been attained. Tomkins found a larger number of micro- 
 organisms in affected areas than elsewhere. For instance, 6,000 
 colonies of bacteria per cubic metre within the area and 1,600 to 
 2,300 without the area, but he did not identify the various species 
 nor investigate their pathogenic action. In the discharges Klein 
 found the following : — 
 
 (a) A mobile spore-bearing bacillus which proved to be the 
 bacillus amylobacter. 
 
 (6) A bacillus resembling bacterium termo. 
 
 (c) A thin non-mobile bacillus, in some examples containing 
 two or four granules ; it grows in clumps and corresponds to the 
 bacillus of Escherlich. 
 
 {d) Various forms of micrococci differing from one another in 
 size and arrangement ; while some formed exquisite chains, others 
 formed more or less sarcina-like groups, while still others were 
 aggregated in clumps or zoogloea. 
 
 Careful microscopical examination of the tissues and blood of a 
 number of cases of diarrhoea failed to discover any micro-organisms 
 save in one case in which a bacillus was discovered strikingly like 
 that described by Gaffky as the cause of typhoid fever. Dr. Klein 
 is apparently not certain that it is identical ; it grew in gelatin 
 
xxxii.]- DR. BALLARD ON THE ETIOLOGY OF DIARRHCEA. 543 
 
 more rapidly than Gaffky's bacillus, and had a greater resisting 
 power to mercury perchloride ; it was fatal to mice, and the fost- 
 moriem appearances were those of septicaemia. 
 
 (406) General Results of Dr. Ballard's Inquiry. 
 
 The general results of Dr. Ballard's inquiry is summed up in 
 the following eighteen paragraphs : — 
 
 A. — General Conditions. 
 
 1. Atmospheric Temperatiire. — That a high atmospheric tempera- 
 ture conduces to a high diarrhceal mortality, and a low atmospheric 
 temperature to a low diarrhceal mortality, is an established fact 
 which no one can dispute. But my inquiry shows that the in- 
 fluence thus exerted is not a direct influence, excepting so far 
 as it affects also infant mortality from all causes. It is not the 
 main cause of the diarrhceal mortality. Its influence is very great, 
 but is exerted indirectly. 
 
 2. Temperature of the Earth. — This is a far more important 
 condition. I have made for London and many other towns in 
 the kingdom a large number of charts, showing week by week 
 for many years the earth temperature at a depth of one foot 
 from the surface, and at a depth of four feet from the surface, 
 each chart showing also the diarrhceal mortality of the corre- 
 sponding weeks. The general result shown by these charts is as 
 follows : — (a) The summer rise of diarrhceal mortality does not 
 commence until the mean temperature recorded by the four-foot 
 earth thermometer has attained somewhere about 56° F., no 
 matter what may have been the temperature previously attained 
 by the atmosphere or recorded by the one-foot earth thermo- 
 meter. (5) The maximum diarrhceal mortality of the year is 
 usually observed in the week in which the temperature recorded 
 by the four-foot earth thermometer attains its mean weekly maxi- 
 mum, (c) The decline of the diarrhceal mortality is in this 
 connection not less instructive, perhaps more so than its rise. 
 It coincides with the decline of the temperature recorded by a four- 
 foot earth thermometer, which temperature declines much more 
 slowly than the atmospheric temperature, or than that recorded by 
 the one-foot earth thermometer (so that the epidemic mortality 
 
544 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 may continue, although declining), long after the last-mentioned 
 temperatures have fallen greatly, and may extend some way into 
 the fourth quarter of the year. I do not wish it to be inferred that 
 -the atmospheric temperature and the temperature of the more 
 superficial layers of the earth exert no influence on diarrhoea. 
 Their influence, however, is little, if at all, apparent until the tem- 
 perature recorded by the four-foot earth thermometer has risen as 
 .stated as above. Then their influence is apparent, but it is a sub- 
 -sidiary one. 
 
 3. Rainfall exerts an Influence -on Diarrhoea, but (so far as is 
 -apparent at present) not equally in all periods of the diarrhoeal 
 season. The diarrhceal mortality is greater in comparatively dry 
 .seasons and less in wet seasons, especially if the drought on the one 
 hand, and rainfall on the other, be remarkably protracted and 
 excessive. But here again the tendency of the inquiry has been 
 to show that the influence exerted is not direct (e.g., by a washing 
 ■of the atmosphere, so to speak), but indirect, viz., by its effect 
 mainly in preventing the rise and (probably to a less extent) in 
 hastening the fall of the temperature of the earth. 
 
 4. Air Movement. — Wind and comparative calm affect the diar- 
 jrhoeal mortality. Other things being equal, calm in the diarrhoeal 
 :season promotes it, and high winds tend to lessen it. 
 
 B. — Conditions of Locality. 
 
 5. Elevation above Sea Level. — This has apparently an influence on 
 ■diarrhoeal mortality, but not a very remarkable or powerful one. 
 It is an influence which when we regard large areas is lost sight of 
 in the midst of much more powerful influences, and is not perhaps 
 to be distinctly seen until we compare among themselves the dif- 
 ferent parts of comparatively small areas. In such areas we may 
 often see that the lower levels are more affected than the higher 
 levels ; but even here it is not easy to estimate the extent of this 
 influence on account of the disturbance of the result by other more 
 potent influences. But even when most obvious, it has appeared 
 to me that elevation is not an influence that bears specially upon 
 diarrhoea ; it affects also, and to much the same extent, mortality 
 from other causes. It seems, in short, to influence diarrhceal mor- 
 taHty only in so far as it affects infant mortality from all causes 
 together. 
 
XXXII.] DR. BALLAED ON THE ETIOLOGY OF DIAREHQEA. 545 
 
 6. Soil. — I think I am in a position to say that the influence of 
 soil is a decided one ; and that although it may be observed in 
 respect to some other causes of mortality (and so is not altogether 
 peculiar to diarrhoea), it is observable most distinctly in relation to 
 that disease, (a) Where the dwelling-houses of a place have as 
 their foundation solid rock, with little or no superincumbent loose 
 material, the diarrhoeal mortality is, notwithstanding many other 
 unfavourable conditions and surroundings, low, and may indeed be 
 altogether unnoticeable. Deep and wide and frequent Assuring of 
 a rock in a town, or superficial alternations of rock with looser 
 material, modify this immunity. (6) On the other hand a loose 
 soil, permeable more or less freely by water and by air, is a soil on 
 which diarrhoeal mortality is apt to be high. So far as I can see 
 at present, of all natural soils, sand is the most diarrhoea], other 
 things being equal, unless I class with it surface mould to a con- 
 siderable depth. Gravel (a very indefinite term, which has a 
 different meaning in different places) varies in its relation to 
 diarrhoeal mortality in proportion as the loose element of it or the 
 stony element and the size of the stones it contains vary. The 
 more gravel approaches sand in its fineness, or to rock in its coarse- 
 ness, its relation to diarrhoea appears to be greater or to be less. 
 Dwellers on loose slabby rock, as commonly seen overlying solid 
 rock, have more or less diarrhoea in proportion as the slabby 
 material is in small pieces, and mixed with looser earthy matter, or 
 in larger blocks with little intervening earth. Clay soils, other 
 things being equal, do not appear to be in themselves among those 
 soils specially favourable to high diarrhoeal mortality ; when they 
 have seemed to be so, the connection has appeared to me to 
 be otherwise explicable. A soil which is a mixture of clay, sand, 
 and stones (commonly called a " marl ") is apparently favourable or 
 unfavourable to diarrhoeal mortality in proportion as it is loose or 
 permeable on the one hand, or plastic on the other, (c) The 
 presence of much organic matter in any soil renders it distinctly 
 more favourable to high diarrhoeal mortality than it otherwise 
 would be. Such organic matter (organic fouling), however, need 
 not be specially of a fsecal or excremental nature to exert this 
 influence, hence diarrhoeal mortality is apt to be high where 
 dwellings are built upon -made ground, the refuse of towns, or upon 
 the site of market gardens ; or where the earth beneath and about 
 
 N N 
 
546 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 dwellings is polluted by neighbouring collections of liquid filth in 
 cesspits, or where sewage has soaked into it from imperfect drains 
 and sewers, or from the surface of the ground. It is the opportu- 
 nities for the collection of organic filth in the fissures of certain 
 kinds of rock that seem to impart to these rocks, where towns are 
 built upon them, a diarrhoeal character. 
 
 (d) Moisture or Dryness of a Soil. — Excessive wetness and com- 
 plete dryness of soil appear to be both unfavourable to diarrhoea. 
 A degree of moisture specially favourable is an amount of habitual 
 dampness which is decided although not sufficient to preclude the 
 free admission of air between the constituent physical elements of 
 the soil. Such a degree of dampness occurs when in the diar- 
 rhoeal seasons the sub-soil water stands sufficiently near to the 
 surface to maintain by capillary attraction the dampness brought 
 about by previously greater nearness of the water to the surface ; 
 or when the soil, as in the case of marls, contains sufficient of the 
 clayey element to imprison enough of the water saturating it some 
 time previously. It is scarcely necessary to add that the requisite 
 degree of dampness may be produced not only from a source below 
 but from a surface source — for instance, it may be the result of a 
 previous flood or of watery matter habitually soaking in from the 
 surface about houses, or from leakages of such conduits as sewers 
 or drains. 
 
 7. Density of Population. — Aggregation favours, dispersion over 
 areas disfavours, diarrhoeal mortality. There is nothing new in 
 this ; it is (together with the influence of temperature) the lesson 
 annually repeated to us by the Registrar-General who every year 
 indicates the fact that the diarrhoeal mortality of towns much 
 exceeds that of non-oppidan parts of the country, and that the 
 diarrhoeal mortality of large towns on the whole exceeds that of 
 small towns. The same general lesson is taught by the comparison in 
 particular towns of different parts of the same town, such as I have 
 instituted in the course of this inquiry. But it is to be observed 
 that the influence of aggregation of population is noticed also in 
 respect of irifant mortality from other causes : it is not limited to 
 diarrhoeal mortality, although (as shown in the provisional table) it 
 appears most marked in the case of diarrhoea. Moreover, it is to 
 be kept in mind that the parts of towns .most densely populated 
 are custoinarily the parts where the inhabitants are, of the lowest 
 
XXXII.] DR. BALLARD ON THE ETIOLOGY OF DIARRHCEA. 547 
 
 social grade, and where other conditions favourable to diarrhoeal 
 mortality are most abundantly operative. The influence of density 
 of population on the prevalence of diarrhoea is commonly much 
 less direct than in the case of such diseases as measles and scar- 
 latina, although, as will be seen later on, the malady does on occa- 
 sion spread from person to person. 
 
 8. Density of Buildings (whether dwelling-houses or other on 
 area). — This is a different thing from population on area, as may 
 be seen in almost every factory town, although, very commonly, 
 the two conditions are combined. My inquiry tends to show that 
 in a town, crowding of buildings, of whatever sort, in such a way as 
 to cover area more or less closely with buildings, promotes diar- 
 rhoeal mortality. This condition is seen in operation, for instance, 
 most distinctly in parts of factory towns where buildings other than 
 dwelling houses occupy much of the space, and where, consequently, 
 the density of resident population on the area is not so great as it 
 would be if the same space were covered wholly with dwelling 
 houses. It is probable that this difference of density of buildings 
 upon area is one of the circumstances which have to do with 
 the difference of diarrhoeal mortality between large and small 
 towns. 
 
 9. Bestridion of and Impediments to the Free Circulation of Air 
 Promote Diarrhoeal Mortality (a, about dwellings). — One cause of 
 restriction and impediment lies in the condition last mentioned : 
 this is most obvious where small dwellings are shut in among large 
 and taU buildings, as in many courts and narrow streets of factory 
 towns. Such causes also seem in operation where streets are built 
 in such a direction or are so arranged (e.g., like the mortar between 
 bricks in a wall) as that they cannot be swept by the prevalent 
 winds of the diarrhoeal season ; or where the space at the rear of 
 houses in a street, or between neighbouring streets, similarly can- 
 not be swept by currents of air, e.g., when the space between the 
 rear of the houses is narrow and the ends of such space are 
 obstructed by the buildings of a cross street or any other way. 
 Very long, narrow streets, especially under the above-mentioned 
 circumstances, are apt to preserit an excessive diarrhoeal mortality. 
 Openly built towns which from their surface configuration are so 
 arranged that impediments to the circulation of air are compara- 
 tively trifling, have, as a rule, less diarrhoeal mortality than those 
 
 N N 2 
 
548 A MANUAL OP PUBLIC HEALTH. [chap. 
 
 in which impediments abound, other things being equal. (6 
 within dwellings) : The dwellings in which the free passage of air 
 through them is most effectually prevented are those which are 
 built " back to back." Taking these then as criteria, it may suffice 
 to say, that the results of the Boards' inquiry into the mortality 
 from diarrhoea and other causes in dwelling-houses of this sort are 
 to the following effect, viz., that the absence of free domestic 
 ventilation increases very greatly and very obviously the mortality 
 from diarrhoea, and this very much more than it increases the 
 mortality from all causes put together, more indeed than it does 
 the mortality from the seven principal " zymotics " put together, 
 and very much more than it affects the mortality from all causes, 
 except these seven " zymotics." 
 
 10. Domestic Darkness and general Dirtiness of Dwellings are con- 
 ducive to Diarrhoeal Mortality.- — Dirtiness with bad ventilation con- 
 stitutes a condition known as " fustiness." It is a common-place 
 condition in the crowded and poor parts of towns, and it is very 
 much in the parts where these conditions prevail that the diar- 
 rhoeal mortality is highest. But these conditions are so associated 
 with other conditions conducive to the same result that I cannot at 
 the present time define the extent of the influence of this special 
 cause apart from them. The fact, however, is notorious. I am 
 satisfied, from my own observations, that among the same class of 
 people, the diarrhoeal mortality is greater in proportion as general 
 fustiness prevails in their dwellings. Darkness of dwellings is 
 rarely associated with cleanliness or satisfactory ventilation. The 
 influence of " fustiness " and its frequent concomitant darkness, is, 
 I think, more obvious in respect of diarrhoea than in respect to the 
 mortality from other causes. 
 
 11. Sewer or Cesspool Emanations, especially in a concentrated 
 form, and suddenly let loose, may occasion attacks of fatal 
 diarrhoea. Emanations of this sort, I think I have reason to be- 
 lieve, are of themselves capable of occasioning a diarrhoeal epide- 
 mic even in a non-diarrhoeal season of the year, and hence in 
 diarrhoeal seasons such emanations may well be believed to have 
 an influence on epidemic diarrhoeal mortality. Unusual diarrhcEal 
 mortality may, however, from time to time be observable in locali- 
 ties where there are no sewers to emit foul air, and where there is 
 no reason for believing that cesspit emanations have been previously 
 
XXXII.] DE. BALLARD ON THE ETIOLOGY OP DIAREHCEA. 549 
 
 unusual in amount, or have gained access to dwellings with 
 unusual readiness. 
 
 12. Atmospheric fouling from mere Coal Smoke or from the 
 Gaseous Emanations from Chemical Works or of Chemical Refuse 
 appears to be inoperative, at any rate in the neighbourhoods 
 habitually exposed to them, excepting so far as such atmospheric 
 fouling may lower the general standard of infant health. 
 
 13. Filthy Accumulations of Domestic Refuse in Privies, Ashpits, 
 Dustbins. — Comprising, as these do, an abundance of decomposing 
 organic material, animal and vegetable, such accumulations pro- 
 mote, wherever they exist, diarrhoeal mortality ; especially they do 
 so where free movement of air is impeded, and the atmospheric 
 fouling, due to them is consequently concentrated. Fixed recep- 
 tacles of filth may remain dangerous, even when emptied, on 
 account of the encrusted state of their walls. 
 
 14. Undefined Polluted Condition of Drinking Water has from 
 time to time appeared to give rise to epidemic diarrhoea, and 
 this irrespective of the season of the year ; but, so far as I have 
 been able to ascertain, water-pollution has little or nothing to do 
 in the way of direct causation with the diarrhoeal mortality that 
 occurs annually in this country in the summer. 
 
 C. — Conditions Eelating to the Population. 
 
 15. Social Position. — It is notorious, and especially so among 
 medical officers of health that the diarrhceal mortality of towns 
 is very disproportionately distributed among the several social 
 classes of the population, being comparatively small among the 
 well-to-do portion of the community, and comparatively very 
 great among families of the lower social grade. The more 
 closely this general belief is looked into, the more confirmation 
 it gains. Dr. Grimshaw's tables, in his paper on " Class Mortality 
 Statistics " (British Medical Journal, August 13, 1887), give 
 statistical evidence in this direction ; but a careful study of Dr. 
 Grimshaw's figures indicates that this condition influences the 
 mortality from all other causes even to a greater extent than it 
 
 • does diarrhceal mortality alone ; but although I have thought it 
 desirable to advert to this consideration, it must not be forgotten 
 how much this term " social position " involves when we compare 
 the well-to-do with the poorer classes of the community, and each 
 
55b A MANUAL OF PUBLIC HEALTH. [chap. 
 
 with an intermediate class, both as respects the localities in which 
 they severally dweU and the circumstances under which^they 
 live. ' 
 
 16. Food. — Although there is, I think, ground for the popular 
 notions which associate epidemic diarrhoea with the consumption 
 of articles of diet, the almost equally common notion that such 
 diarrhoea arises from indigestibility of food or from faulty diges- 
 tion on the part of the consumer of it is not, I am disposed to be- 
 lieve, so well founded ; rather I am inclined to think of epidemic 
 diarrhoea due to food arising through some extraneous substance 
 in the food, which substance is by itself an efficient cause of the 
 malady. 
 
 {a) As regards the influence of the mode of feeding of young 
 infants, the incidence of diarrhceal mortality upon infants fed, 
 on the one hand, exclusively on the breast, and, on the other hand, 
 partially or entirely on other kinds of food, is, of special interest. 
 The general conclusions arrived at by medical men who have 
 studied the raatter, and by medical officers of health who have 
 adduced statistics in support of their opinions thereon, are 
 generally to the effect that infants fed from the breast are re- 
 markably exempt from diarrhoea as compared with infants that 
 have been fed otherwise ; and that feeding from the bottle had 
 been principally concerned in the fatal diarrhoea of infants. But 
 my difficulty about accepting these conclusions in their entirety 
 has hitherto been absence of data as to the proportion of healthy 
 children fed in these different ways. In this difficulty. Dr. Hope, 
 the assistant medical officer of health for Liverpool, has come to 
 my assistance, and has made some comparative statistical inquiries 
 among infants in that city who were healthy, and among others 
 who had died of diarrhoea in the summer season, and the general 
 result of his inquiry, so far as I have at present worked upon his 
 tables, is this : First, that infants fed solely from the breast are 
 remarkably exempt from fatal diarrhcea, even among the low-class 
 Irish, the degree of exemption being exactly the same among the 
 Irish as among the English and other races in this city ; second, 
 that infants fed in whatever way with artificial food, to the exclu- 
 sion of breast milk, are those which suffer most heavily from fatal 
 diarrhcea; thirdly, that children fed partly at the breast and partly 
 from other kinds of food suffer to a considerable extent from fatal 
 
XXXII.] DR. BALLARD ON THE ETIOLOGY OF DIARRHCEA. 551 
 
 diaxrhoea, but very much less than those which are brought up 
 altogether by hand ; fourthly, as respects the use of the bottle, it 
 is decidedly more dangerous than artificial feeding without the use 
 of the bottle. 
 
 (6) It is to be inferred generally, from observations which I have 
 made, that the circumstances of food-keeping, of its exposure to 
 telluric emanations (e.g., as in underground cellars), or to emana- 
 tions from accumulations of domestic filth (e.g., when kept in 
 pantries, &c.), to which such emanations have more or less free 
 access, tends to render it liable to produce diarrhoea, especially 
 where the storing place for food is dark, and is not exposed to 
 currents of air. 
 
 17. Maternal Neglect and Carelessness in Infant Management. — 
 In estimating (apart from other considerations already mentioned) 
 the influences of this element of causation, I adopt as a criterion 
 the prevalence of fatal diarrhoea among infants who are illegitimate 
 as compared with its prevalence among the legitimate. The col- 
 lective experience of three places — Salford, Great Yarmouth, and 
 Scarborough — is, for all practical purposes, to this effect, viz. : 
 First, that the infants most liable to be neglected, viz., those which 
 are illegitimate, suffer exceptionally from all causes of infant 
 mortality, but from diarrhoeal mortality rather more than from other 
 causes of death. Secondly, that in years of high epidemicity this 
 greater tendency on the part of the illegitimate infants to suffer 
 from diarrhceal mortality is lost sight of Thirdly, that in years of 
 low epidemicity the tendency above mentioned is most obvious, 
 i.e., the presumably less potent or less abundant specific cause (in 
 such years) operates fatally and more easily on the illegitimate 
 than on the better-cared-for class of infants. Fourthly, in a highly 
 epidemic year this class of infants seems to suffer earlier than the 
 class of infants better cared for. 
 
 18. Occupation of Females from Home. — This which has often 
 been assigned by medical officers of health and others as a fruitful 
 cause of infantile fatal diarrhcea resolves itself mainly into the 
 question of maternal neglect, with the substitution more or less of 
 artificial feeding for feeding at the breast, matters which have been 
 dealt with in preceding paragraphs. 
 
 Having regard to the broad facts already indicated, and to 
 
552 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 others which have yet to be exhibited by me, a working hypothesis 
 or provisional explanation that would best accord with the totality 
 of the evidence in my possession, bearing on the production of 
 epidemic diarrhoea may be stated as follows : — 
 
 That the essential cause of diarrhoea resides ordinarily in the 
 superficial layers of the earth where it is intimately associated 
 with the life processes of some micro-organism not yet detected, 
 captured, or isolated. 
 
 That the vital manifestations of such organism are dependent 
 among other things, perhaps principally, upon conditions of season 
 and on the presence of dead organic matter which is its pabulum. 
 
 That on occasion such micro-organism is capable of getting 
 abroad, from its primary habitat the earth, and having become 
 air-borne, obtains opportunity for fastening on non-living organic 
 material, and of using such organic material both as nidus and as 
 pabulum, in undergoing various phases of its life history. 
 
 That in food, inside as well as outside of the human body, 
 such micro-organism finds, especially at certain seasons, nidus 
 and pabulum convenient for its development, multiphcation, or 
 evolution. 
 
 That from food as also from the contained organic matter of 
 particular soils, such micro-organism can manufacture by the 
 chemical changes wrought therein through certain of its life pro- 
 cesses, a substance which is a virulent chemical poison ; and that 
 this chemical substance is, in the human body, the material cause 
 of epidemic diarrhoea. 
 
 It will be observed that this provisional hypothesis is sufficiently 
 elastic to include as a common cause of diarrhoea chemical products 
 of bacterial life manufactured indifferently within or outside the 
 human body. 
 
 Elasticity to this extent of a provisional hypothesis has been 
 necessary for the reason that in the present state of our knowledge 
 certain cases and groups of cases of diarrhoea not distinguishable 
 from epidemic summer diarrhoea, have now and again been found 
 to possess the faculty of being directly communicable from person 
 to person. 
 
 It will be obvious that in the stools of such infective cases of 
 diarrhoea the hypothetical organism causative of the malady may 
 be looked for with good hope of success. 
 
XXXII.] DIARRHCEA. 553 
 
 (407) Practical Action to he Taken as Preventive of Diarrhaa. 
 
 The practical action a Medical Officer of Health should take in 
 
 regard to diarrhoea is, in the first place, to ascertain from mortality 
 
 statistics and from any registers of sickness which are accessible 
 
 the localities and houses in which year by year diarrhoea mostly 
 
 prevails. He will find that as a rule the same houses are attacked 
 
 with remarkable regularity; to these houses he will direct his 
 
 attention, and study drainage, water-supply and their general 
 
 sanitary conditions. One of the main objects of his research will 
 
 be the conditions under which food is stored. In the homes of 
 
 artisans and the poorer class in cities, those who can afford but 
 
 two or three rooms, it is useless to talk of a " pantry," the household 
 
 food is put into a cupboard or simply exposed in the dwelling, or 
 
 it may be sleeping room. In such cases contamination of the food is 
 
 almost impossible to prevent, but much may be hoped from the 
 
 people themselves, If the people of this class had the necessary 
 
 knowledge, they would understand that it is unwise to buy in any 
 
 stock of food of a fermentable character, such as sausages, meat, 
 
 or milk ; food only just sufficient for the day should be bought, 
 
 the milk be at once boiled, and no food eaten without thorough 
 
 cooking. In the better class of houses, besides the general details 
 
 of drainage, ventilation, &c., special attention should be paid to 
 
 the situation of the pantry, and it should be particularly noted 
 
 whether the incoming air passes over any drain or foul collection 
 
 of matter. The writer has known the air pouring into pantries 
 
 and safes where food is kept derived from defective water closets, 
 
 from close yards trapped with imperfect bell traps and from 
 
 similar places. In some districts medical officers of health have 
 
 distributed leaflets containing instructions to the people how to 
 
 preserve their children and themselves from diarrhoea. They are 
 
 told not to give their children any milk but that which has been 
 
 boiled, to keep their food in a proper place, mothers never to 
 
 suckle their children without first cleansing well the nipple, and 
 
 when diarrhoea actually occurs to thoroughly disinfect the excreta. 
 
 There can be little doubt that a certain proportion of the people 
 
 to whom these leaflets are delivered, read and profit by the 
 
 instruction. 
 
SECTION IX. 
 ISOLATION HOSPITALS. 
 
CHAPTER XXXIII. 
 
 THE PRINCIPLES OF CONSTRUCTION OF ISOLATION HOSPITALS. 
 
 (408) Infectious Hospitals. 
 
 A LARGE amount of experience, both as regards the construction 
 and administration of infectious hospitals, has been acquired during 
 the last thirty years, and the results of this experience are easily 
 accessible, thanks to the reports of Dr. Bristowe and Mr. Holmes 
 in 1863, to the inquiry of Dr. Thome Thome in 1881, and to the 
 work of the Asylums Board. 
 
 In this chapter the chief material used is Dr. Thome Thome's 
 very able summary : — 
 
 The first principle to be laid down is the absolute necessity of 
 buildings set apart for small-pox, scarlet and other infectious fevers. 
 A sanitary authority, not providing facilities for isolation, has failed 
 to fulfil one of the great purposes for which it was instituted. 
 
 The second principle is that the construction of such hospitals, 
 is best carried out with deliberation in non-epidemic times, ex- 
 perience having demonstrated that those which have been hastily 
 run up to meet sudden emergency, have provided accommodation 
 of a most indifferent kind, have failed to meet the permanent 
 wants of a district, and the cost has been in relation to usefulness 
 large. 
 
 The third principle is that smaU-pox hospitals should be at least 
 a mile from inhabited dwellings. 
 
 (409) &ite. 
 
 It is seldom that there is a free untrammelled choice of site, but 
 the considerations most weighty are (1) moderate elevation ; (2) 
 
558 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 ample and pure water supply ; (3) facilities for drainage ; and (4) a 
 dry healthy soil. The authorities generally also agree that it is 
 desirable the opposite side windows of the ward pavilions should 
 face respectively east by south and west by north. 
 
 (410) Hospital Construction. 
 
 Hospitals for infectious diseases are composed of (1) an adminis- 
 trative block ; (2) wards ; (3) outbuildings, such as wash-house, 
 disinfecting chamber, mortuary. 
 
 (1) Administrative Block. — This should always be constructed 
 in excess of the requirements of the permanent wall buildings — it 
 is by far the most important block. It would indeed be practical 
 in rural districts to rely wholly upon a good permanent administra- 
 tive block and four small permanent wards, extending the accom- 
 modation as required by means of tents or huts. The general con- 
 struction of the administrative block should of course follow the rules 
 and regulations governing the erection of niodern dwelling houses 
 generally ; it is, however, more important than even in the above to 
 shut out the ground air by means of concrete or asphalt. Most of the 
 administrative blocks have consisted of only one story, but con- 
 sidering that nurses have to take some part of their rest in the day, 
 it is preferable to have two stories ; sleeping rooms on the first floor 
 being more quiet. The smallest administrative blocks contain the 
 following : — kitchen ; scullery ; pantry, or larder ; medical officer's, 
 room 9,nd dispensary combined ; bedrooms ; one or more water-closets. 
 The larger administrative blocks contain provision for the accom- 
 modation of a resident medical officer, a mess room for the nurses 
 and staff, bathrooms, &c. The administrative blocks should be 
 some little distance from the ward buildings, communicating 
 with them by means of a covered way — this covered way is best 
 open at the sides. ., . . 
 
 (411) The Wards. 
 
 The permanent wards should be constructed of brick or stone ; 
 at Weymouth concrete has been used advantageously. Corrugated 
 iron hospitals lined with matchwood and wooden huts have all 
 been failures as regards temperature and comfort. 
 
 "At Nottingham, where the two layers of wood forming the 
 walls are six inches apart, the interspace being filled with sawdust, 
 
 / 
 
 i 
 
xxxm.] ISOLATION HOSPITALS. 559 
 
 it was on one occasion found impossible even when large fires were 
 maintained niglit and day to raise the temperature near some of 
 the beds beyond 32° F. In the Alcester rural district, where there 
 is a very similar building, the temperature was found in the winter 
 of 1880-81, and under the same conditions, to fall to 38° F." 
 
 If attempts be made to remedy these inherent defects then the 
 initial cost is brought up to that of stone or brick buildings, while 
 the maintenance is greater and the durability les^. 
 
 The wards iisually consist of a single story, but there may be 
 reasons, such as limited area of site, to prefer two stories rather 
 than encroach upon the airing ground. 
 
 There must be ample space for the whole of the wards and 
 buildings, the number of patients per acre should not be more than 
 twenty. The floor space per patient should be 144 square feet as 
 a minimum, the cubic space at least 2,000 cubic feet, the window 
 surface should be in the proportion of 1 square foot to about every 
 70 cubic feet. Excessive window surface is to be avoided. 
 
 Dr. Angus Smith, F.R.S., made some careful experiments as to 
 the ventilation of the Children's Hospital at Pendlebury, which 
 has window surface in the proportion of 1 square foot for every 
 35 cubic feet, but it was found that owing to this extent of window 
 surface the ward air could not be kept pure and at the same time 
 equably warm. 
 
 If according to these principles a ward for four patients be de- 
 signed, the floor might be 24 feet square, and 14 high, which will 
 give 2,000 cubic feet per bed and 144 square feet of floor space per 
 bed, the windows 4 in number may be 3 X 5 feet, giving 1 square 
 foot to every 88 cubic feet. The windows should serve the purpose 
 of both lighting and ventilation, hence the double hung sliding 
 sash window is the best type. The position of the windows should 
 be opposite each other, one being in the centre of each side wall, 
 the others near the angles beyond each end bed. The walls should 
 be lined with Parian cement or glazed bricks, so that they can be 
 readily washed and disinfected. All architraves, cornices and 
 ledges where dust could collect must be avoided. 
 
 (412) Ventilation. 
 
 However efficient windows of the class mentioned may be as 
 ventilators, in all cases Tobin's tubes should also be placed at the 
 
560 A MANUAL OP PUBLIC HEALTH. [chap. 
 
 angles of the walls ; and experience has shown that in order to 
 change quickly and completely the air of the wards at least twice 
 daily, openings must be made at the floor level — these openings 
 should be capable of being closed by a sliding door — two will be 
 enough on opposite sides, but they should be of considerable 
 length, 4 feet by 6 inches. 
 
 The superior results of mechanical ventilation in the case of 
 schools has been referred to at page 85, and the same remarks 
 apply to hospitalsi 
 
 (413) Warming. 
 
 A small ward like the one suggested may be warmed by an open 
 fire-place — Green's grate is a good one for the purpose, the grate 
 may be at either end. A larger ward would probably have to be 
 heated by pipes or by centrally placed stoves. 
 
 (414) Closets. 
 
 A closet should be placed at the end of the ward, a small lobby 
 having cross ventilation being interposed. If a water-closet be 
 used it should be provided with an automatic disinfecting 
 apparatus discharging either 90 per cent, phenol into the pan, or 
 a 2 per cent, solution of corrosive sublimate.^ It would be still 
 better if the dry system were adopted for the excreta, using saw- 
 dust which has been saturated with petroleum and burning it in a 
 special crematory furnace. 
 
 (415) Sinlis — Drainage. 
 
 The ward must have a sink to throw slops down, and this 
 necessitates a drain. No evil is recorded to have resulted from 
 connecting fever hospitals with the public sewer system, but if 
 there are no sewers available the ward and other buildings can 
 drain into impervious cesspits of proper construction, the drainage 
 of course being trapped, and provided with ventilating shaft and 
 disconnecting chamber. In some places where the local conditions 
 are favourable sub- soil irrigation has been successfully employed. 
 
 ^ Dissolved by tlie aid of ammonium chloride. 
 
XXXIII.] ISOLATION HOSPITALS. 561 
 
 (416) Furniture,. 
 
 The four bedsteads must be of iron, and have wire-coil or wire- 
 spring mattresses — so as to form a bedstead and mattress in one, 
 and then horse-hair beds placed upon them ; the latter easily admit 
 of disinfection in a hot-air apparatus, and the wire-coil mattresses 
 can be washed and cleaned in situ. There may be a few rugs on 
 the floor, or pieces of carpet, for these are easily cleaned and freed 
 from infection. 
 
 A laundry is an essential part of the hospital, and should form 
 an annex to the administrative block. 
 
 (417) Disposal of the Dead. 
 
 The bodies of patients dying of small-pox as well as those dying ' 
 of typhus, it is certain are highly infectious ; but there is not an 
 equal amount of evidence as to infection from scarlet fever ; never- 
 theless it is safest to treat the corpse in all cases as likely to be 
 injurious to the living, save in the presence of strong disinfectants. 
 Cotton wool steeped in a 5 per cent, alcoholic solution of corrosive 
 sublimate should be packed carefully into the mouth, the nostrils, 
 ears, and other apertures of the body, the whole surface of the body 
 should then be sponged with a saturated aqueous solution of the 
 same salt, and finally packed in sawdust mixed with sanitas pow- 
 der. In this way a fairly perfect disinfectant combined with con- 
 cealment of foul odours is attained. 
 
 The mortuary proper, that is the space within which the bodies 
 themselves are placed, should be well ventilated. For this purpose 
 there should be oblong openings close to the floor covered with 
 wire gauze, and swing windows also protected by gauze to prevent 
 the entrance of flies, and by blinds to shade off direct sunlight. 
 
 (418) The Local Government Board Hospital Plans. 
 
 Plans have been issued by the medical department of the Local 
 Government Board,^ as a guide to local authorities in the construc- 
 tion of hospitals. The first plan is that of the smallest hospital, 
 simply consisting of a cottage-like building to hold two patients 
 ' Seventeenth Annual Report (Supplement), p.. 199. 
 
 
 
562 A MANUAL OP PUBLIC HEALTH. [chap. 
 
 of each sex. A second plan is that of a larger but still small 
 hospital for six patients, with separation of sex, and also of one 
 infectious disease from another. The building is a long narrow 
 one, and should face north and south if the site allows. The men's 
 wards have a verandah on one aspect, the women's on the other. 
 The roof of the verandah is so planned that it does not run close 
 to the eaves, but to a point which marks the division of the window 
 into sash and hopper. The wards and the nurses' rooms open 
 direct on to the verandah ; this is surely objectionable, and the 
 addition here of a lobby would be an improvement. 
 
 The third and fourth plans are here reproduced, the one being 
 a plan for a pavilion of twelve beds, the other being a plan of a 
 block for ten beds. In all these plans provision is made for 144 
 square feet of floor space, 12 linear space of wall space, and at 
 least 2,000 cubic feet of air space per bed. The block plan would 
 be improved by the addition of lobbies to the doors opening into 
 the verandah, and one or two windows for the purpose of better 
 ventilation in the long blank wall of the end wards. The absence 
 of a proper bath-room also invites criticism. Nor in cold weather 
 will it be very comfortable for patients well enough to move about 
 to have to brave the cold draught in the verandah to use the 
 closet ; but these details evidently admit of remedy. 
 
 It is, lastly, to be mentioned that the four plans all presume 
 that the boundary fence is at least 40 feet from the hospital 
 buildings. 
 
 (419) The BuperinteTidence and Management of Ho^itals. 
 
 The principles of the management of infectious hospitals are, so 
 far as daily routine and discipline goes, no different from those 
 of other institutions, but there are special points to be considered 
 with regard to preventing the spread of infection by the nurses, 
 attendants, patients, visitors, and their friends. 
 
 The following rules,^ adopted by the Asylums Board, are all 
 that in practice will be found to work ; if rules are too stringent 
 they fail from impracticability. The Asylum Board rules are good 
 
 ^ These rules are extracted from the Mamml of Regulations of the Asyhims 
 Board. Of course the rules selected are only those which are in one way or the other 
 connected with infection. 
 
<-..40.. 
 
 — a 
 
 
 EXAMPLE OF ARRANGEMENT OF BUILDINGS 
 ON A RESTRICTED SITE 
 
 Plan 1 
 
 PLAN OF A WARD PAVILIo|n FOR 12 BEDS 
 
 PLAN OF A BLOCK FOR TEN BEDS 
 
 Plan 2, 
 
 R.S. R.CLARK, PRINTERS, EQIflBLiRGH 
 
XXXIII.] DUTIES OF HOSPITAL STAFR 563 
 
 common-sense precautions, and may be well taken as a model, little 
 details being altered to suit local requirements ^ — 
 
 (420) DiUies of Nurses. 
 
 To see that the clothing found upon each patient is sent to the 
 disinfecting room. 
 
 To see that all soiled and dirty linen be set aside, and sent to 
 the patients' laundry at the earliest possible opportunity. 
 
 In every case of death to superintend the washing, laying out, 
 and shrouding of the corpse, and to give orders for its removal to 
 the mortuary. 
 
 To be careful that all dust, rags, and combustible refuse of 
 any kind from the wards are burnt, and not thrown into the 
 dusthole. 
 
 (421) Duties of the Laundry Superintendent. 
 
 To see that all ai-ticles are placed in the disinfecting tanks 
 separately, and not in bundles. 
 
 (422) Duties of the Gate Porter. 
 
 To keep the gates, and to prevent any person not being a 
 principal officer of the hospital, or a visitor to a principal officer, 
 or an officer of the Board of Management, an inspector of the 
 Local Government Board, a minister of religion, or any other 
 person authorised by law, or by the Local Government Board, or 
 Board of Management, from entering into or going out of the 
 hospital without the written leave of the medical superintendent, 
 or of the steward or matron acting under his authority. 
 
 To keep a book to be supplied by the Board of Management, in 
 which he shall enter the name of every officer, and the name and 
 business of every other person who shall go into or out of the 
 hospital, together with the time when such officer shall go in 
 or out. 
 
 Not to allow any male or female subordinate officer to pass the 
 gates in the uniform or dress worn in the hospital. 
 
 To understand that unless a patient's name is entered in the 
 visiting book as being in a dangerous condition, he or she is 
 progressing favourably. 
 
 o o 2 
 
564 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 The contractors are not to employ in the delivery of stores at 
 the hospitals any person who is not certified by the medical 
 superintendent as having been efficiently vaccinated or revaccin- 
 ated. The gate porter will see that the conditions of this 
 resolution are complied with. 
 
 (423) General Regulations. 
 
 No member of the staff is permitted to leave the hospital pre- 
 mises without having first entirely changed his or her wearing 
 apparel. 
 
 Nurses and those attending patients are to be permitted to leave 
 the ward half an hour before leave commences, for the purpose of 
 entirely changing their wearing apparel, and if possible taking a 
 bath. 
 
 (424) Regulations as to Condition of Patients. 
 
 Upon the admission of a patient, a letter with a copy of the 
 regulations is to be sent to the nearest known relative or friend, 
 setting forth the state of the patient ; should any serious change 
 for the worse take place, a letter is to be sent daily to the relative 
 or friend, stating how the patient is progressing, which letter is to 
 be continued until the patient is in such a condition as to render 
 further communications unnecessary ; but should the patient be- 
 come dangerously ill, notice is to be sent by the steward of the 
 hospital to the nearest known relative or intimate friend, with an 
 intimation that the patient may be visited ; and the steward may, 
 at the discretion of the medical superintendent, and subject to the 
 approval of the Committee of Management, make arrangements 
 for the conveyance of the visitor to and from the hospital. 
 
 Applications for information as to the condition of patients must 
 be made in writing to the medical superintendent, who will reply 
 by return of post. It is very undesirable that friends of patients 
 should personally make inquiries at the hospital. 
 
 (425) Visiting. 
 
 The visiting of patients is to be limited to the nearest relatives 
 and intimate friends of patients dangerously ill. One visit only 
 
XXXIII.] DUTIES OF HOSPITAL STAFF. 565 
 
 will be allowed daily to each patient. Visits, which will not be 
 permitted without the permission of the medical superintendent, 
 are, as a rule, to be limited in duration to a quarter of an hour. 
 In urgent and special cases, however, the medical superintendent 
 is empowered to increase the number of visitors to two, and to 
 extend the duration of the visit. 
 
 Visitors are warned that they run great risk in entering the 
 hospitals. They are advised not to go into the wards of the small- 
 pox hospitals without having been properly re vaccinated, and if 
 they reside where the case visited occurred, are earnestly re- 
 quested to urge the remainder of the occupiers of such house to 
 call at once on the public vaccinator (whose address can be 
 obtained from any of the parish officers) for the purpose of being 
 vaccinated. 
 
 Visitors are further advised not to enter the wards of any of the 
 hospitals when in a weak state of health, or in an exhausted con-- 
 dition, but to partake of a good meal before entering the hospitals. 
 They will be required when in the wards to carefully avoid touch- 
 ing the patient, or exposing themselves to his breath, or to the 
 emanations from his skin, and will not be permitted to sit on the 
 bed or handle the bedclothes, hut will be allowed to sit on a chair 
 by the bedside at some little distance from the patient. 
 
 Visitors will also be required to wear a wrapper (to be provided 
 by the Board) to cover their dress when in the wards, and to wash 
 their hands and face with carbolic soap and water before leaving 
 the hospital, or to use such other mode of disinfection as may be 
 directed by the medical superintendent. 
 
 Visitors are strongly urged not to enter any omnibus, tram 
 car, or other public conveyance, immediately after leaving the 
 hospital. 
 
SECTION X. 
 FOOD. — DIET. 
 
CHAPTER XXXiy. 
 
 THE PRINCIPLES OF DIET. 
 
 Foods are scientifically divided into : — 1. Water. 2. Meaty or 
 albuminous. 3. Starches or Carbohydrates. 4. Fats. 6. Mineral 
 matters. 
 
 (426) Water in Food. 
 
 This varies much ; some succulent fruits contain quite 90 per 
 cent, of water ; green vegetables from 60 to 90 per cent. Meat 
 about 75 per cent. Artificial baked products such as rusks contain 
 the least water. 
 
 Hence it is not absolutely necessary to replace the fluids of the 
 body by water per se, there are at the present time in England a 
 few persons who affirm that they drink neither tea, coffee, soup, 
 fermented nor unfermented liquids. They obtain the necessary 
 water entirely from fruits such as oranges and vegetables, such as 
 water melons, and the like. 
 
 The amount of water, taken as water or in the shape of liquids, 
 such as tea, coffee, soup, or beer, varies much according to custom, 
 to climate, and to exercise ; in our own climate two and a half pints 
 daily may be put as a sufficient quantity ; the water in the solid food 
 will amount to about two pints, making a daily total of four and a 
 half pints. 
 
 Water is entitled to the name of food, for it does not act merely 
 as a dilutent of the secretions, or a solvent assisting excretion, but 
 it helps to build new tissue and to repair old. When deprived of 
 food and water it is the latter want that is felt the soonest ; if water 
 
570 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 be supplied, involuntary as well as intentional experiment has shown 
 that life may be sustained without food even for so long a period in 
 some individuals as forty days, always provided that there are no 
 additional strains upon the system, such for example as bodily 
 exertion or mental distress. 
 
 (427) Albumimms Materials. 
 
 The albuminous matters are so called because their type is that 
 of the albumen of the egg. The albumens are contained both in 
 vegetable and animal substances. The careful auto-experiments of 
 Rutgers ^ have shown that weight for weight there is no difference 
 in nutritive power between vegetable and animal albumen. 
 
 The chemistry of the albumens has not been thoroughly worked 
 out, but it is certain that the albuminous molecule is of great com- 
 plexity. 
 
 Sulphur is an essential constituent of most of the albumens 
 which have hitherto been isolated ; it is probable that this sulphur 
 plays an important part in nutrition, supplying the sulphur for the 
 sulphur acids of the bile, and assisting to build up albuminous 
 tissues. 
 
 That the body requires a daily supply of some form of nitrogen- 
 ous food is conformable both to experience and theory. All the 
 important functions of the body are carried on by nitrogenous fluids 
 or solids. The muscles abound with nitrogen, the brain, the ner- 
 vous system, the blood, the fluids of the body, and the cells contain 
 nitrogen, and this not as an accidental but as a leading constitu- 
 ent. Nitrogen is indeed so intimately associated with life, that 
 wherever it is found in combination it would seem to be derived 
 from present or past life. 
 
 A purely meat diet can sustain life indefinitely, but it must 
 be remembered that such food is not simple, it is complex, for 
 meat contains fat, sugar (carbohydrate), albumen, and salts. The 
 nitrogen of the food mainly leaves the body as urea by the urine, 
 there is also a rather large number of other nitrogenous constitu- 
 ents, but their total weight in comparison to that of urea is not 
 large ; a small portion of undigested and a smaller portion of secre- 
 tory nitrogen leaves the body by the alimentary canal. 
 
 ' Public Health, vol. i., p. 21. 
 
XXXIV.] FOOD— THE NITROGEN QUESTION. 571 
 
 (428) The Relation of Nitrogen to Work. 
 
 The idea was long held that in muscular exertion the muscle 
 wasted, and that to repair this waste a certain quantity of nitrogen- 
 ous matter " flesh formers " was required. This is now known to 
 be erroneous, so far from muscle wasting on exertion it often 
 grows ; a person, for instance, living a sedentary life and then going 
 methodically to work to train his muscular system, if healthy and 
 young, shows a decided increase in the hardness, the power and 
 the bulk of his muscles at the end of a few weeks. Should the 
 exercise be continued, he reaches a point at which the muscle 
 neither grows nor diminishes. On the other hand, if he return 
 to his desk, in a longer or shorter time, the muscles go back to 
 their flabby and sedentary state. Hence so far from wasting by 
 exercise it may be shown that if there is any change it is rather 
 the other way. 
 
 The most recent experiments show that the body stores up 
 nitrogenous substances to a certain point, and that if the outside 
 nitrogenous matters be cut off the stores are drawn upon ; but 
 that a man taking a regular diet and following a regular occu- 
 pation is in a state of nitrogenous equilibrium," that is, the output 
 is equal to the income ; the equations rarely balance exactly day by 
 day, but taking a series of days, the mean result is remarkably equal, 
 and it is thus seen the output of nitrogen has for its dominating 
 cause the amount taken in. It is not now held that the food of the 
 muscles is par excellence the albumens, but rather the carbohy- 
 drates, the muscles being looked upon as the parts of a grand oxidiz- 
 ing machine in which the carbohydrates are burned up into water 
 and carbon dioxide. It is far more probable that the nitrogenous 
 matters are chiefly used up in the secretions, and are the food of 
 the blood. They at all events increase tissue change to a consider- 
 able degree. 
 
 The storage of nitrogen is a normal endowment of the living 
 body, by its aid the resources of the body are economized ; nitrogen 
 storage is not the only storage ; sugar is stored in the liver to be 
 given out as the system requires it ; fat is accumulated in a number 
 of parts, and sulphur, from some experiments of the author, seems 
 also to be stored. 
 
572 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 If nitrogen is cut off, the store are drawn upon, but when a 
 normal diet is again taken, that which has been diminished is 
 replaced by marked storage or retention. Any sudden and severe 
 exertion draws heavily upon the nitrogen. 
 
 For example, in one of Mr. North's ^ numerous experiments in 
 which he walked thirty-two miles in eight-and-a-quarter hours, the 
 nitrogen at once rose far above the daily excretion, and. continued 
 for several days to be above the normal. Notwithstanding that 
 , with the exception of bodily labour or rest, the conditions of food 
 (intake), as to both quantity and quality were identical ; the out- 
 put of total nitrogen, sulphates and phosphates may be traced by 
 means of the diagram, the thirty-two miles walked on the 28th is 
 indicated by a vertical line. 
 
 (429) Quantity of Nitrogen Required. 
 
 The quantity of nitrogen required in the form of vegetable or 
 animal albumen, is not known with the greatest accuracy ; but 
 this is certain, that the quantity has been a little overstated by 
 writers on. the subject. Mr. North, a man weighing about 131 
 lbs., and living upon an experimental diet, found nitrogen accumu- 
 lation to take place when the daily supply did not exceed 17'6 
 grms. (284"4 grains), hence the limit for this particular individual 
 must be below 17"6 grms. 
 
 In experiments made by the author, in which a man weighing 
 122 lbs. lived on whole meal products and distilled water for 
 twenty-eight days, there were indications that 175 grains of 
 nitrogen, had the carbcn been increased, would have maintained 
 the bodily weight ; the diet sufficient according to the late Dr. 
 Lewis ^ to maintain Hindoos, of the average weight of 110 lbs. con- 
 tains 207 grains of nitrogen. Indoor operatives in England support 
 life and body weight on a diet which averages about 179 grains of 
 nitrogen. From all the facts I gather that the nitrogenous limit is 
 something near 1'78 grain per pound of body weight ('25 gram per 
 kilo); in other words an adult of the standard weight of 150 lbs. 
 would require 267 grains. This, be it noted, is a minimum, but 
 
 1 Proceedings of the Boyal Society, No. 241, 1885. 
 ^ Proceedings of the Boyal Society, vol. xlv. 509. 
 
XXXIV.] FOOD.-CARBOIIYDRATES AND FATS. 573 
 
 when the inquiiy is what is a safe average for use in calculating 
 diets, the answer is something near 290 grains ; Moleschott put it 
 higher, viz., 316 grains. 
 
 (430) Carbohydrates. 
 
 The type of the carbohydrates is sugar or starch, and the com- 
 position of both sugar and starch is simply that of a union of 
 carbon and water ; bence the name " carbohydrate." The molecular 
 weights of sugar and starch are however not identical. The 
 chemical formula for starch being CgHj^gOj, or six atoms of carbon 
 united intimately with five atoms of water (HjO) ; the chemical 
 formula for cane sugar is ^I'^ifin, or twelve atoms of carbon 
 united with eleven atoms of water. It follows that the percentage 
 composition of both when carefully dried is the same. Thus : — 
 
 Carbon 44 "4 5 per cent. 
 
 Hydrogen 6-06 1 ^. „.55 
 
 Oxygen 49-49/ " '™ 00 oo „ „ 
 
 The four chief carbohydrates taken in food are ordinary cane 
 sugar, glucose, sugar of milk, and starches, such as wheat starch in 
 bread, oat starch in oatmeal, rice starch in rice, and so forth. It 
 must also not be lost sight of, that meat contains a carbohydrate 
 (inosite). When a larger quantity of carbohydrate is consumed 
 than is necessary for the needs of the body, it is stored up in the 
 liver under the form of glycogen, and given out to the blood as 
 required ; hence a healthy person will never have more sugary 
 substances in his circulation and secretions than normal. When 
 this storehouse faculty of the liver becomes profoundly out of 
 order, the disease known as diabetes is produced. 
 
 (431) Fats. 
 
 All ordinary fats are combinations of fatty acids with glycerin ; 
 for instance, palmitin is a union of three molecules of palmitic acid 
 with one of glycerin, stearin is the union of three atoms of stearic 
 acid with one of glycerin ; olein, caproin, carpylin, are all of 
 analogous composition. Glycerin having the formula C3H5 (HOjg, 
 it is obvious that instead of the three hydroxyls being replaced by 
 three of the same fatty acid, they may be replaced by two fatty 
 
574 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 acids of one kind and one of another, or even tbree dififerent fatty 
 acids, as for example : — 
 
 l( 18 35 2/9 ■ 1 • • 
 
 C3H5 S p( -rj n ' ~ Distear palmitin. 
 
 I '-'16 "-31^2 
 Cl8H3602 
 
 CgHg ' CjgHggOa = Stear-oleo-butyrin. 
 
 Animal fats afford several instances of this complex composition ; 
 butter, for example, used to be considered as mainly composed of 
 olein, stearin, palmitin, butyrin, with smaller quantities of caproin, 
 caprylin, and rutin. The author has however shown that it is im- 
 probable that tributyrin exists in butter save in small quantities, 
 but that the 6 per cent, of soluble acids are in the main united 
 with glycerin as complex ethers. Animal fats generally are neutral 
 in composition, not a few vegetable fats have a small quantity of 
 free fatty acid. The fats when heated to 220° C. in a silver lined 
 iron closed tube, with a little water split up into fatty acids and 
 glycerin ; they are also decomposed by treatment with superheated 
 steam, but the ordinary method used by the analyst is to saponify 
 with potash or soda, and thus unite the fatty acid with the alkali, 
 subsequently decomposing the soap with a mineral acid. 
 
 Fat when it reaches the first part of the intestines is emulsified 
 by the pancreatic and other secretions, and is believed to be in 
 great part absorbed as fat, but some portion is undoubtedly 
 saponified. 
 
 The fat of the body is not entirely formed from the fat consumed. 
 Lawes and Gilbert gave a pig food which contained one hundred 
 parts of fat, but the fat produced in the pig was four hundred and 
 seventy-two parts, or almost five times as much as that given as 
 fat. Bees fed on pure sugar and water will produce wax. The 
 accepted view from the foregoing and other experiments is that 
 fat is formed partly from fat, partly from carbo-hydrates, and partly 
 from albuminous matters. 
 
 (432) Mineral Matters. 
 In the pipe bowl of the earth, a slow oxidation by means of the 
 air goes on for ever ; beast and bird, king and peasant, are burnt 
 
XXXIV.] DIGESTIBILITY OF FOODS. 575 
 
 up ; Tiotliing remains but an ash. The phosphates of lime, mag- 
 nesia, the chlorides of potassium and sodium, a little iron, silica, 
 fluorine, and a few other substances, may be mechanically dis- 
 sipated but preserve their form, when brain and nerve, muscle and 
 all else that has built up the fabric of life has been totally changed 
 to gaseous or fluid elements.' 
 
 A certain proportion of mineral substances is necessary for the 
 .development of growth, and for the maintenance of vigour. Dur- 
 ing growth when bone is being formed, lime and magnesia is 
 absorbed and retained, but in the adult it is capable of proof, that 
 there is mineral equilibrium, the earthy phosphates taken in are 
 excreted by the bowels and kidneys. Mineral matters abound in 
 food, seeds such as wheat are characterized by a large content of 
 phosphates, leaves such as cabbages, roots such as turnips or 
 carrots, give an ash in which the phosphates are comparatively 
 speaking much less than in seeds. Fruits give ashes rich in car- 
 bonates derived from organic acids. The only mineral matter 
 there is any craving for, is salt. Common salt is in all the fluids 
 of the body, and seems a necessary constituent. 
 
 The malady called " rickets " is mostly of tuberculous origin. It 
 was at one time thought to be due to a deficiency of phosphates in 
 food, an improbable origin, for it would be difficult with a mixed 
 diet to starve the tissues of opportunity of obtaining their phos- 
 phates ; the condition of the bones in rickets is rather due to a 
 want of power in the body to assimilate the phosphates and 
 mineral substances presented to them. 
 
 (433) Digestibility of Foods. 
 
 It was early discovered that a chemical analysis of food was no 
 accurate measure of its utility as a food ; weight for weight foods 
 of approximately the same composition have different values when 
 passed through an animal body. Digestion is always imperfect ; 
 if it were perfect, that which passes away should not be able to 
 nourish other animals ; but this is so far from being the case that, 
 to take an example, horse's dung will abound in particles of the oat 
 or whole grains, so little acted upon as to be a food for birds. 
 
 ' "Diet in Kelation to Health and "Work," by A. Wynter Blyth. Eealth Exhibi- 
 tion Hand-hook. London, 1884. 
 
576 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 Hence if it could be found what amount of food completely absorbed 
 would maintain a particular individual in health, yet that person 
 would have to eat over and above the quantity, just as the stoker 
 of a steam-engine has to supply the fire with an excess of coal 
 over the theoretical quantity required to drive the engine. Again, 
 if by careful concentration of very digestible nutriment into a small 
 bulk it is attempted to feed a person for a long time, considerable 
 discomfort is produced, because the intestines require a certain 
 bulk before they are stimulated to peristaltic action, and the re- 
 sulting constipation from such concentrated food is likely to 
 produce general disorder. 
 
 The various degrees of digestibility of foods have been found out 
 in the following ways : — 
 
 (1) By experiments in the laboratory; the chemist submitting 
 different foods to the action of the juice of the pancreas; of the 
 stomach, &c. at a regulated heat for a regulated time. 
 
 (2) By experiments on the human body, in those rare cases in 
 which a fistula or opening leading into the stomach has been 
 caused by disease ; or in healthy people, watching the stages of 
 gastric digestion by the removal of the products by the stomach 
 pump. 
 
 (3) By experiments on animals in which an artificial opening 
 into the stomach has been made. 
 
 (4) By analysis of " the income and output," i.e., of the food 
 going into the body, and of the food residues (excreta) which 
 pass out of the body. 
 
 Of these methods the last is by many degrees the most certain, 
 for no unnatural condition or element is introduced; besides 
 which, a food residue, which has passed the length of the whole 
 canal, may with more confidence have its value subtracted from 
 the food, than a food residue which has been submitted to the 
 action of a small portion of the canal. In this last method of ex- 
 periment in some cases a simple food has been taken, as for 
 example, whole meal bread, in others a complex diet. With regard 
 to feeding men or animals on simple foods it must be borne in 
 mind that the digestible value of the food thus obtained may not 
 be the same as when mixed with other foods, that is to say, that if 
 a certain proportion of A is digested when taken alone and a certain 
 proportion of B is digested when taken alone, and then equal parts of 
 
XXXIV.] 
 
 FOOD. 
 
 577 
 
 A and B are given it does not follow that the digestible value of 
 A and B will be the mean of the values found when they were 
 exhibited separately, for under these circumstances sometimes 
 more, sometimes less of one or the other constituent is digested. 
 There are also individual differences in power of digestion ; thus 
 the author found that in his experiments on whole meal bread, one 
 individual digested 88 per cent., another quantities varying from 
 83 to 84 per cent, of the dry substance. 
 
 The following table gives mean values according to the results 
 of various experimenters : — '^ 
 
 
 Parts digested of 
 
 100 parts of the 
 
 perfectly dried 
 
 solid. 
 
 Amount of solid food 
 
 passing away from 
 
 the body by the 
 
 alimentary canal. 
 
 Sugar . . . 
 
 100-00 
 
 
 Eice • 
 
 96-0 
 95-00 
 
 . . ■. 4-00 
 
 "Wheaten bread 
 
 5-00 
 
 Roast meat . 
 
 94-80 
 
 5-20 
 
 Hard boiled eggs 
 
 94-75 
 
 5-25 
 
 Milk and cheese in tbe proportion of 2 '4 : 
 
 1. 94-00 . 
 
 6-00 
 
 Corn flonr ... .... 
 
 93-30 . 
 
 6-70 
 
 Milk and cheese in the proportion of 2 : 
 
 1 . 93-20 . . 
 
 6-80 
 
 Milk (830 parts of fluid : 100 of solid . 
 
 91-0 
 
 9-00 
 
 Potatoes 
 
 90-60 
 
 9-40 
 
 Eye bread . . ... 
 
 88-9 
 
 . 11-1 
 
 Milk and cheese equal parts of dry solids 
 
 88-7 
 
 . 11-3 
 
 Whole meal made into bread or cakes . 
 
 84-5 
 
 . . 15-5 
 
 Black bread 
 
 83-0 
 
 17-0 
 
 Carrots, Celery, Cabbage 
 
 76-0 
 
 24-0 
 
 Peas, Beans 
 
 52-4 
 
 47-6 
 
 Gelatin 
 
 50-0 
 
 50-0 
 
 The word digestion in the table is used in its physiological 
 sense, that is, digestible foods of which small residues leave the 
 body — indigestible foods of which large residues leave the body, it 
 does not at all follow that the latter cause discomfort. The popular 
 meaning of " indigestible " is at variance with the above, for it is 
 used to denote those foods which by evolving gas cause distension, 
 or by the formation of soluble products give rise to headache, 
 nausea, or other signs of slight poisoning. 
 
 1 In particular the experiments of Rubner, Zeitschrift f. Biologie, 1879, s. 118 ; 
 of G. Meyer, ibid., 1871, I. ; of A. Stnimpell, Centr. f. medicin. Wissen., 1876 ; of 
 H. Weiske, Zeitsch f. Biol., 1870, s. 456 ; and of the author, in Proceedings of the 
 Boyal Society, vol. xlv. 
 
 P P 
 
Ozs.l 
 
 
 Grains. 
 
 
 4-2 
 
 = 
 
 290 nitrogen. 
 
 
 18-7 
 
 = 
 
 4184-4 carbon. 
 
 
 1-05 
 
 = 
 
 459 '3 mineral 
 
 substances. 
 
 578 A MANUAL OF PUBLIC HEALTH. [chap 
 
 (434) The Standard Diet. 
 
 A large amount of work has been done in comparing and 
 chemically analysing foods of various nations and of persons of 
 various ages and occupations ; and the results have been reduced 
 to food equivalents, so that it is now known what quantity of the 
 four constituents of solid food is necessary to support ordinary 
 labour. 
 
 The standard diet for adult men of the average weight of 150 lbs. 
 in this climate is as follows : — 
 
 Albuminoids 
 Fat . . . 
 Carbohydrates 
 Salts . . 
 
 (435) Construction of Dietaries. 
 
 The Medical Officer of Health is rarely called upon to construct 
 a dietary, but he may often have to criticise one and to reduce it 
 to equivalents. 
 
 In the construction of a diet, it is not enough to ensure that the 
 proper quantity of albuminoids,^ fat, sugar, and mineral substances 
 are supplied ; but there must be variety, and there must be, 
 especially in cases where salt meat is taken, fruits, or fresh vege- 
 tables introduced, in order that scurvy be prevented. From a food 
 chemist's point of view the statute compelling British shipowners 
 to supply sailors with a daily amount of limejuice, should be 
 
 ■• The nitrogen in grains may be calculated by multiplying the albuminoids (ozs. ) 
 by 69, the carbon by multiplying by 233. The carbon derived from the fat may be 
 obtained by multiplying by 345 '6, and from the carbohydrates other than sugar by 
 multiplying by 194 2. 
 
 ^ Whether the albuminoids are derived from the vegetable or the animal kingdom 
 entirely is a matter of indifference, and mainly regulated by custom. Vegetarians 
 have taken much pains to show that meat is unnecessary and even hurtful, but the 
 truth is that there are whole tribes who live on meat alone and enjoy high health, 
 others living on fruits and vegetables alone who also enjoy high health. The ques- 
 tion of vegetarianism is not to be settled by chemical research, it is rather a question 
 of morality and iestheticism. On both these points the position of the vegetarian is 
 on extremely. strong one, and it is a pity that he should weaken it by arguments 
 drawn from comparative anatomy and other sources which have only an indirect 
 bearing upon the subject. 
 
xxxiv.j 
 
 DIETAEIES. 
 
 579 
 
 repealed, for it acts indirectly in permitting bad salt food to be 
 given, and so long as tbe regulated amount of limejuice be served 
 to the men the owners escape punishment ; the common sense 
 method is to allow shipowners perfect freedom to feed the men 
 how they please ; but should scurvy break out on a vessel and it 
 be proved to be due to an ill-arranged dietary, then subject the 
 parties responsible to a severe penalty. With the numberless con- 
 trivances to dry, tin, or bottle vegetables there is absolutely no 
 need for lime juice. 
 
 In the construction of diets and also in their comparison use may 
 be made of the following tables. 
 
 The way the tables are to be used is best shown by an example. 
 A dinner consists of 2 ozs. of moderately fat beef, 4 ozs. of potatoes, 
 4 ozs. of cabbage, and 5 ozs. of bread, it is required to express this 
 in food equivalents. 
 
 The percentage composition of fat beef will be found in Table 
 XL VII. hence, as it is now required to know the " equivalents o f 
 2 ozs." ; each of the numbers in the table will have to be multiplied 
 by xJtt, that is '02, the result will be, water 1'44! oz., albuminoids "^S, 
 fat '10 ; ash (mineral substances) 03. Similarly the percentages 
 of the components of the potato (Table LI.) have to be multiplied 
 by XCT7 or 'O^^, of the cabbage (Table LI.) by ywtt o^ "04, and the 
 percentages of bread by "05. 
 
 The whole 15 ozs. are then expressed in ozs. and tenths as 
 foUows : — • 
 
 Table XLVI. 
 
 
 Water. 
 
 NitrogenoQS 
 substances. 
 
 Carbo- „ ^ 
 hydrates. **'^- 
 
 Ash. 
 
 The 2 ozs. of beef equal . . 
 The 4 ozs. of potatoes 
 The 4 ozs. of cabbage . . 
 The 5 ozs. of bread . 
 
 1-44 
 3-03 
 3-60 
 1-92 
 
 •43 
 ■07 
 •07 
 •34 
 
 •82 
 •20 
 ■04 
 
 0^10 
 0^01 
 O^Ol 
 2-62 
 
 •03 
 
 •04 
 •05 
 •06 
 
 
 9-99 
 
 •91 
 
 1^06 
 
 2^74 
 
 ■18 
 
 The total adds to 14^ I 
 
 1 ozs. tbe woody fibre not being included. 
 
 p p 2 
 
580 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [CHAl>. 
 
 Table XLYII. 
 
 Percentage Composition oe Vakioits Fokms of Animal Flesh oe 
 
 Meat. 
 
 
 "Water. 
 
 Nitrogenous 
 substances. 
 
 Fat. 
 
 Nitrogen free 
 
 extractive 
 
 matter. 
 
 Ash. 
 
 Bacon fat, salted and dried 
 
 13-9 
 
 9-0 
 
 74-1 
 
 
 3-0 
 
 ( minimum 
 
 32-49 
 
 10-87 
 
 5-80 
 
 
 0-75 
 
 Beef (fat) ■ ' maximum ... 
 
 73-60 
 
 19-94 
 
 56-11 
 
 
 1-53 
 
 mean 
 
 54-76 
 
 16-93 
 
 27-23 
 
 
 1-08 
 
 (■minimum 
 
 68-50 
 
 16-99 
 
 1-00 
 
 
 0-75 
 
 Beef (moderately fat) "j maximum 
 
 78-00 
 
 25-03 
 
 9-86 
 
 
 2-02 
 
 Imean . . 
 
 72-25 
 
 21-39 
 
 5-19 
 
 
 1-17 
 
 ("minimum 
 
 75-21 
 
 20-18 
 
 0-61 
 
 
 1-14 
 
 Beef (lean) ^ maximum 
 
 78-16 
 
 22-17 
 
 3-46 
 
 
 1-20 
 
 vmean 
 
 76-71 
 
 20-61 
 
 1-50 
 
 
 1-18 
 
 Fowl 
 
 70-82 
 
 22-65 
 
 3-11 
 
 2-33 
 
 1-09 
 
 Hare 
 
 74-16 
 
 23-34 
 
 1-13 
 
 0-19 
 
 1-18 
 
 Kidney (sheep's) 
 
 78-60 
 
 16-56 
 
 3 '33 
 
 0-21 
 
 1-30 
 
 Mnttonj^^'^y^^* ■^-^ • ■ 
 \ moderately fat 
 
 47-91 
 74-79 
 
 14-80 
 18-11 
 
 36-39 
 
 5-77 
 
 0-05 
 
 0-85 
 1-33 
 
 Pig's liver .... 
 
 72-37 
 
 18-65 
 
 5-66 
 
 1-81 
 
 1-51 
 
 f minimum 
 
 40-27 
 
 12-55 
 
 28-03 
 
 
 0-47 
 
 Pork (fat) < maximum 
 
 54-63 
 
 16-58 
 
 46-71 
 
 
 1-07 
 
 I mean . . 
 
 47-40 
 
 14-54 
 
 37-34 
 
 
 .0-72 
 
 (■minimum 
 
 69-32 
 
 17-32 
 
 3-73 
 
 
 0-98 
 
 Pork (lean) <. maximum 
 
 76-14 
 
 24-47 
 
 11-77 
 
 
 1-64 
 
 (.mean 
 
 72-18 
 
 19-91 
 
 6-81 
 
 
 1-10 
 
 Tripe .... 
 
 67-1 
 
 13-3 
 
 17-1 
 
 
 2-50 
 
 Veal -f^^'^*) ■ 
 
 ^^^^ t(Iean) - - . . 
 
 72-31 
 78-82 
 
 18-88 
 19-86 
 
 7-41 
 0-82 
 
 0-07 
 
 1-33 
 
 0-50 
 
 Eggs (hens) . . 
 
 73-67 
 
 12-55 
 
 0-35 
 
 
 1-12 
 
 Egg albumen 
 
 86-49 
 
 12-67 
 
 0-25 
 
 
 0-59 
 
 Egg, yelk of . 
 
 50-79 
 
 17-24 
 
 31-75 
 
 0-13 
 
 1-09 
 
XXXIV.] 
 
 TABLES FOR CALCULATING DIETARIES. 
 
 681 
 
 Table XLVIII. 
 
 Pbkobntagb Composition of Fish. 
 
 Codfisli .... 
 Eels . 
 Gudgeon . . 
 
 ( fresh . 
 Herrings -| salted 
 
 1^ smoked 
 Lamprey . . . 
 
 '^-'^^'''^ {sStd- 
 Oyster . . . 
 
 Pike 
 
 Salmon 
 
 Sardine (preserved) 
 Skate . . . 
 
 Sole 
 
 Sprat . . 
 WMting . . . 
 
 Water. 
 
 Nitrogenous 
 
 Fat. 
 
 substances. 
 
 18-50 
 
 3-00 
 
 13-57 
 
 5-02 
 
 17-37 
 
 2-68 
 
 10-11 
 
 7-11 
 
 18-97 
 
 16-67 
 
 21-12 
 
 8-51 
 
 20-18 
 
 25-59 
 
 23-42 
 
 6-76 
 
 20-82 
 
 14-10 
 
 4-95 
 
 0-37 
 
 19-86 
 
 0-79 
 
 18-75 
 
 6-22 
 
 22-30 
 
 2-21 
 
 24-03 
 
 0-47 
 
 11-94 
 
 0-25 
 
 22-73 
 
 15-94 
 
 15-09 
 
 0-38 
 
 Nitrogen free 
 
 and extractive 
 
 matter. 
 
 0-39 
 
 1-61 
 
 o'38 
 2-62 
 1-60 
 2-95 
 
 0-45 
 0-98 
 0-50 
 
 Ash. 
 
 1-00 
 
 1 
 
 11 
 
 3 
 
 44 
 
 2 
 
 07 
 
 17 
 
 24 
 
 1 
 
 24 
 
 1 
 
 41 
 
 1 
 
 55 
 
 16 
 
 27 
 
 2 
 
 37 
 
 
 
 38 
 
 
 
 58 
 
 23 
 
 72 
 
 1 
 
 71 
 
 1 
 
 22 
 
 
 
 46 
 
 1 
 
 08 
 
 Table XLIX. 
 
 Pbeoentage Composition of Milk, Cheese, and othek Daip.y Pkoducts. 
 
 
 
 Casein 
 
 
 
 
 
 Water. 
 
 and 
 Albumin. 
 
 Fat. 
 
 Milk- sugar. 
 
 Ash. 
 
 Milk . . 
 
 87-55 
 
 3-41 
 
 3-64 
 
 4-69 
 
 0-71 
 
 Skim mOk . . - - 
 
 90-11 
 
 3-37 
 
 0-46 
 
 5-34 
 
 0-72 
 
 Cream 
 
 28-58 
 
 1-42 
 
 67-62 
 
 2-25 
 
 0-12 
 
 DevonsMre cream . 
 
 28-68 
 
 4-05 
 
 65-01 
 
 1-77 
 
 0-49 
 
 Buttermilk , , , 
 
 90-62 
 
 3-78 
 
 1-25 
 
 3-38 
 
 0-65 
 
 Condensed milk (preserved " 
 with cane sugar) . . . . ' 
 
 24-42 
 
 10-33 
 
 9-02 
 
 milk sugar 12-64 
 
 1-93 
 
 
 
 
 cane ,, 41-66 
 
 
 Condensed milk (without 
 addition) 
 
 28-99 
 
 17-81 
 
 15-67 
 
 2-53 
 
 35-00 
 
 Butter ... 
 
 14-14 
 
 0-86 
 
 83-11 
 
 .0-70 
 
 1-19 
 
 Butterine 
 
 12-01 
 
 0-74 
 
 82-03 
 
 
 5-22 
 
 Cheese. 
 
 
 
 
 
 
 1. Soft Cheese— 
 
 
 
 
 
 
 Fromage de Brie 
 
 5187 
 
 18-30 
 
 24-83 
 
 
 5-00 
 
 Camembert . . 
 
 51-30 
 
 19-00 
 
 21-50 
 
 3-60 
 
 4-70 
 
 Eoquefort (fresh) 
 
 11-84 
 
 85-43 
 
 1-85 
 
 Lactic acid '88 
 
 
 2. Hard Cheese- 
 
 
 
 
 
 
 American cheese . 
 
 22-59 
 
 37-20 
 
 35-41 
 
 
 4-80 
 
 Cheddar cheese . 
 
 27-83 
 
 44-47 
 
 24-04 
 
 
 3-66 
 
 Dunlop cheese . 
 
 38-46 
 
 25-87 
 
 31-86 
 
 
 3-81 
 
 Gloucester (single) 
 
 21-41 
 
 49-12 
 
 25-38 
 
 
 4-09 
 
 Stilton (fresh) . 
 
 32-18 
 
 24-31 
 
 37-36 
 
 2-22 
 
 3-93 
 
 Gruyere ... 
 
 34-68 
 
 31-41 
 
 28-93 
 
 1-13 
 
 3-85 
 
 Gorgonzola . ... 
 
 43-56 
 
 24-17 
 
 27-95 
 
 
 4-32 
 
 Parmesan . 
 
 27-56 
 
 44-08 
 
 15-95 
 
 6-69 
 
 5-72 
 
 Skim cheese 
 
 48-02 
 
 32-65 
 
 8-41 
 
 6-80 
 
 4-12 
 
582 
 
 A MANUAL OF PUBLIC HEALTH. 
 
 [chap. 
 
 Table L. 
 
 Percentage Composition of vAKiotrs Flours and Leguminous 
 
 Meals. 
 
 
 Water. 
 
 Nitrogenous 
 substances. 
 
 Fat. 
 
 Starch, 
 &c. 
 
 Woody 
 fibre. 
 
 Ash. 
 
 i 
 
 1. Meal. 
 
 
 
 
 
 
 
 Barley meal 
 
 15 -06 
 
 11-75 
 
 1-71 
 
 70-90 
 
 0-11 
 
 0-47 
 
 Buckwheat meal . 
 
 14-27 
 
 9-28 
 
 1-89 
 
 72-46 
 
 0-89 
 
 1-21 
 
 Maize . 
 
 12-50 
 
 9-50 
 
 3 60 
 
 70-70 
 
 2-00 
 
 1-70 
 
 Oatmeal 
 
 10-46 
 
 15-50 
 
 6-11 
 
 63-67 
 
 2-24 
 
 2-02 
 
 Eye meal 
 
 14-24 
 
 10-97 
 
 1-95 
 
 69-74 
 
 1-62 
 
 1-48 
 
 "Wlieaten flour (fine) . . 
 
 14-86 
 
 8-91 
 
 1-11 
 
 74-18 
 
 0-33 
 
 0-61 
 
 ,, ,, (seconds) . . . 
 
 12-18 
 
 11-27 
 
 1-22 
 
 73-65 
 
 0-84 
 
 0-84 
 
 "Whole meal 
 
 13-56 
 
 12-66 
 
 1-82 
 
 67-77 
 
 2-66 
 
 1-53 
 
 2. Starch. 
 
 
 
 f— '~^ 
 
 
 
 Arrowroot 
 
 16-52 
 
 0-88 
 
 82-41 
 
 
 0-19 
 
 Maize starch .... 
 
 11-90 
 
 2-37 
 
 85-30 
 
 
 0-43 
 
 Sago . 
 
 12-89 
 
 0-81 
 
 86-11 
 
 
 0-19 
 
 Tapioca 
 
 13-3 
 
 0-63 
 
 85-95 
 
 
 0-12 
 
 Wheat starch . . 
 
 11-30 
 
 1-12 
 
 87-05 
 
 
 0-53 
 
 Macaroni (stars) . ... 
 
 14-01 
 
 8-69 
 
 0-32 
 
 76-49 
 
 ... 
 
 0-49 
 
 (pipe) 
 
 15-86 
 
 8-19 
 
 0-29 
 
 75-06 
 
 
 0-60 
 
 3. Leguminous Seeds. 
 
 
 
 
 
 
 
 Beans (fresh and green) . 
 
 86-10 
 
 4-67 
 
 0-30 
 
 6-60 
 
 1-69 
 
 0-64 
 
 „ (dried) . 
 
 14-84 
 
 23-66 
 
 1-63 
 
 49-25 
 
 7-47 
 
 3-15 
 
 Peas (green) 
 
 80-49 
 
 5-75 
 
 0-50 
 
 10-86 
 
 1-60 
 
 0-80 
 
 „ (dried) . . 
 
 14-31 
 
 22-63 
 
 1-72 
 
 53-24 
 
 5-45 
 
 2-65 
 
 „ (shelled) 
 
 12-73 
 
 21-12 
 
 0-82 
 
 60-94 
 
 2-64 
 
 1-75 
 
 Pea meal (dried) 
 
 8-12 
 
 28-10 
 
 2-97 
 
 50-17 
 [ 1-20 
 .^ Sugar 
 [ 6-82 
 
 8-02 
 
 2-55 
 
 Kidney beans . 
 
 88-36 
 
 2-77 
 
 0-14 
 
 1-14 
 
 0-57 
 
 
 
 
 
 
 
 Lentils 
 
 12-51 
 
 24-81 
 
 1-85 
 
 54-78 
 
 3-58 
 
 2-47 
 
 Millet 
 
 11-26 
 
 11-29 
 
 3-56 
 
 67-33 
 
 4-25 
 
 2-31 
 
XSXIV.] 
 
 TABLES FOK CALCULATING DIETARIES. 
 
 583 
 
 Table LI. 
 
 Peboentage Composition of Succulent Vegetables. 
 
 
 Water. 
 
 Nitrogenous 
 substance. 
 
 Fat. 
 
 Cabbohtdeates. 
 
 Woody 
 fibre. 
 
 Ash. 
 
 Sugar. 
 
 Nitrogenous 
 free extrac- 
 tive matter. 
 
 Asparagus . . 
 
 [ comnion . . 
 Beet • 
 
 I sugar .... 
 
 93-32 
 
 87-88 
 
 1-98 
 1-07 
 
 0-28 
 0-11 
 
 0-40 
 6-55 
 
 2-34 
 2-43 
 
 1-14 
 1-02 
 
 0-54 
 0-94 
 
 83-91 
 
 2-08 
 
 0-11 
 
 9-31 
 
 2-41 
 
 1-14 
 
 1-04 
 
 Cabbages . . . 
 Carrots . ... 
 
 89-97 
 87-05 
 
 1-89 
 1-04 
 
 0-20 
 0-21 
 
 2-29 
 6-74 
 
 2-58 
 2-60 
 
 1-84 
 1 46 
 
 1-23 
 0-90 
 
 ""'"''^ {stalks . . . 
 
 81-57 
 
 4-64 
 
 0-79 
 
 1-26 
 
 7-87 
 
 1-41 
 
 2-46 
 
 89-57 
 
 0-88 
 
 0-34 
 
 0-62 
 
 5-94 
 
 1-24 
 
 1-41 
 
 Cauliflower 
 
 90-39 
 
 2-53 
 
 0-38 
 
 1-27 
 
 3-74 
 
 0-87 
 
 0-82 
 
 1 dried & roasted 
 Chicory ■ 
 
 Ifresh .... 
 
 10-69 
 75-69 
 
 6-29 
 1-01 
 
 1-52 
 0-49 
 
 15-54 
 3-44 
 
 55-00 
 17-62 
 
 6-11 
 0-97 
 
 4-85 
 0-78 
 
 Cucumber ... 
 
 95-60 
 
 1-02 
 
 0-09 
 
 0-95 
 
 1-33 
 
 0-62 
 
 0-39 
 
 Garlic (leaves & stalks) . 
 Horse radish 
 
 90-82 
 76-72 
 
 2-10 
 2-73 
 
 0-44 
 0-35 
 
 0-81 
 
 3-74 
 15-89 
 
 1-27 
 2-78 
 
 0-82 
 1-53 
 
 Lettuce ...... 
 
 94-33 
 
 1'41 
 
 0-31 
 
 
 2-19 
 
 0-73 
 
 1-03 
 
 Onions (bulbs . , , . 
 
 Parsley 
 
 Potatoes 
 
 64-66 
 85-05 
 75-77 
 
 6-76 
 3-66 
 1-79 
 
 0-06 
 0-22 
 0-16 
 
 0-75 
 
 26-31 
 
 6-69 
 
 20-56 
 
 0-77 
 1-45 
 0-75 
 
 1-44 
 1-68 
 0-97 
 
 Eadishes 
 
 93-34 
 
 1-23 
 
 0-15 
 
 0-88 
 
 2-91 
 
 0-75 
 
 0-74 
 
 Savoys 
 
 87-09 
 
 3-31 
 
 0-71 
 
 1-29 
 
 4-73 
 
 1-23 
 
 1-64 
 
 Spinach 
 
 90-26 
 
 3-15 
 
 0-54 
 
 008 
 
 3-26 
 
 0-77 
 
 1-94 
 
 Turnips 
 
 85-01 
 
 2-95 
 
 0-22 
 
 0-40 
 
 8-45 
 
 1-76 
 
 1-21 
 
 Water-melon • . . . 
 
 95-21 
 
 1-06 
 
 0-60 
 
 0-27 
 
 1-16 
 
 1-07 
 
 0-63 
 
584 
 
 A MANUAL OF PUBLIC HEALTH. [chap, xxxiv. 
 
 Table LIL 
 
 Peeobntagb Composition op Fkuits. 
 
 
 Water. 
 
 Nitro- 
 genous 
 
 sub- 
 stances. 
 
 Freel 
 Acid. 
 
 Sugar. 
 
 Nitrogen free 
 substances, 
 extractives, 
 
 Cellu- 
 lose and 
 seeds. 
 
 Ash. 
 
 Almonds 
 
 5-39 
 
 24-18 
 
 
 f 
 
 fat 
 53-68 
 
 } 
 
 7-23 
 
 6-56 
 
 2-96 
 
 Apple . 
 Apricot 
 Bilberry 
 Blackberry 
 
 83-58 
 81-22 
 78-36 
 86-41 
 
 0-39 
 0-49 
 0-78 
 0-51 
 
 0-84 
 1-16 
 1-66 
 1-19 
 
 7-73 
 4-69 
 5-02 
 4-44 
 
 5-17 
 6-35 
 0-87 
 1-76 
 
 1-98 
 
 5-27 
 
 12-29 
 
 5-21 
 
 0-31 
 0-82 
 1-02 
 0-48 
 
 Chestnut 
 
 51-48 
 
 5-48 
 
 
 t 
 
 1 
 
 fat 
 1-37 
 
 \ 
 
 38-34 
 
 1-61 
 
 1-72 
 
 Cherry .... 
 
 Cocoanut (white 
 
 solid part). . 
 
 80-26 
 } 5-32 
 
 0-62 
 
 0-91 
 
 10-24 
 
 fat 
 66-16 
 
 } 
 
 1-17 
 
 6-07 
 ? 
 
 0-73 
 1-55 
 
 Cocoanut milk . 
 
 91-50 
 
 0-46 
 
 
 
 fat 
 •07 
 
 J 
 
 6-78 
 
 
 1-19 
 
 Currant 
 Damson . . . 
 
 84-77 
 81-18 
 
 0-51. 
 0-78 
 
 2-15 
 0-85 
 
 ( ^'21 1 
 
 6-38 
 6-15 
 
 . 0-90 
 4-92 
 
 4-57 
 5-41 
 
 0-72 
 0-71 
 
 Kg (as sold) 
 
 31-20 
 
 4-01 
 
 ) also fatty / 
 ) matter ( 
 
 
 49-79 
 
 
 i-51" 
 
 4-98 
 
 2-86 
 
 Filberts 
 
 3-77 
 
 15-62 
 
 { 1-44 ' 
 
 t 
 
 fat 
 66-07 
 
 1 
 
 ) 
 
 9-03 
 
 3-28 
 
 1-83 
 
 Gooseberries 
 
 Grapes . 
 
 Mulberries 
 
 Oranges 
 
 Peaches 
 
 Pears . 
 
 Plums 
 
 85-74 
 78-17 
 84-71 
 89-01 
 80-03 
 83-03 
 84-86 
 
 0-47 
 0-59 
 0-36 
 0-73 
 0-65 
 0-36 
 0-40 
 
 1-42 
 0-79 
 1-86 
 2-44 
 0-92 
 0-20 
 1-50 
 
 7-03 
 24-36 
 9-19 
 4-59 
 4-48 
 8-26 
 3-56 
 54-56 
 
 1-40 
 
 1-96 
 
 2-31 
 
 0-95 
 
 7-17 
 
 3-64 • 
 
 4-68 
 
 3-52 
 3-60 
 0-91 
 1-79 
 6-06 
 4-30 
 4-34 
 
 0-42 
 0-53 
 0-66 
 0-49 
 0-69 
 0-31 
 0-66 
 
 Kaisins 
 
 32-02 
 
 2-42 
 
 
 1 also tatty ( 
 ] matter ( 
 
 7-48 
 
 1-72 
 
 1-21 
 
 Raspberries 
 Strawberries 
 
 86-21 
 87-66 
 
 0-53 
 1-07 
 
 1-38 
 0-93 
 
 
 0-59 
 3-95 
 6-28 
 
 ) 
 
 1-54 
 0-48 
 
 5-90 
 2-77 
 
 0-49 
 0-81 
 
 Walnuts . . 
 
 4-68 
 
 16-37 
 
 
 { 
 
 fat 
 62-86 
 
 
 7-89 
 
 6-17 
 
 2-03 
 
 ' The free acid is different in different fruits. The chief free acid of the apple, 
 pear, plum, apricot, peach, and cherry is malic acid ; that of the grape, tartaric acid ; 
 in oranges and lemons, citric acid ; and in strawberries and raspberries the acidity is 
 due to a mixture of citric and malic acids. 
 
SECTION XI. 
 
 THE DUTIES OF SANITARY OFFICERS. 
 
CHAPTER XXXV. 
 
 the duties oe sanitary officers. 
 
 Duties and Qualifications of Medical Officers of Health. 
 
 (436) Qualifications of Medical Officers of Health. 
 
 The qualifications of a Medical OflScer of Health are expressly 
 laid down by the Local Government Act, 1889, sect. 18. " Except 
 where the Local Government Board, for reasons brought to their 
 notice, may see fit in particular cases specially to allow, no person 
 shall hereafter be appointed the Medical Officer of Health of any 
 county or county district, or combination of county districts, or the 
 deputy of any such officer, unless he be legally qualified for the 
 practice of medicine, surgery and midwifery. 
 
 "No person shall after the 1st of January, 1892, be appointed the 
 Medical Officer of Health of any county or of any such district or 
 combination of districts as contained according to the last published 
 census for the time being a population of 50,000 or more in- 
 habitants, unless he is qualified as above mentioned, and also is 
 either registered in the medical register as the holder of a diploma 
 in sanitary science, public health or State medicine under section 
 21 of the Medical Act, 1886, or has been during three consecutive 
 years preceding the year 1892, a Medical Officer of a district or 
 combination of districts, with a population, according to the last 
 published census of not less than 20,000, or has before the passing 
 of this Act been for not less than three years a Medical Officer or 
 Inspector of the Local Government Board." 
 
 The qualifications then with regard to future appointments are, 
 adequate experience in a sufficiently populous place, or passing a 
 particular examination. 
 
588 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 (437) Duties of Medical Officers of Health. 
 
 There are at the preseut time several classes of Medical Officers 
 of Health. 
 
 I. Medical Officers of Health for a county, as for example the 
 county of London. 
 
 II. Medical Officers of Health for exclusively urban districts, as 
 for example Metropolitan Health Officers, or those for Liverpool, 
 Manchester, Bradford. 
 
 III. Medical Officers of Health for a port sanitary district. 
 
 IV. Medical Officers of Health for combined rural and urban 
 districts. 
 
 V. Poor-law Medical Officers, acting as Medical Officers of 
 Health and others. This last class of appointments is profoundly 
 unsatisfactory ; individual officers here and there do good work, and 
 this is cited as a defence of the system ; but as a rule the appoint- 
 ments of this nature are only colourable, and the duties are insuffi- 
 ciently performed by medical men whose occupations do not admit 
 of their paying the requisite attention to the subject. 
 
 I. Duties of County Medical Officers of Health. 
 
 This class of officers, created by the Local Government Act of 
 1889, has so recently been called into existence that there is but 
 little experience as yet as to the nature of the duties. It is, 
 however, obvious, that presuming the County Officer has official 
 connexion with Officers of Health of the districts, he will receive 
 regularly all the reports annual, monthly, or special that they 
 have submitted to their respective authorities. He will tabulate 
 and study the statistics relative to sickness and mortality. He 
 will personally with the aid of the local Medical Officer of Health 
 investigate any unusual incidence of disease. He will, where 
 necessary, urge upon the local authority to undertake schemes 
 of sewerage or water supply. His advice will be specially valu- 
 able in drawing out local regulations as to offensive trades, the 
 framing of bye-laws and the like. The legislation which is now 
 confidently expected in the formation of district councils will, with- 
 out doubt, define the relation that the County Council will have to 
 the district boards, and make this outline of the duties possible to 
 be put into practical effect. 
 
XXXV.] DUTIES OF HEALTH OFFICERS. 589 
 
 II. Duties of Urban Medical Officers of Health. 
 
 In urban districts there is a good deal of variety in the duties. 
 Some urban districts, like those of the metropolis, are governed by 
 special, local or general Acts. For example, the City of London 
 has a code of laws differing in detail from the rest of the country ; 
 the other metropolitan districts are governed by the Metropolis 
 Local Management Acts, by the Sanitary Act of 1866, by the 
 Nuisance Removal Acts and several others. (The Public Health 
 Acts as a whole are not in force in the metropolis.) Hence the duties 
 laid down by the Local Government Board (see page 601), are 
 not in force in the metropolis,^ but they are chiefly regulated by 
 custom and by resolutions of the Vestry or District Board. Similarly 
 local Acts obtained from time to time modify the details of the 
 work in some urban districts. Nevertheless as a whole they are 
 similar in all, and in the following sketch, the details of ofificial 
 duty are those which seem to the writer, from his personal experience 
 and from a study of what is actually done in the model urban dis- 
 tricts, as likely to ensure efficiency of local health administration. 
 
 (a) Attendance at the Health Office. — It is essential that the 
 Health Officer attend with the greatest regularity at stated and 
 published times at an office provided by the Local Authority in 
 order that he can interview the inspector or inspectors, give them 
 directions, and be accessible to any person who desires personally to 
 lay a complaint or to consult the Health Officer. 
 
 (6) Supervising the Work of the Inspectors. — The Inspectors should 
 be compelled to submit each morning a diary of the work of the 
 preceding day ; the diary being written with sufficient detail to 
 show exactly how they have been employed, what visits they have 
 made, and so forth. Their outside work should be checked by 
 occasional visits of the Health Officer to premises previously 
 visited by the Inspectors, and by comparing the state as reported by 
 the Inspector with the state found. The Medical Officer of Health 
 will particularly note any grave defects which may have been passed 
 over by the Inspector, thereby proving incompetence or negligence. 
 
 (c) Inspection of Premises. — The Health Officer should personally 
 inspect premises in certain cases, viz., when the Inspector's report is 
 disputed ; when legal action for the enforcement of a sanitary order 
 - Save in those instances in which half the salary is paid by the L. G. B. 
 
590 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 is considered necessary ; in the special cases in whicli illness is said 
 or supposed to be due to the sanitary condition of premises ; in all 
 cases of complaint of nuisance caused by noxious trades. He should 
 also make from time to time house to house inspections of houses 
 let in lodgings (tenement houses), and registered lodging-houses. 
 
 (d) Inspection of Bakehouses, Slaughierhouses, and Cowhouses. — In 
 these cases also the Medical Officer of Health should make personal 
 inspections ; he is indeed required by law to inspect personally 
 bakehouses, for it is he alone who is recognized by the Factory Act. 
 It is also advisable for the Medical Officer of Health to inspect at 
 least once a year personally cowhouses and slaughter-houses. 
 
 (e) Supervision, of the Water Supply. — It is to be presumed that 
 all urban districts have a public water supply. It is evidently the 
 duty of the Health Officer to watch the supply narrowly. Taking 
 the simplest case in which a water company and one only, suppHes 
 a district. To guard against chance pollution from defective ferrules 
 or supply pipes or faulty conditions of the main itself, it will be 
 necessary to take on the same day a number of samples, and by 
 chemical analysis to ascertain whether they are all of practically 
 identical quality. No elaborate analysis is necessary for this, 50 
 c c. of each may be placed in a glass cylinder and equal quantities 
 of Nessler solution run in. The colouration should, of course, be 
 all equal. A determination of chlorine should also be made of 
 each (see page 169), this ought also to be equal. Should the 
 simple examination detailed show equality in chlorine and in 
 colouration on the addition of Nessler, an analysis of one sample 
 will then be an analysis of the whole. Should there be any differ- 
 ence found, then that particular sample should be most carefully 
 analyzed and the reason of the difference ascertained by examining 
 the iittings in the house, the supply pipe under the street and so 
 forth. 
 
 (/) Work under the Notification Act. — Every urban district will, 
 without doubt, have to follow the majority of both urban and rural 
 districts, and adopt the Infectious Disease Notification Act. It will be 
 the dutyof theMedical Officer of Health to cause an inquiry to be made 
 as to the state of any premises in which infectious disease has been 
 notified. In the writer's opinion a certificate under the Act jus- 
 tifies a demand for entry by the officer, for he has reasonable cause 
 to suspect a nuisance. He will also insist upon disinfection on 
 
sxxv.] DUTIES OF HEALTH OEEICEES. 591 
 
 recovery, death, or removal of the patient. Any inquiry as to 
 infectious disease will be incomplete if it does not embrace the 
 antecedent history of the patient for some days before the period 
 of incubation of the particular malady. Take for instance enteric 
 fever, then the history of the patient must go back at least three 
 weeks before the date of first symptoms. If the sufferer is a child 
 and has attended school it is the duty of the Medical Officer of 
 Health to see that the school authorities be informed of the illness, 
 and if the malady is infectious, e.g., scarlet fever, other members of 
 the family should not be allowed to go to school, so long as risk of 
 infection remains. It will be the policy and duty of the Medical 
 Officer of Health to remove compulsorily, where legally enabled to 
 do so, or by persuasion, all infected persons to a hospital if such a 
 building has been provided by the local authority ; for it is 
 obvious that early removal from population centres is the sheet 
 anchor of disease prevention. 
 
 {g) Becords of Sanitary Condition — Routine Office Work. — -The 
 Medical Officer of Health should aim at the high ideal of en- 
 deavouring to collect in his office details as to the drainage, water 
 supply, construction, tenancy and disease history of every single 
 house in his district. The information should be contained in 
 indexed books, so that at any time, he can in a few minutes 
 give the whole sanitary history of the house. If this were done, 
 all persons for the first time entering or contemplating to enter 
 into residence, whether as lodgers or in permanency, would apply 
 at the health office and get that information which can now 
 only be laboriously obtained by applying to several distinct persons 
 supplemented often by a somewhat expensive investigation. No 
 small amount of office work is taken up with correspondence. It 
 is scarcely necessary to say that all letters going out of the office 
 should be copied, and a copy kept in an indexed book, and all letters 
 coming into the office should be stamped with the date of receipt 
 and filed. The author uses a Shannon file, but any arrangement 
 which admits of easy and quick reference to a particular letter will 
 answer the purpose. 
 
 In indexing and keeping correspondence or other documents it 
 is found in practice best to keep each year separate. 
 
 (A) Enforcement of Sanitary Orders. — The method of enforce- 
 ment of sanitary orders varies a little in different districts. The 
 
592 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 author goes over all the orders of the vestry week by week, and 
 marks those which are completed with the date of completion ; as 
 to those that are not completed, he has a special report from the 
 inspector. If not complied with, and it is in his opinion necessary 
 to take legal proceedings to enforce the same, he passes the order 
 on to the vestry clerk, who on consultation with the solicitor 
 directs the inspector of nuisances to take out a summons. In 
 most districts, all cases for summons go before a committee, or the 
 sanitary authority, a procedure which entaUs delay and inequality 
 of action. Inequality of action is inseparable from any process 
 which is dependent upon a show of hands. The proper way is 
 to treat all sanitary orders of a routine character as orders which 
 are to be enforced by law, and once therefore the order has been 
 given by the sanitary authority for a particular owner to do a 
 certain work it should by implication be the duty of the clerk to 
 the authority to put the usual machinery in motion without a fresh 
 report to the local authority. On the other hand, matters out of 
 the usual routine, and more particularly prosecutions involving 
 large interests and possibly entailing considerable expense, should 
 be specially brought before the authority and the necessary powers 
 to proceed obtained. Once an order is reported as not obeyed, 
 the Health Officer's responsibility for the time ceases untU a 
 magistrate's order is obtained ; it is then his duty to see whether 
 the magistrate's order is obeyed or not, and to report the same to 
 the sanitary authority. 
 
 (i) Eeports of an Urban Medical Officer of Health. — The reports 
 may be divided into two classes ; those which are mere summaries 
 of past events, and those which are reports upon present condition, 
 and usually require some action to be taken by the sanitary 
 authority. Among the first class are the ordinary periodical 
 reports — weekly, monthly, quarterly, annual. 
 
 It may be taken as a principle that every ratepayer in an 
 urban district has a right to be informed periodically of the health 
 of the district. Hence in towns of sufficient size, the reports of 
 the Health Officer which appear in a periodical form should be 
 printed and circulated. The circulation should not only be 
 amongst the members of the sanitary authority, but should be 
 sent to all medical practitioners, to all local libraries and institutions, 
 and to any resident who desires a copy. 
 
XXXV.] REPORTS OF MEDICAL OFFICERS OF HEALTH. 593 
 
 Such reports usually contain weekly meteorological returns, 
 births and deaths, sickness returns under the Notification Act, 
 brief accounts of any epidemic which has prevailed, of the results 
 of prosecutions and other kindred matters; the whole written 
 without padding with extraneous material. It is to the author's 
 mind an abuse of such reports to make them the vehicle of 
 hobbies, of controversial questions, or to ventilate therein the 
 great social questions of the day. The aim of the periodical 
 reports should be mainly historical, to put in a more or less per- 
 manent form the local sanitary history of the district. The 
 Health Officer cannot take a better example than the weekly 
 health return for the city of Manchester, issued by Dr. Tatham ; 
 for instance, the return for the week ending January 25th, 1890, 
 is thus arranged : — 
 
 (1) Meteorology, sickness, and condition of the public health. 
 
 (2) Notification and local distribution of cases of infectious 
 sickness. 
 
 (3) Hospital isolation of patients suffering from infectious 
 diseases. 
 
 (4) Comparative statistics of births and deaths in recent 
 weekly periods. 
 
 (5) Local distribution of deaths in registration sub-districts. 
 Pauperism^ — weekly number of persons relieved by the Guardians. 
 
 (6) Eegister of sanitary work done during the week. 
 
 This last is as important as any (although probably the least 
 read) ; as the form of Dr. Tatham 's register seems to be gener- 
 ally useful the author has adopted it, and it may be well to 
 reproduce it : — 
 
 Exam'ph of Dr. Tatham s Weekly Eegister. 
 
 REGISTER OF SANITARY WORK. 
 
 Week ending 25th January, 1890 : — 
 
 Nuisance Department. 
 
 Number of Complaints Received { f™^ J"ft|j^j j^^^^(^^i Qffieer of Heklth . . ^6 
 
 ^ Pauperism is intimately connected with sanitaiy condition, but some may take 
 exception to this being included. It is of course not absolutely essential. 
 
 Q Q 
 
591 A MANUAL OF PUBLIC HEALTH. [cHAr. 
 
 NuisASOB Depabtmbnt {continued). 
 
 'Of Dwelling-houses ... ■ 838 
 
 ,, Cellars .... . • • . . 5 
 
 „ Schools .... • 1 
 
 ,, Lodging-houses U^ 
 
 Inspections ( „ Dairies and Milkshops 175 
 
 , Bakehouses 37 
 
 , Canal Boats • ^ 
 
 , Tips for Refuse • " 
 
 , Miscellaneous Inspections .... 394 
 
 o , ,, ^ . ( Observations Made 17 
 
 S™''^'^ -^^"""'="* i Proceedings taken before Magistrates 3 
 
 •u J A J li i- i Samples collected for Analysis .... ... .40 
 
 Food Adulteration I pj,^^igg^jjjgg^^^g^^,^foj,g Magistrates . . 
 
 Ashpits reported to Health Department for Emptying .98 
 
 Notices issued for Abatement of Nuisances ... 315 
 
 Letters Written for Abatement of Nuisances 53 
 
 Reports made to Medical Officer of Health 9 
 
 Health Department. 
 
 Infectious Patients removed to Hospital ... 29 
 
 Infected Articles Removed and Stoved . . 289 
 
 Rooms Fumigated after Infectious Disease 98 
 
 Rooms Stripped and Dressed with Caustic Soda after Infectious Disease 43 
 
 Visits by Disinfectors on account of Infectious Disease 180 
 
 Pails Emptied during the week (number) 83,000 
 
 Ashpits Emptied during the week (number) ... 197 
 
 Tons of Refuse Removed from amidst the homes of the people . . 4,713 
 
 Square Yards of Street Surface Swept and Cleansed 8,142,828 
 
 Number of Courts and Passages Swilled with Water .... . . . . 355 
 
 Markets Depaetment. 
 Unwholesome Food — Number of Seizures made . . 5 
 
 Public Health Office. 
 
 Notifications of Infectious Attacks received and Registered . . . .54 
 
 Statistical Returns to Government and other Departments, &c. 228 
 
 Cautionary Notices to Schools re Infectious Sickness . 22 
 
 Cautionary Notices to Libraries re Infectious Sickness ... . . 
 
 The same principles that have been laid down with respect to 
 monthly or weekly or quarterly reports are applicable to annual 
 reports. They should be simple chronicles showing the sanitary 
 work, the sickness, and the movement of the population so that the 
 ordinary reader will be able to grasp fairly the condition of the 
 district. The bulky, over tabulated, and expensive annual reports 
 issued by several urban Health Officers, should not be taken as 
 models ; many of them are stuffed out with discussions of matters 
 not directly affecting the district ; above all things let the report 
 be local ; the information accurate, and as much as possible stick 
 to facts. Reports ought to be all on one uniform plan, and it 
 
xxxv.J REPORTS OF MEDICAL OFFICERS OF HEALTH. 595 
 
 would even be convenient if they were of one uniform size. Spot 
 maps and the graphic method of representing statistics are 
 to be commended. In the best spot maps, the ground-work 
 of the map is shaded according to the density of the population ; 
 from those not thus shaded, a person who does not know the 
 density of the population might draw the erroneous deduction 
 that a portion thickly speckled with scarlet fever deaths had a 
 serious meaning, although the greater incidence on that part was 
 due merely to superior density of population. A sickness spot 
 map is far superior to a mortality spot map, for it not unfrequentJy 
 happens that in, for instance, typhoid fever, a large number of 
 cases may occur which result in but few deaths. The very general 
 adoption of the Infectious Disease Notification Act will now enable 
 Medical Officers of Health to make spot maps of their districts for 
 those particular maladies which cannot but be valuable. In Man- 
 chester it may be mentioned the Health Officer sends a spot map 
 (disease chart) to each of the free public libraries and public 
 reading rooms every week. 
 
 In the future, photography will also be largely used both as 
 a convenient means of record and also as useful evidence in legal 
 proceedings — the more especially since successive improvements 
 in the instruments have rendered the operation itself simple and 
 learned with facility. The following figure (Fig. 53), copied from 
 one of Dr. W. J. Simpson's Reports of the Health of Calcutta, at 
 once shows the great utility of a photograph. The picture clearly 
 represents excessive pollution of earth and water and faulty ex- 
 crement disposal. 
 
 The other class of reports are mostly made with a special object 
 in view, that is to represent to the authority the desirability of 
 doing something, or else they are special reports upon the action 
 taken by himself or officers. If the Medical Officer of Health 
 .makes any recommendation, its best position is at the end of the 
 report, and such recommendation should be in the clearest and 
 most precise language. Once having recommended a course of 
 action to a sanitary authority, and the course of action recom- 
 mended having been ignored, the responsibility lies altogether on 
 the authority, and is taken away from the Health Officer. It is 
 therefore unwise on his part to shovr any irritation on the subject, 
 or to caustically allude to it in subsequent reports. If the matter 
 
 Q Q 2 
 
596 A MANUAL OP PUBLIC HEALTH. [chai>. 
 
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 for the public health of his district, a good opportunity may be 
 waited for, and the identical thing recommended in a different 
 
XXXV.] DUTIES OF A POET MEDICAL OFFICER OF HEALTH. 597 
 
 way. Experience shows that a really necessary thing is ulti- 
 mately carried, although the opposition at first be violent and 
 demonstrative. 
 
 (438) Duties of a Port Medical Officer of Health. 
 
 Duties appertaining to an officer having charge of a port of some 
 size will alone be considered, those pertaining to the smaller 
 ports being only different in the amount of inspecting necessary to 
 be performed. It must be borne in mind that by sect. 110 of the 
 Public Health Act, all ships save those belonging to Her Majesty's 
 Government, or to foreign governments are as regards nuisances to 
 be treated as houses. The old quarantine Act of George IV. is 
 still in force, but the chief regulations respecting the duties of 
 sanitary officers are contained in the general orders of the Local 
 Government Board of 1883. 
 
 The duties of a Port Health Officer may be divided into ordi- 
 nary routine duties, and to special duties with regard to possible 
 cholera invasion. 
 
 The ordinary routine duties in respect to the supervision of the 
 inspectors, attendance at an office, &c., are not different to those 
 of other Health Officers. 
 
 Naturally the most important work is in reference to the inspec- 
 tion of incoming vessels in which there is reason to suspect that 
 sickness is on board. This knowledge is obtained in various ways ; 
 in a properly arranged Port Health Office, the daily and medical 
 press is methodically perused for the purpose of learning of the 
 existence of disease in foreign or home ports, and by the aid of 
 the information thus acquired and from the Shipping Gazette, the 
 vessels expected, and the approximate times of their arrival are 
 obtained. Such ships are visited without delay, either by the 
 Medical Officer of Health personally, or by his inspectors. Under 
 the Quarantine Act also all diseases whatsoever on board vessels 
 entering a- port and not arriving coastwise are to be reported to the 
 Customs, who detain the ship until she is released by the Health 
 Officer of the port. The Customs therefore report these cases to 
 the Health Office, and it is one of the most essential duties of a 
 Port Medical Officer of Health to board such vessels, and to see the 
 cases of illness, and to ascertain whether the illness is one of an 
 
598 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 infectious nature or not. If the disease is infectious, then by 
 section 125 of the Public Health Act, the patient may be removed 
 from the vessel to a hospital. In large ports also the sanitary 
 authority have made, under section 125 of the same Act, notifica- 
 tion and disinfection compulsory on the masters. There is then 
 this important and essential difference in the duties of land and 
 port Medical Officers of Health. In the latter, it is no part of 
 routine duty to visit cases of sickness for the purpose of diagnosing 
 disease, but with the Port Medical Officer of Health, he may be 
 daily obliged to investigate for himself the nature of the sickness, 
 and cause the patient to be removed or not according to circum- 
 stances, and the vessel to be detained until properly disinfected. 
 
 The special duties in connection with apprehended cholera 
 invasion are of two kinds, viz. (1) the obtaining full and early 
 information respecting the disease, and (2) those involved in 
 preventing the spread of infection. 
 
 The channels through which information is obtained are thus 
 summarized by Dr. Armstrong : — ^ 
 
 1. Vigilant observation of records of cholera in foreign countries. 
 
 2. Arrangements with the Customs, for the earliest possible 
 information of arrivals of infected or suspected vessels, or vessels 
 from infected countries. 
 
 3. The publication of printed information in the port on the 
 subject of " Cholera and its prevention." 
 
 4. Careful inquiry into the water supply of ships. 
 
 5. Inquiry into cases of ailment of a suspicious character on 
 shipboard (diarrhoea, &c.). 
 
 6. The engagement of a sufficient staff. 
 
 7. The keeping of a " Homeward-bound Register." 
 
 8. The provision of special accommodation for cases of cholera. 
 (See also ante in the chapter on cholera.) 
 
 (439) The Eeport of a Port Medical Officer of Health. 
 
 In the 16th Annual Report of the Local Government Board 
 (Supplement) is given Mr. Armstrong's annual report to the River 
 Tyne Port Sanitary Authority for the year ending December 31st, 
 1886, as an example. It would therefore be well, as this report has 
 
 ' IhMic Health, vol. i. p. 40. 
 
XXXV.] DUTIES OF A MEDICAL QFFICER OF HEALTH. 599 
 
 received official sanction, to follow its arrangement as far as 
 practicable. The following is a general outline of the report : — 
 
 1. Infectious Disease, in the Port. — ^Under this heading is given a 
 short succinct history of the cases of infectious disease admitted 
 into the isolation hospitals, the diseases reported on various vessels 
 from foreign ports and similar matters. 
 
 2. Cholera Precautions. — In this section details of the special 
 precautions against the importation of cholera are given, and a 
 table shows the number of vessels which arrived from infected 
 ports during the year. 
 
 3. Hospital Accommodation. — Under this heading the nature of 
 the existing hospital accommodation is given. 
 
 4. General Sanitary Work. — This is the most important part of 
 the report. It gives the total number of vessels arriving in the 
 port, the total number of vessels inspected, their nationality, and a 
 summaiy of their sanitary condition. 
 
 The number of notices served to abate nuisances or structural 
 or other defects are given as follows : — 
 
 C^^»^- remedied I'™''>"S- 
 on notice. 
 
 Defective ventilation ... .. 8.. ..7 .. 1 
 
 Iron deck to line with wood . 21 . . 16 . 5 
 
 Defective bulkhead 5 3 . 2 
 
 Defective drainage . . . 12 . . . 10 2 
 
 Defective lighting ... 5 .... 4 . 1 
 
 Defective water-closet 10 . . . . 10 
 
 61 50 11 
 
 Notices were also served or orders to abate nuisances to remedy 
 
 sanitary defects, either in the crew spaces, closets, peaks, holds, or 
 
 bilges, as follows : — 
 
 British steamers 338 
 
 British sailing vessels . . . 116 
 
 Foreign steamers .... 98 
 
 Foreign sailing ships 99 
 
 651 
 
 (440) The Duties of a Medical Officer of Health in a Comhined 
 
 District. 
 
 These are somewhat different in detail. If the district is of any 
 great extent it is practically impossible for the Health Officer to 
 attend daily at any office, and personal interviews must take place 
 
600 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 by appointment. In the same way supervision of the inspector's 
 work can only be intermittent. Nevertheless the examination of 
 their diaries should never be omitted, and their capability tested 
 by noting any mistakes of omission or commission with respect to 
 premises which have been inspected by them. It is specially im- 
 portant in a combined district for the Health Officer at least once 
 a year to visit every village and town to ascertain the purity of the 
 water supply, the proper disposal of the sewage, and the general 
 health. In this annual survey he should place himself ia com- 
 munication with the clergymen of the different parishes, the 
 relieving ofl&cers, with the schoolmasters, with the veterinary 
 surgeons, with the medical men, and any others who are likely 
 to afford him information. 
 
 No small amount of labour must be devoted in combined dis- 
 tricts a great portion of which is of a rural character, to inspection 
 of the dairy farms, and to see that the regulations given at page 
 275 are properly carried out. It is most decidedly the duty of 
 the Health Officer to make a personal and detailed inspection at 
 least once a year of every milk-producing farm. 
 
 (441) The Reports of a Medical Officer of Health to a Covilined 
 
 District. 
 
 It has hitherto been of necessity that separate annual reports 
 to each of the authorities governing a combined district have been 
 made ; in some districts there exists the requisite machinery 
 enabling the medical officer to have these reports printed in one 
 volume, in others this has not been done. It is obvious that the 
 preferable plan is to give a summary of the whole combined dis- 
 trict, and to follow this summary by the details belonging to each 
 separate area, and to conclude with a subject index. It would also 
 be useful if every Health Officer published each census year an 
 index of the preceding ten years' reports; in this way reference 
 could be made rapidly to the past history of the district. 
 
 (442) Bi(,ties of Medical Officers of Health as laid down ly the 
 Local Government Board. 
 
 The duties of a Medical Officer of Health have been laid down 
 by the Local Government Board as follows : — 
 
XXXV.] DUTIES OF MEDICAL OFFICERS OF HEALTH. 601 
 
 Didies. 
 
 The following shall be the duties of the Medical Officer of Health in respect of 
 the district for which he is appointed ; or, if he shall he appointed for more than 
 one district, then in respect of each of such districts : — 
 
 1. He shall inform himself, as far as practicable, respecting all influences affecting 
 or threatening to affect injuriously the public health within the district. 
 
 2. He shall inquire into and ascertain by such means as are at his disposal the 
 causes or origin and distribution of diseases within the district, and ascertain to 
 what extent the same have depended on conditions capable of removal or mitigation. 
 
 3. He sha)l by inspection of the district, both systematically at certain periods 
 and at intervals as occasion may require, keep himself informed of the conditions 
 injurious to health existing therein. 
 
 4. He shall be prepared to advise the sanitary authority of all matters affecting 
 the health of the district, and on all sanitary points involved in the action of the 
 sanitary authority or authorities ; and in cases requiring it he shall certify, for the 
 guidance of the sanitary authorities or of the justices, as to any matter in respect of 
 which the certificate of a Medical OfiBoer of Health or a medical practitioner is 
 required as the basis or in aid of sanitary action. 
 
 5. He shall advise the sanitary authority on any question relating to health 
 involved in the framing and subsequent working of such bye-laws and regulations as 
 they may have power to make. 
 
 6. On receiving information of the outbreak of any contagious, infectious, or 
 epidemic disease of a dangerous character within the district, he shall visit the spot 
 without delay, and inquire into the causes and circumstances of the outbreak, and 
 advise the person competent to act as to the measures which may appear to him to 
 be required to prevent the extension of the disease, and, so far as he may be lawfully 
 authorized, assist in the execution of the same. 
 
 7. On receiving information from the inspector of nuisances that his intervention 
 is required in consequence of the existence of any nuisance injurious to health, or 
 of any overcrowding in a house, he shall as early as practicable take such steps 
 authorized by the statutes in that behalf as the circumstances of the case may 
 justify and require. 
 
 8. In any case in which it may appear to him to be necessary or advisable, or in 
 which he shall be so directed by the sanitary authority, he shall himself inspect and 
 examine any animal, carcase, meat, poultry, game, flesh, fish, fruit, vegetables, 
 corn, bread, or flour, exposed for sale and intended for the food of man, which is 
 deemed to be diseased, unsound, or unwholesome, or unfit for the food of man ; and 
 if he finds that such animal or article is diseased or unsound or unwholesome, or 
 unfit for the food of man, he shall give such directions as may be necessary for 
 causing the same to be seized, taken, and carried away, in order to be dealt with by 
 a justice according to the provisions of the statutes applicable to the case. 
 
 9. He shall perform all the duties imposed upon him by the bye-laws and regu- 
 lations of the sanitary authority, duly confirmed, in respect of any matter affecting 
 the public health, and touching which they are authorized to frame bye-laws and 
 regulations. 
 
 10. He shall inquire into any offensive process of trade carried on within the 
 district, and report on the appropriate means for the prevention of any nuisance or 
 injury to health therefrom. 
 
 11. He shall attend at the office of the sanitary authority, or some other appointed 
 place, at such stated times as they may direct. 
 
 12. He shall from time to time report in writing to the sanitary authority his 
 proceedings, and the measures which may require to be adopted for the improvement 
 or protection of the public health in the district. He shall in like manner report 
 with respect to the sickness and mortality within the district as far as he has been 
 enabled to ascertain the same. 
 
 13. He shall keep a book or books, to be provided by the sanitary authority, in 
 which he shall make an entry of his visits and notes of his observations and instruc- 
 tions thereoQ, and also the date and nature of applications made to him, the date 
 
C02 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 and result of the action taken thereon, and of any action taken on previous reports, 
 and sliall produce such book or books whenever required to the sanitary authority. 
 
 14. He shall also prepare an annual report, to be made at the end of December in 
 each year, comprising tabular statements of the sickness and mortality within the 
 district, classified according to diseases, ages, and locality, and a summary of the 
 action taken during the year for preventing the spread of disease. The report shall 
 also contain an account of the proceedings in which he has taken part or advised 
 under the Sanitary Acts, so far as such proceedings relate to conditions dangerous or 
 injurious to health ; and also an account of the supervision exercised by him or on 
 his advice during the year in regard to offensive trades, bakehouses, and workshops. 
 
 15. He shall give immediate information to the Local Government Board of any 
 outbreak of dangerous epidemic disease within the district, and shall transmit to the 
 Board, on forms to be provided by them, a quarterly return of the sickness and 
 deaths within the district, and also a copy of each annual and of any special report. 
 
 16. In matters not specifically provided for in this order, he shall observe and 
 execute the instructions of the Local Government Board on the duties of Medical 
 Ofiicers of Health, and all the lawful orders and directions of the sanitary authority 
 applicable to his ofBce. 
 
 17. "Whenever the Disease Prevention Act of 1855 is in force within the district, 
 he shall observe the directions and regulations issued under that Act by the Local 
 Government Board, so far as the same relate to or concern his oflice. 
 
 (443) Duties and Qualifications of Inspectors of Nuisances. 
 
 Qualifications. — An inspector of nuisances should of course be in 
 good health and suffer from no physical infirmity interfering with 
 his duties. On his first appointment his age should not be below 
 twenty-one nor over forty ; persons over forty, who for the first 
 time apply for such a slenderly paid post as that of an inspector of 
 nuisances, are as a rule men who have failed in other walks of life. 
 On the other hand, these remarks do not apply to men seeking 
 second or third appointments with good records ; age in such cases 
 must be considered on its merits — the writer has known very 
 efficient inspectors, with great endurance and activity, over sixty 
 years of age. The best foundation for a young inspector of 
 nuisances is the requisite knowledge of the sanitary law, the 
 principles of drainage, of water supply, and the methods of inspec- 
 tion generally, enabling him to have passed such an examination 
 as that which is held several times a year by the Sanitary Insti- 
 tute ; this examination once passed, and its teaching supplemented 
 by the practical experience of a year's training as assistant inspector 
 in a large urban or combined district. 
 
 The duties ordinarily devolving upon an inspector are set forth 
 in sufficient detail in the Local Government Board's order printed 
 at the end of this chapter. They naturally vary according as to 
 whether the district is exclusively urban or urban and rural, or 
 
 & 
 
XXXV.] DUTIES OF AN INSPECTOR OF NUISANCES. 603 
 
 whether the duties are those of a port sanitary inspector. In a 
 great many districts it devolves upon the inspector to take, on 
 behalf of the authority, legal proceedings. This he does by virtue 
 of sec. 259 of the Public Health Act, which enables the local 
 authority to appear before any court " by their clerk, or by any 
 officer or member authorized generally or in respect of any special 
 proceeding by resolution of such authority, and such person being 
 so authorized is at liberty to institute and carry on any proceeding 
 which the local authority is authorized to institute and carry on 
 under the Public Health Act." Likewise in the metropoUs it is 
 the custom in more than one district for the inspectors of nuisances 
 to take out summonses in their own name on behalf of the 
 authority, and to conduct cases of routine without the aid of a 
 solicitor. 
 
 It is questionable whether this is a wise course. It would seem 
 more reasonable in all cases to employ a solicitor, in the way that 
 the best local authorities do, or, should the clerk to the authority 
 be legally qualified, to take proceedings by the clerk. 
 
 Dealing with things as they are, it is essential that the inspector 
 should acquire a knowledge of the ordinary procedure of the 
 police-court, and be able to fill up the summons, draw out a 
 magistrate's order, and so on. All these matters are really 
 simple. 
 
 The inspector of nuisances should be under the orders of the 
 Medical Ofiicer of Health. In many rural districts the inspectors 
 enjoy too great a degree of independence, and are not so amenable 
 to discipline as in urban districts; this is in a great measure due 
 to the unsatisfactory appointment in the smaller districts of the 
 poor-law ofiicers as Medical Officers of Health. 
 
 As a rule the inspectors should have no other appointment and 
 devote their whole time to their duties. The Local Government 
 Board expressly state that it is undesirable that the office of 
 relieving officer, or of superintendent of police, should be united 
 with that of inspector of nuisances. On the other hand, in small 
 districts, the office of surveyor, vaccination officer, inspector of 
 weights and measures and inspector of markets, and the like 
 public officers are often combined, and the combination is found 
 to be conducive to economy and efficiency, provided the officer 
 appointed is a man of suitable character and energy. 
 
604 A MANUAL OF PUBLIC HEALTH. [chap 
 
 (444) Duties of Fort Sanitary Inspector. 
 
 The only duties which may require special description will be 
 those of a port sanitary inspector. In this case it is essential that 
 the officer should know something of the management and con- 
 struction of ships; a half-pay naval officer, who has passed the 
 examination of the Sanitary Institute, should make an excellent 
 inspector for a port. The Tyne port has three inspectors — one, 
 the chief, was chief mate of a merchantman, the one assistant was 
 a ship's carpenter, the other a sea-going engineer. The duties of 
 these three officers are thus described by Mr. Armstrong ^ : — 
 
 The chief inspector attends at the station at 8.30 A.M. He' 
 examines the list of arrivals during the previous night and up to 
 8 in the morning, which is brought from the water-guard office 
 by the assistant inspector on night duty. He instructs the assistant 
 coming on duty at 9 o'clock ; attends to correspondence ; prepares 
 list of arrivals to board and calls to make during the day ; revises 
 Shipping Gazette for reports of homeward-bound vessels ; attends to 
 any office work on hand. Then proceeds on steam-launch to board 
 vessels, selecting first the most important, e.g. those from abroad 
 or specially noted. If working the lower reaches of the river he 
 returns to station about 1 p.m., and meets the assistant inspector 
 of the day, who reports, and receives further instruction. The 
 chief inspector, or the assistant on duty, calls at the water-guard 
 office at 1.30 p.m. for list of arrivals. The afternoon is spent in 
 visiting vessels on the river or in the docks, after which he returns 
 to the station, and generally seads the launch to moor at 5 P.M. in 
 winter or 6 p.m. in summer ; again meets the assistant on duty and 
 receives his report ; completes any office work remaining. Re- 
 visits office at 8 p.m. to receive list of arrivals. 
 
 On Sundays the chief inspector remains in office to receive re- 
 ports or boards arrivals bringing up near the station and requiring 
 immediate attention. 
 
 On Monday the Chief Inspector attends at once to particular 
 vessels entering dock, e.g., passenger steamers with emigrants due 
 that day. He overlooks the general work of the assistants, directs 
 the crew of the launch, makes periodical examination of the 
 launch, sees to her cleansing, repairs, stores, &c., checks accounts 
 1 Public Health, vol. i. p. 26. 
 
XXXV.] DUTIES OF PORT SANITARY INSPECTOR. 605 
 
 and forwards them to the central office ; reports on moorings, 
 safety and repairs of the hospitals ; attends meetings of the 
 authority. It is also his duty to carry on the correspondence of 
 his office, to keep and periodically present to the Medical Officer 
 of Health for examination and signature, an official log ; to make, 
 and direct the assistant inspectors to make, observations as to 
 smoke and other nuisances, to keep a list of owners of steam-craft 
 on the river, to examine cattle boats and vessels with perishable 
 cargoes, the closet accommodation, cleanliness, lighting, ventila- 
 tion, cubic space, water, provisions, &c., of ships ; to inspect periodi- 
 cally the gangways and conveniences abutting on the port, to 
 keep a record of all emigrants passing through the port, and under 
 the direction of the Medical Officer of Health, to advise the 
 Medical Officers of Health of other British ports of the same ; to 
 meet the Medical Officers with the launch as required ; to attend 
 to the posting or distributing of notices, inform the Customs of 
 any vessels due and suspected of having infectious sickness on 
 board ; to make preliminary inquiry into sickness reported on 
 shipboard ; and except in ailment of unmistakably non-infectious 
 character to notify to the Medical Officer or Assistant Medical 
 
 Officer Each assistant inspector comes on duty at 9 A.M. 
 
 on alternate mornings and remains on duty 24 hours. He ex- 
 amines the list of arrivals, receives the instructions of the Chief 
 Inspector as to which dock he shall visit, &c., inspects vessels, and 
 reports sickness noted on returning to office about 1 p.m. In the 
 afternoon visits a different dock, or inspects on the river as re- 
 quired, returning to station at 7.30 P.M., meets quarantine boat at 
 North Shields and extracts list of arrivals since 1.30 p.m. from 
 sheets in water-guard office, deals with or reports on matters re- 
 quiring attention, boards vessels about which he has particular 
 instructions, returning to station about 8.40 p.m. and leaving again 
 to catch 9.45 p.m. ferry, and meet quarantine boat at North 
 Shields, returning to station at 10.40 p.m., where he remains at 
 .liberty to rest on the office couch, but ready for a call at any 
 moment. Turns out again at 5.30 A.M. to meet quarantine boat at 
 North Shields returning to station, crosses again at 8 A.M. for 
 arrivals up to that hour, and returning to station is relieved by 
 the other assistant inspector at 9 A.M. The time spent in the 
 office is occupied in entering up inspection book, log book (which 
 
606 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 each signs at the end of his watch) and homeward-bound register, 
 particulars from Shipping Gazette, &c. 
 
 In the long days and when fishing craft are at the fish quay, 
 North Shields, the Assistant Inspector on duty devotes from two to 
 three hours before 8 am. inspecting these vessels. 
 
 The assistants as they go about their duties are instructed to 
 make observations as to nuisances, &c., and to inquire of the Cus- 
 toms officials, dock police, and others for information as to any- 
 thing requiring their interference. 
 
 (445) Duties of Inspectors as laid down by order of the Local Gomrnmenl Hoard. 
 
 1. He shall perform either under the special directions of the sanitary authority, 
 or (so far as authorized by the sanitary authority) under the directions of the Medical 
 Officer of Health, or in cases where no such directions are required, without such 
 directions, all the duties specially imposed upon an inspector of nuisances by the 
 Sanitary Acts or by the orders of the Local Government Board. 
 
 2. He shall attend all meetings of the sanitary authority when so requii-ed. 
 
 3. He shall by inspection of the district, both systematically at certain periods, 
 and at intervals as occasion may require, keep himself informed in respect of the 
 nuisances existing therein that require abatement under the Sanitary Acts. 
 
 4. On receiving notice of the existence of any nuisance within the district, or of 
 the breach of any bye-laws or regulations made by the sanitary authority for the 
 suppression of nuisances, he shall, as early as practicable, visit the spot, and inquire 
 into such alleged nuisance or breach of bye-laws and regulations. 
 
 5. He shall report to the sanitary authority any noxious or offensive businesses, 
 trades, or manufactories established within the district, and the breach or non- 
 observance of any bye-laws or regulations made in respect of the same. 
 
 6. He shall report to the sanitary authority any damage done to any works of 
 water supply or other works belonging to them, and also any case of wilful or 
 negligent waste of water supplied by them, or any fouling by gas, filth, or otherwise 
 of water used for domestic purposes. 
 
 7. He shall from time to time, and forthwith upon complaint, visit and inspect 
 the shops and places kept or used for the sale of butchers' meat, poultry, fish, fruit, 
 vegetables, corn, bread, or flour, or as a slaughter-house, and examine any animal, 
 carcase, meat, poultry, game, flesh, fish, fruit, vegetables, corn, bread, or flour which 
 may be therein ; and in case any such article appear to him to be intended for 
 the food of man and to be unfit for such food, he shall cause the same to be seized, 
 and take such other proceedings as may be necessary in order to have the same dealt 
 with by a justice ; provided that in any case of doubt arising under this clause he 
 shall report the matter to the Medical Officer of Health, with thu view of obtaining 
 his advice thereon. 
 
 8. He shall, when and as directed by the sanitary authority, procure and submit 
 samples of food or drink and drugs suspected to be adulterated, to be analyzed by 
 the analyst appointed under the Sale of Food and Drugs Act, 1875, and upon receiving 
 a certificate stating that the articles of food or drink or drugs are adulterated, cause 
 a complaint to be made and take the other proceedings prescribed by that Act. 
 
 9. He shall give immediate notice to the Medical Officer of Health of the occur- 
 rence within his district of any contagious, infectious, or epidemic disease of a 
 dangerous character, and whenever it appears to him that the intervention of such 
 officer is necessary in consequence of the existence of any nuisance injurious to 
 health, or of any overcrowding in a house, he shall forthwith inform the Medical 
 Officer thereof. 
 
 10. He shall, subject in all respects to the sanitary authority, attend to the 
 instructions of tlie Medical Officer of Health with respect to any measures which may 
 
XXXV.] DUTIES OF INSPECTORS OF NUISANCES. 607 
 
 be lawfully undertaken by him under the Sanitary Acts for preventing the spread of 
 any contagious, infectious, or epidemic disease of a dangerous character. 
 
 11. He shall enter from day to day, in a book to be provided by the sanitary 
 authority, particulars of his inspections and of the action taken by him in the 
 execution of his duties. He shall also keep a book or books, to be provided by the 
 sanitary authority, so arranged as to form, as far as possible, a continuous record of 
 the sanitary condition of each of the premises in respect of which any action has been 
 taken under the Sanitary Acts, and shall keep any other systematic records that the 
 sanitary authority may require. 
 
 12. He shall at all reasonable times when applied to by the Medical Ofi&cer of 
 Health, produce to him his books or any of them, and render to him such informa- 
 tion as he may be able to furnish with respect to any matter to which the duties of 
 inspector of nuisances relate. 
 
 13. He shall, if directed by the sanitary authority to do so, superintend and see 
 to the due execution of all works which may be undertaken under their direction for 
 the suppression or removal of nuisances within the district. 
 
 14. In matters not specifically provided for in this order, he shall observe and 
 execute all the lawful orders and directions of the sanitary authority, and the 
 orders which the Local Government Board may hereafter issue applicable to his 
 ofiice. 
 
 
SECTION XIL 
 INSPECTION OF FOOD. 
 
 E K 
 
CHAPTER XXXVI. 
 
 THE INSPECTION AND SEIZURE OF UNWHOLESOME FOOD. 
 
 (446) Powers of Inspecting Food. 
 
 Under the 116-119th sections of the Public Health Act in the 
 country generally and in the Metropolis under the Nuisance 
 Removal Acts, 1855, s. 26, and 1863 s. 2, 3, and the Sanitary 
 Amendment Act 1874, s. 54, 55 ^ medical officers of health or 
 inspectors of nuisances have pretty extensive powers of inspecting 
 at " all reasonable times," any animal, carcase, meat, poultry, game, 
 flesh, fish, fruit, vegetables, corn, bread, flour or milk exposed for 
 sale, or deposited in any place for the purpose of sale, or of 
 preparation for sale, and intended for the food of man — the 
 burden of proof always resting on the party charged, of showing 
 that the meat, &c., was not deposited for sale ; if any of the 
 substances mentioned appear " diseased or unsound or unwhole- 
 some, or unfit for the food of man, he may seize and carry away the 
 same himself or by an assistant, in order to have the same dealt 
 with by a justice." It is the magistrate's duty, if he consider the 
 case proved, to order the food to be destroyed, or so disposed of as 
 to prevent it being sold or used as food for man, while the offender 
 may be fined up to £20, or imprisoned up to three months. A 
 warrant to search premises may be also obtained from a justice on 
 complaint made on oath by a medical officer of health or by an 
 inspector of nuisances. By the Horseflesh Act 52 and 53 Vict. c. 11, 
 similar powers as to inspection, examination, and seizure are given 
 of horseflesh sold for human food and not legibly labelled 
 horseflesh. 
 
 ^ In Scotland, under the Public Health Act (Scotland), a. 26. 
 
 R R 2 
 
612 A MANUAL OF PUBLIC HEALTH. [chap, xxxvi. 
 
 Some articles of food, such for example as eggs, do not seem to 
 be included in the list. The words are general enough to embrace 
 all conditions of the foods mentioned which may render them 
 unsuitable for use, such for example as incipient decomposition 
 in all its forms up to putridity, mouldiness, the bruising of fruit, 
 the mustiness of flour, the admixture of dirt, and also such diseases 
 of corn as ergot ; the words also embrace every species of disease 
 which may be assumed as injurious, and in the author s opinion 
 milk or other similar substances which can be proved to have 
 been exposed under conditions which render it probable that the 
 germs of infectious disease may have been absorbed come also 
 under the section. 
 
 In a police-court case at Maidstone, it was proved that children 
 peeling after scarlet fever were allowed to pick currants, and that 
 such currants were sent to the London market ; the justices 
 refused to convict under the Public Health Act, a decision pro- 
 bably wrong, and one which would not be upheld by a superior 
 court. 
 
CHAPTER XXXVII. 
 
 POISONOUS FOOD. 
 
 (447) The Development of Poison in Food. 
 
 Cases occur from time to time in which after partaking of 
 some article of food, the person is seized with illness, which most 
 frequently takes the form of intestinal irritation, and may indeed 
 lead to death. Of the different kinds of butchers' meat, pork is 
 accredited with by far the greater number of cases, but beef, veal, 
 and mixtures such as sausages, brawn, and meat pies, have all 
 given rise to symptoms of poisoning, and careful chemical 
 investigation have shown that all ordinary vegetable and mineral 
 poisons have been absent. 
 
 The cases may be divided into two classes — viz., one class in 
 which it would seem probable that a saprophytic micro-organism 
 has split up the albumen of the meat and produced a poisonous 
 substance, as for example tyro-toxicon ; another class which is 
 more obscure, but a theoretical explanation may be suggested — viz., 
 that the meat was derived from a diseased animal, in the flesh of 
 which were one or more ptomaines produced during life and not 
 decomposed or altered by cooking. 
 
 (448) Porh-Pie Poisoning at Retford. 
 
 One of the best examples of the first class is the pork-pie and 
 
 brawn poisoning at Retford investigated by Mr. Spear.^ The 
 
 material that was proved to have caused 70 cases of illness of 
 
 varying severity and one death was derived from a pig, the sixth 
 
 ^ Supplement to the Seventeenth Sep. Loc. Gov. Board. 
 
614 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 survivor of a litter of seven which had come into the Retford 
 Co-operative Society's possession in April, 1887. For six weeks 
 before its slaughter, it was fed entirely on meal, and to all 
 appearances was a perfectly healthy pig ; it was slaughtered on the 
 8th of November ; 50 lbs. of the pork were handed over to the 
 baker to make pork pies and brawn ; a leg and two sides were 
 found in salt at the stores when Mr. Page made his inquiries, the 
 remainder (about three stone) had been sold as fresh pork between 
 the 9th and 12th of the month ; no case of illness could be 
 discovered from the consumption of the pork in its fresh state, 
 but from that made into pie and brawn the outbreak was en- 
 tirely traced, the majority of those consuming it suffering from 
 diarrhoea and other symptoms of gastro-enteritis. 
 
 The pies ,and brawn were made and cooked on the 10th of 
 November, the temperature of the oven being 220°F., or above, 
 and they were purchased by various families and consumed, from 
 about the 13th to the I7th. Presuming, then, that the meat was 
 properly sterilized by cooking, it must have attained its noxious 
 qualities in about 48 hours. There was some evidence that of 
 the few persons who ate the brawn on the 11th, that is the day 
 after cooking, a minority only of these became affected, while after 
 the 11th a majority of those who consumed either the brawn or. 
 pies became ill. 
 
 Dr. Klein submitted the pie and brawn to a microscopical and 
 bacteriological examination. On opening the pie there was 
 observed in its depths a wide crack in which was a continuous 
 layer of a greyish brown viscid scum. This scum was made almost 
 entirely of minute thick rods rounded at the ends, constricted 
 in the middle, and in many places arranged in long chains. The 
 single or dumb-bell rods were mobile, those in chains quiescent. 
 There were also present micrococci in small groups or zoogloea, 
 and a few yeast cells. The micrococci were cultivated and 
 proved not to be pathogenic. The minute thick bacillus was 
 cultivated and found to grow freely at a temperature of 38°C., 
 which is one of the distinctions laid down by Dr. Klein to differen- 
 tiate it from a bacillus of similar form in connection with a veal- 
 pie poisoning investigated by him on a previous occasion. The 
 rods are mobile 8yu. to 1-2/i in length, about '5/^ in thickness, 
 many of them constricted in the middle, forming a sort of 
 
XXXVII.] . POISONOUS POOD. 615 
 
 dumb-bell. Cultivated on alkaline nutritive gelatin in streak 
 cultivation at 20°, in 24 hours there is a whitish continuous line 
 like a line of white paint ; after 24 hours a distinct blue colour 
 appears in the gelatin immediately in contact with the streak, 
 becoming more gradually diffused into the depth. 
 
 In broth also after about ten days at 35° the liquid becomes 
 slightly greenish. Twelve mice fed directly with the pie, became 
 very ill, one of the twelve died. Two dogs were fed with the pie 
 but the effect was but little evident. Mice were also fed with the 
 cultures and suffered from the same kind of illness, some of the 
 mice dying, those that died showed the same post-mortem signs, 
 viz. congestion of stomach and intestines, and enlargement of 
 spleen, kidneys and hver. The remarkable fact was discovered 
 that cultures from ten days to a fortnight old had no effect on 
 mice. 
 
 (449) The Arlford Sausage Poisoning Case. 
 
 As an example of the other type of meat poisoning may be 
 cited the Arlford ^ sausage poisoning case investigated and described 
 by Dr. Ballard. In this case a gardener aged forty-two purchased 
 in Chester half a pound of sausage. At about 11 A.M. the same 
 morning he ate the sausage, and in three-quarters of an hour was 
 found extremely ill with choleraic symptoms ; the man died after 
 a week's illness, pneumonia apparently supervening, but there was 
 no post-mortem examination. 
 
 The sausage eaten was part of a consignment of American 
 manufacture ; on the man's illness being discovered, the rest was 
 put aside, portions of the sausages being experimented on by 
 Dr. Klein. Some were found to be innocuous, others very 
 poisonous to small animals such as mice and rabbits. "In all 
 instances where the animals became ill, the illness showed itself 
 soon after the feeding, viz. from a quarter of an hour to a few 
 hours. The animals became quiet, and in some instances, 
 especially in the rabbits, there was vomiting a quarter of an hour 
 after feeding ; they neither cared to take food, nor to move ; their 
 faces were pinched and their eyes small. In the case of the mice 
 their coats became very rough. This state soon grew worse, the 
 animals becoming comatose, the temperature rapidly sank and 
 ^ Supplement to the Eleventh AnnvM Rep. of the Loc. Qov. Board. 
 
616 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 the animals soon died. In some cases they lingered on for several 
 days, recovered slightly, took food again and became a little more 
 lively ; but when killed they showed the same post-mortem 
 appearances as those that died spontaneously, only in a milder 
 degree. On post-mortem examination, the appearances found were 
 haemorrhages in the stomach, congestion of the lungs, enlarged 
 kidneys, the cortex of the organs being pale, the medulla 
 hypersemic. On microscopical examination of the kidney, the 
 important fact was ascertained that most of the urinary tubules 
 contained casts, that many Malpighian corpuscles and the tissues 
 surrounding them were in a state of disintegration, without 
 however there being present any inflammatory cells (pus corpuscles), 
 so that this disintegration was evidently the direct result of some 
 destructive agency circulating in the vessels of the glomeruli of 
 the Malpighian corpuscles." In this case there was evidently 
 some soluble poison, probably of bacterial origin. 
 
 The student may also refer to the instructive cases of poisoning 
 by meat at Welbeck and at Nottingham, both investigated by 
 Dr. Ballard,^ the symptoms of which somewhat differed from the 
 above in being more like a specific (typhoid) fever. 
 
 (450) Diarrhoea from Milk or Cheese — Tyro-toxicon, 
 
 In cases in which it seems likely that either milk or cheese 
 has produced intestinal disturbance, carefully examine for diazo- 
 benzene butyrate, also named tyro-toxicon, a- very poisonous sub- 
 stance which is formed with considerable ease. If, for instance, a 
 minute fragment of butyric ferment be added to milk in a bottle 
 and the bottle corked up, tyro-toxicon is formed. The testing for 
 tyro-toxicon is a simple matter : — supposing the substance is milk, 
 a sufficient quantity of carbonate of soda is added to give a 
 decided alkaline reaction, and then the liquid is shaken up with 
 an equal bulk of ether ; this operation is best done in a tube with 
 a stopcock at the bottom. The tube is allowed to stand until 
 the ether rises to the top ; if there is no proper separation a little 
 strong alcohol will assist matters by clearing the liquid up ; the 
 milk is now run off and the ethereal layer separated. The ether 
 is poured into a flat dish or saucer and allowed to evaporate 
 ■^ Swpplenunt to the Tenth Annual Rep. of the Lot. Gov, Board. 
 
XXXVII.] OUTBREAKS OF ILLNESS CONNECTED WITH FOOD. 617 
 
 spontaneously; the residue left on evaporation is dissolved in a 
 little water and filtered through wet filter paper to free it from fat 
 and again the filtrate shaken up with ether, the ethereal layer is 
 once more allowed to evaporate spontaneously ; the residue con- 
 tains any tyro-toxicon present in a sufficiently pure state to admit 
 of tests being applied. The most convenient test is a mixture of 
 equal bulks of pure phenol and sulphuric acid. This strikes an 
 orange red or purple colour with very small quantities of 
 tyro-toxicon. Another test is to evaporate the solution to dryness 
 with strong potash ; a compound is formed soluble in alcohol but 
 which is precipitated by ether in the form of crystals. 
 
 If cheese is to be tested the cheese is triturated with water 
 and carbonate of soda added, and the solution or emulsion shaken 
 up as before with ether. 
 
 (451) Method of Investigating outlreaks of Diarrhoea or Illness 
 supposed to result from tad Food. 
 
 In these investigations it will be far simpler and more certain 
 to pursue a properly thought-out plan of investigation than go 
 haphazard to work. The only way is to examine each person 
 separately as to what he or she has eaten for one, two, or three 
 days previously, bearing in mind that it is of equal importance to 
 examine those who have not suffered, as well as those who have 
 suffered. The inquirer will find it convenient to draw out the facts 
 in a tabular form according to the plan drawn out below, putting a 
 simple mark / against the particular article eaten on each day, 
 and denoting by a single stroke that the substance has been 
 eaten sparingly, a double stroke thus x that it has been eaten 
 or drunk in fair quantities and a treble stroke thus ^ that it 
 has been taken in large quantities. 
 
 The table on the following page gives at a glance much informa- 
 tion : for instance, take the dairy products — it is obvious that not 
 alone did every one of the family use milk but the boy drank it 
 largely and we will presume unboiled ; the milk may therefore be 
 excluded in the same way the butter. is excluded; on the other 
 hand the master and mistress both eat Gorgonzola cheese and both 
 suffered, but this fact is neutralized by the fact that two others 
 who did not eat this cheese were also ill ; hence it can hardly be 
 
618 
 
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XXXVII.] OUTBREAKS OF ILLNESS CONNECTED WITH FOOD. 619 
 
 the cheese ; and proceeding in this way with each item, there is 
 one substance found — the pork — which the sufferers took alone and 
 no one else, hence when this stage is arrived at the attention maj' 
 be concentrated to this particular article, and strict inquiry made 
 concerning it — that is, where it was bought, and so forth ; it may then 
 be possible to find out whether any other families have had pork 
 from this particular animal or not, or bought pork the same day 
 from the same butcher. In this way ultimately the evil may be 
 traced back to its source. In such work as this he who is 
 capable of taking the most trouble will be most likely to succeed. 
 An apparently simple inquiry consumes much time and demands 
 the exercise of natural powers of observation and keenness that 
 some persons are never able to acquire. 
 
CHAPTER XXXVIII. 
 
 UNFIT VEGETABLE SUBSTANCES. 
 
 (452) Decomposed Vegetables. 
 No special details need be here given upon the appearances 
 which vegetable substances present when partially or completely 
 decomposed ; all persons of ordinary intelligence can distinguish 
 between fresh and stale vegetables. On the other hand, differences 
 of opinion will occiir with regard to fruit ; if fruit such as apricots, 
 strawberries, gooseberries are but partially decomposed, it is 
 doubtful whether it is fair to seize and destroy them, because the 
 condition is so evident that the public are not defrauded, and 
 bruised and partially mouldy fruit is often sold for making 
 preserve at a low price. Hence in these cases the medical 
 officer must be entirely guided by the extent of the decomposition 
 or condition, and the Author's advice is only to act in those 
 cases of a decided character. 
 
 (453) Unhealthy condition of Flour or Bread. 
 Flour may be simply musty ; here again, unless the mustiness 
 is pronounced, it will not be wise to condemn as unfit for food. 
 If it smells only faintly such flour will make fairly eatable bread ; 
 on the other hand, flour with evident and strongly smelling musti- 
 ness should be unhesitatingly condemned. 
 
 (454) Ergot in Flour. 
 
 Since ergot causes a special malady, there can be no possible 
 difference of opinion that ergotised flour if discovered should be 
 unhesitatingly condemned. Such flour is dark in colour and has 
 a peculiar odour. Examined by the microscope the little dark 
 masses of ergot may be seen ; if also the flour be stained by aniline 
 
CHAP. XXXVIII.] COEN COCKLE SEEDS IN FLOUR. 621 
 
 blue, all starch granules damaged by ergot, or as for that by any 
 other fungus, will be stained intensely. A portion of the flour 
 may be exhausted by boiling strong alcohol, the alcoholic solution 
 acidified by dilute sulphuric acid and examined by the spectroscope. 
 If the flour is ergotised, the solution ■will be more or less red and 
 show in dilute solution two absorption bands, one lying in the 
 green near e and a broader and stronger band in the blue between 
 / and g. On mixing the original solution with tw^ice its volume 
 of water and shaking up with ether or amyl alcohol, or benzine or 
 chloroform, if ergot be present any of these solvents become of 
 a red colour. 
 
 (455) Corn Cochle Seeds in Flour. 
 
 A mixture of these seeds with flour will make the flour unfit 
 for use, the active principle of the Agrostemma or lychnis cithago 
 being saponin, a glucoside with marked irritant properties. The 
 seeds are in shape not unlike a rolled up- caterpillar, the surface 
 being beset with little warty projections arranged in rows. The 
 surface of the testa, or seed covering, shows, when examined by 
 the microscope, very large thickened cells '1 to '6 mm. diameter, 
 forming on the surface branching tubercles, beneath which is 
 a loose parenchyma made up of two layers or rows of simple cells ; 
 this rests on a thin epithelial membrane composed of flat cells, 
 most of which exhibit a peculiar striation ; next to this comes the 
 main substance of the seed, the endosperm, composed of ordinary 
 large-celled parenchyma, filled with very minute starch granules ; 
 and lastly, there is the embryo, the structure of which cannot be 
 distinguished from the embryo of other seeds. There are little 
 bodies scattered among the endosperm, consisting of egg or spindle- 
 shaped finely granulated grains, from '02 to "1 mm. in long diameter, 
 consisting wholly of saponin, starch, and mucin ; these bodies are 
 not peculiar to corn cockle seeds, but occur in other plants of the 
 same natural order — that is, in the clove-worts. F. Beneke has 
 examined the sizes in various plants and gives the maximum as 
 follows : — spergula "030 mm., beta '057 mm., spinacia '64 mm., 
 agrostemma •122 mm., hence over '07 mm. points to corn cockle. 
 Flour containing corn cockle seeds yields a larger percentage of 
 oil to ether, and the ether extract has an acrid taste and is of a 
 pronounced yellow colour. 
 
CHAPTER XXXIX. 
 
 INSPECTION OF FISH AND MEAT. 
 
 (456) Inspection of Fish. 
 
 Fish are subject to various parasitic diseases, but the purpose 
 of inspection will be mainly to ascertain whether the fish are stale 
 or fresh. Since a large proportion of both inspectors and medical 
 officers have at one time or another of their lives been amateur 
 fishermen, they will probably know perfectly well the signs of a 
 fresh fish, the bright prominent eye.^ the healthy gills, the peculiar 
 feel of the whole body and the absence of odour when the mouth 
 and gills are opened and the inspector's nose applied close. In 
 a dark place fish beginning to decompose will also here and there 
 shine with a phosphorescence, but before this takes place an odour 
 will nearly always be detected. The slightest taint in fish renders 
 them unfit for use and justifies condemnation. 
 
 (457) Inspection of Meat. 
 
 Since it is only possible in a minority of cases to tell from a 
 
 1 One of the best descriptiona of the dodges of fishennen is to be found in Black- 
 more's novel, The Maid of Sker. " I felt that I could trust nobody to have proper 
 faith, especially when they might behold the eyes of the fish retire a little, as they 
 
 are apt to do when too many cooks have looked at them When the eyes of a 
 
 fish begin to fail him through long retirement from the water, you may strengthen 
 his mode of regarding the world (and therefore the world's regard for him) by a 
 delicate bit of handling. Keep a ray fish always ready — it does not matter how stale 
 he is — and on the same day on which yoii are going to sell your bass, or mullet, or 
 cod, or whatever it may be, pull a few sharp spines, as clear as you can, out of this 
 good ray. Then open the mouth of your languid fish and embolden the aspect of 
 either eye by fetching it up from despondency with a skewer of proper length 
 extending from one ball to the other. It is almost sure to drop out in the cooking, 
 and even if it fails to do so none will be the wiser, but take it for a provision of 
 nature — as indeed it ought to be." 
 
CHAP. XXXIX.] CHARACTERISTICS OF GOOD MEAT. 623 
 
 look at the muscles or flesh of a slaughtere'd animal whether 
 it was in good health or the reverse, the medical officer should 
 aim at inspecting the entire carcase. 
 
 It does not admit of two opinions that, knowing what we do of 
 the importance of a healthy meat supply, the time has come to 
 insist upon a proper inspection of meat; this proper inspection 
 can only be made if in each town the slaughtering is centralized ; 
 it is to be hoped that ultimately such meat inspection will occupy 
 the whole time of one or more pathologists who should have every 
 appliance for the microscopical examination and also for bacterio- 
 logical research. 
 
 A medical officer of health is expected by the law to give a 
 glance at a leg of mutton, or a piece of beef, to detect there and 
 then the seeds of disease and to at once convey it before a 
 magistrate. Hence as this is an impossibility, the work is either 
 not done at all, or the inspection is only made of absolutely putrid 
 pieces of meat, or of cases concerning which special information 
 has been given. 
 
 (458) Characteristics of Good Meat. 
 
 All fresh meat is acid to test paper ; directly decomposition 
 commences the acidity diminishes and then is replaced by an 
 alkaline reaction. If a little meat is chopped up and warm water 
 poured upon it, the odour should not be disagreeable ; on the 
 other hand, meat from a diseased animal has a sickly peculiar 
 smell and occasionally it possesses a distinct odour of the medicine 
 which the farrier has drenched the sick animal with. In this way 
 sometimes aloes may be smelled. The colour of the meat should 
 be normal ; each animal's meat has a colour of its own, the peculiar 
 pale tint of veal or of mutton, and the deep red of beef are 
 examples ; any marked deviation from the colour is a suspicious 
 sign. Calves, sheep, and pigs, being freely bled to death, should 
 the meat of these animals have an abnormal red hue it may be 
 a sign that they were not killed in the usual manner and therefore 
 this will again be suspicious. 
 
 Meat which is sodden and contains much water is not un- 
 frequently diseased. 
 
 To examine meat practically a knife should be run into it, well 
 
624 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 into the centre of the mass, and the knife carefully smelled on 
 withdrawal ; if opportunity admits a portion of the suspected meat 
 may he examined by the microscope. 
 
 A portion may also be soaked in distilled water and a little 
 litmus added so as to test its reaction. 
 
 To detect trichinae see page 629. 
 
 (459) The Detection of Tulercle Bacilli. 
 
 To detect tubercle bacilli in meat it will be necessary to very 
 carefully dissect out any little portion which looks suspicious; 
 cut fine sections of it and stain the sections with Gibbes' double 
 stain. 
 
 Gibbes' double stain is made by dissolving 2 parts of rosaniline 
 hydrochlorate, 1 of methylene blue, in 3 parts of aniline oil, and 
 15 parts of rectified alcohol ; lastly dilute with 15 parts of water. 
 
 The sections are soaked in this solution first made very hot for 
 several hours, the excess of stain is washed away with methylated 
 spirit ; the sections are dried and mounted in Canada balsam. The 
 search for tubercle bacilli must be made with a high power and 
 with good illumination. 
 
 Muscular tissue may contain the germs of tubercle and yet the 
 most experienced microscopist fail to detect them, but by injecting 
 the flesh juice into guinea-pigs their presence may yet be shown — 
 e.g. : At Munchen some experiments have been made recently by 
 Steinheil ^ as to the possibility of infecting guinea-pigs with the 
 products from the muscles of persons affected with phthisis. The 
 material used was portions of the psoas muscles of nine patients 
 who died of phthisis. The muscle was cut up into very fine 
 pieces, and submitted to the pressure of a screw press. The 
 juice obtained was injected into guinea-pigs. Of eighteen guinea- 
 pigs thus treated fifteen died of tuberculosis, although no tubercle 
 could be detected in the muscles so used. Steinheil draws the 
 conclusion that the muscular flesh in advanced human phthisis 
 is infectious as a rule; hence the possibility that the flesh of 
 animals affected with bovine tuberculosis is dangerous cannot be 
 denied. 
 
 1 Munchen med. TVochenschrifi, 1889, Nos. 40 and 41. 
 
XXXIX.J DETECTION OF TUBERCLE BACILLI IN MEAT. 625 
 
 This method is unfortunately not open at present to English 
 medical officers of health, being a breach of the Vivisection Act. 
 It is only in those large towns and places where the local authority 
 possesses an ice chamber in which to deposit suspected meat that 
 any prolonged investigation can take place ; the officer has usually 
 to decide there and then ; whereas in common justice to all parties 
 it would be better for there to be a proper place for the meat to 
 be taken to and there detained and a thorough and complete 
 examination to be made. 
 
 s s 
 
CHAPTER XL. 
 
 DISEASES OF ANIMALS RENDERING THEIR FLESH MORE OR LESS 
 UNFIT FOR FOOD. 
 
 (460) Measles in the Pig and the Ox. 
 
 This is a parasitic disease, little cysts being scattered about the 
 muscular system, each cyst containing the larval or hydatid stage 
 of a tape-worm. The parasite is called the bladder-worm, or 
 cysticercus cellulosce. A different species affects the pig to that of 
 the ox, but the naked eye appearances and the distribution in each 
 is very similar. The way in which these parasites gain access to 
 animals is as follows : — A human being afflicted with tape-worm 
 passes the segments of the mature tape-worm full of thousands of 
 eggs. These eggs are in some way or other swallowed by pigs or 
 oxen (or, as for that, by sheep), the eggs are hatched inside the 
 body. The embryo when hatched makes its way into the tissues 
 by the aid of a peculiar apparatus round its mouth consisting 
 of six booklets, and there develops not into a tape-worm but 
 into the hydatid or bladder form. Nor will it further develop, 
 save the animal is killed and the living hydatid pass into the 
 human or other intestine, then it enters on its completed exist- 
 ence, and fastening by means of the booklets, or in the bookless 
 form by suckers, on to the mucous membrane, grows into a 
 tape-worm many feet in length. Each joint of a tape-worm may 
 contain as many as 53,000 eggs, so that if only a few joints 
 of the tape-worm are eaten, and only a portion of the eggs 
 hatched yet enormous numbers of hydatids may be formed. When 
 the embryo arrives at its resting-place a cyst or bladder forms at 
 the spot, in the centre of which the worm is coiled up ; it is about 
 
Plate YL 
 
 B. J- R C f. a.rh . Ed ' n h y j-qA 
 
CHAP. XL.] TRICHINA— TRICHINOSIS. 627 
 
 a third of an inch in its longest diameter, or from the size of a pea 
 to that of a cherry in the retracted state, it is oval, but when the 
 head and neck is extended it is bottle or gourd-shaped. The 
 vesicle is filled with an albuminous, milky-coloured fluid, and in 
 the retracted state exhibits a dense white spot at one point of its 
 surface. Hydatids in pigs are specially to be looked for in the 
 muscles of the tongue, the neck, and the shoulders ; but hydatids 
 may be found in the liver, kidney, brain, and many tissues in the 
 body. During life the existence of measles is often detected, the 
 pig is thrown down, a piece of wood is thrust across the jaws, and 
 the tongue pulled outside the mouth, the organ is carefully 
 examined underneath towards the root and the bridle where, if 
 present, the cysts may be seen and felt, still their absence is not 
 conclusive evidence that they do not exist elsewhere. 
 
 In the ox, the hydatid is to be looked for in the same situations 
 as in the pig. 
 
 The naked eye appearances of measles (cysticercus hovis) in 
 beef are represented in Plate VI., which has been dra^wn (natural 
 size) from a specimen in the College of Surgeons' Museum 
 (No. 123 in Catalogue). This cysticercus if taken into the human 
 intestine may develop into, the tape-worm known as the tcenia 
 medio-cannelata ; neither the bladder- nor the tape-form are pro- 
 vided with hooks. 
 
 The diaphragm, the tongue, the superficial muscles of the 
 shoulder, breast, loin, hip, or quarter, and the eyelids, are the 
 special likely places. The heart, too, in the majority of cases is 
 also affected. 
 
 Hydatids have a considerable power of resistance to both heat 
 and cold, but they perish at a temperature of 170° F., and, of 
 course, at the temperature of boiling water, so also a lengthened 
 exposure to cold, or smoking will destroy them, and prolonged 
 immersion in brine. Nevertheless, it is not safe to allow any 
 measly meat to be sold, for it is never certain that such meat will 
 be cooked properly, and the signs of death in such low animal 
 forms are deceptive. 
 
 (4(61) Trichince — Trichinosis. 
 
 The trichina spiralis is a minute worm, parasitic in the muscular 
 system of man and animals. The disease affects pigs and men, 
 
 s S 2 
 
628 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 but neither oxen nor sheep. The pigs, become trichinous from 
 eating offaV man becomes trichinous from eating pork or bacon or 
 ham derived from a trichinous pig. • 
 
 The male worm is only ^V inch when fully developed, the female 
 is longer, the length being |- inch ; the body is rounded and 
 thread-like, the head is narrow, finely pointed, unarmed, with a 
 simple central small mouth opening ; the posterior extremity of the 
 male is furnished with a bilobal caudal appendage, the anal 
 aperture being situated between these divergent appendages ; the 
 penis consists of a single spicula cleft above, so as to assume a 
 V-shaped outline. The female has the genital outlet placed far 
 forward, at about the end of the first fifth of the long diameter of 
 the body ; the eggs measure in their long diameter raVir inch, these 
 are hatched in the body of the parent ; the reproduction is there- 
 fore viviparous. 
 
 The females contain mostly from 500 to 600 eggs. The new- 
 born young being hatched, commence their wandering. They 
 penetrate the wall of the intestines and pass into the muscles, 
 proceeding in the course of the intermuscular connective tissue. 
 It is specially those muscles which are nearest to the cavity of the 
 abdomen in which the majority of the trichina are found. It takes 
 about fourteen days for the embryos to attain the full growth. 
 Soon after the introduction of the parasite into the muscle, 
 the infested muscular bundle loses its structure, and at the spot 
 where the worm coils itself up a lemon-shaped or globular little 
 cyst is developed. In this cyst there may be from one to three 
 trichinae. The cyst often becomes calcified. 
 
 During this migration the individual affected suffers from pains 
 in the limbs, and often swelling about the joints with fever ; there 
 is also often diarrhcea and peritonitis. The disease is likely to be 
 confused with rheumatism, rheumatic fever, tuberculosis, enteric 
 fever, and pyaemia. If a considerable quantity of trichinous meat 
 is consumed, the embryo may be produced in prodigious numbers 
 and the results are then likely to be fatal. In 1863, out of 103 
 persons who ate sausages made of an affected pig, at Hettstadt, 
 eighty-three died from trichinosis, and there are several similar 
 cases on record. In 1873, 250 persons suffered from trichinosis at 
 Magdeburg, Germany. Many died and most were seriously ill. 
 ' It ha3 been suggested that rats are also a source of trichinae. 
 
Pi, ATE vn 
 
 Ji j-R r-!a..-k.Fd.^.7anj.rqi 
 
XL.] EXAMINATION OF MEAT POR TRICHINA. 629 
 
 Bits of muscle removed by a trocar from some of the sufferers and 
 weighing about a gramme were found to contain as many as 800 
 trichinae. The symptoms produced are not usually immediate but 
 follow after from five to six days. 
 
 It is not known how many pigs in this country are affected with 
 trichinosis. 
 
 In America the Massachusetts State Board of Health have from 
 time to time published the results of their supervision over the meat 
 ' supply ; thus in 1879 Dr. F. S. Billings examined 2,701 hogs, 154, or 
 5"7 per cent, were trichinous ; in 1881 6,068 hogs were examined, 191 
 or 3'15 per cent, were trichinous. Professor E. L. Mark gives a 
 return of careful exammation of hogs raised near Boston, from 
 which it appears during the period 1883—1888, out of 3,064 hogs 
 394 or 12'86 per cent, were found trichinous. 
 
 (462) Exaviination of Meat for Trichincs. 
 
 The best part to search for trichinae is the diaphragm, 25 per 
 • cent, of the total worms being found in that large muscle ; after the 
 diaphragm come the muscles of the shoulder and those of the loins 
 but in a hog thoroughly infested, there is no muscle in which they 
 may not be found, provided trouble is taken ; the muscles of the 
 back are those least affected. 
 
 A low power is only necessary (30 to 40 diameters), little bits of 
 the muscle are teased out with needles and placed, after flattening 
 out by the cover-glass, and adding a little glycerin, in the field of 
 the microscope. Non-encysted trichinae may be readily discovered 
 in this way, on the other hand those that are encysted require 
 special treatment ; if the cyst is calcified a little hydrochloric acid 
 will soon clear it up, the muscular substance may also be disinte- 
 grated by potash, which will not affect the cyst, but on the contrary 
 render it more visible. By adopting such processes there should 
 be no diflSculty in identifying the worm if present. Plate VII. 
 represents (natural size) a specimen of muscle from the human 
 subject containing encysted trichinae (Royal College of Surgeons' 
 Museum). Professor Mark ^ takes nine slips of meat from the 
 pillar of the diaphragm, and if no trichinae is found in any one of 
 
 1 Twentieth Report of the Massach. State Board of Health. 
 
630 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 the nine samples the hog is passed as non-trichinous. He states 
 that in several instances trichinse were only detected in the eighth 
 or ninth slip examined. 
 
 (463) Vitality of Trichince. 
 
 Trichinae when encysted, have considerable tenacity of life. 
 Miiller found, for example, that trichinous flesh steeped in strong 
 brine for 8-10 days was still able to infect rabbits. Trichinae will 
 withstand drying in the air or sun, and will live in putrified meat, 
 but meat which has been boiled or roasted thoroughly experiment 
 has shown is perfectly safe, but as trichinse are not killed by a tem- 
 perature of 122° F., the meat may still infect if the interior of 
 the joint has not been brought to a sufficiently high temperature. 
 
 (464) Glanders and Farcy. 
 
 Horseflesh derived from a gland ered horse is decidedly unfit for 
 human food, although sold under its proper appellation " horse- 
 flesh." Glanders is a micro-parasitic disease affecting the horse, and 
 which may be transmitted to man and cattle by inoculation. It is 
 associated with a special bacillus the size of the tubercle bacillus. 
 The difeease is especially characterized by nodules and ulcers in the 
 mucous membrane of the nose, the lymphatics also become affected, 
 and nodules form in the internal organs, that is the lung, spleen, 
 and liver. 
 
 (465) Variola of Sheep. 
 
 Variola or small-pox of sheep is an eruptive malady analogous 
 but not identical with the small-pox of the human subject. There 
 is a definite eruption which proceeds from red points to nodules, 
 and then becomes pustular, the pustules ultimately break, then 
 scab, the scab after a time becomes detached, leaving a cicatrix. 
 The changes are chiefly in the skin, but also the mucous mem- 
 branes of the nose and eyes are affected, the lymphatic glands are 
 also inflamed. The flesh looks healthy, and apart from the skin 
 the meat might be sold without detection. Variolous sheep are 
 said to have been largely eaten in Paris at the time of the last siege 
 of that city without injury. Nevertheless the meat of such animals 
 should most decidedly be condemned. 
 
Plate VlTl 
 
 ■-h.l'd7.^:hurql, 
 
XL.] PNEUMO^ENTERITIS OF THE PIG. 631 
 
 (466) Piieumo-Enteritis of the Pig. 
 
 This disease has been exhaustively investigated in a series of 
 researches by Dr. Klein, see the 7th Annual Report of the Local 
 Government Board (Supplement to Kep. of Medical Officer for 1877). 
 It has been called a great variety of names, such aS pig typhoid, 
 hog cholera, malignant erysipelas, red soldier, purples, blue disease, 
 and others. It has also been confused with splenic fever or anthrax. 
 It is an infectious malady caused by special micro-organisms having 
 considerable resemblance to the bacillus anthracis. 
 
 The disease is somewhat common in England, and causes when 
 prevalent great losses to swine farmers. 
 
 In mild cases the skin is normal, but the inguinal glands are en- 
 larged and red. The lymphatic glands of the pelvis are distinctly 
 enlarged. So are also the mesenteric glands and the glands in 
 the ligamentum gastro-hepaticum. Greater or smaller portions of 
 these masses of lymph glands show redness of their cortical part, a 
 redness due to haemorrhage in the cortex of. the gland. 
 
 The peritoneum is but slightly inflamed, but in the peritoneal 
 cavity is a small quantity of fluid or solid lymph. The serous 
 covering of the small and large intestine is hyperaemic. 
 
 In the mucous membranes of the intestines are very evident 
 changes ; that of the duodenum is intensely red, and on the crests of 
 the folds are small haemorrhages. The ilio-caecal valve, the caecum 
 and colon, are also more or less congested, and very often there are 
 minute haemorrhages. There are always small ulcers on the ilio- 
 caecal valve, and a few also on the colon. Plate VIII. represents 
 a portion of the mucous membrane of the ileum, of a pig which 
 had died of pig typhoid (Royal College of Surgeons' Museum). 
 In the mild forms the colon and rectum are filled with normal 
 faecal matter. The lungs are usually congested, and many lobules 
 in a more or less advanced stage of pneumonia. The bronchial 
 glands are red and enlarged. 
 
 The muscular structure of the heart shows in most cases minute 
 haemorrhages, the same is to be said of the endocardium. 
 
 In the front part of the tongue on both upper and lower surfaces 
 there are occasionally haemorrhages. 
 
 In the severer cases all these pathological signs are much accent- 
 uated, and there are often patches of redness of the skin. 
 
632 A MANUAL OF PUBLIC HEALTH. [ohap. 
 
 In the general muscular system no naked eye changes are to be 
 seen, hence a single joint of pork derived from a pig, which has 
 suffered or died from pneumo-enteritis, might be passed as good by 
 any observer who had had no opportunity of investigating the in- 
 ternal organs. 
 
 In severe cases Klein states that the muscular tissue appears 
 pale, soft, and moist, and on microscopic examination the muscular 
 fibres are seen to be in a state of fatty degeneration. He further 
 states that his assistants consumed without injury salt pork 
 derived from carcases of pigs used in his experiments which had 
 suffered from the mild attacks produced by inoculation. 
 
 In examining a pig's carcase for signs of pneumo-enteritis the 
 most constant changes are the diseased condition of the lungs, the 
 intestinal glands, and the congestion and ulceration of the lining 
 membrane of the gut. If these are healthy the animal cannot 
 have suffered from pneumo-enteritis. The liver, spleen, and kid- 
 neys in the milder forms are healthy, hence the normal condition 
 of these organs must not be taken as evidence of previous good 
 health. The bacillus associated with the disease is two to three 
 /i long (but it is capable of growing to a great length), it is 
 actively motile, which distinguishes it from anthrax. Spore form- 
 ation has been observed. The bacilli can be cultivated in broth 
 or hydrocele fluid. From artificial cultures the disease may be 
 produced in pigs, mice and rabbits. The bacilli are not to be 
 found in the blood or spleen, but may be found in the lung, in the 
 sanguineous fluid of the trachea, in the peritoneal exudation, and in 
 any purulent collection, such as abscesses at the seat of inoculation. 
 So far as is known the disease is not transmissible to man. 
 
 (467) Swine Plague. 
 
 This is an affection of the digestive organs of which the large 
 intestine is principally involved. The latter is as a rule the seat 
 of diphtheria. At the same time the lymphatic glands are affected, 
 and there may be observed traces of a general slight infection. 
 The disease may be accompanied by slight lung affections. 
 
 (468) St. Anthony's Fire. 
 In this disease the symptoms cannot be differentiated from 
 py£emia or anthrax. The most important changes are bright 
 
XL.] PLEURO-PNEUMONIA. 633 
 
 patchy redness of the skin, enlargement of the spleen, inflamma- 
 tion with minute haemorrhages of the stomach and intestines, 
 infiltration and congestion of the kidneys ; there may also be puru- 
 lent foci in the liver, but save in the worst cases the muscular 
 system will show little if any alteration. 
 
 (469) Foot and Mouth, Disease. 
 
 This is a disease often epizootic among cattle and sheep. The 
 milk of affected cows will produce the same malady in man, and 
 such milk should be destroyed. The essential features of the 
 disease are the formation of blebs or blisters on the toncfue, the 
 lining membrane of the mouth, the udder of cows, and between the 
 claws of the hoof; the blisters soon break and leave ulcers. The 
 changes in the internal organs are of too general a nature or too 
 slight in character to be pathognomic, so tbat unless the mouth, 
 feet, and mucous membranes be inspected there will be but little 
 chance of ascertaining whether a given animal has suffered from 
 foot and mouth disease or not. A special micro-organism, a strep- 
 tococcus, is associated with the disease, and has been found in the 
 fluid of the vesicles and in the milk. The cocci occur singly, in 
 dumb-bell, and in curved chains. They can be readily cultivated 
 in the ordinary nutrient media, and do not liquefy the gelatin. 
 The flesh of animals suffering from foot and mouth disease is said 
 to be innocuous, but there have been few exact experiments, and it 
 is safest to consider all animals affected with general diseases unfit 
 for use as food. 
 
 (470) Pleuro-Fneumonia. 
 
 The pleuro-pneilmonia of cattle is a very fatal and contagious 
 disease ; the post-mortem characters are confined to the organs of 
 the chest, the lungs are deeply congested and enormously increased 
 in weight, they sink in water, have lost their crepitant feel, are 
 more or less cedematous, and when cut in two they have a marbled 
 appearance, the pleura or lining membrane is adherent, being 
 covered with a fibrinous layer, and there is more or less effusion. 
 The cellular tissue between the chest wall and the pleura is seldom 
 affected, and the butcher by removing the lungs and stripping off 
 the pleura removes all traces of disease. The flesh, once the lungs 
 
634 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 are removed, will look like ordinary flesh, save in cases of lojag 
 duration, when of course the animal will be wasted. There is 
 reasonable doubt whether the flesh of animals suffering from 
 pleuro-pneumonia is hurtful ; the existing evidence is rather to the 
 effect that it has been consumed by large populations without 
 injury. Nevertheless it should be an offence to sell the carcases 
 of animals which have died from or suffered from this disease as if 
 from a healthy animal. 
 
 From what has been said it is obvious that, save the organs of 
 the chest be inspected, there is no chance of detecting the facts 
 after death, although from noting that the pleura has been stripped 
 off there may be a well grounded suspicion that something was 
 wrong. 
 
 (471) Cattle Plague. 
 
 Cattle plague is occasionally epizootic in the British Islands. 
 It is a highly contagious malady attended with diarrhoea, injection 
 of the mucous membrane, and is accompanied by an eruption. 
 The post-mortem signs in mild cases are not marked. There will 
 be found congestion and ecchymoses in the gastro-intestinal 
 mucous membrane, especially on the free borders of the mucous 
 folds in the fourth compartment of the stomach and around the 
 pylorus. In severe cases the alterations in the intestines and 
 stomach are more profound. Not alone congestion of the entire 
 surface but haemorrhages, extravasations of blood and ulcers are to 
 be seen. Sometimes there are extensive excoriations from the 
 shedding of the epithelial layers of the mucous membrane. There 
 is injection of the trachea and bronchi in the worst cases ; here 
 again the epithelial layer may have been shed, leaving excoriations. 
 The lungs are often emphysematous, the heart is usually flabby 
 and friable, the blood is dark coloured and coagulates imperfectly. 
 The skin may be found in parts desquamating, in parts covered 
 with pustules or papules. In mild cases the meat apai't from the 
 internal organs will not look different from any other meat, on 
 the other hand in severe cases the meat itself will be dark coloured 
 and the muscular tissues soft. There is no difference of opinion 
 that animals which have died of cattle plague are unfit for human 
 food. 
 
Plate IK 
 
 
 '**^ 
 
 
 W*, 
 
 -^ -^ ^-^ / 
 
 it :<--.^ -rSa.-'A.S'd^n,?,!,^ 
 
SL.j ACTINOMYCOSIS. 636 
 
 (472) Tuberculosis. 
 
 Tuberculosis has been fully considered at page 462. The ques- 
 tion as to whether an apparently local affection of the lung also 
 affects the entire body has been now definitely answered in the 
 affirmative, and the safest course is to consider tubercle always 
 generalized, and to condemn the whole carcase for the slightest 
 tuberculous taint; it would also be a just and sufficient ground to 
 condemn any milk derived from a tuberculous cow or other animal 
 as not fit for human food. 
 
 (473) Actinomycosis. 
 
 This is a somewhat common disease of cattle, and occasionally it 
 has been found to be a cause of disease and death to man. Pos- 
 sibly it is more common both in animals and men than is believed, 
 for the symptoms during life and the appearances after death may 
 be readily mistaken for local and generalized tuberculosis or for 
 those of septicaemia. 
 
 The disease is caused by the " ray fungus " (actinomyces) ; this 
 (see Fig. 54) parasite forms rosettes of club-shaped elements. 
 They may be seen as little white or yellowish specks by the 
 unaided eye. The method by which it gains access to the body is 
 unknown, but presumably it is swallowed with the food, and then 
 effects an entrance into the tissues. Once in the tissues a local 
 inflammatory action is set up and a neoplasm is formed very 
 similar in appearance to tubercle. Often these tubercle-like 
 nodules break down and suppurate. In cattle there is a pre- 
 dilection for the disease to attack the lower jaw. It also invades 
 the lung and sometimes the bones. 
 
 The lithographic plate (Plate IX.) contains a representation of 
 specimens in the Museum of the Eoyal College of Surgeons, No. 
 2,274 and 2,274c. The specimens are from the tongue of an ox 
 profoundly affected with actinomycosis. The tongue was much 
 enlarged, protruding four or five inches from the mouth. It is ex- 
 cessively hard and dense. The connective tissue is much increased, 
 in the centre a great portion of the substance is converted into a 
 pale and to the naked eye structureless medullary mass. There 
 are several nodules, these are most numerous in the middle of the 
 tongue, the size of the nodules varies from that of a bean to very 
 
636 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 minute hardly distinguishable points. The nodules are for the 
 most part aggregated in elongated masses, which are placed be- 
 tween the vertical muscular fibres. The transverse section shows 
 well the white medullary growth. 
 
 The appearance of one of the tufts when examined by the 
 microscope is delineated in Fig. 54. They are capable of cultiva- 
 
 r 
 
 yr 
 
 Fig. 64. 
 
 tion in a nutrient medium, as, for instance, peptone-gelatin, and 
 the disease may be propagated in animals by inoculation. The 
 writer considers it the duty of the sanitary officers to condemn as 
 unfit for human food an animal suffering from this disease ; even 
 although the malady is in appearance localized. 
 
 (474) Anthrax. 
 
 Anthrax is a rapidly fatal disease, killing numbers of oxen 
 and sheep yearly in this and other countries ; it is caused by 
 the multiplication of a bacillus, the bacillus anthracis, within 
 the body. 
 
 We have here only to deal with the post-mortem characteristics. 
 A peculiar feature of anthracoid maladies is their tendency to 
 putrefaction even before life is extinct. Immediately after death 
 the body of the animal often becomes immensely swollen and 
 deformed from a large development of gas. Everywhere in the 
 subcutaneous tissue there are infiltrations of serum, the same infil- 
 tration extends between the muscles ; the muscles themselves are 
 of a dark red, violet, or black tint, and very friable. So that in a 
 
XL.] ANTHRAX. 637 
 
 case of any severity, a single joint of the meat will have an entirely 
 different naked-eye appearance to healthy meat. In different 
 parts there may be tumours which are tilled with a collection of 
 gelatinous, citron-coloured matter, infiltrating into the subcutane- 
 ous connective and intermuscular textures and destroying the 
 tissues ; in these parts decomposition is mostly more advanced 
 than in others. The blood is black, fluid, a.nd stains the tissues 
 everywhere. The heart is soft and flaccid, with haemorrhages in 
 its substance. There are special changes in the spleen. As a rule 
 the spleen is enormously enlarged, sometimes ruptured, it is jet 
 black, and from its cut surface flows a fluid which has been likened 
 to china ink. The liver, the kidneys, the lungs, are all congested, 
 and here and there minute haemorrhages or larger extravasations 
 of blood are to be seen. 
 
 A microscopical examination of the blood of the heart, or the 
 inky fluid, or the tissue of the spleen, shows innumerable little rods ; 
 the rods vary a little in size, according to the animal from whence 
 they have been derived ; they are usually from 5-20/i long and 
 1-V25fi broad ; within the body they do not form spores. The 
 rods stain intensely with aniline dyes ; they are straight, or some- 
 times slightly curved, rigid, and have no power of self-movement. 
 They readily admit of cultivation in feebly alkaline broth, or in 
 nutrient gelatin, or in blood serum, or on potatoes. All the culti- 
 vations have a more or less characteristic appearance, so that a 
 bacteriologist can in not a few cases identify the growth by exami- 
 nation with a low magnifying power ; for instance, in a stab culture 
 in gelatin there is first a whitish line in the track of the inoculat- 
 ing needle, and from it fine filaments spread out in the gelatin. 
 Occasionally a little isolated spot develops, from which rays extend 
 in all directions like the silky filaments of thistle-down (Crook- 
 shank). The gelatin slowly liquefies and the growth subsides as 
 a flocculent mass. By artificial cultivations the rods may develop 
 into threads of great length. Rods cultivated on the surface of a 
 solid medium form spores, or if a little anthrax blood be taken 
 and allowed to dry with free access of air, spores are formed, and 
 once formed preserve their vitality for years. An inoculation with 
 these spores of a small animal, such as a mouse or guinea-pig, 
 produces death in from twenty-four to forty-eight hours. Sheep 
 fed on potatoes, which have been the medium for cultivating the 
 
638 A MANUAL OF PUBLIC HEALTH. [chap. 
 
 bacillus, die in a few days. It used to be taught that pigs have 
 an immunity from the disease, but this Prof. Crookshank has 
 shown to be erroneous. He has produced anthrax in swine by 
 feeding them on anthrax offal ; by injection of the blood of a 
 bullock which had died of anthrax, and by injection of artificial 
 cultures, he has also reproduced the disease in guinea-pigs and 
 mice by inoculation of blood from a pig which had died of anthrax. 
 
 The general and post-mortem signs of anthrax in the pig he 
 thus describes : — 
 
 From the point of entrance of the virus there extends a yellowish 
 jelly-like oedema of the subcutaneous areolar tissue. If the disease 
 is induced by ingestion of anthrax offal, the tonsils are found to be 
 ulcerated, and constitute the point of access of the bacilli to the 
 blood. In such cases the characteristic symptom is enormous swel- 
 ling around the throat. If the inoculation is by hypodermic injec- 
 tion, the same oedematous infiltration of the tissues occurs at the 
 place selected for inoculation. Death may occur very rapidly in 
 twenty-four hours, or not until five or six days. There is usually 
 a rash-like discolouration of the skin, sometimes loss of power over 
 the limbs, and a general weakness and disinclination to move ; or 
 the animal may lie helplessly on its belly and utter plaintive cries 
 when disturbed. At the post-mortem the most characteristic 
 feature is the gelatinous oedema which in the case of ingestion of 
 offal is found around the throat. There is usually congestion of all 
 the organs and engorgements of the heart and large vessels, fluid 
 in the cavity of the chest and abdomen, and enlargement and 
 hsemorrhage into the lymphatic glands. There is in some cases 
 inflammation of the intestines, and submucous and subserous 
 haemorrhages. The spleen may be normal in size, pale and flabby, 
 and the liver also only slightly congested and friable ; in other 
 cases the condition is characteristic, the spleen is the seat of 
 haemorrhage, causing more or less local enlargement, superficially 
 of a deep purple colour ; the liver also may be greatly congested, 
 very friable and marked with purple patches. The examination of 
 the blood of the heart and spleen for anthrax bacilli must be 
 carried out with great perseverance and discrimination, as they are 
 only present in small numbers, and in some cases have given place 
 entirely to septic organisms. Inoculation with the blood will cor- 
 respondingly produce, either typical anthrax or malignant oedema, 
 
XL.] SYMPTOMATIC ANTHRAX. 639 
 
 or some other form of septicaemia. Possibly in the cases from in- 
 gestion of offal the ulcerated condition of the throat affords a 
 nidus and means of access for septic organisms also, and it is well 
 known that blood in a state of putrefaction may contain the 
 bacillus of malignant oedema. In the presence of putrefactive 
 organisms the anthrax bacillus rapidly disappears. If, therefore, 
 inoculation of guinea-pigs or mice is used as a test for ascertaining 
 the nature of an outbreak in swine, it must not be concluded, if 
 Pasteur's or some other form of septicaemia result, that the disease 
 was not anthrax ; while, on the other hand, the discovery of the 
 anthrax bacillus in the blood of the pig, or the production by in- 
 oculation of anthrax in guinea-pigs or mice with the blood of the 
 pig, is positive evidence as to the nature of the original disease. 
 
 (475) Charbon Sympfomatique. 
 
 This is a common epizootic in this country and the Continent ; 
 it has long been known under various names, such as quaHer ill, 
 black leg, and others, and has been confused with anthrax, to which 
 it bears some resemblance. Our knowledge of the malady is 
 derived from the researches of Arloing, Cornevin, and Thomas in 
 France and by Dowdeswell in this country. 
 
 The disease is caused by a special micro-organism — the Clostri- 
 dium of symptomatic anthrax. The microbes are rods specially 
 distinguished from the bacillus anthracis by being rounded at the 
 ends and having at one end mostly a shining spore, and by being 
 motile. The rods can be easily cultivated, but contrary to the b. 
 anthracis they grow best with exclusion of air because they are 
 anaerobic. 
 
 The pathological signs after death differ from anthrax in at 
 least two important characters — the spleen is neither enlarged nor 
 black and the blood has not the black fluid appearance as in 
 anthrax. Otherwise there is the same oedema, the same friability 
 of the muscles, haemorrhages into the tissues of organs, &c. 
 
 There can be no doubt of the flesh being injurious, and any 
 animal affected with the disease should not be used for the 
 purpose of human food. Mr. Dowdeswell remarks,^ " In the case of 
 
 1 "On the ^Etiology of Charbon Symptomatique," by 6. F. Dowdeswell. M.A., 
 F.L.S., F.C.S., &c. Thirteenth Annual Report of the Local Government Board, 
 Supplement, 1883, 1884. 
 
640 A MANUAL OF PUBLIC HEALTH. [ohap. xl. 
 
 rodents I have found tlie flesli of infected animals, i.e., the tissues 
 of the parts principally affected, to be distinctly toxical to others 
 of the same species when eaten. Guinea-pigs, like rats, are 
 omnivorous, and readily eat the flesh of their dead comrades how- 
 ever well they are supplied with other food ; in two experiments I 
 found that giving the limb of an infected animal to another, in 
 each case occasioned its death some days subsequently. This 
 agrees with the accounts in this country of persons who have been 
 poisoned, though not fatally, by eating the flesh of infected 
 cattle." 
 
INDEX. 
 
 T T 
 
INDEX. 
 
 A. 
 
 ABC process of sewage disposal, 228 
 Acrolein, nuisance from, 290 
 Actinomycosis, 635 
 Addresses — "mortality ledger," 11 
 Age distribution, 15 
 
 in the classification of causes of death, 
 12 
 Air, 48—57 
 
 composition of expired, 60 
 movement, principles governing, 68 
 practical examination of, 95 — 103 
 pump, for ventilation, 80 
 required per head per hour, 63 
 town and country, difference between, 
 
 56 
 velocity of, which can be borne without 
 
 discomfort, 67 
 weight of, 48 
 Albuminous materials in food, 570 
 Alkali, manufacture of, 296 
 Alkalinity of water, X71 
 Alma Square outbreak of typhoid from 
 
 water, 506 
 Almonds, 584 
 
 Alumina as a precipitant of sewage, 227 
 Alumina process of treating sewage, 228 
 Ammonia in town air, 55 
 
 in water, estimation of, 55 
 Analysis, interpretation of, 173 
 
 of water (solutions required), 164 
 Anderson process of sewage disposal, 229 
 Andrews, Dr. (Chicago), on the relation of 
 
 temperature and consumption, 450 
 Anemometer, 114 
 Aneroid barometer, 125 
 Aniline manufacture, 298 
 
 water as a disinfectant of tubercle, 
 484 
 Animals, contamination of air by, 61 
 
 Anthrax, 636 
 Antiseptics, 313 
 Apples, composition of, 584 
 Apricots, ,, ,, 584 
 
 Area of ellipses, 110 
 Arithmometer, 40 
 
 Arlford sausage poisoning cases, 615 
 Amott's valve, 77 
 Arrowroot, composition of, 682 
 Arsenic calcining, 304 
 Artesian wells, 142 
 Asiatic cholera. See Cholera 
 Asparagus, composition of, 683 
 Asylum Board rules for hospital manage- 
 ment, 562 ' 
 Atmospheric pressure, 47 
 Atmosphere, percentage composition of, 50 
 Aufrecht's researches on tuberculosis, 452 
 
 B. 
 
 Bacilli anthraois, resistance and heat of, 
 
 319. 
 Bacilli tuberculosis, universal presence of, 
 
 in tubercle, 456 
 Bacon, composition of, 680 
 
 curing, 273 
 Bacteria in air, 95 
 Bakehouses, inspection of, 598 
 Ballard's account of the sausage poisoning 
 cases, 615 
 inquiry into causes of diarrhoea, 539 — 
 552 
 Ballast burning, 307 
 Banbury v. Page, 244 
 Bang's researches on the milk of tuber- 
 culous cows, 477 
 Banner's researches on tetanus, 410 
 Barking Creek reservoir, 211 
 Barley meal, composition of, 582 
 
 T T 2 
 
644 
 
 INDEX. 
 
 Barometer, glycerin, 120 
 mercury, 121 
 principles of the, 119 
 reading, 123, 124 
 Baumgarten's discovery of the tubercle 
 bacillus, 456, 458 
 method of inoculating tubercle, 455 
 Beans, compcsition of, 582 
 
 digestibility of, 577 
 Beef, composition of, 580 
 Beet, ,, „ 583 
 
 Bell traps, 190 
 
 Benham's disinfecting apparatus, 330 
 Berekholtz's researches on the effects of 
 
 drying the comma bacillus, 520 
 Bigelow, U.S., system of warming a school 
 
 at, 94 
 Bilberries, composition of, 584 
 Birth and death rates, calculation of, 12 
 Bishop Anrkknd Sanitary Authority u. 
 
 Bishop Auckland Iron and St<'el Com- 
 pany, 243 
 Blackberry, composition of, 584 
 Blackman air propeller, 84 
 Bleaching powder, 336 
 manufacture, 300 
 Blood boiler, trade of, 249 
 Blood drier, trade of, 248 
 Bollinger's experiments on tubercle, 459 
 Bone boiling, trade of, 253 
 regulations as to, 254 
 Bonome's researches on tetanus, 409 
 Bovine tuberculosis, 480 
 Bower's apparatus for distilling sawdust, 
 
 289 
 Bower's trap, 188 
 Bow windows, how to cube, 109 
 Boyle and Charles, laws of, 49 
 Boyle's exit ventilator, 77 
 Bradford's patent disinfector, 332 
 Bramah closet, 234 
 Bread, black, digestibility of, 577 
 ,i white, „ ,, 577 
 
 unhealthy, 620 
 Brick burning, 306 
 
 drains, defects of, 182 
 Broad Street pump, 611 
 Bromine, 337 
 
 Bromine, Cash's experiments as to, 338 
 Browicz's observations on typhoid, 493 
 Buchanan and-Bowditch, on the connection 
 
 between dampness and consumption, 450 
 Buchan and Mitchell's curves illustrating 
 
 the seasonal prevalence of mortality, 
 
 451, 493, 541 
 Buckwheat meal, composition of, 582 
 Budd's observations on the pathology of 
 
 typhoid fever, 501 
 Buhl's researches on tuberculosis, 452 
 
 Bujwid's observations on tlie comma bacilli 
 
 of cholera, 523 
 Butter, composition of, 581 
 Butterine, ,, ,, 581 
 
 Cabbages, composition of, 583 
 
 digestibility of, 577 
 Calculation of birth and death rates, 12 
 Candlemaking, 250 
 
 bye-laws relative to, 251 
 Carbohydrates, 573 
 Carbolic acid, 346. See also Phenol 
 
 estimation of purity of, 347 
 
 manufacture of, 295 
 
 powders, 348 
 
 soaps, 348 
 Carbon dioxide in air, 51 
 
 estimation of, 96, 99 
 Carbon, fixation of, by plants, 53 
 Carbon oxide, method of estimation, 102 
 Carle and Rattone's researches on tetanus, 
 
 409 
 Carnelly's observations on ventilation, 85 
 Carrots, composition of, 583 
 
 digestibility of, 577 
 Cash's experiments on the halogens, 337 
 Catchment areas, 144 
 Catgut manufacture, bye-laws as to, 259 
 Cat's and diphtheria, 438, 439 
 Cattle plague, 634 
 Causes of death, 7 
 Celery, composition of, 583 
 
 digestibility of, 577 
 Censuses, local, 5 
 Census periods, method of calculating 
 
 populations between the, 3 
 Chamois leather, manufacture of, 282 
 Chantemess and Vidal's experiments on 
 the typhoid bacillus, 346 
 
 method of detecting the typhrdd 
 bacillus in water, 161 
 Cliarbon symptomatique, 639 
 Charcoal boxes for sewer ventilation, 202 
 Cheese, composition of, 581 
 Chelsea AVater Company, 153 
 Chemical disinfectants, 335 
 Chemical examination of water, 163 
 Cherries, composition of, 584 
 Chestnuts, ,, ,, 584 
 
 Ctiicory, „ ,, 583 
 
 Chloride of lime manufacture, 169 
 Chlorine, 169, 336 
 
 Cash's experiments with, 388 
 
 Fischer and Proskauer's experiments 
 with, 343 
 
 Klein's experiments with, 343 
 
 VVeedon process of manufacture, 300 
 
INDEX. 
 
 645 
 
 Cliolnra and altitude, 514 
 
 bacteria of, 519 — 524 
 
 general order relating to, 536 
 
 and the East London Water Company, 
 512 
 
 epidemic of, 1848-9, 509 
 „ 1854, 510 
 „ 1866, 512 
 
 history of, in England, 509 
 
 in Southampton, 1866, 529 
 
 lessons from the "epidemics of 1849 
 and 1854, 512 
 
 mortality in relation to age and sex, 
 514 
 
 official memorandum as to prevention, 
 534 
 
 post-mortem appearances in, 518 
 
 propagation of, by clotlies, 531 
 water, 529 
 
 sicca, 517 
 
 symptoms of, 516 
 Ckiand Bey's lamp, footnote, 353 
 Clamp burning, 306 
 Clarke's process of softening water, 176 
 Cleanliness, effect on the ail' of rooms, 66 
 Closets for Ixospitals, 560 
 Coal gas, amount of carbon dioxide evolved 
 by, 66, 67 
 
 manufacture-, 291 
 Cocoanut, composition of, 584 
 Codfish, ,, ,,581 
 
 Coke and breeze manufacture, 305 
 Colmar's straight arithmometer, 43 
 Combustion, atmospheric impurity from, 65 
 Comma bacillus of cholera, 579 
 
 chemical tests for, 523 
 
 experiments with, on animals, 527 
 Comparative mortality, 18 
 Cones, solidity of, 111 
 Constant water supply, 148 
 
 fittings, 149 
 Contoiir lines, 144 
 Cooper's ventilator, 76 
 Copper ore smelting, 304 
 Copper-zinc couple, 170 
 Corn cockle seeds in flower, 621 
 
 flour, digestibility of, 577 
 Con'osive sublimate as a disinfectant, 334 
 Cowls and shafts as ventilators, 78 
 Cowkeeping, 274 
 Cowsheds and milkshops, 275 
 
 regulations as to structure of, 277 
 Cream, composition of, 581 
 Creasote as a disinfectant, 352 
 Cresol, cresylie acid, as a disinfectant, 317, 
 
 347 
 Crookshank on the appearance of the 
 
 tubercle bacillus, 454 
 Crossness sewage works, 211 
 
 Cube of cylinders, 107 
 
 domes. 111 
 
 prismoids. 111 
 
 rectangular and triangular spaces, 104 
 
 rooms of an irregular shape, 106 
 Cubic content of irregular spaces, 112 
 
 space, 104—112 
 
 for hospitals, 559 
 Cucumber, composition of, 583 
 Cunningham's researcli on the comma 
 
 bacillus of cholera, 521 
 Currall's window ventilator, 75 
 Currants, composition of, 584 
 
 infectious, 612 
 Cysticercus bovis, 627 
 
 D. 
 
 Dairies, 274 
 
 cowsheds and milkshops order, 275 
 regulations as to structure, 279 
 
 Dairymen, regulation of the trade of, 275 
 
 Damsons, composition of, 684 
 
 Daremberg's observations on tubercle in 
 different kinds of animals, 463 
 
 Deacon process of chlorine manufacture, 3 00 
 
 Dead, disposal of, 561 
 
 Dead ends of sewers, 197 
 
 Death, causes of, 7 
 mean age at, 22 
 proportional distribution of, 19 
 returns, 5 
 
 De Cbaumont's formula (ventilation), 70 
 
 Dent and Hillyer's valve closet, 235 
 
 Deutschmann's researches on tuberculosis, 
 452 
 
 Dew-point, determination of, 129 
 
 Diarrhcea and altitude, 544 
 bacteriology of, 542 
 and cesspool emanations, 548 
 and density of buildings, 547 
 and density of population, 546 
 and filthy accumulations, 549 
 and food, 550 
 and maternal neglect, 551 
 and social position, 549 
 and temperature, 543 
 and ventilation, 547 
 and water pollution, 549 
 as preliminary of cholera, 517 
 and darkness and dirt, 548 
 from atmospheric fouling, 549 
 method of investigating outbreaks of, 
 
 617 
 from milk or cheese, 616 
 mortality and sickness from, 539 
 predisposition to, 542 
 pi'evalence of, 553 
 
646 
 
 IXDEX. 
 
 Diarrhcea, seasonal influonoos with regard 
 to, 540 
 
 symptoms of, 540 
 Dietaries, construction of, 578 
 Diet, principles of, 569 
 
 standard, 578 
 Diphtheria, 429 
 
 bacteriology, 431 
 
 geographical distribution of, 429 
 
 mortality of, 329 
 
 nature of diphtheria poisoning, 433 
 
 prevention of, 439 
 Dip-stone trap, 191 
 Disinfectants, 313 
 
 testing of, 314 
 Disinfection, chemical, 334 
 
 by heat, 318, 329 
 
 in the puerperal condition, 441 — 3 
 
 of drains and closets, 359 
 
 of the sick-room, 358 
 
 of tubercle, 484 
 
 of typhoid excreta, 507 
 Doulton's pipes, 186 
 Drainage, inspection of, 192 
 
 of hospitals, 560 
 Drain pipes, varieties of, 185 
 
 sewers, 195 
 Drains and sewers, legal distinction be- 
 tween, 181 
 Drains, brick, 182 
 
 tests for, 193 
 Drop method of testing disinfectants, 315 
 Dust, 95 
 
 Dusty trades, 449 
 Dynes's hygrometer, 127 
 
 E. 
 
 East London Water Company, 151 
 Eberth's researches on typhoid, 494 
 Edington and Jamieson on scarlet fever, 
 
 394 
 Edmonson's circular arithmometer, 40 
 Eels, composition of, 581 
 Effluvium nuisances, 271 
 Egg albumin, composition of, 580 
 Eggs, composition of, 580 
 Eiselsberg's researches on tetanus, 411 
 Electrolytic treatment of sewage, 231 
 Ellison's conical ventilator, 76 
 English cholera. See. Diarrhoea 
 Enteric fever. See Typhoid 
 Epidemic pneumonia. See Pneumonia 
 Ergot in flour, 620 
 Erysipelas, 426 
 
 bacteriology of, 427 
 
 disinfection in, 428 
 
 etiology of, 427 
 
 inortaJity of, 426, 427 
 
 Esparto grass, 289 
 
 liquor, 289 
 Eytelwein's formula, 216 
 
 F. 
 
 Fans as ventilators, 82 
 Farre on cholera, 509 
 Fats (food), 573 
 Fats, melting of, 250 
 
 bye-laws regulating the trade of, 251 
 Fat storage, 571 
 Fcllmongers' trade, 255 
 Field's flush tank, 187 
 Figs, composition of, 584 
 Filberts, „ ,, 584 
 Filter-beds of the London water companies, 
 
 154 
 Filters, domestic, 175 
 Finkler and Prior's bacillus, 522 
 Fischer's observations on the disinfection 
 
 of the tubercle bacillus, 484 
 Fischer and Proskauer's experiments on 
 
 chlorine and bromine, 343 
 Fish, inspection of, 622 
 Flannel, scorching temperature of, 325 
 Flap-traps, 188 
 Flax retting, 288 
 Flies and tuberculosis, 461 
 Flour, unhealthy condition of, 620 
 Food, 569—584 
 
 and diarrhoea, 650 
 Food, digestibility of, 575 
 Foods, poisonous, 613 
 Food, power of inspecting, 611 
 Food, water in, 569 
 Foot and mouth disease, 633 
 Fortin's barometer, 122 
 Fowl, composition of, 580 
 Fowls and tuberculosis, 457, 463 
 Frank's process for developing bromine 
 
 vapour for use in disinfection, 344 
 Fried fish, nuisance from, 286 
 Fuller's spiral rule, 35 
 
 G. 
 
 Gaffky's account of an outbreak of typhoid 
 
 fever, 506 
 GafFky's research on typhoid, 494 
 Gamalcia's views on pneumonia, 416 
 Garcia del Huerto's description of cholera, 
 
 508 
 Garlic, composition of, 583 
 Gas, effects of burning, upon the air, 66, 67 
 Gases, difi'usion of, 59 
 Gate-porter, duties of (hospitals), 563 
 
INDEX. 
 
 647 
 
 Gaultier's researches on tuberculous milk, 
 
 478 
 Gelatin, digestibility of, 577 
 Giaeomi, de, ou the discovery of tubercle 
 
 bacilli in excreta, 483 
 Giant cells (tuberculosis), 464 
 Glanders and farcy, 630 
 Glasgow case of tuberculous meat, 482 
 Glass, manufacture of, 301 
 Glycerin barometer, 120 
 Gluemaking, 283 
 
 bye-laws as to the trade of, 284 • 
 Gooseberries, composition of, 584 
 Goux system, 233 
 
 Grand Junction Water Company, 153 
 Grapes, composition of, 584 
 Grates, 88 
 Grease traps, 192 
 
 Great "Western Railway v. Bishop, 243 
 Ground water theory of typhoid fever, 504 
 Gudgeon, composition of, 581 
 Guibal fan (ventilation), 83 
 Gut scraping, 256 
 spinning, 256 
 
 bye-laws as to the trade of, 257 
 
 H. 
 
 Hardness of water, 170 
 Hare, composition of, 580 
 Head of water, 219 
 
 Heat, injury by, in the process of disin- 
 fection, 323 
 
 required for disinfection, 319 
 Herrings, composition of, 581 
 Heywood. and Lloyd's arrangement for 
 
 collecting offensive vapours, 291 
 Hille's sewage process, 228 
 Hinckes Bird's ventilating window seat, 
 
 74 
 Hoffmann's observations on tubercle in 
 
 flies, 461, 462 
 Holden's sewage process, 228 
 Holtze's observations on the tubercle 
 
 bacilli, 484 
 Hopper closet, 235 
 Horseflesh Act, 611 
 Horseradish, composition of, 583 
 Hospitals, administrative block, 558 
 disposal of the dead from, 561 
 furniture of, 561 
 general management of, 564 
 infectious, 557 — 565 
 in relation to small-pox, 370 
 Local Government Board, plans of, 
 
 561 
 site, of, 557 
 
 superintendence and management of, 
 562 
 
 Hospitals, ventilation of, 560 
 
 visiting of, by patients' friends, 564 
 wards of, 558 
 warming of, 560 
 Hovorka and F. Winkler's method of 
 
 cultivating the cholera bacillus, 522 
 House drainage, general method of, 187 
 drains, fall of, 186 
 size of, 187 
 Hueppe and Cartwright Wood's researches, 
 
 365 
 Hueppe's method of cultivating bacilli, 
 455 
 researches ou the comma bacillus, 522 
 Hydatids, 627 
 
 Hydraulic formulse, 216—222 
 Hygrometers, 127 
 
 L 
 
 Immunity, 364 
 
 India-rubber, manufacture of, 287 
 
 Inspectors of nuisances, duties of, 602 
 
 as laid down by the Local Govern- 
 ment Board, 606 
 Interception sewers, 205 
 Intermittent filtration, 223 
 Inverted syphons (sewers), 201 
 Iodine, 337 
 
 Cash's experiments on, 338 
 
 trichloride, 345 
 Iron, galvanizing of, 302 
 Iron salts as a precipitant of sewage, 228 
 Ironstone and tap cinder manufacture, 302 
 Iron in water, detection of, 162 
 Irrigation of land (sewage), 223 
 Isolation hospitals. See Hospitals 
 
 J. 
 
 Jeannel on tuberculous flesh, 481 
 Jennings' inlet, 76 
 
 pipes, 186 
 Jones, E., method of coke-pile burning, 306 
 
 K. 
 
 Kastner's researches on the meat of tuber- 
 culous animals, 481 
 
 Eeeling's sewer ventilator, 203 
 
 Kennedy and Frost's water meters, 147 
 
 Kent Water Company, 150 
 
 Kerstein's method of detecting tubercle 
 bacilli in urine, 483 
 
 Kidney, composition of, 580 
 beans, ,, ,, 582 
 
648 
 
 INDEX. 
 
 Kiln burning, 306 
 
 Klebs and CrUdeli's researches on the 
 
 bacilli of malaria, 487 
 Klebs' bacillus and diphtheria, 431 
 researches on tuberculosis, 452 
 typhoid, 494 
 Klein's experiments on disinfection by 
 corrosive sublimate, 335 
 investigation of pig typhoid, 631 
 observations on the comma theory of 
 
 cholera, 523 
 observatioiis on giant cells, 464 
 researches on diphtheria, 435 
 scarlet fever, 392 
 typhoid fever, 493 
 Knackers' yards, 268 
 
 bye-laws governing, 269 
 Koch's experiments on the disinfecting 
 properties of phenol, 351 
 experiments on the propagation of 
 
 cholera, 527 
 preventive measures against cholera, 
 
 532 
 researches on cholera, 519 
 tuberculosis, 423 — 454 
 typhoid, 494 
 Kussner's method of experimenting with 
 
 tubercle, 459 
 Kutter's formula, 220 
 
 Lakes as a source of water supply, 143 
 
 Lambeth Water Works, 153 
 
 Lamprey, composition of, 581 
 
 Laundries for hospitals, 561 
 
 Laundry superintendent, duties of, 563 
 
 Lawes and Gilbert's experiments on the 
 
 formation of fat, 574 
 Lead or copper in water, detection of, 162 
 Leather dressing, 282 
 Lemielle's ventilator, 81 
 Lentils, composition of, 582 
 Lesser's clinical evidence of the infectious 
 
 nature of tuberculosis, 460 
 Lettuce, composition of, 583 
 Lichtheim's observations on tubercle bacilli 
 
 in excreta, 483 
 Liernur system of sewage disposal, 230 
 Life, mean duration of, 22 
 probable ,, 23 
 tables, construction of, 24 
 extended, 30 
 short, 27 
 Lime burning, 305 
 
 process for the treatment of sewage, 
 
 227 
 Street tunnel, ventilation of, 82 
 
 Lindsay's experiments on cholera, 621 
 Lingard on the relationship of scrofula, 
 
 476 
 Litre and gallon, relation between, 166 
 Lodging houses, cubic space allowed in, 
 
 104 
 Loefder's experiments on diphtheria, 431 
 Lombard, C, on mortality from consump- 
 tion in relation to dust, 449 
 London sewage, cost of, 214 
 
 recommendations of the Royal Com- 
 mission relative to, 214 
 quantity of, 212 
 sewers, 205 — 215 
 
 arrangement at outfall of, 211 
 size of, 205 
 
 storm overflow of, 213 
 pumping stations, 208 
 water supply, 150 — 155 
 Louvres (ventilation), 75 
 Lowe's method of distilling carbolic acid, 
 
 295 
 Lupus and tuberculosis, 476 
 Lydtin's experiments on the milk from 
 
 tuberculous cows, 477 
 Lyon's disinfecting apparatus, 331 
 
 M. 
 
 Mackerel, composition of, 581 
 
 McKinnel's tube, 77 
 
 Macleod's experiments on the propagation 
 
 of cholera, 528 
 Macaroni, composition of, 582 
 Mactear's process of dealing with alkali 
 
 waste, 297 
 Magendie's experiments on cholera, 524 
 Maize, composition of, 582 
 Malaria, malarious tracts, 487 — 489 
 effects of, 487 . 
 prevention of, 489 
 Manure as a nuisance, 245 
 manufacture, 254 
 
 bye-laws as to, 254 
 Marchiafava's researches on the blood of 
 
 malarious persons, 487 
 Mark's investigation of trichinous hogs, 
 
 629 
 Marshall's experiments on cholera, 524 
 Marsh gas in air, 55 
 Martin's experiments on tuberculous milk, 
 
 477 
 Mean age at death, 22 
 after lifetime, 22 
 duration of life, 22, 23 
 Measles, 374 
 
 etiology of, 377 
 
 measures to be taken in outbreaks of 
 377 
 
INDEX. 
 
 649 
 
 Measles, seasonal prevalence of, 375 
 statistics relative to, 374 
 symptoms of, 376 
 ia the pig and ox, 626 
 Meat and tubercle, 477, 481, 482 
 Meat, characteristics of, 623 
 diet, 570 
 
 inspection of, 622 
 roast, digestibility of, 577 
 Mechanical ventilation as compared with 
 
 natural in point of cost, 85 
 Medical officer of health, duties of, 588 
 as laid down by Local Government 
 
 Board, 601 
 to combined district, duties of, 599 
 to county authority', duties of, 588 
 to port district, duties of, 597 
 to urban district, duties of, 589 
 reports of, 592 
 qualifications of, 587 
 Meidiugen stove, 89 
 Meldola's test for nitrites, 162 
 Melting of wax, &c., in disinfection by heat, 
 
 328 
 Mercuric chloride as a disinfectant, 334 
 Merthyr Tydvil sewage system, 224 
 Meta-cresol, 347, 350 
 Metaphenelene diamine test for nitrites, 
 
 162 
 Metropolitan sewer system, 206 
 Metropolis, sewerage of, 205 — 215 
 Meyer's case of cholera propagation, 575 
 Micro-organisms in air, 56 
 
 parasitic diseases (classification of), 
 
 365 
 strife, 363 
 Middlesborough epidemic of pneumonia, 
 424 
 typhus, 402 
 Milk, composition of, 581 
 condensed, 581 
 and scarlet fever, 391 
 and tuberculosis, 476 — 480 
 and typhoid, 507 
 digestibility of, 577 
 shops, legidations as to cleanliness of, 
 
 279 
 regulations for the prevention of con- 
 tamination of, 276 
 skim, 581 
 Millet, composition of, 582 
 Mills and Macleod's experiments on cholera, 
 
 529 
 Mineral matters in food, 574 
 Mines, ventilation of, 80 
 Mond's process of dealing with alkali 
 
 waste, 297 
 Morrison's formula (ventilation), 70 
 Mortality ledger, 11 
 
 Mortuary (hospital), 561 
 Moule's earth closet, 232 
 Mulberry, composition of, 584 
 MuUer and Truomi's experiments on tuber- 
 culosis, 461 
 Mutton, composition of, 580 
 
 N. 
 
 Naphthylamine test for nitrates, 162 
 Nazareth House, outbreak of typhus, 404 
 Nephalometric method of estimating carbon 
 
 dioxide, 98 
 New River Company, 151 
 Nioati and Rietsch's experiments on the 
 propagation of cholera, 527 
 on the vitality of comma bacilli, 521 
 Nicolaier's researches on tetanus, 409 
 Nitrates, 162, 169 
 Nitrites, tests for, 161, 162 
 Nitrogen, quantity required, 572 
 relation to work, 571 
 storage, 571 
 Nitrogenous equilibrium, 571 
 Nocard and Roux on the tubercle bacillus, 
 
 455 
 Nocard on eating meat of tuberculous 
 
 animals, 481 
 North's experiments on the nitrogen ques- 
 tion, 572 
 Notification Act, work under, 590 
 Nottingham disinfecting apparatus, 333 
 Nuisances, 241—248 
 
 classification of effluvium, 271 
 distinction between private and 
 
 public, 241, 242 
 from deposits, 245 
 from drains, 245 
 from horse-keeping, 273 
 under the 91st section Public Health 
 Act, 244 
 Nurses, duties of (hospitals), 563 
 
 0. 
 
 Oatmeal, composition of, 582 
 Occupation, influence of, on tubercle in- 
 fection, 449 
 Office work, 591 
 Onions, composition of, 583 
 Oranges, ,, ,, 584 
 Organic matter in air, 96 
 Ortho-cresol, 347, 350 
 Osier's anemometer, 137 
 Overcrowding, 247 
 Overdryiug (disinfection), 326 
 Oxalic acid, manufacture of, 288 
 Oysters, composition of, 581 
 Ozone in air, 54 
 
650 
 
 INDEX. 
 
 P. 
 
 Pail system, 232 
 Pan vvatercloset, 234 
 Para-cresol, 347, 350 
 Parsley, composition of, 583 
 Parson's experiments on the effects of dis- 
 infecting by heat, 325 
 Pawlowsky's method of cultivating tubercle 
 
 bacilli on potatoes, 455 
 Peaches, composition of, 584 
 Peas, ,, „ 582 
 
 digestibility of, 577 
 Peppermint test for drains, 193 
 Pettenkofer's views on the etiology of 
 cholera, 532 
 the etiology of typhoid fever, 504 
 volumetric method of estimating 
 carbon dioxide, 101 
 Petrin's researches on the chemical action of 
 
 the comma bacillus, 523 
 Phenol as a disinfectant, 317, 346 
 Phenol and cresol as disinfectants, 349, 350, 
 
 352 
 Phenol, experiments on the disinfecting 
 
 power of, by Koch, 351 
 Phenol-phthalein method of estimating 
 
 OO2, 97 
 Phenyl-acetic and phenyl-propionic acids 
 
 as disinfectants, 352 
 Photography in practical work, 595 
 Picric acid, manufacture of, 298 
 Pig-keeping, 272 
 Pig's liver, composition of, 580 
 Pigs suffering from tubercle from drinking 
 
 infected milk, 479 
 Pig typhoid, 631 
 Pike, composition of, 581 
 Pio Poa and Ufferduzzi, on pneumonia, 
 
 416 
 Pleuro pneumonia, 633 
 Plums, composition of, 584 
 Pneumo-enteritis, 631 
 Pneumonia, 414 
 etiology of, 416 
 infection of, 414 
 
 epidemic of, at Middlesborough, 416 
 preventive measures as to, 425 
 Polygons, how to cube, 110 
 Poonah steamship, case of, 529 
 Porion-Davis' evaporator, 289 
 Pork, composition of, 580 
 Pork-pie poisoning, 613 
 Portland cement manufacture, 307 
 Port medical officer of health's reports, 
 
 589 
 Port sanitary inspector's duties, 604 
 Potatoes, composition of, 583 
 digestibility of, 577 
 
 Poten's experiments on tuberculosis, 458 
 Pottery, firing of, 309 
 Precipitation processes, summary of, 229 
 Prisons, cubic space allowed in, 104 
 Pritchett's miniature hot water appara- 
 tus, 79 
 Puerperal fever, 440 — 443 
 Pumping stations (London sewerage 
 
 system), 208 
 Pyramids, how to calculate cube of. 111 
 Pyroligneous acid as a disinfectant, 289 
 
 Q. 
 
 Quittel's views on tuberculous milk, 477 
 
 E. 
 
 Rabies, 408 
 
 Eadcliife, N., on cholera, 512 
 
 Radishes, composition of, 583 
 
 Raisins „ ,, 584 
 
 Rainfall in relation to water supply, 145 
 
 Rain gauges, 133 
 
 measurement of, 133 
 
 Raspberries, composition of, 584 
 
 Raymond and Arthaud on tuberculosis, 458 
 
 Recklinghausen's observation on typhoid, 
 493 
 
 Reeves' apparatus for sewer ventilation, 203 
 
 Reidel, Otto, experiments on the disin- 
 fecting power of iodine trichloride, 345 
 
 Reports of medical officer of health, 598, 
 600 
 
 Respiration, impurities from, 60, 61 
 
 Rice, digestibility of, 577 
 
 Rickets, 575 
 
 Ridge lines, 144 
 
 Rivers as a water supply, 141 
 
 Road gullies, 202 
 
 Roasting coffee, nuisance from, 287 
 
 Robin's anemometer, 137 
 
 Rodet's method of detecting the tubercle 
 bacillus, 497 
 
 Roeckners patent evaporator, 289 
 
 Rosenbach on tetanus, 409 
 
 Roux and Yersin on diphtheria, 433 
 
 Rye bread, digestibility of, 577 
 
 Rye meal, composition of, 582 
 
 S. 
 
 Sago, composition of, 582 
 
 Saint Anthony's fire, 632 
 
 Sal ammoniac manufacture, 293 
 
 Salmon, composition of, 581 
 
 Salt glazing, 309 
 
 Salt in air, 56 
 
 Salt manufacture, 299 
 
INDEX. 
 
 651 
 
 Sanderson'sjB., experiments on cliolera,526 
 Sanitary orders, enforcement of, 591 
 
 work, 593 
 Sardines, composition of, 581 
 Sausage skin manufactui e, 256 
 Saussure's hygrometer, 129 
 Savoys, composition of, 683 
 Scarlatina. See Scarlet Fever 
 Scarlet fever, 378 
 
 albuminuria in, 389 
 
 incubation of, 378 
 
 isolation period, 390 
 
 mortality of, 380, 38i 
 
 seasonal prevalence of, 380 
 
 sequelse of, 388 
 
 sex and age in relation to, 381 
 
 and milk, 391 
 Schill and Fischer's ezj)eriments on the 
 action of phenol on tuberculous matters, 
 351 
 Schmidt's clinical evidences of tubercle 
 
 infection, 460 
 Schmidt's experiments on tubercle infec- 
 tion, 459 
 Schools, cubic space in, 104 
 
 systems of warming, 90 — 94 
 Scorching (disinfection), 324 
 Scott's sewage process, 228 
 Scrofula, tubercle bacilli in, 484 
 
 relation to tuberculosis, 476 
 Scutch, accumulation of, as a source of 
 
 nuisance, 284 
 Seabury's sulphur candles, 353 
 Season, influence of, on tuberculosis, 451 
 Separate system of sewerage, 197 
 Septic diseases, bacteriology of," 442 
 Septic diseases, influence of season on, 
 
 440 
 Sex in classification of causes of death, 12 
 Sewage, chemical treatment of, 225 
 
 composition of, 226 
 
 disposal of, 223—237 
 
 dry systems of, 231 
 
 precipitants of, 225 
 
 store reservoirs, 202 
 Sewers, 194—204 
 
 capacity of, 200 
 
 dead ends of, 1 97 
 
 flushing of, 196 
 
 shape and construction of, 198 
 
 size of, 197 
 
 ventilation of, 202 
 Sherringham's valve, 76 
 Shore system of sewage discharge, 230 
 Siemen's water meter, 147 
 Silk ribbons, temperature which they will 
 
 bear without injury, 325 
 Simon on cholera, 510 
 Sinks in hospitals, 560 
 
 Sirena and Beruice's experiments on tuber- ■ 
 
 culosis, 461 
 Skate, composition of, 581 
 Slaughterhouses, 263 
 
 bye-laws as to, 265 
 Sleeping rooms, impurity of air in, 65 
 Slow combustion stoves, 89 
 Small-pox, incubation of, 366 
 infection of, 869 
 mortality of, 368 
 outbreaks of, duty of the sanitary 
 
 authority in, 370 
 seasonal prevalence of, 368 
 Smoke as a nuisance, 247 
 Smoke test for drains, 193 
 Smut, 329 
 
 Snell's, Saxon, thermohydric grate, 90 
 Soap boiling, 253 
 
 bye-laws as to, 254 
 Soeoloff''s observations on typhoid, 494 
 Soil, influence of, in relation to tuber- 
 culosis, 450 
 Soil pipes, 237 
 Soles, composition of, 581 
 Solid residue of waters, 167 
 Southampton epidemic of cholera, 1866, 
 
 529 
 Southwark and Vauxhall Water Company, 
 
 152 
 Spear on typhoid fever at Mountain Ash, 
 
 605 
 Spear's account of poisoning at Eetford, 
 
 through pork-pies, 613 
 Spelter, calcining of, 302 
 Spinach, composition of, 583- 
 Spiral rule (Fuller's), 35—37 
 Spirillum sputigenum, 623 
 Sprats, composition of, 581 
 Sputum of the phthisical, 482 
 Stables, nuisance from, 273 
 Stains, fixing of, by heat, 327 
 Statistics, 3 — 43 
 Steam heating, 91 
 
 jet (ventilation), 81 
 penetrating power of, 321 
 Steel springs and saws, manufacture of, 
 . 302 
 
 Steep gradients in sewers, 201 
 Steinheil's experiments on tuberculous 
 
 meat, 624 
 Steinthal's clinical evidences of tubercle 
 
 infection, 460 
 Stevens' drawer ventilator, 76 
 Stoves, 88 
 
 Strauss on the tuberculosis of fowls, 463 
 Strawberries, composition of, 584 
 Streptococcus lanceolatus in pneumonia 
 and cerebro-spinal meningitis, 416, 
 418—421 
 
652 
 
 INDEX. 
 
 Streptococcus scai-latinse, 571 
 Sugar, digestibility of, 517 
 
 storage, 571 
 Sulphates, estimation of, 171 
 Sulphate of ammonia manufacture, 293 
 Sulphur in albumen, 570 
 
 storage, 571 
 Sulphuretted hydrogen, estimation of, 103 
 
 in air, 55 
 Sulphuric acid, manufacture of, 298 
 Sulphurous acid as a disinfectant, 353 
 
 Cash's researches on, 357 
 
 Wolffhugel's researches, 354 
 Sunlight, registration of, 136 
 Sutton's description of cholera, 517 
 Swine plague, 632 
 Symons' rules for placing rain gauges, 134 
 
 T. 
 
 Tables as aids to calculation, 35 
 Tauneries, nuisance from, 281 
 Tanning, 280 ' 
 Tapeworm, history of, 626 
 Tapioca, composition of, 582 
 Tar, distillation of, 294 
 Temperature and diarrhoea, 543 
 Temperature in relation to disinfection, 
 
 313 
 Tetanus, 408—412 
 Thiersch's experiments on the propagation 
 
 of cholera, 526 
 Thread method of testing disinfectants, 
 
 315 
 Tin burning, 304 
 Tin plate manufacture, 303 
 Tobin's tubes, 69, 77 
 Tomkins's researches on diarrhoea, 542 
 Touissaint's researches on tuberculosis, 
 
 452 
 Traps, 188—192 
 Trichinas, 627 
 
 vitality of, 630 
 Trichinosis, 627 
 Tripe boiling, 261 
 
 bye-laws regulating, 262 
 
 composition of, 580 
 Tubercle and phenol, 351 
 
 sulphurous acid, 357 
 Tubercle bacilli, artificial cultivation of, 
 
 454 
 Tubercle bacilli, characteristics of, 453 
 
 detection in meat of, 624 
 
 disinfection of, 482 — 485 
 
 infection, influence of occupation on, 
 449 
 Tubercle bacilli in excreta, 483 
 Tubercular virus, disinfection of, 336 
 
 Tuberculosis, 444, 635 
 
 acute miliarv, 475 
 
 and milk, 467—480 
 
 bacteriology of, 451 
 
 experiments on the disinfection of, 
 341 
 
 influence of age and sex on, 445 
 
 pathology of, 465 
 
 prevention of, 485 
 
 probability of dying from, 448 
 
 propagation of, 445 
 
 statistics of, 444 
 
 by tuberculous food, 462 
 Tucker Greenleaf on bacteria in dust, 449 
 Turnips, composition of, 583 
 Typhoid bacillus, identification of, by 
 Chantemesse and Vidal, 346 
 
 method of detecting it in water, 496 
 Typhoid fever, bacteriology of, 493 
 
 diagnosis of, 503 
 
 disinfection in, 607 
 
 incubation of, 491 
 
 mortality of, 491 
 
 pathological appearances in, 500 
 
 predisposition to, 500 
 
 prevention of, 507 
 
 propagation of, 505 
 
 seasonal prevalence, 492 
 
 statistics of, 490 
 
 symptoms of, 499 
 
 theories as to the propagation of, 503 
 
 ulceration in, 465, 502 
 Typhus fever, 395 
 
 etiology of, 398 
 
 incubation period of, 395 
 
 influence of race, 402 
 
 isolation of, 405 
 
 mortality of, 400 
 
 seasonal prevalence of, 401 
 
 statistics, 395 
 
 symptoms, 396 
 Tyro-toxicon, 616 
 
 TJ. 
 
 Urine in tuberculosis, 4.83 
 
 V. 
 
 Vaccination and small-pox, 368, 372 
 Tallin's experiments on disinfection by 
 
 heat, 327 
 Variola in the sheep, 631 
 Vegetables, digestibility of, 620 
 Ventilation, 68—94 
 
 affected by friction, 69, 70 
 
 coefficients of friction, 72 
 
 Curral's method, 75 
 
 Cooper's method, 76 
 
INDEX. 
 
 653 
 
 Ventilation, cowls and extraction shafts, 
 78 
 
 dependent on water power, 80 
 
 gas as an aspirating agent in, 79 
 
 Hinckes Bird's window-sash method, 
 74 
 
 inlets and ontlets, 69 
 
 louvres, 75 
 
 mechanical, 80 
 
 of hospitals, 539 
 
 of sewers, 202 
 
 of tunnels, 72 
 
 perforated sashes, 75 
 
 principles of natural, 74 
 
 reports upon, 112 
 
 simple openings, 73 
 
 swinging windows, 76 
 Veraguth's experiments on the propagation 
 
 of tuberculosis, 459 
 Visiting infectious hospitals, 564 
 Von Wehde's experiments on the infectious 
 
 nature of tuberculosis, 461 
 
 W. 
 
 Walnuts, composition of, 584 
 "Warming, 87—94 
 
 and ventilation, 79 
 
 by open fireplaces, 87 
 
 general principles of, 87 
 
 hospitals, 560 
 
 hot water system of, 91 
 
 hot water Mgh pressure system of, 90 
 Wash-out closet, 235 
 Water, analysis of, 157 
 
 biological examination of, 159 
 
 closets, 233 
 
 colour of, 157 
 
 filtration of, 175 
 
 head of, 219 
 
 in food, 569 
 
 melon, composition of, 583 
 
 meters, 147 
 
 microspopical examination of, 158 
 
 pure, 156 
 
 seal, 189 
 
 smell of, 188 
 
 softening of, 175 
 Waters, classification of, 172 
 
 Water supply, 141 — 155 
 constant, 147 
 general principles of, 146 
 per head, 143 
 to dairies, 276 
 
 quantity required for towns, 144 
 superintendence of, 596 
 Watson Cheyne on tuberculosis, 458 
 Weichelsbaum on the propagation of the 
 
 tubercle bacillus, 456, 459 
 Weighing, 165 
 Weldnu process of chlorine manufacture, 
 
 300 
 Wells as a source of water supply, 141 
 Wesener's researches on the propagation 
 of tubercle by feeding animals with 
 tuberculous food, 462 
 West Middlesex W^ater Company, 152 
 Wetting articles in steam disinfection, 330 
 Wheaten flour, composition of, 582 
 Whipple- Cassella's universal sunshine re- 
 corder, 136 
 Whiting, composition of, 581 
 Whole meal, composition of, 582 
 digestibility of, 577 
 flour, products of, 572 
 Whooping-cough, 412, 413 
 Wigner's water scale, 174 
 Wind anemometer, 137 
 Wolfram on the tubercle bacilli, 484 
 Wood, Cartwright, and Hueppe's researches, 
 
 365 
 Wood, distillation of, 289 
 naphtha, 289 
 pulp manufacture, 289 
 Woodhead's examination of tuberculous 
 cows, 478 
 researches on the pathology of tuber- 
 culosis, 465—475 
 
 Yersin's experiments on the disinfection of 
 tubercle, 485 
 
 Zinc, detection of, in water, 163 
 Zurn's researches on tubercuolsis, 452 
 Zymotic death-rate, 18 
 
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