AN EPITOME 
 OF GENERAL HYGIENE 
 
 PREPARED FOR USE IN THE DEPART- 
 MENT OF HYGIENE IN THE 
 COLLEGE OF THE CITY 
 OF NEW YORK 
 
 By THOMAS A. STOREY, 
 
 Ph.D. {Physiology, Stanford University); M.D. (Harvard), Professor of Hygiene, 
 
 College of the City of Neiv York; Inspector of Physical Training, Military 
 
 Training Commission, State of Nein York; Secretary-General, Fourth 
 
 International Congress on School Hygiene; Executive Secretary, 
 
 United States Interdepartmental Social Hygiene Board. 
 
 SECOND EDITION 
 
 NEW YORK 
 THOMAS A. STOREY 
 
 COLLEGE OF THE CITY OF NEW YORK 
 1920 
 
New ^ark 
 
 *tatB (^allege of AgricttlJute 
 
 Kt ((arneU Blnttietaitg 
 
 iCibrarg 
 
GENERAL HYGIENE 
 
 By THOMAS A. STOREY, 
 
 Ph.D. (Physiology, Stanford University); M.D. (Harvard), Professor of Hygiene, 
 
 College of the City of New York; Inspector of Physical Training, Military 
 
 Training Commission, State of New York; Secretary-General. Fourth 
 
 International Congress on School Hygiene; Executive Secretary, 
 
 United States Interdepartmental Social Hygiene Board. 
 
 SECOND EDITION 
 
 NEW YORK 
 THOMAS A. STOREY 
 
 COLLEGE OF THE CITY OF NEW YORK 
 1920 
 
Cornell University Library 
 RA 425.S7 
 
 General hygiene, 
 
 3 1924 003 522 624 
 
DEFINITIONS OF THE MAIN DIVISIONS 
 OF HYGIENE 
 
 Hygiene. The science and the art of preserving health. " A part of 
 the wisdom of the Egyptians at least 1500 b.c." 
 
 General Hygiene. The natural laws that govern health. The science 
 of hygiene includes scientific information concerning the agents that 
 injure health, the contributory causes of poor health, the carriers of 
 disease, the defenses of health and the producers of health (constructive 
 hygiene). 
 
 Individual Hygiene. The applications of the natural laws of hygiene 
 for the health welfare of the individual. 
 
 Group Hygiene. The applications of the natural laws of hygiene for 
 the health welfare of groups of individuals, the members of a group 
 being associated more or less intimately with each other for considerable 
 periods of time under common environmental influences, common 
 hygienic advantages and disadvantages and under common health respon- 
 sibilities and regulations. Includes the hygiene of such groups as the 
 family, the school, the occupations and certain public institutions. 
 
 Intergroup Hygiene. The application of the natural laws of hygiene 
 for the health welfare of associated groups of humans, the several groups 
 being dominated by common interests, exposed to common health dangers 
 and competent to establish and enforce common standards of individual 
 and group responsibility for community health. Includes the hygiene 
 of the rural community, the village, the city, the town or township, the 
 county, the State, the nation and alliance of nations. 
 
 The subject matter of individual hygiene, group hygiene and inter- 
 group hygiene falls very logically into several main divisions. These 
 divisions have been designated in this syllabus as: Educational hygiene, 
 informational hygiene, defensive hygiene, and constructive hygiene. 
 
 The important subdivisions of defensive hygiene are protective 
 hygiene, preventive hygiene, remedial hygiene, and aggressive hygiene. 
 
 Educational hygiene is the instruction or training in hygiene that 
 leads to the formation of habits of good judgment in matters that re- 
 late to health, and to the formation of good habits of conduct in rela- 
 tion to the preservation of health. 
 
 Informational hygiene is concerned with the acquisition of accurate 
 
and scientific knowledge relative to hygiene, and it is concerned also 
 with the various methods that are effective for the distribution of this 
 knowledge. 
 
 The term " defensive hygiene " needs no explanation other than 
 that connected with the definitions of its subdivisions, which follow. 
 Protective hygiene is a subdivision of defensive hygiene and deals with 
 the passive measures that may be adopted for the care of the body and 
 its organs, such as: The building and equipment of habitations or the 
 wearing of clothes, the habit of washing one's hands, and chewing one's 
 food well, and so on. This, of course, is a very large subdivision of 
 hygiene. Preventive hygiene includes more active procedures, such as 
 vaccination, or inoculation for the prevention of smallpox or typhoid 
 fever or other disease. Remedial hygiene covers first aid and emergency 
 treatment, medical and surgical care, nursing, dentistry, and so on. Ag- 
 gressive hygiene is a term that applies best to group of intergroup pro- 
 cedures that are concerned with the eradication of disease, using the 
 word " disease " in a very broad sense. A " safety-first " campaign is 
 a part of intergroup aggressive hygiene. The campaign against venereal 
 diseases that was developed so vigorously during the Great War was a 
 powerful piece of intergroup aggressive hygiene. 
 
 Constructive hygiene covers those parts of hygiene that have to do 
 with growth, development, and the improvement of physiological func- 
 tions. It includes nutrition, play, recreation, exercise and athletics, work, 
 and rest. 
 
 The utility of this framework or outline described above is recom- 
 mended not only for the larger divisions of practical hygiene, but also 
 such subdivisions of group hygiene as domestic hygiene, school hygiene, 
 or institutional hygiene, and for such subdivisions of intergroup hygiene 
 as rural hygiene, municipal hygiene, State hygiene, or national hygiene. 
 
A WORD TO THE TEACHER AND TO THE 
 
 STUDENT 
 
 A slacker is a human who, being able, fails; one who can but does 
 not try; one who could but does not " deliver the goods." 
 
 There never has been a place for such men and for such women; 
 but the dead weight of their burden, the size of their useless expense 
 and the extent of their damage to the community and to the nation is 
 felt more to-day than ever before and we are in no mood for such 
 company. 
 
 It is possible to be a teacher-slacker or a student-slacker. There 
 may be civilian-slackers and there may be soldier-slackers. The type 
 of one's occupation does not exclude him from the class. 
 
 The program of instruction in hygiene outlined in this syllabus 
 is for the teacher and for the student who proposes to make good. Its 
 usefulness depends upon the determination of each to "deliver the goods." 
 
 A successful instruction in hygiene means fewer men in the civilian 
 or military discard, less sickness, fewer postponable deaths, longer lives, 
 greater national human resource, and larger national happiness. But 
 there can be no successful instruction in and no adequate realization 
 of these possibilities if either the teacher or the student is a slacker. 
 
 The effective presentation of this subject may be accomplished 
 through recitations, discussions and quizzes, written exercises, inspec- 
 tions, and conferences. Lectures, demonstrations, lantern slides and 
 motion pictures may serve a useful purpose if employed occasionally and 
 witbout reducing the necessity for thoughtful study on the part of the 
 student and instructor. Informational hygiene is not of much use unless 
 it in some way becomes applied hygiene. The instructor is wholly just- 
 ified in holding his pupil responsible for the practice of a reasonable 
 degree of good individual hygiene. Poor posture, unclean wearing ap- 
 parel, dirty fingernails, skin, or hair, poor dental hygiene, uncorrected 
 visual defects, unsatisfactory care of the feet, poor muscular condition, 
 and so on, are, within reasonable limitations, evidences either of poor 
 instruction or of poor application by the student and should be treated 
 and recorded as such.- Every recitation should require a thoughtful and 
 careful preparation from the student and from the instructor. 
 
 Instruction concerning the facts of General Hygiene and their prac- 
 
tical application in Individual Hygiene and in Group Hygiene and Inter- 
 group Hygiene, as contemplated in this outline and syllabus, involve: 
 
 A persistent emphasis of health as a national resource — of man 
 power and of women power as a national asset. 
 
 An insistence that individual health is a serious patriotic duty and 
 a compelling social obligation. 
 
 An impressive reiteration of the supreme importance of saving the 
 enormous amount of time, productivity, and resource lost in peace time 
 and in war time on account of avoidable accident, preventable disease, 
 and remediable physical defect. 
 
 A constant repetition that will drive home the disturbing fact that 
 we lose every day in peace or in war the services of an enormous army 
 of men and women because of physical defect, poor health, avoidable 
 accident, preventable disease, and postponable death. 
 
 A convincing statement and restatement of the fact that national 
 health depends equally upon the health habits of the individual on the 
 one hand and upon those of the community on the other, and that the 
 health progress of neither can go very far without the other. 
 
 A deliberate and persistent effort to secure a compelling realization 
 by the student of the fact that poor development, incapacity, inadequacy, 
 poor health, and sickness are visually a man's own fault. 
 
 The establishment of an ideal that will not permit the individual 
 to expose himself uselessly to disability or disease. 
 
 The cultivation of a biting conscience that will sting as against the 
 accusation of being a slacker or a spy whenever a man yields to the 
 temptation of being needlessly sick, as with gonorrhea or syphilis, or 
 becomes voluntarily unfit for peace-time or war-time service, as with 
 drunkenness or sexual excess, or in any other way " aids the enemy " 
 through habits that take his strength, put him ovtt of condition, and make 
 him a burden to those about him. 
 
 Thomas A. Storey. 
 
THE SCOPE OF HYGIENE 
 
 A.— General Hygiene. 
 
 I. The Agents That Injure Health. 
 
 n. The Carriers of Pathogens. 
 
 HI. The Contributory Causes of Poor Health. 
 
 IV. Defenses of Health. 
 
 V. Producers of Health — (Constructive Hygiene). 
 
 B. — Individual Hygiene. 
 
 I. Informational and Educational Hygiene. 
 
 II. Defensive Hygiene — The Care of the Body and Its Organs. 
 
 III. Constructive Individual Hygiene. 
 
 IV. Individual Hygiene in Relation to Group and Intergroup 
 
 Hygiene. 
 
 C. — Group Hygiene. 
 
 I. General Group Hygiene. 
 II. Special Group Hygiene. 
 
 Hygiene of the Home and the Family. 
 School Hygiene. 
 Occupational Hygiene. 
 Institutional Hygiene. 
 
 D. — Intergroup Hygiene. 
 
 I. General Intergroup Hygiene. 
 II. Special Intergroup Hygiene. 
 Rural Hygiene. 
 Village and City Hygiene. 
 State Hygiene. 
 National Hygiene. 
 
Cornell University 
 Library 
 
 The original of tiiis book is in 
 tine Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924003522624 
 
GENERAL HYGIENE 
 
 PART ONE 
 THE AGENTS THAT INJURE HEALTH 
 
 11 
 
INTRODUCTORY 
 
 Whether you know it or not, you young men of the City College 
 are training yourselves poorly or effectively for the life that you are to 
 lead. Every boy and every girl in this country is training a man or a 
 woman every day — ^physically, mentally, and spiritually — for the de- 
 mands and for the exigencies of maturity to-morrow. This training is 
 largely unconscious and in the majority of cases one-sided, incomplete 
 and poor. As a result, maturity finds a vast army of our men and 
 women unfit for the demands of life in the home or in the community, 
 and in the service of the country for peace or for war. When we grow 
 up, too many of us find that we are not ready. Our years of youth have 
 been wasted and lost. Are you wasting yours ? 
 
 Furthermore, whether he knows it or not, the adult human is train- 
 ing himself each day for the days that are to come. The child and the 
 youth have growth and development and functional excellence to 
 achieve. The adult must train to conserve his health or, as he grows 
 older, slowly lose much of what he has. The training of the adult is 
 harder or easier because of the habits of living, good or bad, that 
 dominated his life when young. What are you doing for the man you 
 are to be? 
 
 It is obvious that the period for intelligent direction, for wisdom, 
 and for vision in the training for life — in the building of manhood and 
 womanhood — is the combined period of infancy, childhood, and youth. 
 This is your period. Are you making use of it? 
 
 The fundamentally important and tremendously large factor in this 
 too often neglected training from infancy to old age, inclusive, is the 
 physical training, or physical education or hygiene of the individual and 
 of individuals in groups. This training is concerned with the acquisition 
 and conservation of health. It is concerned with good health — a quality 
 that is not satisfied with merely "being well." 
 
 Good health — good, active, aggressive health — is the most important 
 thing in the world. 
 
 If you wish to learn something about the value of health, ask the 
 man who has lost his health — ^go to the woman who is trying to buy 
 back her health. 
 
 13 
 
Good health — the quality of your physiology that gives you normal 
 organic growth, normal development, and normal function; the state 
 of body and mind that makes it harder for you to be sick and easier 
 for you to get well; the physical condition that brings you a feeling of 
 comfort and well-being, a resiliency and an enthusiasm for the dayV- 
 work; the thing that removes the fatigue of yesterday and restores 
 your energy for to-day — good health makes possible for you a full 
 measure of success in your life's work, whatever that work may be. 
 
 Good health depends largely upon good health habits. Your health 
 to-morrow depends on your habits to-day. "Yesterday is a dream and 
 to-morrow is a vision. But to-day lived right makes of every yesterday 
 a dream of happiness and of every morrow a vision of hope." 
 
 Health habits may be classified as: (i) Habits of information — the 
 use of reliable literature and lectures; regular health examinations by 
 competent health advisors. (2) Habits of bodily care — conservation of 
 vision, teeth, etc. (3) Habits of protection — avoidance of the agents 
 that injure health and of the carriers of disease. (4) Habits of con- 
 structive hygiene — wise habits of nourishment, adequate excretion, 
 sufficient work, exercise and play, and satisfying rest. 
 
 The Department of Hygiene in the College of the City of New York 
 aims to give you practical instruction leading to the formation of health 
 habits along these several lines. 
 
 The elective courses offered in physiology and bacteriology are 
 fundamental to an intelligent knowledge of the human body and some 
 of the living agents that injure and destroy its health. 
 
 The medical examinations required here every half year enable you, 
 while you are here, to practice habits of health examination and care of 
 physical defects. The College is doing all it can to make these ex- 
 aminations useful. Their real value, however, depends upon the use 
 you make of them. 
 
 The Health Talks that we plan to give you once or twice a week will 
 bring to you information on the basis of which you may establish habits 
 of protection against the causes and carriers of disease, and assist you 
 also in the formation of wise habits of daily living. 
 
 Our required courses in physical exercise and our free provisions 
 for recreation, play, and for athletic training, are maintained by the 
 college in order to give you opportunities to secure more nearly your 
 full bodily growth, organic development and functional perfection; and 
 to make it possible for you to acquire such habits of constructive 
 hygiene as will conserve and increase your future years of vigorous 
 usefulness. 
 
 Remember, then, you are training a man ; building a citizen ; you are 
 
 14 
 
to-day master of the man you are to be. (i) Good, active, aggressive 
 health is the most important thing in the world, not for its own sake 
 but because the best success of whatever you undertake to do depends 
 upon the good health with which you back up your undertaking. 
 (2) Good health depends upon: (a) Habits of information — good, re- 
 liable literature, lectures, and demonstrations; and regular, careful, 
 s^erious health examination; (b) sane common sense habits of bodily 
 care, correction and repair; (c) vigilant but reasonable habits of health 
 protection, and (d) wise habits of constructive hygiene — adequate 
 nourishment, effective excretion, sufficient work, exercise, and recrea- 
 tion, and satisfying rest. 
 
 II 
 
 CLASSIFICATION OF THE AGENTS THAT INJURE HEALTH 
 
 We can not expect in a series of short talks such as we are giving 
 you, to cover all the common agents that injure health. It is, further- 
 more, impossible for us, under these conditions, to make a thorough 
 study of any single cause of disease. All we plan to do is to make you 
 acquainted with the most important of these enemies of health. These 
 agents may be classified with a fair degree of completeness as follows: 
 
 A. — Direct or Primary Causes of Health Injury 
 
 (i) Heredity. Limited to the inheritance of some morbid condi- 
 tions and to increased susceptibility , to certain diseases. "There is no 
 true inheritance of infectious disease." 
 
 (2) Mechanical agents. Pressure applied in various ways, usually 
 accidentally, causing fractures, concussions, bruises, lacerations, etc. 
 
 (3) Physical agents, (a) Light; X-ray and other rays; electricity; 
 (b) heat and cold; (c) atmospheric pressure. 
 
 (4) Chemical agents, (o) Inorganic poisons such as lead, arsenic, 
 mercury and phosphorus; (6) organic poisons such as alcohol, opium, 
 cocaine; food poisons such as physiological poisons in shell-fish and 
 mushrooms ; and some of the products of decomposition of animal and 
 vegetable matter. 
 
 (5) The vegetable parasites known as "bacteria." They cause 
 such diseases as typhoid fever, relapsing fever, diphtheria, whooping- 
 cough, epidemic cerebro-spinal meningitis, erysipelas, lobar pneu- 
 monia, acute rheumatism, Asiatic cholera, plague, bacillary dysentery, 
 
 IS 
 
Malta fever, anthrax, glanders, tetanus, gonococcus infection, leprosy 
 and tuberculosis. 
 
 (6) Vegetable parasites other than bacteria. Actinomycosis, 
 oidomocosis, mycosis, etc. 
 
 (7) Protozoa or unicellular animal organisms, (a) Malaria; (b) 
 tympanosomiasis or sleeping sickness, caused by a trypanosome ; 
 (c) amebic dysentery; (d) syphilis, caused by the treponema pallidum. 
 
 (8) Multicellular animal parasites or metazoa (worms and insects 
 principally), (o) Fluke worms; (b) tapeworms; (c) round worms 
 such as hookworm, pinworm, trichenella spiralis, various filaria; (d) 
 leeches; (e) tongue worms; (/) acarines. 
 
 B. — The Indirect or Contributory Causes of Poor Health 
 
 The contributory causes of poor health are those influences that 
 make it easier for human beings to become sick or harder for them to 
 get well. They include: 
 
 (i) Those influences that favor the production, distribution or 
 vitality of the specific causes or carriers of disease. 
 
 (2) Those influences that tend to interfere with or break down our 
 environmental defenses against poor health and disease. 
 
 (3) Those influences that tend to weaken or destroy our bodily 
 (anatomical and physiological) defenses against disease. 
 
 The following may be cited as examples of contributory causes of 
 poor health: (The subject will be covered another term.) 
 
 (i) These influences may exist in the environment, e.g., excessive 
 fog; excess of moisture in the air or soil; high and low temperatures; 
 excess of or lack of sunshine ; warm, dry and stagnant air ; air contami- 
 nations; noise. 
 
 (2) These influences may be physiological, e.g., age; sex. 
 
 (3) They may reside in abnormal bodily conditions, e.g., heredity; 
 defective vision; obstructed breathing; decayed, unclean teeth and sore 
 gums; flat feet; curved spine, flat chest; obesity, emaciation; chronic 
 disease; after-aifects of acute disease; affects of trauma (gross in- 
 juries, injuries from dust, irritating vapors, gases, chemicals). 
 
 (4) They may be connected with insufficient bodily nourishment, 
 e.g., insufficient food; poor food; bad habits of eating; insufficient air; 
 insufficient water. 
 
 (5) Interference with excretion may be a contributory cause of 
 disease, e.g., by way of the respiratory tract, the genito-urinary tract, 
 the skin or the bowels. 
 
 (6) Interference with special functional activities may contribute to 
 
 16 
 
the production of disease, e.g., through the lack of physical exercise, or 
 through nervous excitement, worry, apprehension, fear or depression, 
 or through lack of sleep. 
 
 Remember : That the indirect or contributory causes of poor health 
 are those influences which tend to make it easier for you to be sick and 
 harder for you to get well. The exciting causes of poor health act 
 more certainly and more injuriously when the contributory causes have 
 prepared the way. 
 
 Ill 
 
 THE HYGIENE OF HEREDITY 
 
 The vehicle of inheritance, (a) All living things — ^plants or animals 
 — are produced by the union of two germ cells (parent cells), or they 
 are produced by the division of a single parent cell. (&) The nucleus 
 of the parent cell is the vehicle of inheritance. The problems of in- 
 heritance are problems of the nucleus of the germ cell. 
 
 The inheritance of disease and the inheritance of tendencies to be- 
 come diseased are limited to those morbid conditions in the parent 
 which may affect the quality of the nucleus of the parental germ cell. 
 
 Examples of racial hereditary disease, (o) White races are more 
 susceptible to yellow fever than other races. (6) The negroes, to sleep- 
 ing sickness, (c) The negroes and American Indians to tuberculosis, 
 (rf) Gout is more common to the English, obesity to the Dutch, and 
 obesity and diabetes to the Jews. 
 
 Examples of family hereditary disease. (a) Reappearance of 
 identical diseases — gout. (6) Appearance of related diseases — obesity, 
 rheumatism, gout, (c) Inheritance through father — gout, (rf) In- 
 heritance through mother — hemophilia. (^) Family tendencies to in- 
 fectious disease— a lack of resistance to tuberculosis, acute rheumatism, 
 measles, scarlet fever, etc. (/) Constitutional or nutritional diseases, 
 tendencies to gout, rheumatism and diabetes, {g') Nervous diseases 
 and tendencies to nervous diseases. The most common type of hered- 
 itary manifestation of disease. Hysteria, migraine, epilepsy, various 
 convulsive affections, various paralyses, certain atrophies, and various 
 forms of mental abnormality, including idiocy, imbecility and insanity. 
 
 The possibility of there being such a thing as the inheritance of 
 acquired injury. (») No such thing as inheritance of gross mutilations ; 
 nor transmission of maternal impressions ; nor inheritance of training or 
 lack of training; nor inheritance of infectious disease, (i) Poisons cir- 
 
 17 
 
culating in the blood may injure the germ cells directly or indirectly 
 through injury of other organs so that these injuries may result in the 
 production of damaged offspring. Alcohol may lead to steriUty, early 
 death of infant, or to mental, moral or physical weakness of offspring. 
 Lead poisoning and poisoning with nitrate of mercury have same in- 
 fluence as alcohol. Bacterial poisons may be in same class, (c) Severe 
 constitutional disease is known to have a profound influence on the germ 
 cells, producing sterility, death of infant, production of weaklings, and 
 imperfections in later generations. 
 
 Syphilis is an example of a constitutional affection having seriously 
 important influence on heredity. The infection itself is not inherited. 
 The infection may be transmitted congenitally. The constitutional 
 affects of the disease may offer severe injury to the germ cell, causing 
 . sterility, death of the unborn or newly born child, or weakness, in- 
 capacity and uselessness in the living offspring. 
 
 Your health problems of heredity are: (a) The health problems 
 resulting from your heredity, and (b) the health problems which you 
 transmit. You have some control over (a) and you have a large con- 
 trol over {b). 
 
 Community, hygiene and heredity, (a) Alcoholism, venereal disease, 
 industrial disease, etc., in their possible relation to the emphasis, initia- 
 tion and transmission of hereditary diseases are serious community prob- 
 lems, (b) The relation of pauperism, mental degeneracy and crime to 
 heredity justifies community interference with the initiation and per- 
 petuation of such heredity, (c) The fact that war destroys the fit and 
 leaves the unfit and the less fit to dominate posterity is a matter deserving 
 the most serious concern of all society, {d) Field of eugenics. 
 
 IV 
 
 PROBLEMS OF HEALTH AND DISEASE THAT ARISE 
 DURING THE PRENATAL PERIOD 
 
 Every human being is the product of the union of two germ cells, 
 a maternal germ cell and a paternal germ cell. 
 
 The union of these two parental germ cells forms a single cell which 
 is called the fertilized ovum. 
 
 This single cell contains all the heredity and all the possibilities 
 which the parental stock is able to contribute. 
 
 Rapidly this single cell divides into two cells; these two into four; 
 the four into eight; the eight into sixteen; and so through a process 
 
 18 
 
of multiplication by two the single cell becomes hundreds, thousands, 
 and thousands of millions of living tissue cells. For a prenatal period 
 of about 287 days these living cells are multiplying, organizing, adjust- 
 ing and developing into a human form, a human structure, a human 
 being. 
 
 During this prenatal period, the growing human embryo may be in- 
 jured or diseased through serious injury, disease or poor health of the 
 mother. This injury may be accomplished by overwork of the mother, 
 rough treatment or insufficient nourishment of the mother, leading to 
 weak, puny or non-resistant offspring, or even to the birth of a dead 
 infant. Heart disease, kidney disease, syphilis, and other diseases of 
 similar importance may bring about these results. 
 
 Alcoholic women, and women who work in lead and with nitrate of 
 mercury may be unable to bear live children; or lose them soon after 
 birth; and may bear idiots, imbeciles and epileptics. 
 
 Poisons like alcohol, lead, mercury, arsenic, carbon monoxide and 
 morphine easily pass from the circulation of the mother to that of the 
 unborn child. 
 
 Infectious diseases do not often pass from the mother to the fetus, 
 but such transmissions do occur. There are recorded cases of fetal 
 infection with syphilis, tuberculosis, smallpox, chickenpox, measles, 
 scarlet fever, erysipelas, septic disorders, acute rheumatism, typhoid 
 fever, cholera, cerebro-spinal meningitis, influenza, mumps, relapsing 
 fever, malaria and yellow fever. The list is a long one but the number 
 of cases on record is small. (Adami.) 
 
 The influences that may lead to injury of the unborn infant as de- 
 scribed above may be classified as: (a) Physical or mechanical; (b) 
 nutritional; (c^ toxic; (d) infectious. 
 
 Problems of Health that Arise at Child-birth 
 
 Child-birth not infrequently exposes the infant to physical or 
 mechanical injury, or to contact infection. It occasionally happens that 
 the life of the infant must be sacrificed in order to save that of the 
 mother. This situation is rare and is usually the result of natural in- 
 terferences with the normal delivery of the child. More commonly it 
 is necessary for the physician to assist the birth by manual or in- 
 strumental measures. These procedures save many lives, both of 
 mothers and infants, but they are occasionally accompanied by physical 
 injuries of more or less serious importance to the mother and to the 
 child. 
 
 The most common and the most serious infection of infants at this 
 
 19 
 
time is gonorrhea. Less common infections are from various pus 
 organisms. Gonorrhea in the new born is usually located in the eyes. 
 Fortunately, this serious infection is becoming less common, but it is 
 probably even yet fair to state that more infants are made blind in this 
 than in any other way. Thus the infant suffers because of the careless 
 hygiene of its parents. A disease of shame and sin so far as the 
 parents are concerned, and a disease of careless uncleanliness so far as 
 the child is concerned. 
 
 SUMMARY 
 
 The prenatal period and the period of birth are, then, periods in 
 which the hygiene of human life requires special forethought and care. 
 The overworked mother, the underfed mother, the sick mother, must 
 necessarily fail to protect and to nourish her unborn babe adequately. 
 Responsibility for such failure must rest upon the father quite as much 
 as the mother. This responsibility is often a responsibility of society 
 itself. The community regulation of women's work is of great im- 
 portance in those occupations which stamp their damage upon the 
 power of motherhood and on the vitality of offspring. 
 
 It must be obvious, too, that the unborn babe and the babe at birth 
 are often made to suffer in punishment for the unhygienic habits of 
 either or both parents. The various infections, particularly those of 
 syphilis and gonorrhea, figure especially in events of this sort. 
 
 V 
 
 THE MECHANICAL AGENTS THAT INJURE HEALTH 
 
 The mechanical causes of injury, poor health and disease, are the 
 common factors that give serious importance to most of the accidents 
 that happen to human beings. 
 
 These mechanical causes of injury are classified by Adami as fol- 
 lows: (a) Concussion, (b) Puncture, with which may be included 
 the influence of projectiles under high velocity, (c) Section, (d) 
 Contusion, with which may be included lacerations and tearing, (e) 
 Compression. (/) Distension, (g) Atmospheric pressure. 
 
 These influences operate most commonly in the accidents that occur 
 in our various industrial enterprises, such as railroads, mines, metal- 
 lurgical plants, factories and construction works. The lowest estimate 
 (1916) places the fatal accidents to adult workers in the United States 
 at 35,ocx> a year, with an additional 1,250,00x3 non- fatal accidents. 
 
 20 
 
(Journal of the American Medical Association.) The Massachusetts 
 Industrial Accident Board (191 5) estimates 75,000 fatal accidents 
 yearly to workers of all ages and more than 3,000,000 non-fatal acci- 
 dents. 
 
 Drowning may be classed as mechanical injury to human life. There 
 were in 1915, in the area of registration, 6,514 deaths from accidental 
 drowning. This is a very strong argument in favor of a swimming re- 
 quirement for all children. 
 
 Murder and suicide are commonly effected by mechanical means 
 though not infrequently chemical. Reports from the registration area 
 containing 67.1 per cent, of the total population of the United States 
 indicate that in 1915 there were in this area 11,216 suicides and 4,670 
 homicides. 
 
 During its first five months, the Great War was responsible for the 
 loss of more than two million human lives. The gross direct injuries 
 of war are largely mechanical. Estimates made in 1919 place the num- 
 ber above 9,000,000. (War has' a powerful contributory influence on 
 communicable disease, an emphasis on hereditary degeneracies, and a 
 destructive effect on community morals, not to be confused with the 
 direct mechanical effect of powder and ball.) 
 
 Mechanical injury figures largely in the affairs of every community 
 through all divisions of the population. The laborer is most often 
 affected, but accidents involving mechanical injury of varying de- 
 gree of seriousness are common to all classes. 
 
 Mechanical injuries are in a very large degree preventable. Safety 
 appliances are being adopted commonly in our industrial plants. "Better 
 safe than sorry," is the motto of many a "Safety First" campaign in 
 our larger communities. It is a good motto for individual guidance. 
 If half these injurious and fatal accidents could be avoided each year, 
 the saving in human life, human suffering and human misery would be 
 enormous. 
 
 What have you done to protect yourself from mechanical injury? 
 Have you the muscle and the nerve to control a runaway horse? 
 Could you save your life by climbing down a rope fire-escape? Can 
 you jump quickly enough and far enough to avoid an automobile? 
 Can you run fast enough to get out of the way? Could you run long 
 enough ? Could you escape from a sinking boat ? A hundred feet from 
 shore? A half mile? Can you swim? What are you prepared to do 
 to defend yourself and your country from the mechanical injuries of 
 war? 
 
 21 
 
VI 
 
 THE PHYSICAL AGENTS THAT INJURE HEALTH 
 
 The physical agents that injure health may be classified as follows: 
 (a) Atmospheric pressure, diminished pressure, excessive pressure; (b) 
 temperature, low temperature, high temperature; (c) light, insuificient 
 light, excessive light; (d) the X-ray; (e) radium; (/) electricity, light- 
 ning, commercial electricity. 
 
 Variations in atmospheric pressure are not of much importance in 
 the affairs of the ordinary individual. Those who climb high mountains 
 or make balloon ascensions to great heights may suffer with giddiness, 
 rapid breathing, rapid heart rate, nose-bleed, weakness and exhaustion. 
 These are effects of low atmospheric pressure. They are symptoms due 
 to an insufficient supply of oxygen in the blood. Men that work in 
 caissons, building tunnels under rivers, for instance, suffer from the 
 effects of high air pressure. The laborer who returns from such work 
 to normal air pressure too rapidly suffers excruciating pain, and, in 
 some cases, death. The excessive air pressure forces the blood to take 
 on an increased amount of oxygen, nitrogen and carbon dioxide gas. 
 When the excessive pressure is reduced suddenly, it seems that the 
 blood is unable to get rid of its increased amount of nitrogen as rapidTy 
 as it does the other gases it has taken up. The bubbles of nitrogen 
 remaining in the blood cause the pain and fatality. 
 
 Variations in temperature are of importance in temperate and arctic 
 zones. 
 
 Low temperature causes chilblains, frost bites and freezing, none of 
 which are common or of much importance in this part of the woi'ld. 
 In colder climates they are of more serious concern. Six persons froze 
 to death in New York City in the winter of 1916. Three hundred and 
 fifty-four persons died of excessive cold in the area of registration in 
 1918. 
 
 Cold may lower the temperature of the body and thus reduce its 
 resistance to disease. 
 
 High temperature may cause: (i) Heat stroke — a result of hot, 
 moist weather — may be headache, rapid pulse, rapid respiration, loss of 
 consciousness, death. In 191 5, area of registration, there was 407 
 deaths from effects of heat. (2) Burns; may vary in degree from 
 simple redness to cremation. Death follows if half the body is burned 
 enough to cause blisters. Death follows if from one-sixth to one- 
 eighth of the skin surface is destroyed by burning. Burned areas are 
 easily infected. The septic wounds that occur in such areas are often 
 
 22 
 
very serious. The scars that follow burns may cause incapacitating de- 
 formities. In the area of registration (191 5) there were 4,804 persons 
 accidentally burned to death; in addition, 971 lost their lives in con-, 
 flagrations. In New York City in 1916, 428 persons were fatally 
 burned. 
 
 Light as a source of injury to health. Insufficient light; not a 
 specific cause of disease; may contribute to produce, or help produce 
 poor health. A factor in causing eye strain. 
 
 Excess of light, particularly sunlight. The red rays of the sun 
 produce heat. They are factors in heat stroke referred to above. The 
 violet rays and the ultra-violet rays of the sun are of special im- 
 portance. They may cause sunstroke when the rays of the sun fall 
 directly on the head and neck. The symptoms of sunstroke are pains 
 in the head and neck, nervous excitement, convulsions and loss of con- 
 sciousness. Death may come in an hour. In the summer of 1916, fifty- 
 eight persons in New York City died of sunstroke. Milder cases re- 
 cover, but they frequently develop a permanent nervous disorder of 
 some sort. These rays (violet and ultra-violet) cause sunburn. Severe 
 sunburn is very painful. The burned area may easily become infected. 
 
 The X-ray and radium rays are sometimes causes of disease among 
 the specialists who use them or work with them. These rays may 
 cause sterility in the men and women. They sometimes cause "burns" 
 that develop into cancerous growths. 
 
 Electricity as a physical cause of injury. Lightning may cause 
 death or prolonged unconsciousness. Burns from lightning heal very 
 slowly. Commercial electricity used for service and for industrial pur- 
 poses is frequently the cause of injury. The seriousness of this injury 
 depends on the amount of current that passes through the victim; the 
 area of contact, and the region affected. Currents of low voltage and 
 moderate frequency may be fatal if the heart is in the circuit. The 
 electric current may cause nervous disturbances, burns, loss of vision 
 and death. Five hundred and fifteen deaths were reported from elec- 
 tricity (lightning excluded) in 1915 in the area of registration. Two 
 hundred and twenty-one were reported due to lightning. It not in- 
 frequently happens that the heart continues to beat after breathing has 
 been stopped by the electric current. In such cases the use of artificial 
 respiration may save the victim from dying. (The best method of 
 artificial respiration is the Schafer or the prone pressure method.) 
 One should never handle loose electric wires, switches, unless he is cer- 
 tain of their safety and of his own protection. Carelessness has often 
 lead to fatality. 
 
 23 
 
VII 
 
 THE CHEMICAL AGENTS THAT INJURE HEALTH 
 
 Acute poisoning not included in this discussion. It may be noted, 
 however, that there were 1,286 deaths reported in the area of registra- 
 tion from acute poisoning in 1915. Chemical agents may exist in solid, 
 liquor, or gaseous forms. They may be either inorganic chemicals or 
 organic chemicals. 
 
 The Inorganic Chemicals that Injure Health 
 
 Lead. — The cause of chronic lead poisoning. 
 
 Source. — Poisoning from lead is common in those industries in 
 which lead is handled, e.g., lead mining and smelting, zinc smelting, 
 working in lead and lead colors, making lead pipes and various other 
 lead objects, making pottery and earthenware, type making, working 
 in electric storage battery factories, and installing gas and water pipes. 
 
 Susceptibility. — Increased by bad habits, lack of condition, chronic 
 illness. 
 
 Mode of Entrance. — Skin absorption plays a part. Inhalation of 
 vapor of lead is a "questionable occurrence." Ingestion into the 
 stomach is the important route. 
 
 Symptoms. — Varied and inconstant. May be colic, paralysis, con- 
 vulsions, delirium and death. One hundred and fifty-five deaths from 
 chronic poisoning are reported for the area of registration in 1915. 
 Most cases recover. (For effects on offspring see chapter on "In- 
 heritance" and the "Prenatal Period.") 
 
 Avoidance. — Poisoning by lead is avoidable through habits of 
 cleanliness. Lead workers should wear gloves when practicable; always 
 wash their hands before eating ; never put their fingers in their mouths ; 
 omit smoking while hands are smeared with lead compositions; exer- 
 cise care that their food is not contaminated with lead. 
 
 Arsenic. — The cause of chronic arsenical poisoning. Importance has 
 greatly decreased in recent years. Source of poisoning from arsenic is 
 now limited to arsenical beer (England) ; a few industrial occupations ; 
 criminal usage; and the therapeutic use of the drug (Edsall). Massa- 
 chusetts law in 1900 limited the amount of arsenic to be used in color- 
 ing paper and articles of dress. Country is now almost free of poison- 
 ing from this source. 
 
 Mode of Entrance. — Inhalation; external application; ingestion. 
 
 Mercury. — The cause of chronic mercurial poisoning. Importance 
 has greatly decreased since greater care is being used in administering 
 
 24 
 
mercury medically, and since mercury is now less commonly used in- 
 dustrially. Chief sources of mercury poisoning now are mercury mining 
 and smelting, manufacturing of thermometers and barometers, and the 
 manufacture of felt hats. 
 
 Mode of Entrance. — Inhalation of vapor, the chief avenue of entry. 
 Absorption through the skin also important. Ingestion not common. 
 
 Symptoms. — Chiefly mental, nervous and digestive. Recovery 
 probable in mild cases. (For effect on offspring see chapters on "In- 
 heritance" and the "Prenatal Period.") 
 
 Phosphorus. — The cause of chronic phosphorus poisoning. The im- 
 portance of phosphorus poisoning has greatly decreased in recent years 
 because of stringent laws and improved methods of manufacture. 
 Chief source is the white phosphorus used in making matches. 
 
 Mode of Entrance. — Ingestion. Symptoms may be severe. Necrosis 
 of the bones of the jaws is the most common local symptom. This 
 necrosis reaches the surrounding tissues and may become extensive. 
 Foul odor, repulsive appearance, deformity, and death are not uncom- 
 mon effects of the disease. 
 
 Prevention. — Stop using white phosphorus. Keep the mouths of 
 working people clean. 
 
 Carbon Monoxide. — Importance is increasing because of the oppor- 
 tunities for acute and chronic poisoning from various industrial sources. 
 
 Sources. — ^Pure carbon monoxide (from electric furnaces) illum- 
 inating gas; products of combustion. 
 
 Mode of Entrance. — Inhalation. Symptoms arise from injuries to 
 the blood, kidneys and brain. Three hundred and forty-five persons lost 
 their lives from illuminating gas in New York City in 1916. 
 
 The Great War has produced some new poisonous chemicals of 
 terrible power. The gases used in offensive warfare include chlorine, 
 phosgene, xylil bromid or benzyl bromid, phenzl carbylamin chlorid, 
 diphenyl-chloroarsin, dichloro-diethzlsulphid. Used as gas clouds, in 
 gas bombs, and in gas shells. Protective devices have been produced 
 for all these gases. 
 
 The manufacture of high explosives is accompanied by danger to 
 the workmen because of the poisonous properties of some of the 
 chemicals used. Among the most dangerous in this class are picric 
 acid, trinitrotoluol, and the fulminate of mercury. 
 
 2S 
 
VIII 
 
 SOME OF THE ORGANIC CHEMICALS THAT INJURE 
 
 HEALTH 
 
 The most important organic chemical poisons that may be placed 
 in this group are alcohol, opium, morphine, cocaine, various food 
 poisons, snake and other venoms and the organic chemical poisons that 
 cause the auto- intoxications. (This discussion is based largely on the 
 facts presented in Osier's Modern Medicine, Vol. i, Part IV.) 
 
 Alcohol.— Varieties of alcohol. Methyl alcohol, known as wood 
 alcohol, is used to adulterate cheap whiskies. Very dangerous. Ethyl 
 alcohol, main factor in alcoholic drinks. The higher alcohols (Fusel 
 oil). Relation to acute or chronic alcoholism probably unimportant. 
 
 Sources of Alcohol (Ethyl).— Certain patent medicines contain from 
 6 per cent, to 47J4 per cent, alcohol. The public uses large amounts of 
 patent medicines. Many persons acquire the habit of using alcoholic 
 drinks in this manner. Physicians' prescriptions not infrequently con- 
 tain alcohol. The bar-room, the restaurant and the drug-store are the 
 common sources from which alcohol may be secured in one form or 
 another. 
 
 Effects of Alcohol. — Between 1895 and 1905 there were admitted 
 to the alcoholic wards of the Bellevue Hospital 43,916 men and 16,076 
 women. The statistics from many institutions show that from 20 to 75 
 per cent, of these alcoholics have had either an alcoholic father or 
 mother or both parents given to such excesses. (Lambert.) 
 
 Acute Poisoning with ethyl alcohol (ordinary intoxication) may 
 cause death. In 1915 there were 2,945 deaths reported in the area 
 of registration from acute and chronic alcoholism. 
 
 Chronic Poisoning. — The habitual use of alcohol is known to pro- 
 duce the following effects upon men and women : It causes the muscles 
 of the heart to become degenerated and weak. This is not infrequently 
 the cause of premature death. The blood vessels (arteries) often be- 
 come hardened and therefore liable to break. Hardened arteries are 
 factors in causing the symptoms of old age. A broken artery means 
 a hemorrage. If the artery is large, death follows. If the artery is in 
 the brain, death or paralysis follows. The liver may become diseased. 
 This is not uncommonly the basis for a general disability, finally ending 
 in death. The stomach is- usually badly treated by the alcoholic. He 
 suffers from indigestion which is sometimes most severe. Chronic 
 alcoholism sooner or later injures the kidneys. Since the kidneys are 
 the most important excretory organs in the body, such injury is serious. 
 
 26 
 
Chronic alcoholism often causes sterility in women and impotence in 
 men. The brain may be affected, leading to delirium tremens and 
 hallucinations, and to homicidal and suicidal tendencies. The nerves 
 may be paralyzed. The general resistance of the individual is reduced 
 so that he gets sick more easily and recovers with more difficulty. The 
 mortality of alcoholics with pneumonia is twice that of non-alcoholics. 
 The chemical and physical agents that cause disease are more injurious 
 to the alcoholic than to the non-alcoholic. The children of alcoholic 
 mothers have 2.5 times the mortality of those of non-alcoholic mothers. 
 They are often still-born, and if they do live are weak and non-resistant. 
 The children of alcoholic parents are often epileptic, idiotic or weak- 
 minded. The alcoholic is of weak will and blunted moral sense. He 
 is unclean, untidy, and often filthy. He loses his sense of shame, his 
 feeling of domestic or community obligation, and his love for those that 
 should be near and dear. The drunken father and the drunken mother 
 are destroying themselves physically, mentally and morally while they 
 are transmitting their mental and moral weaknesses to their children 
 through heredity and through example. 
 
 The Mortality Bill Against Alcohol (Life Extension Institute's 
 Monthly Letter, Number 12) : "In a number of life insurance com- 
 panies, chiefly in Great Britain, the abstainers were separated from the 
 rest of the policyholders (all accepted as temperate and healthy risks), 
 and the difference in the death-rate determined. In the United King- 
 dom Temperance and General Provident Institution of London over a 
 period of forty-five years the mortality of the non-abstainers, or so- 
 called moderate drinkers, accepted as temperate and healthy risks was 
 2,7 per cent, higher than that among the total abstainers. In the Sceptre 
 Life Association of London over a period of twenty-seven years the 
 mortality of the non-abstainers was 54 per cent, higher than among the 
 total abstainers. In the Scottish Temperance Life Assurance Co. of 
 Glasgow, over a period of twenty-nine years, the mortality of the non- 
 abstainers was 44 per cent, higher than among abstainers. In the Man- 
 ufacturers' Life Insurance Co. of Canada over a period of eight years 
 the mortality of the non-abstainers accepted as temperate and healthy 
 risks was 78 per cent, higher than among the abstainers. There has 
 recently been compiled the experience of forty-three American life in- 
 surance companies extending over a period of twenty-five years. The 
 death-rate • among certain types of drinkers was compared with that 
 among insurance risks generally. The results follow, supporting the 
 evidence derived from British companies: First, those who were ac- 
 cepted as standard risks but who gave a history of occasional alcoholic 
 excess in the past. The mortality in this group was 50 per cent, in 
 
 27 
 
excess of the standard mortality, equivalent to a reduction of over four 
 years in the average lifetime of the group. Second, individuals who 
 took two glasses of beer, or a glass of whiskey, or their alcoholic 
 equivalent, each day. In this group the mortality was i8 per cent, in 
 excess of the standard. Third, men who indulge more freely than the 
 proceeding group, but who were considered temperate and acceptable 
 as standard insurance risks. In this group the mortality was 86 per 
 cent, in excess of the standard. In short, we find among alcohol users 
 the following increases of mortality over the standard or average death- 
 rate among insured risks generally: 
 
 Death-rate in Excess of Standard 
 
 Steady moderate drinkers, but accepted as standard risks 86 per cent. 
 
 Having past excesses SO 
 
 Very moderate drinkers 18 
 
 "This means that steady drinkers who exceed two glasses of beer or 
 one glass of whiskey daily should be charged a heavy extra premium, 
 and that there is a distinct extra hazard even on those who drink to a 
 lesser degree. In these groups, the death-rates from Bright's disease, 
 pneumonia and suicide were higher than the normal. Unfortunately, 
 in the investigation of American companies, no comparison was made 
 with total abstainers. It is evident, however, from the trend of the 
 figures and the results shown by British companies, that such a com- 
 parison would show the abstainers to have a long lead in vitality over 
 the very moderate drinkers." 
 
 Prevention. — Many books are written on alcoholism and its preven- 
 tion. This is a matter of personal and community concern. You must 
 avoid such habits yourself and you must use your influence as a voting 
 citizen to protect your family and your community from this influence. 
 
 IX 
 
 ORGANIC CHEMICAL AGENTS THAT INJURE HEALTH 
 
 — Continued 
 
 Opium and Its Derivatives. — In this group are opium, morphine, 
 codein, heroin and other lesser important drugs. 
 
 These organic chemicals, called alkaloids, are secured through direct 
 purchase, physicians' prescriptions, or in patent medicine. Opium may 
 be smoked. It and the other derived drugs are more commonly taken 
 by mouth or hypodermically. Laws are formulated in many States to 
 
 28 
 
restrict the sale of such drugs. We have also a Federal law to this 
 same effect. Medical teaching nowadays is directed against such use 
 of these drugs as may lead to habit formation. These drugs cause 
 acute poisoning if taken in any but small doses. Death may easily 
 follow. They are taken by unfortunate human beings who have formed 
 a habit of using them. At first, small doses produce a cessation of 
 pain, and sleep. The habit is easily formed. After a while it takes 
 more and more of the drug to produce the desired effects. Very un- 
 desirable effects soon appear. With the smoker of opium the will is 
 weakened. There is loss of memory, despondency, suicidal tendency, 
 general tremor, a deathly pallor, failing eyesight, rapid pulse, chronic 
 bronchitis, indigestion, constipation, itching skin and often vomiting. 
 With those who take opium by mouth there is finally a degeneration 
 of mind, morals and physique. There is a loss of self-respect, with 
 insomnia, emaciation and a tendency to melancholia, dementia and 
 sudden death. With those who take morphine by mouth or the hypo- 
 dermic, there are three stages of the disease: Exaltation, intoxication, 
 and emaciation. The habitue ends by loss of character, will and 
 morals. He is beset with nightmares. His hair falls out; his teeth 
 decay; his face is drawn and aged. Emaciation becomes extreme. A 
 continual delirium may ensue and death ends the habit. The habitual 
 use of morphine and its derivatives is very difficult to break. It is 
 better never to know what drugs you are taking when you are sick. 
 Leave that to your doctor. If you are in pain, don't hunt for relief 
 through drugs. Stick it out as long as you can. Get a good doctor 
 and trust him. 
 
 Cocaine. — This drug is present in certain prescriptions and patent 
 medicines. It is used habitually by the same type of persons that use 
 opium and morphine. It is taken hypodermically or by the mouth. 
 Very small doses sometimes cause death, the sense of sight, hearing and 
 smell become seriously impaired. The patient hears persecuting voices, 
 and sees strange, threatening objects. A delusional insanity develops. 
 Suicidal or homicidal impulses may appear. This drug is more quickly 
 and intensely destructive than alcohol or opium. — (Lambert.) 
 
 Remember: Alcohol, opium, morphine and cocaine are common 
 habit- forming drugs. You should take no chance leading to the forma- 
 tion of such habits. Look out for drinks and patent medicines con- 
 taining these poisons. 
 
 29 
 
X 
 
 CHEMICAL AGENTS— Continued 
 
 Tobacco. — The injuries that may result from the use of tobacco are 
 probably of chemical origin. We possess no accurate information as to 
 the exact nature of the chemical actions involved. The use of tobacco 
 is often attended with such phenomena as nausea (ordinarily only in 
 beginners); indigestion; slightly increased heart rate; moderately in- 
 creased blood pressure; wakefulness; nervous irritability; lessened ac- 
 curacy of muscular coordinations; increased susceptibility to fatigue; 
 dry and irritable lining (mucous membrane) of the nose, throat, tongue 
 and mouth; loss of vision (occasional and temporary), and acid 
 dyspepsia. 
 
 Evidence has been produced which would seem to show that only 
 half as many smokers as non-smokers are successful in the "tryouts" 
 for football squads; in the case of able-bodied men, smoking is accom- 
 panied by a loss in lung capacity amounting practically to lo per cent. ; 
 smoking is invariably associated with low scholarship (Pack, Popular 
 Science Monthly, October, 1912). 
 
 The tobacco habit is not a clean habit. It is frequently offensive to 
 non-users and is the basis for much bitterness on the part of such non- 
 users. It is evidently unwise for children, young adults, and delicate, 
 sickly, nervous, or irritable persons to use tobacco. The habitual 
 smoker should seek regular, careful medical examination for the early 
 detection of such injuries as have been noted above. 
 
 XI 
 
 THE BACTERIA THAT INJURE HEALTH 
 
 Bacteria are very small plants. They are invisible to the naked eye. 
 Some are so small as to be invisible to any but the most powerful 
 microscopes. We have reason to believe that there may be some 
 bacteria too small to be seen with any means now known to science. 
 
 The Non-pathogenic Bacteria. — There are two broad classes of 
 bacteria, e.g., those that cause disease — ^the pathogenic bacteria — and 
 those that do not cause disease — the non-pathogenic bacteria. Unfor- 
 tunately, it seems to be true that under certain conditions non-patho- 
 genic bacteria may become virulent, and therefore pathogenic. It is 
 equally true, fortunately, that pathogenic bacteria sometimes lose their 
 virulence, and thus become, temporarily at least, non-pathogenic. The 
 
 30 
 
non-pathogenic bacteria exist in enormous numbers everywhere. They 
 are far more numerous than the pathogenic bacteria. The cleanest 
 milk you drink contains millions of them. The best city water contains 
 them. Our surroundings, food, air and water are infected by them. 
 But these organisms are ordinarily absolutely harmless. Many of the 
 non-pathogenic bacteria are not only harmless in their relation to dis- 
 ease, but are important in their beneficial relation to health and life. 
 In fact, all human, animal and plant life would disappear in the course 
 of time if the valuable services of some of these bacteria should be lost. 
 
 The Importance of the Non-pathogenic Bacteria to Human, Animal 
 
 and Plant Life 
 
 The "Carbon Cycle." — Carbon is essential to the life of all plants. 
 No plant can live without it. Commonly plants secure their carbon 
 from the carbon dioxide in the air. They "breathe" through their 
 green leaves much as we breathe through the wall of our lungs. The 
 plant retains the carbon and returns the oxygen to the air. The carbon 
 is then used by the plant in building its structure. It is the chief 
 chemical in wood. It is present in all fruits, vegetables, cereals and 
 other vegetable foods. Animals eat the plants and thus secure the 
 carbon which the plants have used in producing their fruits, seeds, 
 leaves and stalks. Animals use this carbon in building their tissues, 
 or in producing their secretions. Every tissue cell in the animal body 
 contains carbon. Human beings eat plants, plant foods and animals. 
 Thus the human animal secures the carbon it needs for its cells from 
 plant life. Every cell in every tissue and every organ of your body and 
 mine contains carbon. Carbon is absolutely essential to all life, animal 
 or vegetable. 
 
 Whenever a plant, or an animal, or a human being discharges ex- 
 cretions from any of its organs, those excretions contkin carbon. Some 
 of the non-pathogenic bacteria "feed upon" those excretions and break 
 them up into simple chemical compounds. Carbon dioxide is one of 
 the important products of the action of bacteria upon organic excre- 
 tions. Whenever a plant, or an animal, or a human dies, the non- 
 pathogenic bacteria "feed" upon the dead body and decompose it. 
 These thus break up the complex chemical compounds into simple 
 chemical compounds. Carbon dioxide is always produced in such bac- 
 terial action. 
 
 The carbon dioxide released by bacteria in their decomposing in- 
 fluence on the dead bodies of the plant, animals and humans, and on 
 the organic excretions, secretions, and discharges from those same 
 
 31 
 
sources, passes into the air, and is again available as plant food. It may 
 be again breathed through the green leaves of living plants and thus 
 continue the "carbon cycle." 
 
 It is obvious that this substraction of carbon from the air, and 
 this addition of carbon to the air must balance. If, through the course 
 of centuries, less carbon were returned than taken out, the air would 
 finally have too little carbon to meet the needs of plant life, and plants 
 and animals and humans could live no longer. 
 
 The "Nitrogen Cycle." — The nitrogen cycle is very like the carbon 
 cycle except that nearly all plants secure their nitrogen compounds 
 from the soil through their roots. When the non-pathogenic bacteria 
 decomposes dead human animal and plant bodies into simpler chemical 
 compounds, they return nitrogen to the soil in simpler forms that are 
 again available for plant life. Some bacteria take nitrogen from the air 
 and store it in the structure of the plant in forms available for animal 
 food. 
 
 Nitrogen is requisite for all human and animal life. Every tissue 
 cell in our bodies must have nitrogen. If the non-pathogenic bacteria 
 should "go out of business" there would be this second reason why 
 all human and all animal life would disappear. 
 
 There are Other "Cycles" of lesser importance such as the "phos- 
 phorus cycle" and the "sulphur cycle." These cycles all demonstrate 
 the fact that human life as we now know it would be impossible with- 
 out the service of the non-pathogenic bacteria. 
 
 Commercial Values of the Non-pathogenic Bacteria. — Some of these 
 bacteria give flavor to butter. Others ripen cheese. Some are im- 
 portant in the manufacture of vinegar, acetic acid, the tanning of hides 
 and the curing of tobacco. 
 
 XII 
 
 PATHOGENIC BACTERIA— Cow/mw^rf 
 
 The Pathogenic Bacteria. — The pathogenic bacteria are the bacteria 
 that cause disease. Our common colds, sore throat, attacks of bron- 
 chitis, are caused usually by pathogenic bacteria. Among the more 
 common pathogenic bacteria are: The bacilli of typhoid fever, the pus 
 cocci, the gonococci, the diplococci of meningitis, the bacilli of diph- 
 theria, the bacilli of whooping-cough and the bacilli of tuberculosis. 
 All bacteria, pathogenic and non-pathogenic, commonly appear in one of 
 three forms. The cocci are round, dot-like forms, such as the pus cocci 
 that cause boils and abscesses. A coccus may be as small as one two-hun- 
 
 32 
 
dred-thousandths of an inch in diameter. The bacilli are longer rod-like 
 forms such as the bacilli of typhoid fever and tuberculosis. The tubercle 
 bacilli average about one fifty-thousandth of an inch in diameter. The 
 spirilla are curved forms such as the spirillum of cholera. The spirilla 
 are the largest of the bacteria. 
 
 Some bacteria are motile because of hair-like fringes (flagellae) 
 which have a characteristic motion. 
 
 Some bacteria produce spores; others do not. A spore is a more 
 resistant seed-like structure which the bacterium manufactures within 
 its body. The spore is usually roundish and much smaller than the 
 bacterium from which it came. More will be said about spores later. 
 Bacteria live in dark, damp, warm and dirty places. They die in sun- 
 shine; drying kills most of them. They do not grow well in the cold. 
 High temperatures destroy them. 
 
 Pathogenic bacteria grow best in the tissues or in the tissue juices 
 of human beings and animals. Some pathogens will grow only in the 
 human beings. Many pathogenic bacteria will not grow in nature. 
 Pathogenic bacteria may remain alive for hours, days, weeks, or even 
 months in favorable surroundings. Some bacteria die more quickly 
 than others under such circumstances. We find tubercle bacilli in 
 human spit. If such sputum is left in dark, damp and warm places, 
 the bacilli in the sputum will live for a long while. Typhoid bacilli 
 will live for a long while in cows' milk. If the milk is warm they will 
 grow there. Pathogenic bacteria are found in the normal human 
 throat; between the teeth; in the nose; under the eyelids; under the 
 nails ; in the creases and pores of- the skin ; in the intestines ; in the 
 respiratory, intestinal and genito-urinary secretions, excretions and dis- 
 charges. 
 
 The Multiplication or Reproduction of Bacteria (applies to all bac- 
 teria). — Bacteria reproduce rapidly. Each bacterium grows by sep- 
 arating into two parts. A bacillus divides transversely so that two 
 bacilli are formed, each about one-half as long as the original bacillus 
 was. A coccus divides into two cocci; a spirillum into two spirilla. 
 We call this multiplication by binary fission. 
 
 It takes a bacterium on the average about one-half hour to divide 
 into two bacteria. Some divide in fifteen minutes ; others take an hour. 
 
 If a single bacterium could be unhindered in its multiplication by 
 binary fission, if all its descendents could multiply without restriction, 
 it would be possible within a day and a half to increase that one single 
 bacterium to 9,544 billions of bacteria, which would weigh fifteen 
 thousand tons. Fortunately, conditions are never favorable for such 
 unrestricted growth. 
 
 33 
 
Some bacteria produce spores. A spore is a "seed" or "egg" which 
 is capable of resisting influences which would destroy the bacterium 
 which produced it. Spores are much smaller than the bacteria from 
 which they come. A spore is much harder to destroy than the adult 
 bacterium. It may lie a long time in a dormant condition. The spores 
 of anthrax are said to have been found alive after thirty years of 
 quiescence. When its surroundings are favorable, when the tempera- 
 ture, the humidity, and food supply are favorable, the spore begins to 
 grow and soon becomes an active bacterium which multiplies in the 
 usual way by binary fission. There are, then, two sorts of bacterial 
 reproduction — one by spore formation, and the other by binary fission. 
 
 XIII 
 PATHOGENIC BACTERIA— CoMfrnw^d 
 
 The Habitat of Pathogenic Bacteria. — The bacteria that cause dis- 
 ease in human beings grow best in the tissues of human beings and 
 other warm-blooded animals. Some of these pathogens will grow only 
 in the tissues of human beings. 
 
 The bacillus of anthrax is common cause of disease in sheep and 
 cattle. It may also cause very serious disease in careless persons who 
 handle infected animals, or their skins or wool. The bacillus of 
 glanders frequently causes disease in horses and cattle. The men who 
 handle such animals are often infected. The bacillus of bovine tuber- 
 culosis causes tuberculosis in cattle. Sometimes the disease is conveyed 
 to children through milk infected by the bovine bacillus. 
 
 There is evidence that the bacillus of avian tuberculosis (tuber- 
 culosis of birds) does not commonly cause tuberculosis in other 
 animals; and that the bacillus of reptilian tuberculosis does not com- 
 monly cause tuberculosis in animals that are not reptiles. There are 
 numerous other bacteria that will grow in animals but not in humans. 
 
 The tubercle bacillus that infects human beings will not infect any 
 of the cold-blooded animals. It will cause disease in monkeys, and 
 various other warm-blood animals. Dr. Harris, Director Bureau of Pre- 
 ventable Diseases, reported that there were 32,048 cases of tuberculosis 
 registered in his bureau at the end of 1918. Each year about 10,000 per- 
 sons die of that disease in New York City. In 1915, in the area of 
 registration, there were reported 98,194 deaths from tuberculosis, all 
 forms. The bacillus of typhoid fever, the coccus of gonorrhea, and 
 the spirillum of cholera seem not to affect other than human animals. 
 The bacillus of typhoid fever causes disease in from 300,000 to 500,000 
 people in the United States every year. The gonococcus makes more 
 
 34 
 
babies blind than any other cause. The spirillum of cholera has been 
 kept out of the United States for some years. It has cost this country 
 thousands of lives and millions of dollars. It is common cause of dis- 
 ease in South America, European and Oriental countries. The bacillus 
 of diphtheria infects children by preference. It may also infect puppies, 
 kittens, horses and mice. Over io,(X)0 died of diphtheria in the area 
 of registration in 1915. 
 
 Some pathogenic bacteria will grow in any of the human organs 
 and tissues. Others seem to be limited to certain organs or tissues. 
 The tubercle bacillus, the pus coccus and the pneumococcus (the cause 
 of lobar pneumonia) may grow anywhere in the tissues. While the 
 tubercle bacillus may grow in any of the organs it grows most com- 
 monly in the lungs and bones. It grows least commonly in the muscles. 
 The pneumococcus, in the same way, grows more commonly in the 
 lungs. The bacillus of diphtheria grows oftener on the surface of the 
 throat and the nose than anywhere else. The diplococcus of menin- 
 gitis grows best in the membranes that cover the brain and spinal 
 cord. Other pathogenic bacteria have their "preferences" for special 
 tissues. These facts explain why we have diseases of different organs 
 — as diseases of the lungs, or the brain, or the bones. 
 
 Avenues Through which Bacteria Gain Access to the Tissues. — 
 Normal healthy body tissues contain no bacteria. Most bacteria can not 
 pass through the normal skin. Many of them can not pass through the 
 normal mucous membranes. The mucous membranes line all the cavities 
 of the body which are connected with the exterior. This includes the 
 mouth, stomach, intestines, nose, eye, genito-urinary apparatus, etc. 
 
 Bacteria may enter the tissues through breaks, wounds, punctures, 
 incisions, lacerations, abrasions and injured regions in the skin and the 
 mucous membranes. These injuries may be microscopic — a bacterium is 
 small — a scratch of a pin, a scratch from a finger-nail, the rubbing of 
 a rough collar or undershirt, the bite of an insect such as the head 
 louse, flea, bedbug, fly or mosquito — any of these may supply an open- 
 ing for the entry of the pathogen. The congestion in the throat fol- 
 lowing exposure to cold or the wet may rupture small capillaries and 
 provide an opening for bacteria. A blow on the chest, on the nose, or 
 on the eye may give the same opportunity. Constipation may injure the 
 mucous membrane of the intestine and supply an avenue of entry. Thus 
 they may enter through the outer surface (skin) of the body, or being 
 inhaled, swallowed or otherwise introduced into the respiratory, in- 
 testinal, genito-urinary or other openings in the surface of the body, 
 they may enter through breaks in the inner surface (mucous mem- 
 brane) which lines those tracts, openings and passages. 
 
 35 
 
There are said to be fifty varieties of bacteria in the normal mouth; 
 there are many bacteria under the eyelids, in the nose, in the decayed 
 teeth, on the gums and on the tonsils. The hair of the scalp and body 
 harbors bacteria. The skin holds them in its pores and creases. They 
 are found on the fingers and under the nails. Some of these bacteria 
 may be pathogenic. 
 
 Injury of any sort to the skin or mucous membrane may afiford an 
 avenue of «itry for the bacteria that cause disease. This injury may 
 be so small that it can not be seen. Bacteria are always present wait- 
 ing to get in. 
 
 Conditions Modifying Infection. — After having gained access to the 
 tissues, further growth of bacteria depends upon several conditions. 
 First: It depends upon the virulence of the bacterium. The same 
 variety of bacteria may in one case be extremely virulent, that is, active 
 and strong, and in another case attenuated, that is, weak and inactive. 
 Second: Further development depends on the number of bacteria. 
 Within certain limitations our tissues will destroy all bacteria that reach 
 them. Third: The avenue of infection has a marked influence. Thus, 
 if the tubercle bacillus enters through the mucous membrane or is in- 
 jected into the tissues, the usual fatal result is probable. If, however, 
 it enters into the skin, the bacteria may be destroyed or limited to the 
 locality in the skin to which they found entry. Fourth: Some tissues 
 destroy all of the organisms of those diseases that. reach them. Fifth: 
 The healthy condition of the body determines its resistance. A normal 
 healthy body will be less liable to infection than a weak, unhealthy 
 body. The juices of a normal healthy body destroy bacteria and 
 neutralize their poisons. 
 
 After bacteria have gained access to the tissues, the development of 
 disease depends on: the virulence of the bacteria; the avenue of infec- 
 tion, and the healthy condition of the individual. Therefore, keep clean, 
 exercise right, play and rest right, eat right, look after your excretions. 
 In this way you will be more likely to secure healthy tissues and thus 
 better protect yourself from disease. 
 
 XIV 
 
 PATHOGENIC BACTERIA— Continued 
 
 The Effects of Pathogenic Bacteria on Human Life. — After having 
 established themselves in the tissues, pathogenic bacteria may cause in- 
 jury in various ways. In nearly all infectious diseases the pathogenic 
 
 36 
 
causes are found at one time or another in the blood. These organisms 
 may be present in such enormous numbers as to interfere with the 
 various seriously important functions of the blood. Remember: The 
 blood stream brings soluble food, oxygen, water, salts and internal 
 secretions to every one of the millions of tissue cells of the body, and 
 it removes from these cells the waste products and secretions which 
 come from every living cell. The bacteria in the blood may establish 
 themselves in such large numbers at special foci in the tissues as to 
 prevent the normal food supply reaching the tissue cells in those affected 
 parts. Being thus robbed of their food, those cells will die, or at least 
 be seriously injured. The presence of enormous numbers of bacteria 
 in sensitive and delicate organs may easily cause injury by obstructing 
 small vessels or by pressure on nerve endings. The more important 
 and serious effects of the pathogenic bacteria are caused by their vital 
 activities. 
 
 During the life of a great community of many billions of bacteria 
 within the human body the following must take place: (i) These bac- 
 teria need food. They may destroy tissues and tissue products in order 
 to satisfy their hunger. (2) Such bacteria manufacture secretions. 
 (3) They must give off excretions. (4) They must form and give 
 off waste products. (It is not possible to separate secretions, on the 
 one hand, from excretions and waste products on the other, except in 
 theory. We know that these several products exist but we can not 
 always separate them from each other.) (5) They die and their dead 
 bodies are dissolved by the action of the tissue fluids. (6) From these 
 excretions, waste products, excretions and dissolved dead bodies, numer- 
 ous injurious chemical substances arise. There are known to be formed 
 in this way various poisonous acids, bases and salts, among which are 
 a number of powerful toxic chemical substances of very great patho- 
 genic importance. Many of these chemical bodies are known as 
 "antigens." The toxin of the diphtheria bacillus is perhaps the best 
 known bacterial poison. (7) All the products that go into solution are 
 likely to be carried by the blood to all the tissue cells of the body. 
 These floating chemicals irritate the tissue cells so they produce new 
 soluble "defensive" chemical bodies of their own. These chemical 
 bodies are known generally as "antibodies." An "antigen" is a chemical 
 body that causes the production of "antibodies." (8) The chemical re- 
 actions between the products of bacterial activity and the products of 
 celliilar activity may result in new injurious chemical compounds. 
 
 During an infection by pathogenic bacteria we have, then, local 
 mechanical injurious effects and local and general toxic (poisonous) 
 chemical effects. And so we have, in these infections, aches and pains, 
 
headache, delirium, paralysis, unconsciousness, nausea, vomiting, chills, 
 fever, rapid breathing and rapid pulse. Some diseases leave us with 
 blind eyes, deaf ears, crippled hearts, useless kidneys, stiflf joints or a 
 damaged mind. Death is by no means the worst injury pathogenic 
 bacteria may cause in man. 
 
 Final Results of Infection with Pathogenic Bacteria 
 
 Some infections are notoriously fatal, (i) 800,000 persons died 
 of cholera in Russia in 1892. (2) Over 98,000 persons died of tuber- 
 culosis in the area of registration in 1915. (3) Over 8,000 people 
 died of typhoid fever in the area of registration in 1915. (4) Over 
 7,500,000 human beings died of bubonic plague in India between 1890 
 and 1915. (5) At one time over 40 per cent, of children infected by 
 the diphtheria bacillus died. Now, with treatment by antitoxin, the 
 rate is less than 9 per cent. 
 
 There are other serious bacterial diseases which might be listed 
 here. On the average about 1,700 persons die of infectious disease 
 every day in continental United States. The majority of these deaths 
 are caused by bacterial infection. 
 
 A number of these infections leave the individual crippled in mind 
 or body., Diphtheria may leave paralyzed nerves. Typhoid fever may 
 leave bad kidneys or a weak heart; meningitis may leave blind eyes or 
 deaf ears; gonorrhea often leaves sterility, blind eyes or crippled joints. 
 
 The majority of persons in good health recover from their first at- 
 tacks of infectious disease. These recoveries are due to the fact that 
 the tissue cells of the human body have the power of manufacturing 
 specific defenses against various infections (antibodies, etc.). 
 
 Elimination of Pathogenic Bacteria from the Human Body 
 
 During an attack of bacterial disease and sometimes for long periods 
 after, the specific bacteria that caused the disease are expelled from 
 the body in enormous numbers, by way of the various avenues of ex- 
 cretion. In fact, the several excretions always contain pathogenic 
 organisms even in health. The organisms that cause disease of the air 
 passages are expelled largely by way of the nose and the mouth. 
 Some of these organisms are swallowed and escape along with the in- 
 testinal excretions. The organisms that cause disease of the intestinal 
 tract are expelled by way of the bowels. The organisms that cause 
 disease of the genito-urinary tract are expelled by way of discharges 
 from that tract. 
 
 38 
 
The Carriers of Disease. — Any agent that brings these pathogenic 
 bacteria to human beings becomes thereby a carrier of disease. The 
 source of nearly all human infection is the human carrier. Pathogenic 
 bacteria may be transferred from one human being to another by direct 
 contact. The most typical examples of infection by direct contact are 
 found in the sexual transfer of venereal diseases. Pathogens may be 
 transferred a little less directly through "droplet infection," that is, by 
 way of the fine spray of mucous and saliva that accompanies coughing, 
 sneezing, etc- The transfer may occur by way of infected food, water 
 and articles in common use. Several insects which feed and breed in 
 human excretions or feed on human blood are known to be carriers, 
 e.g., the mosquito, the fly, the louse and flea. Some animals may serve 
 as carriers, e.g., the cat, the dog, the rat. 
 
 XV 
 
 THE PROTOZOA THAT INJURE HEALTH 
 
 The protozoa are very small animals. Some of them are large 
 enough to be seen by the naked eye, but most of them may be seen 
 only with the help of a microscope. There is evidence that some 
 of the disease organisms that are small enough to pass through the 
 fine pores of porcelain bacteriological filters are protozoa. 
 
 The protozoa are simple one-celled animals. The bacteria are simple 
 one-celled plants. All of the functions, all of the activities, all of the 
 work of these animals are performed by the one simple cell of which 
 each is made. In the higher animals, for example the human animal, the 
 work of living is divided between the millions of specialized cells which, 
 taken together, form the animal body. Thus, our muscle cells do our 
 heavy work; our nerve cells do our feeling, seeing, smelling, tasting, 
 directing and thinking. A nerve cell that assists in the complex func- 
 tion of seeing has no part in the function of smelling. Every cell is a 
 specialist. But in the protozoa, the one microscopic cell does all the 
 things that protozoa are able to do. 
 
 One of the most typical of the protozoa is the ameba. The ameba 
 under the lower power microscope looks like a dirty gray drop of 
 water. When it eats, it flows around the food particle that happens to 
 be in its way. It does not seem to have any particular mouth part. 
 This curious way of eating is called "phagocytosis." It is characteristic 
 of amebas. It is also characteristic of the white blood cells and certain 
 other cells of the human body. When it excretes, the particles excreted 
 seem to be thrown out anywhere through the surface of the ameba. It 
 
travels very slowly by simply flowing along much as a drop of water 
 might if it could push out a tiny projection in any direction and then flow 
 into the little projection. This curious way of moving about is called 
 "ameboid motion." It, too, is characteristic of the white blood cells and 
 certain other cells of the human body. We will have more to say about 
 these white cells at another time. 
 
 The protozoa are not so uniformly alike as the bacteria are. They 
 are all one-celled but they differ in many ways. For these reasons it is 
 hard to describe the protozoa. About seven thousand species of 
 protozoa have been described. 
 
 The protozoa live in sea water, fresh water, damp soil, vegetable 
 matter and animal matter. 
 
 These organisms reproduce by simple division, by sexual conjugation, 
 and by spore formation. They multiply quite as rapidly as bacteria do. 
 
 Some forms of protozoa pass through certain stages of growth in 
 regular sequence, so that from time to time the appearance of the 
 protozoa changes most remarkably. This typical and regular sequence 
 of changes in the case of any given protozoan is called the "life cycle" 
 of that protozoan. 
 
 The life cycle of the malarial parasite, for instance, is made up of 
 a cycle of development which includes a period of development in the 
 red blood corpuscle of the human and a period of development in the 
 stomach and salivary pouches of the mosquito. Other protozoa have 
 even more complex cycles than this. A knowledge of these cycles is of 
 great importance in our warfare against the protozoa that cause dis- 
 ease. 
 
 The pathogenic protozoa require special surroundings. These sur- 
 roundings must be of the right temperature, moisture and darkness and 
 must contain the requisite food. So far as we know the protozoan of 
 malaria will live nowhere else than in human blood and in the body of 
 the mosquito; the trypanosome of sleeping sickness will live nowhere 
 save in warm-blooded animals and certain biting, blood-sucking flies ; the 
 protozoan of smallpox only in humans and cows (monkeys also). 
 
 Protozoa are destroyed by drying; by high and low temperatures; 
 by sunlight and by any radical change in their natural environment. 
 
 Relation of Protozoa to Human Health 
 
 Protozoa are grouped into pathogenic protozoa and non-pathogenic 
 protozoa. It is possible but not probable that under special conditions 
 the pathogenic forms may become non-pathogenic, and the non-patho- 
 genic, pathogenic. 
 
 40 
 
The Pathogenic Protozoa 
 
 The Malarial Parasite. — Malaria is caused by an animal parasite 
 which is called the Plasmodium of malaria. This Plasmodium is so 
 small that it can be sucked through the capillary bore of the proboscis 
 of a mosquito — ^so small that hundreds of them may grow in the 
 stomach of a mosquito ; so small that hundreds of them may live in the 
 salivary pouches of a mosquito waiting to be squirted into human 
 tissues when the mosquito feeds on human beings. It is so small that 
 it can enter the red blood corpuscle (there are 4,000,000 red blood 
 corpuscles in a cubic millimeter of blood with plenty of room to spare) 
 and multiply in the red corpuscle until there are a score or more of 
 the young parasites produced in that single red cell. The parasite of 
 human malaria grows only in the human being and in the anopheles 
 mosquito. Without the mosquito or the human, the parasite could not 
 live. Malaria is a common disease. Malaria is never caused by any- 
 thing else than the Plasmodium of malaria. Malaria is transmitted 
 through the mosquito. Without the mosquito there would be no 
 malaria. The only mosquito that carries this parasite is the anopheles 
 mosquito. 
 
 The trypanosomes form another important group of protozoa, some 
 members of which cause serious disease. The disease caused by these 
 organisms is called trypanosomiasis. Infections from different 
 tr)fpanosomes occur in South America, Africa, Southern Europe, Persia, 
 India, Burma, China and the Philippines. Many kinds of animals are 
 affected as well as man. A typical trypanosonie is a very small, 
 elongated, flattish animal looking something like an eel. It has a 
 flagellum or hair-like process on one end and a finlike membrane ex- 
 tending from the flagellum along the whole length of the body. Its 
 movements are very active. These organisms live and multiply in the 
 blood of animals and man. Life cycles have been described for them. 
 The only disease of human beings caused by these organisms is sleep- 
 ing sickness or human trypanosomiasis. It is caused by a specific 
 trypanosome which is called the Trypanosoma Gambiense. The organism 
 is carried from man to man or from animal to man by the tsetse fly, 
 and perhaps other blood-sucking flies. Up to the present time they have 
 been found alive only in the blood of human beings and some animals, 
 and in the stomach and sucking apparatus of the tsetse fly. This dis- 
 ease is limited to the regions occupied by these flies, which limitation at 
 the present time confines the disease to parts of Africa. Here the 
 disease is a terrible scourge and produces a most serious and fatal 
 sickness. 
 
 41 
 
The ameba is another protozoan, some forms of which cause dis- 
 ease. Amebic dysentery has been found more or less all over the 
 world, particularly in tropical and sub-tropical countries. The ameba 
 is a microscopic organism of very considerable biological interest. I 
 have described it to you rather inadequately in the earlier part of this 
 lecture. I advise you to consult a book on biology or zoology for 
 further information. The chief carrier of this organism is drinking 
 water which has been contaminated by the excretions of persons or 
 animals sick with the disease. The disease itself is very uncomfortable 
 and painful. Many patients die. The endameba buccalis is thought to 
 be the cause of pyorrhea dentalis, a very common and a very important 
 disease of the gums. 
 
 The spirochceta pallida, or the treponema pallidum, is probably a 
 protozoan. This spirochaeta is very small, but is larger than the average 
 bacterium. It is long and slender, shaped like a thread, though some- 
 what broader. It has a curious spiral movement. We have only re- 
 cently been able to cultivate these parasites for laboratory study, so 
 that we have much yet to learn about them. The spirochaeta pallida or 
 treponema pallidum is found in the blood, tissue juices, secretions and 
 sores of syphilitic victims. It is the cause of syphilis, discovered in 
 1905 by Schaudin and Hoffman. This organism is transmitted by in- 
 timate contact as in sexual intercourse, drinking from contaminated 
 cups, eating with contaminated spoons, smoking the pipe of a syphilitic 
 individual, etc. Syphilis is always derived from some one who has the 
 disease. It may come through some innocent medium — a cup, a pipe, 
 a drink, a kiss. It has destroyed more children, crippled more men 
 and women, ruined more homes than you can imagine. It is one of 
 the most common and most serious diseases of civil life and in military 
 life it sometimes does more damage than the weapons of war. It is 
 most frequently secured through illicit sexual intercourse but may be 
 spread by contact from husband to innocent child; from guilty brother 
 to innocent sister, mother or friend. 
 
 XVI 
 
 THE PATHOGENIC METAZOA, OR THE MULTICELLULAR 
 ANIMAL PARASITES THAT CAUSE DISEASE 
 
 This group of agents that cause disease includes a number of 
 higher animal parasites, their eggs, embryos and larvae. The more 
 important members of the group are the flukes, tapeworms and their 
 larvae (bladder worms), hookworms and other round worms. 
 
 42 
 
The Frequency of Parasites. — There is no species of animal and 
 no race or class of men known to be free from parasites. (Stiles.) 
 
 Influence of Parasites Upon Their Hosts. — The injury done may 
 vary with species, size, location and the number of parasites and with 
 the condition and age of the host. This injury may be accomplished in 
 various ways : Nourishment is taken which should go to the host ; blood 
 is taken by the parasite for food ; mechanical pressure irritates or causes 
 atrophy of organs or parts of organs; natural channels may be ob- 
 structed; the wandering of the parasite may cause irritation; sub- 
 stances may be excreted which have a toxic influence and which may 
 change the condition of the body fluids; injury to the intestinal mucosa 
 or to the skin may form points of entrance for bacterial and protozoan 
 infections. 
 
 Trichina 
 
 Description. — The adult worm lives in the upper part of the in- 
 testine. The male is 1.4 to 1.6 mm. long and 40 u. in diameter. The 
 female is 3 to 4 mm. long and 60 u. thick. 
 
 The female lives in the lumen of the intestine or bores into its walls 
 and deposits her young during a period of five or seven weeks. Each 
 female produces about 1,500 embryos in that length of time. These 
 embryos are considerably smaller than the adult organism. They 
 wander with the lymph or blood to the striated muscles. Here they 
 locate and develop into "encysted larvae" or, as they are commonly 
 called, "flesh worms." 
 
 These encysted larvae remain alive and lie curled up in the muscle 
 for years. This larvae stage is the infective stage. When meat con- 
 taining these larvae is eaten, the cysts are destroyed in the stomach and 
 the larvae pass into the small intestine and develop there into adult 
 forms. 
 
 Carriers of Trichina. — Humans, hogs, wild boars, rats, dogs and 
 cats are affected by the disease and contain the encysted larvae in their 
 tissues. The hogs may carry the disease to human beings. The hogs, 
 rats, dogs and cats carry the disease to each other. 
 
 The Disease of Trichinosis is always uncomfortable, frequently 
 serious, and occasionally fatal. It is not a common disease. A small 
 outbreak of trichinosis occurred in the Borough of Queens in Feb- 
 ruary, 1916. Twelve persons were treated at St. Joseph's Hospital. 
 In spite of the best of care four of the patients died. 
 
 43 
 
Tapeworms 
 
 Man becomes afflicted with tapeworms by eating flesh containing 
 the encysted larvae of the parasite! or by eating food that has been con- 
 taminated by the excretions of dogs, cats, rats, mice, or by transferring 
 the eggs directly to his mouth on his fingers. 
 
 Some tapeworms grow as long as thirty feet. Others are only a 
 few millimeters in length. They grow in segments and are flattened. 
 The head end contains suckers and in some forms is armed with hooks. 
 
 Tapeworm disease is caused by eating the larvae of tapeworms in 
 insufficiently cooked beef, pork and fish. Tapeworms of less common 
 occurrence may be secured from dogs and rats by handling them and 
 transferring the eggs on the fingers to the mouth or by eating food 
 they have contaminated. One tapeworm is liable to lay 150,000,000 
 eggs a year, so that the chance of spreading the disease is not to be 
 underestimated. People who carry tapeworms are usually starved. 
 They lose weight, become thin, emaciated, and, if unrelieved, may die. 
 Cook your meats thoroughly; never eat them raw. 
 
 Hookworm 
 
 The Hookworm is an animal parasite of about the size and shape 
 of a slightly bent pin. There are two well-known hookworms — the 
 old world hookworm and the new world hookworm. They are very 
 much alike. The young hookworm develops from eggs that have been 
 cast out in the fecal discharges of human beings sick with hookworms. 
 These eggs hatch if they chance to be left in warm, moist surroundings. 
 After a few weeks the young hookworm is ready to attach itself to 
 its human victim. If the young worm happens to have developed in 
 dejections that were cast in or near a vegetable garden it may be car- 
 ried to the table in green food such as celery, radishes, lettuce and the 
 like. If a bare- footed human walks through the grass in which there 
 are young hookworms, the little worms may get on his feet, bore 
 through the skin and thus find their way by a devious route to the in- 
 testinal canal. The adult life of the hookworm that is picked up by 
 the human is spent in the intestinal canal of that human. Here the 
 worm fastens itself by means of its sharp teeth into the intestinal wall. 
 It sucks the blood of its provident host and poisons him with its toxic 
 excretions. 
 
 The great majority of our Southern farms have no privies. The 
 great majority of our Southern country folks go barefooted. The 
 great majority of our Southern country people are not careful in their 
 habits of hygiene. And so the great majority of our Southern rural 
 
 44 
 
population have hookworms. The hookworm belt reaches from 30 
 degrees south latitude to 36 degrees north latitude and goes around the 
 world. It holds over 400,000,000 persons affected with hookworm. 
 Those people are injured physically, mentally and morally. They are 
 educationally and economically depressed or paralyzed. 
 
 Whenever people suffering with hookworm are persuaded to under- 
 go treatment and to practice habits of good hygiene, their disease dis- 
 appears, and they often become wide-awake, useful citizens. The 
 Rockefeller Foundation has proven the value of hygiene most dra- 
 matically in the hookworm sections of our Southern States. 
 
 XVII 
 
 CAUSES OF CANCER 
 
 Cancer is a disease of middle life and later life. It is one of the 
 most hopeless of all the diseases of mankind. Practically every ad- 
 vanced case has resulted in the death of the patient. 
 
 The cause of cancer is not known. 
 
 Chronic irritations often pass into cancer. Chronic ulcerations, 
 irritated scars, moles, warts, benign tumors, and other irritations of 
 long standing are called precancerous conditions because they fre- 
 quently develop into cancer. We do not know why they develop into 
 cancer. 
 
 Cancer may be produced in some of the lower animals by inoculat- 
 ing them with cancerous tissue from other animals. 
 
 Cancer has been produced in rats that have been fed with cock- 
 roaches in which certain intestinal parasites were present. 
 
 Cancer in mice is more likely to reappear in mouse families in 
 which it has already appeared. We have no proof that human cancer 
 is inherited. 
 
 Fish and dogs have developed cancer when fed on scrapings from 
 aquaria in which fish with cancer had been living. 
 
 Sarcoma has been produced in chickens by inoculating them with 
 a filtered emulsion of sarcomatous material taken from other chickens. 
 These and other animals will undoubtedly enable us finally to discover 
 the cause and the cure for cancer and other like malignant growths. 
 
 Precancerous conditions are dangerous. Take good care of all 
 ulcers, wounds, scars, moles, warts and other irritations. Cancer is on 
 the increase. Fifty-four thousand persons died of cancer in the area 
 of registration in 191 5. 
 
 45 
 
XVIII 
 
 THE UNKNOWN AGENTS THAT INJURE HEALTH 
 
 We do not know the causes of the following diseases: Smallpox, 
 chicken-pox, scarlet fever, measles, mumps, yellow fever, rabies. Rocky 
 Mountain fever, trachoma and break-bone fever. There are other dis- 
 eases in this group. 
 
 Our ignorance concerning the causes of these diseases may be due 
 to: (a) Lack of technique. Our knowledge of micro-organisms de- 
 pends upon our ability to bring them into view ; cultivate them and ex- 
 periment with them. We must isolate a disease cause before we can 
 make a study of it. (b) Many of these causes are too small to be seen 
 with power of magnification now at our disposal. A study of filterable 
 viruses began in 1898. We know that the causes of the following 
 human and animal diseases are so small that they will pass through 
 bacteriological filters. We call such organisms filterable viruses, ultra- 
 microscopic viruses or filtrate viruses. 
 
 The Filtrate Viruses 
 
 Diseases of domestic animals: Pleuro-pneumonia of cattle; African 
 horse sickness, sheep-pox, cattle plague, hog cholera, swamp fever of 
 horses, infections agalactia (sheep and goat), catarrhal fever of sheep, 
 distemper of dogs, infectious stomatites papulosa of cattle, guinea pig 
 epizotic, a peculiar paralysis of guinea pigs, and a rat disease. 
 
 Diseases common to man and animals: Foot and mouth disease, 
 rabies vaccinia and smallpox. 
 
 Diseases of man: Yellow fever, moUuscum contagiosum, dengue, 
 fever, verruca vulgaris, trachoma, sand-fly or three-day fever, poliomy- 
 elitis, typhus fever, trench fever, measles and scarlet fever. 
 
 Diseases of birds: Fowl pest, fowl diphtheria, chicken sarcoma. 
 
 We know very little about these minute causes of disease, but our 
 knowledge is on the increase. At present we know: (i) That some 
 of these diseases are carried by biting insects such as the mosquito, the 
 fly, the louse and the tick. (2) That others are introduced through 
 grosser injuries as in rabies. (3) That some of these diseases are 
 transmitted by contact. (4) All of these disease causes are destroyed 
 by high temperature, some of them more easily than the bacteria, (s) 
 Some of them are more resistant to drying than bacteria are. (6) They 
 resist cold. (7) A few have been cultivated in the laboratory. (8) 
 The extreme minuteness of some of these disease causes, combined 
 with their resistance to drying, may account for their contagiousness. 
 
 46 
 
"Minute particles suspended in air or in liquid obey the laws which 
 govern the diffusion of gases and substances in solution in liquids." 
 (WoUbach.) 
 
 XIX 
 
 LAST HEALTH TALK 
 
 Summarize the objects of the term's work' in Hygiene (see Chap- 
 ter I). 
 
 (o) Aim and usefulness of student health examinations. Present 
 statistics as to teeth, vision, etc., of this class. Point out that "habits" 
 of health examination and physical repair may be formed and urge 
 their continuation. 
 
 (b) Health protection through the avoidance of the causes and car- 
 riers of disease. The "floor talks" this term have indicated ways and 
 means of securing health protection. 
 
 (c) Wise habits of daily life have been emphasized in these floor 
 talks (nourishment, excretion, work, exercise and recreation, and rest). 
 
 (rf) What have you done for the man you are to be? Have you 
 wasted his opportunity? Have you neglected his training? Will he be 
 bigger, stronger, and more vigorous because of your care this term? 
 Will he be sick less, will he be more useful, will he live longer and 
 will he be happier? You are master of the man you are to be — will 
 he thank you or blame you? 
 
 -^ 
 
GENERAL HYGIENE 
 
 PART TWO 
 THE CARRIERS OF DISEASE 
 
 49 
 
INTRODUCTORY 
 
 Every young human owes it to himself and to society of which he 
 is a part, to get ready for the duties and the experiences of citizenship. 
 You as college students have a greater obligation to be prepared because 
 of the educational opportunities that are open to you. As sons of the 
 city and as matriculates of the city's college you have not only an 
 obligation — you have in addition a responsibility. Your obligation is to 
 make yourselves physically fit ; to make yourselves physiologically sound ; 
 and to make yourselves vigorously and enduringly healthy. Your re- 
 sponsibility is to use your educated body and your educated mind to 
 meet fully, completely and intelligently the demands of citizenship in 
 peace or in war for the lasting benefit of your country, your State, your 
 city, and yourself. 
 
 Your State and your city have provided opportunities in this college 
 for your training. The college will do its utmost to give you the best 
 service it affords — but the success of your training here depends upon 
 you. After all has been furnished that can be furnished by the college 
 and by the city and the State back of the college, you and you alone 
 can make your training season here a success. 
 
 The Department of Hygiene is concerned with your health — the 
 most important asset you can possess. If you will make intelligent use 
 of the opportunities provided in this department you will aquire habits 
 of health information, habits of bodily care and repair, habits of health 
 protection, and habits of constructive hygiene that will enable you to 
 achieve and conserve your full growth and full bodily development, and 
 to acquire a vigorous health resource that will conserve your pro- 
 ductive life for service to yourself and for service to society. 
 
 One of the very important problems of health protection is the 
 problem of avoiding the carriers of disease. Every plan for the aquisi- 
 tion and the conservation of individual health and of community health 
 must include wise provisions for the destruction, isolation, and avoid- 
 ance of pathogen carriers. The health talks of this term will be con- 
 cerned with these carriers. 
 
 These talks will be worth while if you will make them, your own. 
 They will be useful if you will make health habits out of them. Their 
 
 SI 
 
service for the protection of your health and for the conservation of 
 your vital resources depends wholly upon you. They will help you 
 meet your obligations and carry your responsibilities to the citizenship 
 for which you are getting ready if you will use them. 
 
 II 
 
 MAN AS A CARRIER OF PATHOGENS 
 
 When we remember that only a few pathogenic organisms reproduce 
 in nature, and that all forms under favorable conditions will live and 
 reproduce in the human body, we are forced to the conclusion that man 
 himself is the most important and the most dangerous disease carrier. 
 
 Man is a carriei' of disease because of the pathogenic organisms 
 which he distributes about him by way of his various excretions in 
 health, in disease, and during recovery from disease. The relation of 
 these various excretions to the spread of disease may be outlined as 
 follows : 
 
 Dissemination of Pathogenic Organisms by Way of the Excretions and 
 Discharges from the Human Nose and Throat 
 
 (a) In Health. — Pus cocci, the organisms that cause boils and 
 abscesses ; streptococci, the organisms that cause severe inflammation with 
 general toxemia (poisoning) ; pneumococci, the organisms that cause one 
 form of pneumonia. They may cause other diseases than pneumonia. 
 Diphtheria bacilli. Ehiring a certain epidemic in Middletown, Conn., 
 over 2 per cent, of the throats of 4,081 apparently healthy individuals 
 showed diphtheria bacilli. After the epidemic subsided over i per cent, 
 of these individuals showed diphtheria bacilli. The cocci of menin- 
 gitis have been found in apparently normal persons. The cause of in- 
 fantile paralysis has been found in apparently normal throats. It is 
 possible that the specific causes of the following diseases may be 
 present in the air passages of healthy persons : Scarlet fever, measles, 
 whooping-cough, mumps, leprosy, and tuberculosis. 
 
 (b) In disease of the nose, mouth, throat, and other upper air pas- 
 sages, and lungs. The organisms that cause colds in the nose, throat 
 and lungs; influenza; bronchitis; the various sorts of pneumonia; 
 syphilis; diphtheria; infantile paralysis; leprosy; tuberculosis, and 
 bubonic plague. The unknown cause of measles, scarlet fever, and 
 other diseases. 
 
 (c) During recovery from disease of the respiratory tract, and 
 
 52 
 
often for some time afterward, the various organisms noted under (6) 
 are eliminated in the excretions from the respiratory tract. Note the 
 importance of this fact. 
 
 Ill 
 
 MAN AS A CARRIER OF PATHOGENS— Continued 
 
 The Dissemination of Pathogenic Organisms by Way of the Excretions 
 and Discharges from the Nose and Throat. — (Continued) 
 
 Methods of Elimination — These organisms are carried out of the 
 body in health and disease by sneezing, coughing, spitting, blowing the 
 nose, forceful talking, forceful whispering, forceful breathing, and by 
 swallowing. 
 
 Methods of Transmission. — The causes of disease contained in these 
 discharges from the nose and mouth in health and in disease reach 
 other people, (a) By direct transmission of organisms from one per- 
 son to another, such as by droplet infection, in coughing, sneezing, and 
 other forms of forceful breathing; by contact infection, as in kissing; 
 contact with dirty fingers or other parts that have been smeared with 
 these discharges; common spoon; apple core; the mother that chews 
 her baby's food or feeds it with her own spoon; cigar-makers that use 
 their own saliva in rolling cigars, etc. (fo) By indirect transmission by 
 way of infected : Dust, food and drink, articles in common use, house- 
 hold vermin, such as rats, mice, flies, water-bugs, fleas, bed-bugs, lice, 
 etc. 
 
 Conditions favorable to the transmission of pathogens from one 
 person to another by way of the excretions and discharges from the 
 nose and mouth are found in (o) Crowded living quarters. (6) 
 Crowded transportation facilities, {c) Army camps, trenches, trans- 
 ports, etc. {d) Groups of people gathered for any purpose, {e) 
 Wherever careless people are found. 
 
 The importance of the human being as a carrier of disease through 
 the dissemination of his nasal and oral excretions and discharges is 
 made evident by the following facts: (a) This is practically the only 
 way in which most of these diseases are spread from one person to 
 another, (fc) Thes^ diseases represent an enormous amount of human 
 misery, suffering, and loss of life. There are always 3,000,000 people 
 sick in these United' States. Seventeen hundred people die every day. 
 At least half this sickness and half these deaths are due to diseases 
 spread by human beings in this manner. For example: (i) In New 
 
 S3 
 
York City each winter there are at least 15,000,000 cases of common 
 cold. (2) In New York City each year there are 50,000 cases of 
 tuberculosis, with from 8,000 to 10,000 deaths. A large number of 
 these are cases of pulmonary tuberculosis. 
 
 IV 
 
 MAN AS A CARRIER OF PATHOGENS— Continued 
 
 Dissemination of Pathogenic Organisms by Way of Discharges from 
 
 the Ears and Eyes 
 
 There are no pathogenic organisms discharged in this manner in 
 health. The middle ear and the eye drain into the nose, so in disease 
 the ear may be affected by various pus organisms and by any of the 
 organisms that cause disease of the nose and throat. In disease the 
 important pathogenic organisms that are found in the discharges from 
 the eyes are the cause of pink eye; the gonococcus; the cause of 
 trachoma; any of the organisms that cause disease of the nose. 
 
 Means of spread of disease from these sources are towels, hand- 
 kerchiefs, etc., fingers, contact. 
 
 Importance of these discharges. 
 
 Dissemination of diseases by way of discharges from the intestinal 
 tract. The pathogenic organisms eliminated in this manner are: 
 
 In health (apparent or real). The colon bacillus is the most com- 
 mon inhabitant of the lower intestine. Not an actively pathogenic 
 organism. It not infrequently becomes virulent. Present in the in- 
 testinal canal normally. The bacillus of typhoid fever has been found 
 in the feces of apparently healthy individuals who have no history of 
 typhoid. One investigator has isolated forty-four varieties of bacteria 
 from forty-eight specimens of feces. Most of these forms are non- 
 pathogenic. They include the bacillus pyrocyaneus, bacillus aerogenes 
 capsulatus, bacillus of tuberculosis, bacillus subtilis, and other forms 
 that are known to be pathogenic. The ameba is sometimes present. 
 The hookworm frequently is present without symptoms. A number of 
 less common higher-animal parasites have been found in the feces of 
 human beings who are apparently well. 
 
 In disease. The number and variety of bacteria and protozoa is 
 enormously increased in intestinal disease. The bacteria present may be 
 forms already there, such as the bacillus of typhoid fever; the spirillum 
 of cholera ; the bacillus of dysentary ; the tubercle bacillus. The animal 
 
 54 
 
parasites present may be the ameba, the treponema of syphilis, the tape- 
 worm, hookworm, various other parasites. 
 
 In recovery from disease, and for a greater or lesser time after- 
 ward. Probably all the organisms that cause intestinal disease. The 
 bacillus of typhoid has been found fifty-five years after recovery of 
 the patient. 
 
 V 
 
 MAN AS A CARRIER OF PATHOGENS— CowfwM^d 
 
 The Dissemination of Pathogenic Organisms by Way of the Discharges 
 from the Intestinal Tract. — (Continued) 
 
 Methods of Elimination of Pathogenic Organisms from the In- 
 testinal Tract. — In the feces. One-third of the weight of the dried 
 feces passed by the normal individual is made up of bacteria bodies. 
 (Stengel.) The average normal daily output by way of the bowels is 
 estimated at 128,000,000,000 bacteria. (Strasberger.) Ninety-nine per 
 cent, of the bacteria in normal feces are dead, but the remaining i per 
 cent, may amount to many hundred millions of live bacteria. In disease 
 the output of bacteria in the feces is enormously increased. The tape- 
 worms, hookworms, and other animal parasites reproduce in the in- 
 testinal canal, and their eggs or offspring are then discharged in the 
 feces. A single tapeworm may lay 150,000,000 eggs in a year. 
 
 Methods of Transmission. — The pathogenic organisms contained in 
 the feces are conveyed to other people as follows: Directly through 
 contact with soiled hands or other parts of the individual. Indirectly 
 through infection of food, water, articles in common use, and infection 
 of food animals, household pets, vermin. 
 
 Conditions favorable to the transmission of disease from one human 
 being to another by way of the feces, (a) Bad habits of personal 
 hygiene. (&) Poor sanitary conveniences, (c) Bad hygiene of food 
 animals, {d) Warm, moist weather, {e) Bad domestic and com- 
 munity sanitation. Note the ease of transmission in trench warfare and 
 careless camp life. 
 
 Importance of the human being as a disseminator of disease through 
 his fecal discharges. If man would so handle the excretions from his 
 bowels that they would not get into the food and drink of animals or 
 other men, there would soon be no more typhoid fever, no more cholera, 
 no more tapeworm, and no more hookworm. There were 350,000 
 people sick with typhoid fever in the United States in 1914. This 
 means that human feces (or urine) had polluted the food or drink of 
 
 55 
 
350,000 human beings. Thirty-five thousand died. There are to-day 
 800,000,000 men, women and children in this world sick with hook- 
 worm. And every case has come from contact directly or indirectly 
 with human feces. New York City has a sewer system, but flies, in- 
 sects, cats, dogs, and vermin may carry their burden of disease 
 organisms from the outlet of the sewer to your pantry and to your 
 table. Importance of sanitary latrines in camp life and in the trenches. 
 
 VI 
 
 MAN AS A CARRIER OF PATHOGENS— CowhwM^d 
 
 The Dissemination of Pathogenic Organisms by Way of the Genito- 
 urinary Discharges 
 
 The pathogenic organisms eliminated in this manner are: In 
 health: Pus organisms. In disease: Bacillus of typhoid fever; the 
 gonococcus; the treponema of syphilis; the bacillus of tuberculosis. 
 After certain diseases (after "recovery") : Gonococcus ; treponema of 
 syphilis; typhoid bacillus. 
 
 Methods of elimination. — Through urinary and genital discharges. 
 
 Methods of transmission. — By direct transmission: Contact; soiled 
 fingers; sexual intercourse. By indirect transmission: Contamination 
 of food and drink; articles in common use; animal and insect carriers. 
 
 Conditions favorable to transmission of disease by these routes: 
 Poor hygiene; bad sanitation; bad community morals; military tempta- 
 tions and practices. 
 
 Importance of the human being as a transmitter of disease by way 
 of his genito-urinary discharges: (a) importance of typhoid, (b) Im- 
 portance of gonorrhea and syphilis. It is impossible to fully appreciate 
 or state the importance of these venereal or so-called social diseases. 
 They are pandemic. No country in the world is free from them. This 
 has been true ever since the pandemic of the fifteenth century when 
 syphilis broke out in its most hideous form in all parts of Europe. Here 
 in New York City investigators tell us that a great many men and boys 
 visit prostitutes every day. Every man and every boy that makes this 
 his practice will sooner or later have syphilis, or gonorrhea, or both. 
 There must be hundreds of thousands of persons suifering with these 
 diseases in New York City. It has been shown in some armies in active 
 warfare that more men have been incapacitated by venereal disease than 
 by their human fighting enemies. The fighting strength of an army may 
 
 56 
 
be reduced 20 per cent, or 30 per cent, by venereal disease unless safe- 
 guarded. (Statement of the American Social Hygiene Association, sum- 
 mer of 1917.) The importance of gonorrhea and syphilis arises from the 
 following facts: (i) These diseases are universal. (2) They are associ- 
 ated with sin, shame, and crime. (3) They ruin the family and the home. 
 (4) They are passed on from the guilty to the innocent. (5) Gonorrhea 
 makes men sterile, unable to become fathers; women sterile, unable to 
 become mothers. (6) Syphilis destroys more young and unborn in- 
 fants than any other cause. (7) Gonorrhea makes more children 
 blind than any other cause. (8) Syphilis places more men, women, and 
 children in asylums for the insane and feeble-minded than any other 
 cause, with the possible exception of alcohol. (9) Syphilis cripples the 
 brain, the nerves, and the muscles. Gonorrhea cripples the joints. 
 Both these diseases deform and incapacitate men, women, and children, 
 mentally, morally, and physically. (10) They destroy individuals, ruin 
 homes, demoralize communities and defeat armies. 
 
 Don't Forget. — These diseases are caused by living organisms which 
 will grow only in human beings. These organisms are distributed from 
 one human being to another most commonly through contact with 
 genito-urinary excretions. The most common carrier of these diseases 
 is the prostitute and the man of loose morals. 
 
 VII 
 
 MAN AS A CARRIER OF PATHOGENS— CoMimwed 
 
 Dissemination of Pathogenic Organisms by Way of the Skin 
 
 The skin may mechanically carry certain organisms which live on 
 it or in it. The most important of these organisms are pus cocci; 
 streptococci; pathogenic contaminations from discharges from the eyes, 
 ears, nose, mouth, rectum, genito-urinary tract, and infected wounds of 
 the skin; and various parasitic insects. 
 
 Certain pathogens have been found in sweat, e.g., the typhoid 
 bacillus and the tubercle bacillus. Probably not common. 
 
 Certain organisms that live in the blood may be drawn through the 
 skin by blood-sucking insects. Some of these organisms and the insects 
 that carry them may be enumerated as follows: (a) The Plasmodium 
 of malaria. May be present without symptoms. Carried by the 
 anopheles mosquito. (&) The cause of dengue, carried by a mosquito, 
 (c) The cause of yellow fever, carried by a mosquito, {d) The filaria. 
 
 57 
 
There are several diseases caused by filaria. Most of them are unim- 
 portant; carried by a mosquito, (e) The trypanosome of sleeping 
 sickness, carried by certain biting flies. (/) The cause of typhus fever, 
 and the cause of trench fever, carried by the louse, (g) The bacillus 
 of bubonic plague, carried by fleas, (h) The unknown cause of Rocky 
 Mountain or spotted fever, carried by a tick. 
 
 Opportunities for blood-sucking insects to draw pathogens from the 
 blood, (o) Organisms present in the blood in health. Cases are re- 
 corded in which malaria parasites have been present with no symptoms. 
 Filaria usually infect with no apparent injury or discomfort to their 
 victims, (b) Organisms present in the blood in disease. In addition 
 to the pathogenic organisms noted above which locate themselves in the 
 blood there are periods during infection from many other organisms 
 during which they are present in the blood. Typhoid bacilli, tubercle 
 bacilli, treponema of syphilis, gonococci, and other organisms have been 
 demonstrated in the blood of patients, (c) Organisms that persist in 
 the blood after recovery of the patient. Probably few in number. The 
 malaria parasite may persist occasionally. 
 
 Methods of elimination. — The insects puncture the skin and suck 
 blood containing pathogenic organisms. These organisms may simply 
 remain alive in the puncturing apparatus or stomach of the blood- 
 sucking insect ; or they may pass through a cycle of development in the 
 insect. 
 
 Methods of dissemination. — The insect carrier either mechanically 
 contaminates the food of human beings, or injects the pathogenic 
 organisms it carries into the blood of the next person it bites, or de- 
 posits pathogens on the surface of the skin. 
 
 Conditions favorable to transmission.. — Congestion and poor personal 
 hygiene favor bed-bugs, lice, etc. Bad community sanitation favors 
 mosquitoes and flies. Poverty, because it is often accompanied by 
 vermin. Mexico, between 1893 and 1913, has a record of 56,719 cases 
 of typhus fever with 14,758 deaths. Army life during periods of active 
 service favorable to vermin, such as body lice. Typhus fever one of 
 the important diseases of armies. The Great War reported epidemics in 
 Turkey, Servia, Russia and other countries. Trench fever, a product 
 of the Great War. 
 
 Importance of human being as a disseminator of disease by way of 
 the skin. — Malaria : 2,000,000 cases a year in the United States ; 12,000 
 deaths. Yellow fever: In 1878 there were 132 United States towns 
 affected, with 15,000 deaths. The epidemic represented the loss of 
 $100,000,000. No epidemics here in recent years. Sleeping sickness has 
 devastated whole sections of Africa, destroying the natives by the 
 
 58 
 
thousand. Typhus fever at one time was the scourge of every army. 
 Bubonic plague is a common epidemic in the Orient, and is accompanied 
 by an enormous mortality. 
 
 VIII 
 
 MAN AS A CARRIER OF PATHOGENIC ORGANISMS- 
 SUMMARY 
 
 I. Man is a carrier of disease because of the pathogenic organisms 
 which he distributes about him in health and disease and after recovery 
 from disease by way of his (a) Respiratory tract, including his nose, 
 throat and mouth, (b) Eyes and ears, (c) Intestinal tract, (d) 
 Genito-urinary tract, (e) Skin. 
 
 II. These organisms may be transferred from one person to another 
 by (a) Direct contact ("contact infection"), (b) Secondary cari-iers, 
 such as infected sewage, food, water, air (droplet infection, dust in- 
 fection), dust, dirt and soil; articles and materials in common use 
 (that is, by more than one person at a time) ; insects and animals. 
 
 III. When we remember that only a few forms of pathogenic 
 organisms reproduce in nature and that all forms under favorable con- 
 ditions multiply freely in the human tissues, we are forced to the con- 
 clusion that man himself is the most important and the most dangerous 
 carrier of disease. In the great epidemics of history he has been the 
 agent that has disseminated such diseases as cholera, typhoid fever, 
 smallpox, yellow fever, syphilis, bubonic plague, and typhus among the 
 nations of the earth. 
 
 IX 
 
 INSECTS AS CARRIERS OF PATHOGENIC ORGANISMS 
 
 General Considerations 
 
 The insects that are known to carry the organisms that cause dis- 
 ease are flies, mosquitoes, fleas, ticks, lice, bedbugs, water-bugs (?), 
 cockroaches (?), kitchen ants (?). 
 
 In view of the fact that our knowledge of these carriers is only a 
 few years old, we are forced to admit that there may be other insect 
 carriers of whose relation to disease we are not at present aware. 
 
 The sources from which insects secure the pathogenic organisms 
 which they carry. 
 
 (a) In general, it may be said that these sources are the infected 
 
 59 
 
breeding-places and the infected feeding-places of insects. The sig- 
 nificant fact in this connection is that human beings and animals are 
 the final sources from which the pathogenic organisms come. These 
 human and animal sources which serve as feeding-places and breeding- 
 places for the insects that may carry the disease are the dead bodies of 
 diseased human beings and animals (uncommon) ; excretions from men 
 and animals; excretions from persons and animals while sick; excre- 
 tions from such sources during recovery; excretions from such sources 
 persisting for long periods of time after recovery, e.g., diphtheria, 
 cholera, typhoid fever; excretions from human beings and animals that 
 have not been sick, e.g., diphtheria, other possibilities; the living 
 human beings and animals on which biting and blood-sucking insects 
 feed while their blood contains pathogenic organisms; while the human 
 or animal is sick; during recovery; for long periods after recovery, in 
 some cases, with no evidence of any infection at any time. 
 
 {b) In particular it may be said that the organisms that cause dis- 
 ease may be picked up by insect carriers in the following common 
 breeding-places and feeding-places of those insects: Garbage which 
 may contain infectious human or animal discharges; the outlets of 
 sewers where human excretions are found; deposits of manure, drop- 
 pings from cattle, horses, swine, sheep, chickens, dogs, human beings, 
 and other animals; hospital and sick-room wastes; the bodies of dead 
 animals; offal from slaughter-houses, meat markets and food stores; 
 warm, dark, damp and dirty places in which human excretions may 
 have been left by human carriers ; the dead bodies of men and animals. 
 
 X 
 
 INSECTS AS CARRIERS OF PATHOGENS— Cowfwwerf 
 Ways in which Insects Carry Pathogenic Organisms 
 
 (a) Passively. — ^The insect that is a passive carrier of disease may 
 carry pathogenic organisms on the outer surface of its body, as in the 
 case of the house-fly that smears its body with the excretions from a 
 case of typhoid fever or pulmonary tuberculosis on which it feeds. It 
 may carry pathogenic organisms in its intestinal canal. The organisms 
 then may pass through and escape with the excretions as in the case 
 of the fly that feeds on the intestinal excretions of a typhoid patient 
 or the sputum of a case of pulmonary tuberculosis. 
 
 (b) Actively or Biologically. — ^The insect that is an active carrier 
 of disease becomes for a time necessary to the life of the pathogenic 
 
 60 
 
organism. We say then that the pathogenic organism is a parasite and 
 the insect is its host. An example of such an active carrier is the 
 anopheles mosquito, which may carry the pathogenic protozoan that 
 causes malaria. 
 
 The distribution of pathogenic organisms by insect carriers. The 
 insect carriers distribute the organisms of disease in the following 
 ways: (o) By wiping or shaking them off their bodies while in con- 
 tact with the food or drink of human beings, or while in contact with 
 articles in common use, or while in contact with human beings them- 
 selves. (6) By excreting them in their intestinal discharges. The 
 mosquito usually defecates when it stings. The organism that causes 
 trench fever is contained in the defections of the body louse. Various 
 pathogenic organisms have been found in the intestinal canal of the 
 mosquito. Tubercle bacilli have been found in the feces of flies, (c) 
 By squirting them into the blood of their victims when they sting them, 
 e.g., the anopheles mosquito and the tsetse fly. {d) And possibly, 
 through their remains, which may be smeared on the skin when the biting 
 insect is crushed by a blow from the victim. 
 
 XI 
 
 INSECTS AS CARRIERS OF PATHOGENS— Co^tiMMsd 
 
 Special Considerations 
 Insects that are known to be active or biological carriers of disease : 
 
 The Ticks: Dermacentor marginatus. — Carries Rocky Mountain 
 fever, or spotted fever. Bitter Root Valley, Colorado, mortality be- 
 tween 70 per cent, and 80 per cent. 
 
 Ornithodros moubata. — Carries "African tick fever," one of the 
 scourges of Africa. 
 
 The Biting Flies: The tsetse fly, glossina palpalis and glossina 
 morsitans. — Carry the trypanosome of sleeping sickness discovered by 
 Bruce and Castellani in 1902 ; an absolutely fatal disease ; has destroyed 
 hundreds of thousands of human beings in Africa. 
 
 Certain Mosquitoes (culex fatigans, and some others). — Carry 
 dengue or break-bone fever. In 1895, 50,000 out of a population of 
 65,000 had the disease in Charleston, South Carolina ; pain excruciating ; 
 no mortality in the otherwise strong. Parasite not certainly known. 
 
 6i 
 
Some evidence to show that it goes through a cycle in man and 
 another in the mosquito. 
 
 Anopheles culex, panoplites, and other mosquitoes. — Carry filaria 
 Bancroft!. (Manson, China, 1876.) Thirty to 40 per cent, of the 
 South Sea Islanders have filaria in their blood; 10 to 50 per cent, in 
 China. This disease, as a rule, causes no symptoms; occurs in tropical 
 and sub-tropical countries; adult worm lives in human tissue (the 
 lymphatics), a thread from three to four inches long. The embryos or 
 larvae swim free in the blood and are thus sucked up by the mosquito. 
 The embryo or larva undergoes a cycle of changes in the tissues of the 
 mosquito lasting fourteen days or longer, depending on the tempera- 
 ture. 
 
 Stegomyia calopis. — (Reed, Carroll, Agramonte and Lazear, Cuba, 
 in 1910.) Carries the leptospira icteroides, the cause of yellow fever. 
 The United States has lost more lives in the past from this disease than 
 any other country. In 1878 an epidemic affected 132 towns in our 
 Southern States with 15,000 deaths and a loss of over $100,000,000. 
 Texas, 1903, over i,oco cases. New Orleans, 1905, over 8,000 cases; 
 900 deaths. Since 1793 the United States has lost over 100,000 lives 
 through yellow fever. Has been a serious disease in army camps. Prob- 
 ably a cycle in man. A cycle of some sort in the mosquito. 
 
 Anopheles mosquito. — Carries the cause of malaria. (Major Ross, 
 1897.) Laveran found the cause. About 2,000,000 cases a year in the 
 United States; 12,000 deaths. Another very important disease in mili- 
 tary camps. A cycle of development in man, and a cycle in the mos- 
 quito. 
 
 Certain Fleas: The rat flea, lemopsylla cheopis. — Carries the bacillus 
 of bubonic plague. Sixth century, one-half of the people of the Roman 
 Empire died from the plague. Fourteenth century, 25,000,000 people 
 died of this disease in Europe; was called "The Black Death." Seven- 
 teenth century, 70,000 died in London alone. Oriental pandemic, 1895- 
 1910, and on; 7,500,000 deaths in India during a period of fifteen years. 
 (Martin, British Medical Journal, November, 191 1.) A disease of his- 
 torical importance in military campaigns. One of the serious concerns 
 of the camp and naval sanitarian. Bacillus pestis, transferred from rat 
 to rat and from rat to man by the rat flea which feeds on rats and on 
 human beings. Not necessarily an active carrier. 
 
 Insects that May Be Passive Carriers of Disease 
 Cockroaches. — Have been known to carry the bacillus of typhoid 
 fever. The intestinal parasites of certain cockroaches are known to 
 cause malignant growth in rats when eaten by them. 
 
 &2 
 
Water-bugs. — Nothing proven, but their habits are bad and their 
 opportunities are sufficient. 
 
 House Ants. — In a class with cockroaches. 
 
 Lice. — Known to have carried t3rphus fever. (Body lice; head lice, 
 probably.) Death-rate, 40 to 50 per cent. Known to have carried re- 
 lapsing fever. Death-rate about 4 per cent. Carriers also of trench 
 fever. 
 
 Bedbugs. — Known to have carried spirillum of relapsing fever and 
 bacillus of bubonic plague. The bacillus of tuberculosis has been found 
 in the intestinal canal of this insect. 
 
 The Gnat. — Carries the unknown cause of "Adriatic" or "Three-day 
 fever." Death rare. 
 
 Fleas. — Chiefly notorious as active carriers. (See above.) 
 
 Mosquitoes. — Chiefly notorious as active carriers. Have been found 
 with living tubercle bacilli in their intestines; also bacillus of leprosy. 
 
 The House-fly. — In July a single fly has been found to carry on 
 his body as few as 570 and as many as 4,400,000 bacteria; and in his 
 body (intestines) as few as 16,000 and as many as 28,000,000 bacteria. 
 
 The following common pathogenic bacteria have been found on the 
 house-fly or in his intestines or in his feces : Bacillus of typhoid fever ; 
 spirillum of cholera; bacillus of bubonic plague; the cause of summer 
 diarrhea; bacillus of tuberculosis. 
 
 The importance of the filthy habits of the house-fly in the home, 
 the community and specially in camp and trench life. One of the 
 lessons learned through our disgraceful experience in the Spanish- 
 American War taught us that the fly as a carrier of typhoid fever may be 
 more dangerous to a dirty, careless camp than a human fighting enemy. 
 
 XII 
 
 INSECTS AS CARRIERS OF PATHOGENS— Cow/ww^d 
 Prevention of Disease from Insect Carriers 
 
 Keep pathogens away from insects. Dispose of human and animal 
 excretions and discharges so they may not supply pathogens to insects 
 that might serve as mechanical carriers. Problems of sewage disposal 
 on the farm, in the village, or in the city, of special importance in mili- 
 tary camps. Use of cesspools, incinerators, septic tanks, sewage farms, 
 etc. Sewage discharges into rivers or large bodies of water. Camp 
 latrines and their care. Yard privies, their dangers and safeguards. 
 
 Keep human carriers away from insects that may serve as active 
 carriers. People with chronic or unsuspected malaria are sources 
 
 63 
 
from which the anophiles mosquito secures the pathogens of malaria in 
 the spring. The human serves as a reservoir through the preceding 
 winter. If all such cases were treated with anti-malarial measures 
 there would be no reappearance of malaria from such a source. People 
 sick with malaria, yellow fever, and other diseases carried by insects 
 should be kept away from such insects. If the insect — mosquito, biting 
 fly, flea, louse, etc. — has no opportunity to find a human carrier, it will 
 not become a carrier unless there is some other animal that serves as 
 a reservoir from which the insect may secure the pathogen. England 
 has no malaria now (1918), but England has many anopheles mos- 
 quitoes that would carry malaria if there were any humans with the 
 disease in England. Unless extraordinary care is taken, soldiers re- 
 turning from malarial countries will reintroduce the malarial parasite 
 into England after the Great War. 
 
 Keep animal carriers away from insects that might secure pathogens 
 from them. It is important to destroy infected rats, ground squirrels, 
 and other animals from which the flea secures the bacillus of bubonic 
 plague. The jungle animals of Africa are sources from which the 
 tsetse fly secures the trypanosome of sleeping sickness. If all such 
 infected animals were destroyed, there would be no more sleeping sickness. 
 
 Destroy the insects that may become carriers. Kill the adult insects. 
 Use fly-traps and fly poisons. Note the bat towers of the South for 
 the destruction of mosquitoes. Delousing equipment for army service. 
 
 Destroy the breeding-places of insects. Dispose of human and 
 animal excretions so they may not serve as breeding-places for insects. 
 Important consideration in building cesspools, privies, latrines, sewers, 
 barns, cow-yards, pig-pens, etc. Dispose of garbage, carcasses of 
 animals and decaying organic matter in which flies may breed. Drain 
 swamp land, dry up pools and other standing water so mosquitoes will 
 not breed there. 
 
 Use screens on windows and doors. "A yard of screen on the 
 window is better than a yard of crepe on the door." 
 
 64 
 
XIII 
 
 ANIMALS AS CARRIERS OF PATHOGENIC ORGANISMS 
 
 A. — General Considerations 
 
 The animals that are known to have carried disease to man are: 
 The dog, the cat, the cow, the horse, the sheep, the hog, the goat, the 
 rat, certain fish. 
 
 We must admit the possibiUty of there being other animal carriers 
 whose relation to disease is yet unknown. 
 
 The organisms which animals may carry: Pathogenic bacteria, 
 pathogenic protozoa, filtrate viruses, higher animal parasites. 
 
 The sources from which animal carriers may secure the pathogenic 
 organisms which they carry: 
 
 (o) Other animals and human beings, (i) By contact. (2) From 
 bites of animals. (3) From excretions. Through direct contact and 
 through contamination of food, water, droplets of saliva in the air 
 (from sneezing, coughing, etc.), dust, articles with which the animal 
 comes in contact. (4) Carniverous animals may become diseased 
 through the diseased flesh which they may eat. 
 
 (&) From insect carriers of disease. Remember that these insects 
 in turn have secured their burdens of pathogenic organisms from other 
 animals or men. They may be passive carriers. They may be active 
 carriers. 
 
 Ways in which animals may carry pathogenic organisms: (o) As 
 passive carriers; pathogenic organisms may be merely mechanically ad- 
 herent to the surface of the skin or in the hair, or these organisms 
 may be present in the alimentary tract, living on its surface or in the 
 food therein contained. (&) As active carriers, (i) The animal may 
 be sick with some specific disease. It may be a carrier during the 
 active phase of the disease. It may be a carrier while recovering. It 
 may be a carrier for a long while after recovery. (2) It may have 
 organisms of disease living in its tissues or on its external or internal 
 surfaces with no evidence of resulting disease. 
 
 Ways in which animals may distribute the pathogenic organisms 
 which they carry: (o) Through contact. Bodily contact with hair, 
 skin, or other parts of the animal which carries disease organisms, or 
 through biting, (fc) Through excretions. These excretions may be re- 
 leased by way of the respiratory tract, the digestive tract, the genito- 
 urinary tract, or open sores or infected wounds of the skin, eyes or 
 ears. These excretions may infect such secondary carriers as droplets 
 
 65 
 
in the air, dust, food and water of men and animals, articles in com- 
 mon use. 
 
 (c) By way of blood-sucking insects. 
 
 {d) By way of their dead bodies, (i) Insect carriers from such 
 sources. (2) Animal carriers from such sources. (3) Commercial 
 carriers of animal foods. Food animals may be diseased and their 
 diseased food products put on the market. Diseased meats. The 
 United States Department of Agriculture, through its Bureau of Animal 
 Industry, between 1906 and 19 12, condemned over 90,000 diseased 
 carcasses and over 4,250,000 parts of carcasses. Diseased milk and 
 milk products. 
 
 (e) Ptomaines. 
 
 XIV 
 
 ANIMALS AS CARRIERS OF PATHOGENS— Conftnu^rf 
 
 B. — Specific Considerations 
 
 I. Specific Carriers. — (a) The dog may carry skin diseases, respira- 
 tory diseases, intestinal diseases, hydrophobia, diphtheria (puppies). 
 One importance of the dog as a source of injury and as a carrier of 
 disease is shown jn the weekly bulletin of the Department of Health 
 for New York City, February 27, 1918, which reads in part as fol- 
 lows: 
 
 NUMBER OF DOG BITES KEPORTED AND THE CHARACTER OF THE 
 CONTROL OF THE ANIMALS 
 
 1915 1916 Decrease 
 
 Total dog bites reported 3,650 3,247 403 
 
 Dogs biting while leashed 404 358 82 
 
 Dogs biting while muzzled * 404 263 141 
 
 Dogs biting while leashed and muzzled 263 120 143 
 
 Not leashed or muzzled 2,334 2,333 1 
 
 Condition of control not known 209 163 46 
 
 Dogs biting (animals licensed) 1,254 
 
 Dogs biting (animals ownerless) 247 
 
 Vicious dogs destroyed (Sec. 10 S. C.) 796 
 
 Rabid dogs (Laboratory confirmation) 113 24 89 
 
 * Many dogs are only apparently muzzled. Recently the courts have decided that 
 an animal which can still bite is not muzzled within the meaning of the law. 
 
 66 
 
NUMBER OF DOG BITES REPORTED AND THE OCCURRENCES OF HUMAN AND 
 ANIMAL RABIES — 1907 TO 1918 INCLUSIVE 
 
 
 1907 
 
 1908 
 
 1909 
 
 1910 
 
 1911 
 
 1912 
 
 1913 
 
 1914 
 
 1915 
 
 1916 
 
 1917 
 
 1918 
 
 Total bites. 
 
 1,104 
 
 4,622 
 
 5,168 
 
 3,792 
 
 4,509 
 
 4,192 
 
 4,366 
 
 4,462 
 
 3,640 
 
 3,247 
 
 2,873 
 
 2,807 
 
 Cases of ra- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 bies (human) 
 
 28 
 
 16 
 
 7 
 
 7 
 
 11 
 
 6 
 
 8 
 
 8 
 
 1 
 
 1 
 
 1 
 
 
 
 Cases of ra- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 bies (anim- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 als, dogs).. 
 
 37 
 
 104 
 
 57 
 
 75 
 
 212 
 
 239 
 
 139 
 
 318 
 
 113 
 
 34 
 
 31 
 
 19 
 
 Deaths from 
 
 
 
 
 
 
 
 
 
 
 
 
 
 rabies (hu- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 man) 
 
 28 
 
 16 
 
 7 
 
 7 
 
 11 
 
 5 
 
 8 
 
 8 
 
 1 
 
 1 
 
 
 
 
 
 {b) The Cat. — (i) As an active carrier (diphtheria). (2) As a 
 passive carrier. The habits of the cat in the city and on the farm 
 give that animal many opportunities to secure infectious material and 
 to distribute it. 
 
 (c) The Cow. — Beef may contain (i) bladder- worms of tinea; 
 (2) various diseases of cattle, foot-and-mouth disease, bovine tuber- 
 culosis ; the bacteria of decomposition ; and their toxic products may be 
 communicated to man through "spoiled" beef. Milk may contain 
 organisms of disease that exist in the cow (mastitis, bovine tuberculosis, 
 etc.). Milk may be contaminated by the excretions from the cow, 
 other animals, or human beings. The clean milk supplied by the Straus 
 depots during recent summers in New York City reduced infant mor- 
 tality from milk-borne diseases. 
 
 (rf) The Horse. — Certain diseases of the horse are transmissible to 
 man. Flesh eaten in some countries. 
 
 (e) The Sheep. — (Anthrax). 
 
 (/) The Goo?.— (Malta fever). 
 
 {g) Certain Fish. — (Bladder- worm or tapeworm). 
 
 {h) Oysters. — (Typhoid, ptomaines). 
 
 (i) The Hog. — (Trichinae, bladder- worms). 
 
 (;") The Rat. — Bubonic plague and the flea, dwarf tapeworm, other 
 possibilities. 
 
 2. Defenses Against Such Carriers. — (a) Prevent the infection of 
 animals. Improve their sanitaiy and hygienic surroundings. Keep 
 human and animal excretions from reaching them. Keep carriers of 
 disease from them, such as rabid animals, biting insects, and human 
 carriers. 
 
 (6) Prevent the infection of humans by animals, (i) Destroy dis- 
 eased animals or effectively isolate them until cured. Destroy rats. 
 
 (2) Keep animal carriers away from humans. Danger from pets. 
 
 (3) Keep animal excretions away from human food, drink, and articles 
 in common use. (4) Inspect and condemn all diseased animal foods or 
 animal products. Federal Meat Inspection, United States Department of 
 
 67 
 
Agriculture, Bureau of Animal Industry, data for last six years, endinj 
 September 23, 1912 : Animals inspected at slaughter, over 321,000,000 
 carcasses condemned, over 90,000; parts of carcasses condemned, ovei 
 4,250,000; reinspection of meat and meat food products in their various 
 preparations, over 37,000,000,000 pounds; condemned on reinspection, 
 over 140,000,000 pounds; exported under certificate, 7,000,000 pounds, 
 (S) Institute rigid sanitary measures in establishments producing animal 
 foods — dairies, packing-houses, meat markets, stockyards. (6) In- 
 stitute and enforce intra-state inspection. 
 
 XV 
 
 THE DISSEMINATION OF PATHOGENS THROUGH 
 
 CONTACT 
 
 A. The most common and the most important contact diseases are 
 the venereal diseases. These diseases may be carried indirectly by sec- 
 ondary carriers, but their most common conveyance is by direct in- 
 timate contact between the human carrier and his victim. This intimate 
 contact is secured under various circumstances, such as: 
 
 (i) Between husband and wife. — The numerous natural honorable 
 and sacred intimacies that characterize the normal relationship between 
 husband and wife make it most difficult for either one to acquire 
 venereal disease without transferring such disease to the other. 
 
 (2) Between parent and child. — (a) The contact between the father 
 and his children is not so intimate as the contact between the mother 
 and her children. If, however, the father has venereal disease, the 
 mother can hardly escape, so the children will be exposed to maternal 
 infection as well, {b) The infant of a gonorrheal or syphilitic mother 
 becomes infected either before birth or at birth, (c) If the mother 
 becomes infected after the birth of her children she may transmit her 
 disease to her children through such intimacies as nursing, feeding, 
 kissing, bathing, or fondling them. Remember, such infection, if it is 
 with the treponema of syphilis, frequently means death to the unborn 
 babe or some physical or mental disability disqualifying and limiting 
 it for life ; if it is with the coccus of gonorrhea, it often means a blind 
 baby — a life without eyes. 
 
 (3) Between members of the same family in which one member has 
 been infected. — The opportunity indicated above as existing between 
 parents and children exists also between sons and daughters, young 
 and old. The opportunities for such intimate contact in the home are 
 commonly present and hard to avoid, even when such avoidance be- 
 
 68 
 
comes seriously necessary. It is, therefore, commonly true that 
 syphilis and gonorrhea are transferred by contact from one infected 
 member of the family to some or all of the remaining members of the 
 family. This transfer of infection is inevitable between husband and 
 wife after one of the two becomes infected and most diflficult to avoid 
 between infected parent and child, or between an infected brother or 
 sister and the other children in the family. 
 
 (4) Between the physician, the nurse and the infected patient. — 
 Many cases are on record in which the physician or nurse has become 
 infected while operating upon or caring for a syphilitic or a gonorrheal 
 patient. 
 
 (5) Between the carrier of venereal disease and his victim under 
 any condition of intimate contact, as in (a) Handling, fondling, kissing, 
 etc. (6) The most common and mosMimportant contact in this con- 
 nection is that which occurs in illegitimate sexual intercourse. Every 
 loose man and every loose woman sooner or later becomes a carrier 
 of one or all of the venereal diseases. (Remember, syphilis is caused 
 by the treponema pallidum; gonorrhea is caused by the gonococcus; 
 and chancroid is caused by a specific bacillus.) Loose moral characters 
 of this sort are found in all parts of the world, in every community. 
 It is not possible to estimate accurately the number of human carriers of 
 syphilis and gonorrhea in New York City. Probably five percent of the 
 population has syphilis, and a very much larger percent gonorrhea. 
 
 The venereal diseases are the most common diseases of mankind 
 excepting possibly tuberculosis. These diseases are mentally, morally 
 and physically destructive. They are distributed by contact infection. 
 The common and important carriers are the men and women who re- 
 sort to illicit, promiscuous sexual intercourse. The man or woman that 
 adopts such a practice must sooner or later suffer the effects of one or 
 all of these diseases and will in all probability be responsible for con- 
 veying such disease to some other human being, who will thus become 
 the victim — ^innocent or guilty — of his passion. 
 
 69 
 
XVI 
 
 THE DISSEMINATION OF PATHOGENS THROUGH 
 
 CONTACT— Continued 
 
 B. The pathogens that are excreted through the respiratory tract 
 are distributed most frequently through contact infection. These 
 pathogens cause such disease as measles, the common cold, diphtheria, 
 tonsilitis, scarlet fever, mumps, meningitis, poliomyelitis, leprosy and 
 whooping-cough. Others might be added. (2) The "contact" necessary 
 for infection from such sources- must be intimate. It must result in the 
 passage of pathogenic organisms from the carrier to the "victim." This 
 may be accomplished through fondling, kissing, biting, or scratching; 
 from passing a pipe from one mouth to another ; through chewing gum, 
 or biting the partially eaten apple of another person; through testing 
 the baby's milk by sucking a sample through the nipple of the baby's 
 bottle; through chewing the baby's food before giving it to the baby; 
 through a bite from another man's plug of tobacco; through drinking 
 from another's cup ; through breathing air into which some one has just 
 sneezed, coughed, or otherwise sprayed his infected respiratory excretions. 
 Opportunities for such infections are specially present in congested 
 subway travel, movie shows, and in the life of the average infant and 
 young child. (Droplet infection.) 
 
 C. More rare are those contact infections in which the individual 
 picks up specific organisms of disease through handling persons who 
 are carriers of disease (sick or well), (i) Doctors and nurses not in- 
 frequently become infected in this manner. Such infections are not 
 confined to any group or class of human disease carriers. The physician 
 or nurse may (and often do) become infected through contact with 
 blood or tissue juices during surgical operations. They may come into 
 intimate contact through the administration of medicine; bathing the 
 patient ; dressing a wound ; or any other of the very necessary and very 
 important offices which they perform. Contact infection under such 
 circumstances is due to carelessness or accident. The intelligent 
 physician and nurse know these dangers and how to avoid them. 
 (2) The same variety of opportunities for contact infection occurs in 
 homes in which some member of the family is sick, especially if the 
 family habits of personal and domestic hygiene are not good. 
 
 D. Contact infection may occur in large crowds where people are 
 brought close together, as in congested subway trains, on the ferry- 
 
boat, in the. street-car, on the elevated train, at the theatre, at the 
 moving-picture show, in the class-room, and so on. Under such cir- 
 cumstances droplet infection is probably the most common variety of 
 contact infection. 
 
 E. The diseases of the intestinal tract are usually not transferred 
 by direct contact, although such conveyance does take place. The soiled 
 fingers of the carrier may come into intimate contact with his victim 
 and thus distribute to him the bacillus of typhoid fever or some other 
 cause of intestinal disease. It is said that 4 per cent, of all typhoid 
 lever cases that recover become chronic carriers. The majority of 
 these are fecal carriers. The fingers of typhoid -carriers or the carrier 
 of any other disease organism are always dangerous and call for most 
 careful hygiene. We have records of a number of men and women 
 who have distributed typhoid fever in this manner for many years — as 
 high as fifty-five years — after they have had that disease. 
 
 F. Summary. — Contact infection is the common mode of conveyance 
 of the causes of venereal and respiratory diseases. It is less commonly 
 the mode of conveyance of other diseases. Such conveyance may occur 
 during the acute stages of these diseases, and under conditions of ap- 
 parent health of the individual long after such diseases are "cured." 
 These diseases may be avoided for the most part by such habits of per- 
 sonal, domestic and community hygiene as will eliminate or prevent con- 
 tact infection. The individual and the community may be defended 
 from contact infection by having no infected contacts. Personal cleanli- 
 ness is a very important protective measure in relation to contact in- 
 fection. 
 
 XVII 
 
 DISSEMINATION OF PATHOGENIC ORGANISMS THROUGH 
 SECONDARY CARRIERS 
 
 Air as a Carrier of Disease 
 
 (o) Disease germs may be blown through the air by the wind, (i) 
 The various human and animal excretions that are exposed to air may 
 contain pathogenic organisms. These organisms may remain alive for 
 hours or days or weeks, depending upon their protection from drying. 
 If air currents set particles of these excretions in motion before the 
 pathogens are dead these currents may serve as carriers of disease. 
 Flakes of sputum, dejecta, urine-soaked dust, and discharges from the 
 
 71 
 
sick-room may qualify for such possibilities. Fortunately such possibili- 
 ties are opposed by the influence of sunlight, sun-heat and dry air, all 
 of which destroy the lives of most pathogens, after a time. (2) Recent 
 experiments indicate that organisms of very small size may not be sub- 
 ject to the ordinary laws of gravity but rather to the laws that govern 
 gases in space. If this is true, the aerial transmission of disease germs 
 of very small size may be much like the transmission of odors of gases 
 in the air. (a) There are a number of diseases whose specific causes 
 are so small as to be able to pass through the pores of the finest 
 porcelain filters. They are so small that they are beyond the range of 
 our most powerful microscopes. These "filtrate viruses" or "ultra- 
 microscopic viruses" may be small enough to escape the laws of 
 gravity which attract heavier bodies. They may obey the laws that 
 govern gases in space, (b) There are a number of human diseases the 
 causes of which are not known. These causes may be filterable. We 
 have no means of testing the filtrates of some of these diseases. It is 
 possible that the specific causes of those diseases may be small enough 
 to fall into this class, (c) It is certain that aerial transmission of the 
 sort that characterizes the movements of gases in space is not charac- 
 teristic of such diseases as typhoid fever, tuberculosis, and diphtheria. 
 The organisms that cause those diseases are relatively heavy, (d) We 
 can not be certain that the causes of smallpox, infantile paralysis and 
 scarlet fever may not be spread in this manner under exceptional and 
 favorable circumstances. 
 
 Dust as a Carrier of Disease 
 
 Dust may be a carrier of disease only in case pathogens in dust are 
 carried to human beings while they are still alive. Sunlight, sun-heat, 
 dry air and other adversities kill most pathogens in minutes, hours or 
 days. The spores of bacteria are very much more resistant than bac- 
 teria themselves. Tubercle bacilli in sputum are protected by the vicid 
 mucous around them. Drying may then be slow. Diphtheria bacilU in 
 membranes from the throat may remain alive for some weeks. Patho- 
 genic organisms in fecal masses will remain alive for short periods of 
 time. Pathogens from any source that are excreted in dark, damp, 
 and dirty places may become parts of dust which are not thoroughly 
 dry. They may thus escape death for short periods. The bacillus of 
 tuberculosis, the bacillus of typhoid fever, the bacillus of diphtheria, 
 and the streptococci of sore throat have been found in dust. Spores 
 of various pathogenic bacteria are found in dust. Dust may be carried 
 by the wind to human beings, to their food, or their drink. Dirty hands 
 
 72 
 
and dirty utensils in common use may be infected under unusual cir- 
 cumstances. May explain the fact that children are more likely to 
 have various diseases than adults. 
 
 XVIII 
 
 DISSEMINATION OF PATHOGENS THROUGH SECONDARY 
 
 CARRIERS— Continued 
 
 Water as a Carrier of Disease 
 
 (a) Families that secure their water from wells are safe from 
 water-borne diseases from that source, provided the drainage into the 
 well is pure. It sometimes happens that the yard privy, the cesspool, or 
 the barnyard drains into the family well, (fe) It not uncommonly 
 happens that communities construct water systems that draw the water 
 supply from the same lake or river into which their community sewage 
 is emptied. Under such circumstances typhoid fever is common. 
 Various other diseases, notably cholera, are carried in the same way. 
 Every community that has spent its money wisely in securing pure 
 water has succeeded in reducing the amount of preventable sickness 
 and the number of avoidable deaths among its citizens. This reduction 
 is not only in typhoid fever, but in various other diseases, (c) Im- 
 portance of pure water in active army life, {d) Fortunately, most of 
 the pathogenic organisms are soon destroyed in water; unfortunately, 
 nearly all pathogens will live for short periods in water. These short 
 periods may be long enough to enable water-borne pathogens to find 
 human victims. 
 
 Food as a Carrier of Disease 
 
 (a) Sources of disease organisms and agents in foods. The food 
 itself may be diseased and thus act as a carrier of that disease to its 
 human consumer. Tapeworms may come from eating raw or in- 
 suificiently cooked beef, pork, or fish infected with the cysterci of tape- 
 worms. Cattle may have tuberculosis, anthrax, or other disease. Food 
 may be infected while in the hands of the producer, the shipper, the 
 transportation agent, the wholesaler, the retailer, or the consumer. 
 Food may be adulterated by the manufacturer or dealer who uses 
 poisonous preservatives or other injurious adulterants. Food may de- 
 compose and thus contain toxic products of bacterial action. 
 
 (b) Decomposed foods. The fermentation of carbohydrate foods 
 
 73 
 
leads to the formation of acids, alcohol, carbon dioxide, water, etc. 
 These end products are not so poisonous as some of the intermediate 
 products of putrefaction. The putrefaction of nitrogenous foods, when 
 complete, leads to the formation of simple non-poisonous compounds such 
 as ammonia, nitrates, carbon dioxide, water, etc. The intermediate 
 cleavage products of putrefaction are poisonous. Some of them are 
 very poisonous. There are many kinds of fermentation and many kinds 
 of putrefaction. "Each particular micro-organism breaks down organic 
 matter in a specific and limited sense." (Rosenau.) Ptomaine poison- 
 ing. "Ptomaines are secondary cleavage products of protein putrefac- 
 tion." The poisonous stages of decomposition of such foods as milk, 
 cheese, and meat occur when putrefaction has not been completed. 
 Cheese is most poisonous — if poisonous at all — when it is "green." 
 (Rosenau.) "Meat, if toxic, is most poisonous from the fourth to the 
 eleventh day of putrefaction." Other foods follow the same rule. The 
 important ptomaines are sepsin, cadaverin and putrescin. "... Most, 
 if not all, cases of so-called ptomaine poisoning are nothing more nor 
 less than acute infections with B. paratyphosus, B. enteritidis, B. 
 cholerae suis and other micro-organisms belonging to this group." 
 (Rosenau.) 
 
 XIX 
 
 DISSEMINATION OF PATHOGENS THROUGH SECONDARY 
 
 CARRIERS— Continued 
 
 Milk as a Carrier of Disease 
 
 "Milk is responsible for more sickness and deaths than perhaps all 
 other foods combined, because bacteria grow well in milk; therefore, a 
 very slight infection may produce widespread and serious results. Of 
 all our foodstuffs, milk is the most difficult to obtain, handle, trans- 
 port and deliver in a clean, fresh and satisfactory condition. It is the 
 most readily decomposable of all our foods. Milk is the only standard 
 article of diet obtained from animal sources consumed in its raw 
 state." (Rosenau.) 
 
 Dirty milk. The sediment in the bottom of the milk jar or in the 
 bottom of your glass of milk is practically always cow manure. 
 
 The organisms of certain bovine diseases will pass through the 
 healthy udder. This is true of the ultra-microscopic virus of foot-and- 
 mouth disease, the virus of malta fever, and the virus of milk sickness. 
 
 The organisms present in the diseased udder will likely be present in 
 the milk. Bovine tuberculosis ; mastitis. 
 
 74 
 
Milk may be infected through contaminations introduced in handling, 
 such as typhoid fever, scarlet fever, diphtheria, human tuberculosis. 
 
 "The diseases most commonly conveyed through milk are tuber- 
 culosis, typhoid fever, diphtheria, scarlet fever, septic sore throat, malta 
 fever, foot-and-mouth disease, and milk sickness ; also some of the sum- 
 mer complaints of children and the diarrheal and dysenteric diseases 
 of adults. ..." (Rosenau.) 
 
 Raw milk is not safe milk. The safest milk is the milk that is 
 pasteurized in the bottle. 
 
 XX 
 
 DISSEMINATION OF PATHOGENS THROUGH SECONDARY 
 
 CARRIERS— Cow/wwed 
 
 Meat as a Carrier of Disease 
 
 (a) Ptomaine poisoning, poisoning from spoiled meats, ptomaine 
 produced by the bacillus botulinus, ptomaine produced by the bacillus 
 proteus vulgaris and the bacillus coli communis. 
 
 (b) Infections carried by meat, sources of these infections, disease 
 of the animal, infection of the meat after slaughter of the animal, 
 varieties of infections carried, (i) Various forms of "meat poisoning." 
 With bacillus enteritidis and bacillus cholera suis. (2) Paratyphoid 
 fever. The paratyphoid bacillus multiplies in meat. (3) Trichinosis. 
 Caused by a round worm that lives its life cycle in the hog or rat. Is 
 communicated to man in raw and insufficiently cooked pork. (4) The 
 pork or measly tapeworm (toenia solium). Conveyed to man by eating 
 raw or insufficiently cooked pork containing the bladder-worms 
 (cysterci) of the pork tapeworm. The cysterci develop in hogs whose 
 food has been contaminated by human feces containing the eggs of the 
 pork tapeworm. These cysterci may develop also in man if his food 
 contains the eggs of the pork tapeworm. This is a very serious dis- 
 ease. (5) The beef tapeworm (toenia saginata). Conveyed to man by 
 eating raw or insufficiently cooked beef containing the bladder-worm 
 (cysterus) of the beef tapeworm. 
 
 Fish as a Carrier of Disease 
 
 Some fish are always poisonous. Some fish are poisonous only dur- 
 ing spawning season. Fish decompose rapidly. Ptomaine poisoning is 
 relatively common from this source. Fish are common victims of bac- 
 terial disease. Human poisoning from this source is not uncommon. 
 Fish tapeworm (Dibothriocephalus latus). Human beings become in- 
 
 75 
 
fected with fish tapeworm by eating fish containing the bladder-worms 
 (cysterci) of fish tapeworms. Same thing occurs in dogs, cats, and 
 foxes that eat infected fish. Fish become infected in streams polluted 
 by human excretions containing the eggs of fish tapeworms. 
 
 Shellfish as Carriers of Disease 
 
 Ptomaines appear as secondary cleavage products of decomposition. 
 Poisoning from shellfish is not uncommon. Typhoid fever and cholera 
 have been carried by oysters. 
 
 Plant Foods as Carriers of Disease 
 
 Mushroom poisoning. Some species of mushrooms are edible; 
 others are poisonous. Potato poisoning. Potatoes contain small 
 amounts of solanin. Very rarely this poison is present in sufficient 
 amount to cause trouble. Rice, when eaten without the bran or peri- 
 carp, may cause beri-beri, a common disease in Japan and other 
 tropical and sub-tropical countries. A disease due to a deficiency of 
 vitamin. Over-milled corn seems to be the cause, or a cause, of 
 pellagra, a common and serious disease in Europe and America. Due 
 to vitamin deficiency. Green foods, such as lettuce, radishes, celery, 
 watercress, when eaten raw, may carry typhoid fever, cholera, dysen- 
 tery, hookworm, and variovis other animal and vegetable parasites 
 which have been brought to those vegetable foods in sewage or in 
 water contaminated with sewage. 
 
 It is evident that the greater and more important part of the dis- 
 eases carried by air, dust, water, or food, comes originally from human 
 sources. These various agents are infected usually through human ex- 
 cretions. Our problem of self-protection here is concerned with keep- 
 ing human excretions from such carriers. 
 
 SUMMARY 
 
 The human being is the most important carrier of disease. He dis- 
 tributes pathogens by way of his excretions — respiratory, fecal and 
 genito-urinary — in health and in disease. His circulation may be a 
 "reservoir" of pathogens for blood-sucking insects while he is sick or 
 when he is apparently well. 
 
 He may transmit the organisms of disease by direct contact or 
 through the infection of animals or insects or through the infection 
 of articles of common use. The most important relationships are 
 secured through "droplet infection" and spitting; illicit sexual inter- 
 course, dirty fingers, and careless disposal of excretions. 
 
 76 
 
The most important insect carriers are the fly, mosquito, flea and 
 louse. 
 
 The most important animal carriers are the cow (by way of her 
 milk), the rat, the dog. 
 
 The most important food carriers are milk and infected (and de- 
 composing) meats. 
 
 Unclean, impure water is a common and dangerous carrier the 
 world over. 
 
 The disease carrier is a serious menace in all types of communities — 
 civic, military or institutional. Community health must be protected 
 against persons that are sick; careless humans that "hawk" and cough 
 and spit without regard for others; men of loose morals; prostitutes; 
 post-febrile carriers (particularly after typhoid fever) ; people that 
 practice bad hygiene; impure milk, bad water, the fly, the mosquito, the 
 flea, the louse, the rat, the dog. 
 
 Cleanliness is the first law of health. 
 
 n 
 
GENERAL HYGIENE 
 
 PART THREE 
 THE CONTRIBUTORY CAUSES OF POOR HEALTH 
 
 79 
 
INTRODUCTORY 
 
 When your city, your State, or your country calls upon you for 
 service, either in peace or in war, you young men of the College of the 
 City of New York must be ready. At the time of the first draft of 
 the Great War, 30 per cent, of the young men of America were found 
 unfit for military service. Our regular army records indicated that 
 only one applicant for enlistment out of every seven was physically fit. 
 The figures of the Life Extension Institute indicate that 50 per cent, 
 of the population of our country are not in sound health. 
 
 A very large part of this health deficiency is preventable and avoid- 
 able. It is a grim indictment of the health training of our nation. 
 During the period from 1916 to 1919, thirteen States passed laws for the 
 compulsory physical training of their future citizens. There is a power- 
 ful and growing demand that we stop wasting the lives of our citizens 
 and conserve them for service in peace or in war. 
 
 What are you doing to conserve your vigor and to acquire a re- 
 source in health that will enable you to serve your country and your- 
 self long and well? 
 
 Are you establishing habits of health information; habits of bodily 
 care and repair; habits of health protection; and habits of constructive 
 hygiene that will make of you the man you ought to be? Are you 
 getting ready? or will you go into the discard? 
 
 Our health talks of this term are concerned with some of the in- 
 fluences that make it easier for you to lose your health and harder to 
 get it back. Your policy of health control should help you protect 
 yourself against these contributory causes of disease. You can use this 
 information for your better training for citizenship; for your happier 
 life; and for your greater personal success in whatever you undertake. 
 
 81 
 
II 
 
 THE CONTRIBUTORY CAUSES OF DISEASE 
 
 The Contributory Causes of Disease are Those Influences That Make 
 it Easier for Human Beings to Become Sick and Harder for 
 Them to Get Well. 
 
 Any influence that favors the production, distribution or pathogenic 
 activities of pathogenic organisms and their carriers may be a con- 
 tributory cause of disease. 
 
 Any influence that tends to interfere with or to break down our 
 environmental defenses against poor health and disease is a contributory 
 cause of disease. 
 
 Any influence that tends to lessen individual human resistance to dis- 
 ease is a contributory cause of poor health. 
 
 Influences That Favor the Production, Distribution or Pathogenic 
 Activity of Pathogenic Organisms and Their Carriers 
 
 The Influence of Seasons. — (i) Respiratory diseases are more com- 
 mon in the winter season than in the summer. This may be due to the 
 fact that human beings are more likely to stay in the house and are 
 therefore in closer and more intimate contact with each other during 
 cold weather. This favors the distribution of disease germs. (2) The 
 intestinal diseases are more common in summer. The warm tempera- 
 ture prolongs the life of pathogenic organisms in infected food or 
 water. Thus pathogens that reproduce in nature multiply more pro- 
 fusely in warm weather than in cold weather. (3) The insect carriers 
 of disease breed more abundantly in the summer months; for example: 
 (o) Mosquito life is most favored in the warm,~moist seasons of the 
 year. Mosquitoes are known to carry various diseases, chiefly malaria 
 and yellow fever, (fc) Flies are produced abundantly throughout the 
 summer. They carry the specific causes of various diseases, as typhoid 
 fever and summer diarrhea. (4) Spring rains and spring thaws are 
 seasonal occurrences in some countries. These seasonal freshets often 
 wash surface accumulations into the reservoirs and other sources of 
 water for human consumption, thus distributing disease germs to humans. 
 Under such circumstances there are characteristic epidemics of various 
 diseases (notably typhoid), the occurrence of which is very greatly 
 reduced through scientific protection of the water supply. Each city that 
 has spent its money wisely for pure drinking water has reduced the 
 occurrence of disease among its citizens. 
 
 The Influence of Climate. — (i) Tropical and sub-tropical climates 
 
 82 
 
favor the growth and vitality of many pathogenic organisms that are 
 not commonly found in cold or temperate climates; for instance: (a) 
 The hookworm is found between 36 degrees north latitude and 30 de- 
 grees south latitude in a belt that goes around the world. In this belt 
 There are over 800,000,000 people with hookworm disease. (fc) 
 Tropical malaria is not commonly found in temperate climates. The 
 parasite will grow only in warm climates. (2) Those climates that 
 furnish warm, moist conditions offer influences under which pathogenic 
 organisms and disease carriers are most likely either to multiply 
 abundantly or at least to remain alive and active for longer periods of 
 time. 
 
 Geographical Location. — (i) Rocky Mountain spotted fever (tick 
 fever) seems to be confined to the Rocky Mountains and high plateaus 
 of some of our Western States. This limitation of the disease may be 
 due to the fact that the tick which carries the disease has not become 
 infected in other localities or that it has not itself entered others. The 
 climatic conditions present in this geographical location may then have 
 no bearing on the occurrence of this disease. (2) The sleeping sick- 
 ness which has destroyed so many human lives in Africa may be con- 
 fined to that country by the same sort of influence that confines spotted 
 fever to some of our Western States. There are biting flies in various 
 parts of the world which could possibly carry the trypanosome of 
 sleeping sickness quite as easily as the tsetse fly of Africa if they 
 had the opportunity. There may be no climatic significance in the 
 geographical location of this disease. 
 
 Ill 
 THE CONTRIBUTORY CAUSES OF DISEASE— CoMimweJ 
 
 Influences That Favor the Production, Distribution or Pathogenic 
 Activities of Pathogenic Organisms or Their Carriers May Be 
 Contributory Causes of Disease. — {Continued) 
 
 Influence of Soil and Drainage. — (i) In warm climates or in warm 
 seasons stagnant surface water becomes a breeding-place for various 
 forms of life, (o) Insect carriers of disease, such as mosquitoes, 
 flourish under such conditions. Various parts of the United States are 
 noted for malaria simply because those localities offer excellent breed- 
 ing facilities for the malarial mosquito. (&) If this stagnant water is 
 infected with sewage containing pathogenic organisms those organisms 
 are likely to remain viable for some time. Fortunately, the competition 
 between pathogenic and non-pathogenic bacteria under such circum- 
 
 83 
 
stances usually results in a victory for the non-pathogenic forms. 
 There is danger, however, that the victory may be delayed too long. 
 (2) Streams that flow rapidly are not such favorable breeding-places 
 for insects as are those slowly moving, swampy streams that pass 
 through more level country. (3) Spring freshets and spring thaws 
 sometimes wash surface sewage into the water supply of cities. This 
 is a common contributory cause of typhoid fever. (4) Sub-soil drain- 
 age sometimes carries sewage from cesspools and latrines into wells of 
 drinking water. Such drainage contributes to the spread of such dis- 
 eases as typhoid fever and cholera. 
 
 Influence of Weather. — (i) Lack of sunshine and excess of fog 
 contribute to the increase of disease. The organisms of disease live 
 longer under such circumstances. More people die in London during 
 foggy periods than during clear periods. Such weather probably has a 
 depressing effect on human vitality. (2) High and low temperatures 
 are contributory causes of disease (climatic, seasonal, geographical), 
 (o) Increased morbidity and mortality from intestinal diseases are 
 common in the hot months, {b) Increased morbidity and mortality 
 from respiratory diseases occur in the cold months. 
 
 IV 
 
 THE CONTRIBUTORY CAUSES OF DISEASE— CowhwM^rf 
 
 Influences That Favor the Production, Distribution or Pathogenic 
 Activities of Pathogenic Organisms or Their Carriers May Be 
 Contributory Causes of Disease. — {Continued) 
 
 Travel, Transportation, Immigration, Commerce and War have fre- 
 quently been contributory causes of disease because they have served as 
 agents for the dissemination of disease organisms. 
 
 The crusaders brought syphilis back to Europe on their return from 
 the Orient. The Spaniards brought smallpox to Mexico. Cholera has 
 been carried to Europe by the caravans from Asia, and from country 
 to country by steamships. The rat carriers of bubonic plague have 
 been carried by ocean vessels from port to port. The same story is 
 true of yellow fever, malaria, measles and various other diseases. 
 
 Congestion, whether in a crowded country home or a crowded city 
 tenement, may be a contributory cause of disease. People communicate 
 their diseases to each other with greater ease under such conditions. 
 Those cities that have spent their money wisely and have enforced in- 
 telligent laws for public health have been able to secure (purchase) 
 
 84 
 
better health for their citizens than can be secured under ordinary cir- 
 cumstances in the country or in cities that have made no such wise in- 
 vestments. (2) Those cities that have not exercised a wise control 
 over their congested districts have paid the penalty in disease and death. 
 
 The report of the health officer of Washington City, 1910, compar- 
 ing death-rates in alley homes with death-rates in street homes, reads 
 as follows: 
 
 Age Death Rate Death Rate 
 
 in Alleys in Streets 
 
 All ages 30.09 17.56 
 
 Under one year 373.49 158.66 
 
 One to four years 30.82 16.75 
 
 Five to twenty years 7.84 5.25 
 
 Over twenty years 27.05 18.08 
 
 Cause OF Death Among Whites Among Negroes 
 
 Alleys Streets Alleys Streets 
 
 Pneumonia 310.9 117.9 432.8 188.1 
 
 Tuberculosis 186.5 121.2 621.3 433.7 
 
 Whooping-cough 62.2 5.3 21.9 15.5 
 
 Diarrhea, under two years of age 62.2 36.8 321.6 137.8 
 
 These contributory causes of disease must be given serious consider- 
 ation in any community plan for community defense against disease. 
 They are influences which the intelligent man must take into account in 
 his plans for the defense of his family and himself against disease. 
 
 V 
 
 THE CONTRIBUTORY CAUSES OF DISEASE— Continued 
 
 The Influences That Tend to Interfere with or Break Down Our 
 Environmental Defenses Against Poor Health and Disease 
 
 War as an influence that interferes with or breaks down our en- 
 vironmental defense against poor health and disease. Until very re- 
 cently war meant more deaths from disease than from guns and cannon. 
 History teaches us that the armies of the past have been devastated by 
 smallpox, syphilis, cholera, typhus, typhoid fever, malaria, and yellow 
 fever. This is due to the fact that military tactics have been slow to 
 include military hygiene. The army created all the favorable condi- 
 tions for the spread of disease without establishing any effective de- 
 fenses against disease. 
 
 In the Napoleonic wars the armies under that great general lost 
 400,000 men from gunfire and wounds, and 600,000 from disease. The 
 Union Army in our Civil War lost 110,000 men from battle and 224,000 
 
 85 
 
from disease. The Spanish- American War (1898) produced a mor- 
 tality in the United States army of seven times as many deaths from 
 disease as from battle. One-third of the entire American force en- 
 gaged were infected by typhoid fever. 
 
 But the armies of history not only suffered enormously from disease 
 themselves, they also carried disease to the civilian population with 
 which they came into contact. In 1813, a war year, the death-rate in 
 Leipzig was trebled. In Paris, in 1814, the defeated army of Napoleon 
 brought to that city an increase in its civilian death-rate from 19,000 
 to 26,000, exclusive of soldiers. In 1870 Germany was almost free 
 from smallpox. In 1871 thousands of French prisoners were taken into 
 Germany. At that time France was overrun with smallpox. These 
 prisoners carried the disease into Germany and between 1870 and '73 
 over 120,000 deaths from smallpox took place in Germany. 
 
 Within the last few years, military and marine hygiene have come 
 to occupy places of the highest importance in the management of armies 
 and navies. As a result our military defenses against disease are now 
 often better than our civilian defenses. It was reported at the annual 
 meeting of the American Public Health Association, 1917, that the 
 occurrence of venereal disease in the regular American Army was less 
 than in the civilian population. 
 
 The very greatest care must be taken to protect our armies and our 
 civilian populations from the diseases that are favored and distributed 
 by war. This care is critically important at the time of and imme- 
 diately after war. Typhoid fever, typhus fever, gonorrhea, and syphilis 
 are enemies as great and as destructive as the Hun and call for the 
 most vigorous defensive precautions. 
 
 Commerce and business as influences that interfere with our environ- 
 mental defenses against poor health and disease. The newspapers of 
 one of our States a few years ago complained bitterly when a health 
 officer made public the fact that bubonic plague existed in his city. 
 They were again bitter in their complaint when a little later the State 
 Board of Health published a bulletin showing that malaria was com- 
 mon in that State. Public knowledge of these facts would injure business. 
 
 The United States inspectors from the Bureau of Animal Industry 
 condemn every year as unfit for consumption thousands of animal 
 carcasses which were intended for the market. These officials con- 
 demn every year millions of parts of animal carcasses prepared for 
 interstate distribution. 
 
 The Board of Health of New York City destroys thousands of 
 quarts of milk each year, thus preventing certain milk dealers from 
 marketing bad milk. 
 
 86 
 
In these and many other ways we have evidence that business and 
 commerce often lead men to adopt poUcies that are antagonistic to the 
 pubUc health. Such men are willing to suppress the truth at the sac- 
 rifice of human life and human health. They often deliberately attempt 
 to circumvent laws enacted for the defense of the public against dis- 
 ease. 
 
 VI 
 THE CONTRIBUTORY CAUSES OF DISEASE— Continued 
 
 Immigration as an Influence that Interferes with Our Environmental 
 Defenses Against Disease and Poor Health 
 
 Stringent laws have been enacted to keep disease carriers from enter- 
 ing this country. It is not an easy matter to detect disease in its in- 
 cipiency. Therefore disease not infrequently enters the United States 
 by this route. (It is only fair to state that our quarantine measures 
 are more than reasonably effective. For instance, we have had no 
 serious epidemics from this source in years. There has been no cholera 
 since 1873.) 
 
 The death-rate from tuberculosis in foreign-born whites is double 
 that of native-born whites in the United States. The later type of 
 immigrant admitted to this country up to the time of this Great War 
 was not a healthy, rugged, resistant type which offered a good founda- 
 tion for a future virile citizenship. Thus, in various ways, immigration 
 may interfere with, break down or get through our community de- 
 fenses against disease. 
 
 Carelessness as an influence that breaks down or interferes with our 
 environmental defenses against disease. Many persons who know 
 better spit in public places. Parents not infrequently permit their chil- 
 dren while recovering from whooping-cough, chicken-pox, measles, 
 scarlet fever and other communicable diseases to mingle with other 
 children before it is safe for them to do so. Too many people are too 
 careless about washing their hands before they eat or before they handle 
 food intended for other people to eat. 
 
 If it is true that 4 per cent, of all people that have typhoid fever 
 become chronic carriers of the bacilli that cause that disease there may 
 be three or four hundred thousand typhoid carriers in continental United 
 States. A single drop of urine from one of these cases may contain 
 3,000,000 typhoid bacilli. Suppose every one of 300,000 such carriers 
 is as careless about washing his hands as you are, how safe would they 
 be as milk dealers, bakers, butchers, grocers, waiters, cooks, dishwash- 
 ers, bartenders, confectioners or cigar-makers? 
 
 87 
 
It is quite as necessary to be careful with other diseases as with 
 typhoid fever. Our best planned community defenses against disease 
 may be easily destroyed by acts of carelessness. 
 
 Vice as an influence that destroys our environmental defenses against 
 disease. Vice is intimately associated with poverty, bad hygiene, bad 
 sanitation, congestion, ignorance, carelessness, alcohol, and sexual im- 
 morality. 
 
 Sexual immorality contributes to the infection of great numbers 
 of men and women. Every human being that becomes loose in his 
 sexual habits sooner or later has gonorrhea, or syphilis, or both. The 
 victims of these diseases are often more easily susceptible to other 
 diseases. 
 
 The alcoholic is more easily susceptible to disease and recovers with 
 more difficulty from disease. These unfortunates are often wrecked 
 mentally, morally and physically. They fill our prisons, hospitals, 
 asylums and graveyards. They do the least amount of harm in the 
 graveyard. 
 
 Vice is a subtle influence within a community, destroying com- 
 munity as well as personal defenses against diseases. 
 
 VII 
 
 THE CONTRIBUTORY CAUSES OF DISEASE— -Continued 
 
 Ignorance as an Influence that Destroys Our Environmental Defenses 
 
 Against Disease 
 
 There is much that we do not know about disease but some of us 
 are less ignorant than others. There are people that know nothing 
 about the living things that cause disease, nothing about the carriers 
 of disease, and nothing about our defenses against disease. Such 
 people when they live together in communities are helpless when 
 epidemics of disease come to them. In India, in the last twenty years, 
 over 7,500,000 people have died of bubonic plague. When bubonic 
 plague is attacked in India for a few years by a native population that 
 knows how to defend itself against that disease there will be very 
 little bubonic plague left. Havana was the home of yellow fever and 
 malaria until men who knew how cleaned up the breeding-places of mos- 
 quitoes. The Panama Canal was impossible until men who knew how 
 destroyed the breeding-places of the malarial and yellow fever mos- 
 quitoes. 
 
 There are people who believe that gonorrhea is no worse than a 
 bad cold. They often pay for their ignorance with sterility, with loss 
 
of eyesight, or with stiff, useless joints. Whenever human beings, 
 through ignorance and carelessness, trifle with communicable disease 
 they must pay the penalty. That penalty is often severe. 
 
 Individuals who are ignorant are more likely to expose themselves 
 to disease. They pay the penalty for their misfortune — and those who 
 are about them help pay the penalty. 
 
 The combination of ignorance, superstition, prejudice and fanaticism 
 produces influences that contribute to the overthrow of our defenses 
 against disease and to the obstruction of wise plans for the improve- 
 ment of our defenses against disease. 
 
 Vaccination against smallpox has saved millions of human lives. 
 There are numerous persons who are opposed to vaccination. 
 
 Ignorance and misunderstanding have led a number of people to 
 oppose experimentation on animals. This opposition is based appar- 
 ently on a mistaken assumption of wanton cruelty in such experimenta- 
 tion. Animal experimentation has taught us our most valuable lessons 
 on the causes of, treatment of, and defenses against disease. Animal 
 experimentation in the hands of competent investigators is carried on 
 with no cruelty and no unnecessary pain. The treatment of animals in 
 preparation for the market is infinitely worse than the treatment of 
 animals used for the purpose of saving human beings from disease. 
 The modern scientific laboratory and the modern scientific investigator 
 are agents working in the interest of humanity. 
 
 Ignorance and certain religious enthusiasm sometimes produce strong 
 oppositions to sane policies of public defense against disease. People 
 in this group are commonly opposed to vaccination, animal experimenta- 
 tion, quarantine, medical treatment of disease, national health super- 
 vision, medical inspection in schools, and so on. 
 
 VIII 
 THE CONTRIBUTORY CAUSES OF DISK ASE— Continued 
 
 Low Medical Standards are Influences that Tend to Destroy Our 
 Environmental Defenses Against Disease and Poor Health 
 
 Our requirements for admission to and graduation from medical 
 schools have been too low. There have been and still are too man;f 
 poorly trained physicians practicing on the public. Medical practice 
 should be in the hands of well trained men and women of the very 
 highest character. Good character is as much a requisite in the prac- 
 tice of medicine as good training. 
 
 Some states have enacted laws which permit inadequately trained 
 
 89 
 
men and women to take responsible control over human life. Standards 
 of admission to medical practice are low in some States. Various non- 
 medical practitioners are admitted to license in some States. 
 
 Every precaution should be taken to guarantee that only wisely and 
 efficiently trained medical practitioners are given responsibility in the 
 treatment of disease. Only men and women of good character and 
 good scientific equipment should serve on our boards of health or other- 
 wise direct our public health activities. 
 
 Politics sometimes operate to weaken and often destroy our de- 
 fenses against disease. 
 
 There should be no politics in municipal, State or national health 
 boards. 
 
 There should be no politics in municipal, State or national hospitals. 
 
 There should be no politics in the formation of our local or State or 
 national laws regulating the public health. All influences that tend 
 to disorganize, suspend or evade provisions and laws for the acquisition 
 and maintainance of public health may be, and often are, contributory 
 causes of disease. It is a matter of most serious importance for us 
 to encourage in every way the development of a sane and scientific 
 policy of personal and public health control so that every citizen may 
 understand the fundamental principles involved and every health official 
 may be wise and effective in the discharge of his duties. 
 
 IX 
 
 THE CONTRIBUTORY CAUSES OF DISEASE— Cow^mwed 
 
 The Contributory Causes of Disease Include Those Influences which 
 Tend to Lessen Human Resistance to Disease 
 
 Human resistance to disease depends upon the healthy condition of 
 the tissue cells of which the human body is formed. Any influence that 
 interferes with the nourishment of the tissue cells, any influence that 
 interferes with the removal of waste products (secretions or excre- 
 tions) from the tissue cells, and any influence that interferes with the 
 work (functional activities) of the tissue cells is an influence that 
 lowers the vitality of the cells, weakens them and makes them un- 
 healthy and less resistant to disease. In other words, the health of the 
 tissue cell depends upon habits of nourishment, excretion, exercise, pro- 
 tection, recreation and rest. Without such wise physiological habits, 
 health is impossible. 
 
 The influence of certain normal conditions of the human body which 
 favor disease. 
 
 90 
 
Age. — Infants ai-e more liable than adults to the following diseases : 
 Whooping-cough, measles, chicken-pox, meningitis, infantile paralysis, 
 broncho-pneumonia, diphtheria, scarlet fever and mumps. 
 
 Typhoid fever and tuberculosis are diseases of young adult life. 
 The average age at death from tuberculosis is about thirty-six years. 
 
 The diseases of old age are lobar pneumonia, Bright's disease, 
 arterio-sclerosis, heart disease and cancer. 
 
 Sex. — Women are more liable to nervous diseases such as hysteria, 
 neurasthenia and cancer. There are certain diseases that occur only in 
 women. 
 
 Men are more commonly affected than women with diseases that 
 are favored by occupational influences, exposure, alcoholism, sexual 
 excesses and other forms of dissipation. 
 
 Heredity. — Tendencies to nervous and mental disease may be in- 
 herited. The children of tubercular parents are more susceptible to 
 tuberculosis than are children of healthy parents. The children of 
 sickly, unhealthy parents are liable to be sickly and non-resistant to 
 disease. War tends to eliminate the healthy, sound stock and leave 
 the weak and poorer heredities for perpetuation and enrtphasis. Alcohol 
 and syphilis are our most important factors in establishing heritable 
 degenerations. Certain occupations tend to produce degeneracies that 
 damage offspring. Occupations involving the use of lead and nitrate 
 of mercury are the most dangerous from this point of view. Moot ques- 
 tions in heredity. 
 
 X 
 
 CERTAIN ABNORMAL PHYSICAL CONDITIONS THAT MAY 
 ACT AS CONTRIBUTORY CAUSES OF DISEASE 
 
 Defective Vision (uncorrected). — Often accompanied by headaches 
 and nervousness. Favors indigestion, epilepsy, and other diseases of 
 nervous origin. Poor health and reduced resistance to disease are not 
 infrequently consequent on the nervous irritation of uncorrected de- 
 fects of vision. 
 
 Obstructed Breathing. — Caused by adenoids, tonsils, deformities of 
 the nose and growths in the nasal passages. Leads to mouth breathing. 
 Nasal breathing is natural breathing. When the air passes through the 
 nose it is moistened, warmed and filtered. When the air is breathed 
 through the mouth it cools the lining of the throat and upper air pas- 
 sages, dries those passages and deposits particles of dust and other 
 foreign matter on their surfaces, and leads therefore to chronic inflamma- 
 
 91 
 
tion of the nasal passages and the throat. Acute infections are favored. 
 Because of connecting canals and passages, disease of the nose and 
 throat often extends to the ear, the eye, the spaces in the bones of the 
 cheek, forehead, and head, and, more rarely, to the brain. Bronchitis, 
 pneumonia and tuberculosis are more commonly associated with chronic 
 troubles of the nose and throat. Tonsilitis, rheumatism and heart 
 disease are related to the evil results of obstructed breathing. 
 
 Decayed Teeth and Sore Gums. — Dirty teeth, teeth with green stain 
 on them, teeth with tartar on them sooner or later decay. Mouths that 
 are not clean, teeth that are not clean, are often accompanied by sore 
 gums. Decayed teeth are often tender and thus interfere with proper 
 chewing. If the teeth are very bad — or lost — chewing may be im- 
 possible. Chewing is essential to good digestion. Decayed teeth are 
 "sore places" in the mouth. Disease organisms may enter the tissues 
 through decayed teeth. Diseases of the jaw, the face, the throat, and 
 the whole body may come from this avenue of entry. Sore gums are 
 sometimes caused by a minute animal — an ameba. They are also 
 avenues through which other organisms may enter the tissues. People 
 with bad teeth, sore gums and dirty mouths get sick more easily and 
 recover with more difficulty than people with good teeth and clean 
 mouths. 
 
 Chronic Disease of the Middle Ear {a "Running. Ear"). — Cause: 
 Usually communicated from disease of the nose and throat (see above). 
 
 Effects on Health. — May suddenly grow worse. May extend to the 
 bones of the head (mastoiditis), great veins, large arteries, or brain, 
 all of which are close to the ear. May lead to loss of hearing. Chronic 
 disease of the middle ear may then, in various ways, lead to poor health 
 and general low resistance to disease. 
 
 XI 
 
 CERTAIN ABNORMAL PHYSICAL CONDITIONS— Continued 
 
 A Defective Heart. — A weak heart is not necessarily a very serious 
 matter. Persons thus affected must exercise their hearts intelligently 
 and within certain wise limitations. Too little exercise for a defective 
 heart may be as undesirable as too much exercise. Too little exercise 
 weakens the heart so that it can not send nourishing blood to the tissue 
 cells — it can not do its regular work. Too much exercise may wear 
 such a heart out or cause serious injury from sudden strain. 
 
 A weak heart unwisely used is a source of poor health. It may be 
 unable to force enough blood to the tissue cells. This means a lack 
 
 92 
 
of oxygen and other food for those cells; they will not be well nour- 
 ished and can not, therefore, be in good health. It may not be able to 
 support the additional work thrown on it when sickness occurs. All 
 fevers, all infections, throw work on the heart. 
 
 Chronic Indigestion. — Leads to under-nourishment and consequent 
 general lack of resistance. 
 
 Genito -urinary Defects and Abnormalities in the male and female 
 contribute in various ways to poor health and to local and general dis- 
 ease. Often a source of nervous troubles of various kinds. 
 
 Infectious Diseases Common Here. — Venereal diseases contribute very 
 largely to poor mental and nervous health, poor physical health, poor 
 heredity. 
 
 Other abnormal conditions that contribute to poor health are: 
 
 Curvature of the Spine. — Functional variety usually of no con- 
 sequence. 
 
 Flat Chest. — Often associated with spinal curvature. May accom- 
 pany poor lungs. Frequently of no significance. 
 
 Flat Feet and Weak Feet. — May have no effect on general health. 
 May not be noticed and may cause no discomfort. May cause great in- 
 convenience, pain and disability, with a general nervous irritability — all 
 of which means poor health. Flat feet and weak feet are sources of 
 very serious military disability. Spinal curvature, flat chest and weak 
 feet may all be parts of a generally weak musculature, and accompany 
 poor nourishment and debility. 
 
 Obesity usually means poor resistance. Mortality and morbidity 
 are high in obese persons. 
 
 Emaciation is usually the effect of acute or chronic disease and is an 
 evidence of lowered vitality. The common consequence of tuberculosis, 
 Bright's disease, indigestion and malignant growth. 
 
 XII 
 
 CERTAIN ABNORMAL PHYSICAL CONDITIONS— CoM^mwed 
 
 Chronic Local Inflammations and Irritations. — May serve as avenues 
 for infection. May develop into cancer, e.g., irritated, bleeding warts, 
 moles, scars and ulcers. 
 
 Chronic Disease. — May interfere with general nutrition, excretion, 
 exercise or rest and thus cause poor health. Long continued disease 
 leads to diminished resistance. It is said that men rarely die of chronic 
 disease. They usually die because of some acute infection which these 
 chronic diseases have made them unable to withstand. Among these 
 
 93 
 
chronic diseases are tuberculosis, hookworm disease, syphilis, 
 gonorrhea, alcohoHsm, lead poisoning, Bright's disease, tapeworm dis- 
 ease, heart disease, chronic indigestion, chronic middle ear infection, 
 chronic disease of the nose and throat, chronic bone disease, and so on. 
 
 The After-effects of Acute Disease. — ^Acute diseases not infre- 
 quently take so much strength and vitality from their victims that they 
 easily succumb to later attacks of the same or other acute diseases. 
 Acute diseases sometimes leave permanent damage behind which make 
 the patient less resistant to other diseases. Scarlet fever often leaves 
 weak kidneys. Diphtheria, rheumatism, tonsilitis, scarlet fever and 
 other acute febrile diseases often damage the heart. Pneumonia, 
 whooping-cough and measles often leave the lungs "weak" and prone 
 to tuberculosis. There are numerous other examples of such effects 
 of acute disease. 
 
 Gonorrhea may destroy vision, ruin the joints and produce sterility. 
 Syphilis may cause paralysis, mental deterioration and sterility. It may 
 establish a heritage of germ cell damage which shows itself later in 
 various nervous diseases, idiocy, imbecility and insanity of descendants. 
 
 Traumatic Injuries. — Gross injuries to the skin, bones or other 
 organs may open avenues of infection, destroy the organs concerned or 
 leave the patient an invalid. 
 
 Minute injuries may be caused by inorganic dust or irritating vapors, 
 gases, and chemicals. These injuries are characteristic occupational in- 
 fluences. Men who work in metal often are forced to breathe air that 
 contains minute particles of metal which lacerate the eyeballs or the 
 lining of the air passages. Lung diseases are common among men in 
 such occupations. 
 
 These various abnormal conditions interfere with the nourishment 
 of tissue cells, or the functional activities or the removal of excretions 
 or with the rest of tissue cells. They subject them to communicable 
 disease either because they open avenues of tissue infection or because 
 they weaken those tissues and make them less resistant to disease, or 
 more liable to permanent deterioration. 
 
 XIII 
 
 INTERFERENCES WITH NOURISHMENT 
 
 Any influence that interferes with the physiology of the tissue cell 
 will injure the cell and may be the source of poor health of the cell 
 and therefore to the human being of whom that cell is a living part. 
 
 94 
 
The physiology of the tissue cell, broadly speaking, is made up of its 
 nourishment, excretion, exercise (function) and rest. 
 
 Influences that Interfere with Nourishment. — (a) Community in- 
 fluences : Anything that interferes with the food supply ; war ; famine ; 
 inadequate transportation or inefficient distribution from any cause; 
 "poverty. 
 
 (t) Domestic or Family Influences: Anything that interferes with 
 the family supply; poverty; bad economic habits (alcoholism); poor 
 quality of food. Food with low fuel values are poor foods. Foods 
 with high fuel values are good foods assuming that they are digestible. 
 Unwise selection of food for family use. Poor cooking. Good food 
 may become poor food if the cooking is poor. The cooking may be 
 insufficient and thus leave the food tough and hard to chew or fail to 
 destroy the organisms that may have infected the food, or fail to make 
 the food palatable and attractive. Poor cooking may therefore lead to 
 poor health. Unattractive table service. An unappetizing and unat- 
 tractive preparation and service of food fails to stimulate either appe- 
 tite or digestion. Distasteful food is digested with difficulty. A meal 
 eaten in unpleasant surroundings is not easily digested. Standards 
 vary. Food that is attractive to one family may not be attractive to 
 another. Surroundings that please one household may be unpleasant to 
 another. Dton't be in a hurry to impose your standards of attraction 
 and pleasure on others. Unattractive food and unattractive service are 
 factors in the production of indigestion and poor health to those per- 
 sons to whom such service is unpleasant. Ventilation as a family 
 problem of "food supply" (oxygen). The air we breathe contains 
 oxygen which is taken up by the blood in the walls of the lungs and 
 carried to the tissue cells. This food (oxygen) is requisite to the life 
 of the tissue cell; without it they die. The results of recent experi- 
 ments seem to show that ordinary air contains enough oxygen to serve 
 our respiratory needs after many repeated passages through the lungs. 
 The disagreeable effects of poor ventilation appear to be due to odors, 
 humidity, high temperature and lack of motion in the air. A dry, hot 
 air with odor and no motion may also be distressing. On the other 
 hand, it is common experience that people who habitually breathe fresh 
 air, particularly out-of-door air, are in better physical condition than 
 people who habitually breathe "old" ajr or much used indoor air. 
 
 95 
 
XIV 
 
 INTERFERENCES WITH NOVRISHMKUT— Continued 
 
 Habits of the Individual that Interfere with the Nourishment of His 
 
 Tissue Cells 
 
 Meals that are eaten under unpleasant emotional excitement (anger, 
 fear, apprehension and the stress of hurry) are not easily digested. 
 Under such nervous influences secretion of digestive juices stops. 
 Under such nervous influences the digestive movements of the in- 
 testinal canal stop. 
 
 Meals that are eaten in distinctly unpleasant surroundings, meals 
 that are not attractive, food that is distasteful, are all sources of indiges- 
 tion. Under such unpleasant influences the digestive secretions and 
 movements stop. 
 
 Rapid eating and insufficient mastication may lead to indigestion. 
 Starchy foods when well mixed with saliva (from the mouth) will 
 undergo partial digestion while they are stored in the upper part of 
 the stomach after the meal. If such food is not well chewed, this op- 
 portunity for digestion is lost and more work is required farther on in 
 the canal. Food that is swallowed in chunks is digested more slowly. 
 Those chunks may in the course of time cause ulceration of the stomach, 
 with the possibility later of malignant growth. 
 
 Overeating may lead to indigestion and lead to undernourishment. 
 
 Indigestible food may cause dyspepsia and lead to poor nutrition. 
 Food that is indigestible for one person may be digestible for another. 
 As a rule corned beef and cabbage are hard to digest. Fried food and 
 greasy food is usually slow to digest. The powers of digestion vary 
 with age and condition. The problems of nourishment for babies, 
 children, adults and old people differ. The powers of digestion vary 
 with the different individuals and with the same individuals at different 
 times. 
 
 Some foods are not as nourishing as others. Charts showing food 
 values may be easily found. The tissues need nourishment made up 
 from protein food, such as meat, eggs and milk. Fatty food such as 
 butter and the fat in meats. Carbohydrate food such as cereals, vege- 
 tables and bread. Certain salts and water found in all foods and in all 
 potable water. Few of us drink enough water. 
 
 Unpleasant excitement, unhappy emotions, vigorous exercise and 
 great hurry are bad influences when they occur immediately before 
 meals or immediately after meals. 
 
 m 
 
Problem of poor respiratory habits and "oxygen starvation" of the 
 tissue cells; the bad effects of chronically poor ventilation of the lungs 
 may be due to lack of oxygen. 
 
 XV 
 
 INTERFERENCES WITH NOURISHMENT— CowiinM^rf 
 
 Bad habits of rest may interfere with nourishment. We regard rest 
 as a condition requisite for adequate tissue nourishment. Relative rest 
 is a term we apply to simple inactivity. The processes of cell nourish- 
 ment go on during relative rest, but not adequately. Absolute rest is 
 secured only by sleep. Absolute rest is requisite for effective tissue 
 nourishment. During periods of rest the tissue cells use food that is 
 brought them in solution by the blood. This food is secured by the 
 blood from the intestinal tract and the lungs. The intestinal tract 
 furnishes dissolved proteins, fatty and carbohydrate food, the various 
 salts and water. The lungs furnish oxygen. From this food the tissue 
 cell builds up its own structure. The muscle cell makes muscle. The 
 nerve cell makes nerve. The bone cell makes bone. Each cell builds 
 its own structure. From this food the tissue cell manufactures the 
 chemical substances with which it does its regular work. The muscle 
 cell manufactures a something which makes it contract. The nerve cell 
 manufactures a something with which it is enabled to send or receive 
 nervous impulses. The brain cell uses its food for the manufacture of 
 a something out of which thoughts are made, or with which the will 
 commands an act. 
 
 We move, we see, we feel, we think, with the food we eat. Your 
 bread and butter to-day will be your thoughts and acts to-morrow. 
 
 Any influence that interferes with adequate rest, interferes with 
 tissue nourishment and may eventually become a cause of poor health. 
 
 XVI 
 
 INTERFERENCES WITH EXCRETION 
 
 The excretions from the tissue cells escape by way of (a) the 
 respiratory tract, (b) the genito-urinary tract, (c) the skin, (d) the 
 bowels. The discharges from the bowels are largely wastes that have 
 simply passed through the alimentary canal. Such wastes are not tissue 
 excretions. 
 
 Interferences with the escape of excretions by the way of respiratory 
 
 97 
 
tract. Carbon dioxide is the chief respiratory excretion. Chief inter- 
 ferences occur in disease of the heart and lungs. Question as to the 
 effect of a considerable increase in the carbon dioxide content of the 
 inspired air. Older theories assumed that carbon dioxide was poison. 
 More recent experiments show that carbon dioxide is much less in- 
 jurious than was then thought. Possibility that an increase in the 
 amount of carbon dioxide in the blood for long periods of time may 
 have an injurious eifect. The ventilation of the lungs is a problem of 
 room ventilation and a problem of right breathing. Influences of 
 sedentary life on respiratory excretion and the influence of exercise as 
 a respiratory stimulant. 
 
 Interferences with the escape of excretions by way of the genito- 
 urinary tract. The excretions eliminated through the kidneys are com- 
 plex. They come from all the tissue cells. They are contained in the 
 urine. Kidney disease may interfere with adequate excretion. The 
 habit of drinking too little water may limit the efficiency of the kidney 
 excretion. Sedentary life and overeating burden the kidneys. Ex- 
 cessive exercises throw work on the kidneys. Good health is not 
 possible if the kidneys are not in good condition. 
 
 Interference with the escape of the excretions by way of the skin. 
 Various glands in the skin assist in the removal of excretions from the 
 blood. A dirty skin is not likely to be an active skin. A sedentary, 
 inactive life makes too little demand on the skin. 
 
 Interference with excretions and wastes by way of the bowels. The 
 discharges from the bowels are in large part material which has been 
 rejected in the digestive tract. Constipation and sluggish intestinal ' 
 action from any cause is injurious. 
 
 The most important interferences with these excretions may occur 
 as follows : (a) A sedentary, inactive life is accompanied by sluggish 
 respiration, inactive skin and inadequate discharges from the bowels. 
 (&) Overeating and under-exercise throw too much work on the 
 kidneys, (c) Excessive exercise burdens the kidneys, (d) If one 
 drinks too little water he will have an acid, irritating urine which, In 
 the course of time, may injure the kidneys, (e) Constipation from 
 any cause is undesirable. One should have at least one full movement 
 of the bowels every day. 
 
 Any of the above "interferences" may lead to poor health and 
 thus become contributory causes of disease. 
 
 The excretions of the tissue cells are cast out of the cells into the 
 blood and carried by the blood to the lungs, the kidneys, the skin, or 
 other excretory organs through which they are eliminated from the 
 body. Excretion from the tissue cells is accomplished during periods 
 
 98 
 
of rest. The wastes accumulate during activity and are removed during 
 periods of rest. It is therefore probably true that rest and sleep are 
 useful for tissue excretion as well as for tissue nourishment. 
 
 XVTI 
 
 INFLUENCES THAT INTERFERE WITH THE EXERCISE 
 (FUNCTION) OF THE TISSUE CELL 
 
 Lack of Physical Exercise. — ^A sedentary life interferes with the 
 normal activities of most of the tissue cells. The muscles are inactive. 
 The nerves that send messages to and from the muscles are inactive. 
 The joints are inactive. The heart and blood vessels are relatively 
 inactive. The lungs do a minimum amount of respiratory work. Aside 
 from those of the brain and certain special organs, all the tissue cells 
 are more sluggish in the human being that leads an inactive, sedentary 
 life. 
 
 The effect of the inactivity of these very numerous tissue cells is 
 shown in weak muscles, poor circulation, sluggish excretions, excess of 
 fat and general debility. These conditions are factors in the produc- 
 tion of early old age, tissue degeneration, and poor health. General poor 
 health from such causes is now greatly on the increase in this country. 
 An apparent increase of 41 per cent, in the death-rate due to degenera- 
 tion diseases during the last twenty years. We have about 410,000 
 deaths annually in the United States from organic diseases of the 
 kidneys and urinary system, and of the heart and circulatory system, 
 including apoplexy and paralysis. (Life Extension Institute, Feb- 
 ruary 2, 1915.) 
 
 Influences of Too Much Physical Exercise. — Muscles that are given 
 heavy, unusual exercise without gradual training become tender and 
 painful. The effects may be temporarily incapacitating. A well- 
 muscled man returning to physical exercise after a period of inactivity 
 may break bones or tendons weakened by disuse. Excessive exercise 
 may cause various asymmetries, enlargement of the heart, dilation of 
 the heart, and rupture. Persons having weak organs need exercise as 
 much as persons with normal organs, but they must exercise with more 
 care. This is particularly true in disease and weakness of the heart, 
 arteries, lungs, hernia (rupture), kidney disease, and chronic ab- 
 dominal diseases (appendicitis). Physical exercise should be avoided 
 in the presence of acute disease, particularly if accompanied by fever. 
 Persons with stiff joints or paralyzed muscles simply have a greater 
 difficulty finding exercise they can do. 
 
 99 
 
A wise and intelligent daily habit of exercise will go a long way 
 toward securing health. Regular habits of exercise are essential to the 
 best of health interest of the weak and strong. Special habits of ex- 
 ercise are necessary for individuals limited by organic weakness or 
 disability. 
 
 XVIII 
 
 INFLUENCES THAT INTERFERE WITH THE EXERCISE 
 (i.e, FUNCTION) OF THE TISSUE CEl.!.— Continued 
 
 Interference with the Function of the Nerve Cell 
 
 Disuse. — Nerve cells that are not used do not develop. They 
 atrophy. (This is true of all cells.) Eyes that have never been used 
 are blind. The child born deaf may never talk. The nerve cells that 
 control his speech are not exercised. When muscles are destroyed the 
 nerve cells that supply them degenerate. If a considerable nerve area is 
 "weakened" by disuse the individual suffers a general debility. This is 
 a condition characteristic of sedentary life. A nerve like any other 
 cell when "weakened" by disuse contributes to the general weakening 
 and non-resistance of the whole body. 
 
 Overuse. — Overuse of the nerve cell produces fatigue of the nerve 
 cell. It is then unable, temporarily at least, to perform its normal func- 
 tion in a normal way. More or less serious disturbances may follow. 
 The nerve cell that is given regular, reasonable exercise becomes a 
 healthy nerve cell and performs its normal functions efficiently. Such 
 a nerve cell is an "educated" nerve cell. 
 
 Causes of Mental and Nervous Disturbances (after August Forel) 
 
 Inheritance. — Damage of the germ cell not uncommonly shows its 
 effect in a damage of the nerve cells of descendants revealed througfi 
 imbecility, idiocy, and other exhibitions of mental degeneracy. 
 
 General Predisposing Elements in the Life of the Individual 
 
 Age — Childhood. — Predisposed to epilepsy, hysteria and hypochon- 
 dria. A period when inherited tendencies may be emphasized by bad 
 mental hygiene in the home or in the school. 
 
 Vigorous Middle Life. — This is the period of life in which mental 
 and nervous diseases are more commonly "acquired" rather than ex- 
 hibited as inherited diseases. It is a time when bad social hygiene, bad 
 
 100 
 
community hygiene, or bad industrial hygiene is brought to bear on the 
 mental and nervous status of the vigorous, active human being. 
 
 Advanced Age. — There is a shrinking of the brain which ac- 
 companies age, accompanied by a tendency to mental deterioration and 
 perversion. 
 
 Sex. — The common predisposing causes of mental and nervous dis- 
 ease that are due to sex are peculiar to women. These causes are 
 associated with childbirth, the climacteric, menstruation and with the 
 period of pregnancy. 
 
 Acquired Causes of Injury to the Nerve Cell 
 
 (a) Purely Bodily or Material Causes. — ^AU poisonings, especially 
 alcohol. Infections, especially syphilis. Metabolic diseases, e.g., gout, 
 disease of the thyroid gland. Abnormal modes of life. Bad habits of 
 personal and domestic hygiene, associated with poor nervous heredity. 
 All direct wounds and local organic diseases of the brain. 
 
 (b) Purely Psychic or Mental Causes (nothing is really purely 
 mental). — Suggestion, auto-suggestion, psychic contagion, strong emo- 
 tions often repeated. 
 
 (c) Mixed Psychic Causes. — Disturbances of sleep. Exaggerated 
 sexual life. Continued purely mental excitement and the dominance of 
 sexual images which finally fill the person completely. 
 
 General consideration of the causes of mental and nervous disease. 
 Tremendously complicated. Rarely act alone. Hereditary tendency the 
 main cause. Alcohol the chief cause of injury to the germ plasma, and 
 therefore the most important cause of bad heredity. Other sources of 
 injury to the germ plasma are noted above. Unhealthy conditions of 
 life and of emotions are next in importance. General tremendous in- 
 crease in mental and nervous disease in most civilized countries. The 
 mental and nervous degenerate of modern times is permitted to pro- 
 create. The strong and healthy are led to war. The world was becoming 
 alcoholized. The world has been syphilized. The modern emotional 
 pace is too excessive and too intense. 
 
 The phenomena of "shell shock" in the Great War are due very 
 largely to the extraordinary and intensely powerful emotional influences 
 that come into the lives of the soldiers. The same influences that lead 
 to nervous disease in civilian life operate in military life. They are, 
 however, more concentrated, more immediate, and more dramatic than 
 in civil Hfe. 
 
 101 
 
XIX 
 
 INTERFERENCES WITH THE HEAT REGULATING CELLS 
 OF THE BODY (VASOMOTOR SYSTEM) 
 
 Warm-blooded animals are able to maintain a fairly even tempera- 
 ture (98.8 degrees F. by mouth) in spite of changes in the temperature 
 of their surroundings. Cold-blooded animals take on the temperature 
 of their surroundings. The human animal helps his heat regulating 
 mechanisms by heating his home in the winter, opening windows in the 
 summer, wearing clothes of different warmths at different seasons, regu- 
 lating the ventilation of living and working quarters. 
 
 The heat regulating mechanism may be interfered with to the health 
 injury of the individual by 
 
 Drafts. — A draft of air of cold temperature is not in itself a cause 
 of disease. It is an influence which contributes to the ease of infection 
 through its effect on the heat regulation of persons of poor resistance. 
 
 Exposure to Wet and Cold. — Affect the activity of the vasomotor 
 system in the same way that drafts do; a common contributory cause 
 of respiratory infection. Produces a local increase in the secretions of 
 the nose and throat — a good culture medium for some bacteria. May 
 have an injurious effect on the white blood corpuscles and other blood 
 defenses against disease when those defensive factors pass through the 
 cooled skin. Wet and cold not infrequently contribute to the respiratory 
 infection of infants, the aged, and persons in poor physical condition. 
 
 Poor Ventilation. — System of ventilation to be effective must pro- 
 duce air in gentle motion; the breeze of an electric fan; supply air of 
 comfortable temperature, between 65 and 68 degrees Fahrenheit ; supply 
 air with a relative humidity between 50 and 70 per cent. ; supply clean 
 air, free from dust, odors, and gases. When ventilation is not efficient, 
 dry, stagnant, hot, bad-smelling air is too often the result. A factor 
 in poor health. 
 
 Insufficient Heat. — The room temperature should be between 65 
 and 68 degrees Fahrenheit. The surface temperature of the body 
 should be maintained out of doors by adequate clothing. Further dis- 
 cussion as above. 
 
 Overheating of Living or Working Rooms. — Increase susceptibility 
 to drafts and cold. Particularly undesirable if the occupant is dressed 
 too warmLv. 
 
 102 
 
XX 
 
 SUMMARY 
 
 In these health talks we have discussed (i) some of the influences 
 that favor the production, distribution or pathogenic activities of patho- 
 genic organisms and their carriers; (2) some of the influences that tend 
 to interfere with or break down our environmental defenses of health; 
 and (3) some of the influences that lessen human resistance to disease. 
 
 This information may be of practical use to you in the formation 
 of your habits of health protection as an individual and as a voting 
 citizen. It may serve you at home, in peaceful occupation, or in war. 
 The principles covered and the facts stated are applicable to all con- 
 ditions of life. But this information, these principles and these facts 
 are of no value and can be of no value to you unless you make them 
 a part of your own equipment and use them in your own life. 
 
 It is the hope of the Department that you have established enduring 
 habits of informational hygiene that will lead you to consult good health 
 literature and to consult regularly safe health examiners and advisors; 
 that you have made it your habit to care for your body and all of its 
 organs; that you have acquired permanent habits of protection against 
 the agents that injure health, the pathogen carriers, and the contribu- 
 tory causes of disease ; and that you are constantly using wise habits of 
 constructive hygiene in your habits of nourishment, your habits of ex- 
 cretion, work, exercise and play, and your habits of rest. 
 
 If you have established such habits you will be better able to play 
 your part in the world; you will live longer; you will serve yourself, 
 your family, and your country more productively, more usefully, and 
 more vigorously. When your call to citizen service comes you will 
 be ready. 
 
 103 
 
GENERAL HYGIENE 
 
 PART FOUR 
 THE DEFENSES OF HEALTH 
 
 lOS 
 
INTRODUCTORY 
 
 Health is on the market. It can be bought. The man or the com- 
 munity that is willing and able to pay the price may buy. New- 
 Orleans has purchased freedom from yellow fever. Money invested in 
 Havana has bought relief from malaria and yellow fever. The United 
 States paid money for health in the Panama Canal Zone and got what 
 it paid for. New York City has bought the lowest municipal death- 
 rate in the world through investments made in its Health Department, 
 in its pure water supplies, in its Department of Sewers, in its Tene- 
 ment House Department, Street Qeaning Department, parks and park 
 control, and so on. The United States spent money on the prevention 
 of venereal disease in the army during the Great War and reduced the 
 occurrericy of gonorrhea, syphilis, and chancroid to one-third its pre-war 
 percentage. 
 
 Whenever a man, a family, a village, a city, or a nation has spent 
 money wisely the purchase has secured a quality and an amount of 
 health improvement that has been worth infinitely more than the 
 monetary cost. 
 
 But there is a point, a limit beyond which the dollar can not go. 
 M'oney will buy clean water. It will destroy the breeding-places of 
 mosquitoes and flies and other pathogen carriers. It will dispose of 
 sewage. But it can not buy habits of individual hygiene. It can not 
 make humans inform themselves wisely concerning the laws of general 
 hygiene, individual hygiene, and group hygiene, or secure for them- 
 selves regular health examinations and advice from competent, honor- 
 able health experts. It can not make them take care of their bodies or 
 avoid intelligently the agents that injure health or the agents that carry 
 pathogens. It can not make humans eat wisely, excrete regularly, work 
 physiologically, recreate and play cheerfully and joyously, and sleep 
 adequately. Money can not buy individual health habits. 
 
 Health in these modern times is a product of community habits and 
 of individual habits of hygiene. The health achievement of either is 
 limited in the absence or failure of the other. A working combination 
 of the two must lead to the lowest morbidity and mortality rates yet 
 secured. We have made one of the greatest advances in recent years 
 along lines of community hygiene. Individual hygiene has lagged. 
 
 107 
 
Upon you, college men, citizens of the future, depends more than on 
 any one else the health defenses of the future. The health habits you 
 are acquiring now will govern you and influence your community then. 
 As you defend your own vigor, and your own physiological resources, 
 so will you defend the health and the vigor of your city and your 
 State. What are you doing? Are you wasting these years? 
 
 II 
 
 OUR NATURAL DEFENSES AGAINST DISEASE 
 
 Our steadily increasing knowledge of the causes and the carriers of 
 disease has furnished us with some information concerning various 
 natural agents whose normal operations tend to protect us from disease. 
 These agents have acted for the conservation of human life unaffected 
 by our ignorance through all the ages during which there has been 
 human life and during which there have been disease-causing enemies 
 of human life. Those natural defenses against disease exist in our en- 
 vironment or in the surface defenses of the human body or in the 
 physiological activities of the bodily tissues. Modern hygiene has 
 amassed information concerning the influences that damage and destroy 
 health; has accumulated facts relating to those natural agents that 
 destroy or interfere with the causes and carriers of disease; and from 
 these sources modern hygiene is organizing rational scientific systems 
 of personal, domestic, institutional, industrial, community and inter- 
 community hygiene and sanitation for the conservation of human life. 
 
 We have then a growing knowledge of the natural agents that pro- 
 tect us from disease and we are more and more commonly utilizing, 
 directing and co-ordinating those agents for the more effective defense 
 of human life. 
 
 Natural Defenses Against Disease 
 
 Environment Defenses: Sunlight, sun heat, high and low tempera- 
 ture, lack of moisture, fresh, clean air, lack of factors requisite to the 
 vitality of animal and vegetable causes and carriers of disease. 
 
 Surface Defenses of the Human Body: External surface — skin, in- 
 ternal surface — mucous membranes, surface secretions, the cilia. 
 
 Internal Defenses of the Human Body: Normal healthy tissue cells, 
 phagocytosis, lysis, formation of antibodies, immunity reactions, in- 
 flammatory reactions. 
 
 108 
 
Utilisation of These Defenses Through Wise Systems of Individual 
 
 and Group Hygiene 
 
 (o) Personal or individual hygiene. (/) Institutional hygiene, 
 
 (i) Domestic hygiene. (g) Military hygiene. 
 
 (c) Community hygiene. (h) Industrial hygiene. 
 
 (d) Rural hygiene. (t ) Inter-community hygiene. 
 
 (e) School hygiene. 
 
 Ill 
 
 OUR NATURAL DEFENSES AGAINST BISEASE— Continued 
 
 The various organisms that cause disease and the various agents 
 that cany disease are present all about us. Man in health and in dis- 
 ease eiqiels myriads of pathogens by way of his respiratory, fecal, 
 genito-urinary and other excretions and discharges. One human being 
 sick with tuberculosis may expectorate billions of tubercle bacilli in a 
 single day, enough, if evenly distributed, to infect the entire human 
 race. There are always, approximately, 3,ooo,ocx5 persons sick with 
 some disease or other in the United States and each one is more or less 
 constantly discharging his many billions of pathogens. 
 
 Every one of those pathogenic organisms, under favorable condi- 
 tions, is capable of enormous increase in numbers. A single bac- 
 terium, if left alone, if not restricted in its natural tendency to multiply 
 by simple division, would within a few days produce enough bacteria 
 to equal the bulk of the earth. A single tapeworm may produce 150,- 
 000,000 eggs in a year. Evidently there are some very effective reasons 
 why these many varieties of disease-causing organisms have not de- 
 stroyed the human race and covered the universe. Those reasons con- 
 stitute our natural external defenses against disease. 
 
 Our Natural External Defenses Against Disease 
 
 Sunlight. — Destroys most pathogenic organisms rapidly. The ultra- 
 violet rays are the destructive agents. The bacillus of tuberculosis 
 present in sputum may live in sunlight for twenty hours or more. The 
 amount of time it takes sunlight to destroy bacteria varies under differ- 
 ent conditions. The important point for us to remember is that this 
 bactericidal action of sunlight takes time. Furthermore, the spores of 
 some bacteria resist sunlight for a long time. The spores of the 
 bacillus of anthrax are said to have been found capable of growth after 
 exposure for thirty years in the surface soil of a pasture. 
 
 109 
 
Drying is another influence that destroys most pathogens rapidly. 
 The bacteria that cause boils and abscesses are fairly resistant. The 
 cause of infantile paralysis is resistant. Tubercle bacilli in sputum and 
 diphtheria bacilli in membrane expelled from the throat may live for a 
 long time. The larvae of the hookworm will live for weeks in moist, 
 warm grass, green vegetables or soil, but they die very quickly if their 
 surroundings are dry. 
 
 Low temperatures are not favorable to pathogenic growth and 
 freezing destroys most but not all such organisms. The bacilli of 
 typhoid fever have been recovered from ice. 
 
 High temperature destroys all pathogens, even spores, but the 
 temperatures in nature are never high enough to accomplish this result 
 effectively. We use heat as a germicide. In nature, the combination 
 of sunlight, sun heat and fresh air is destructive to pathogens, and in 
 time to most of their spores. 
 
 Lack of Favorable Environment. — The life of bacteria and other 
 pathogens depends upon darkness, moisture, warmth and food. The 
 heat and light of the sun are continually making conditions unfavorable 
 for such life. In addition, other factors which we do not understand 
 are at work making it impossible for -most pathogens to live long or 
 reproduce themselves outside the human body. There are a few, how- 
 ever, that do live in nature, either in adult form or larvae form or as 
 spores, and there are some that reproduce in nature and multiply, but 
 in every case nature must supply a particularly favorable environment 
 or the organism will not continue to live. It may truly be said that for 
 most pathogenic organisms the only perfect environment is found in the 
 human or animal body or in the bacteriological laboratory. Remember, 
 therefore, in your battle against disease that sunshine and sun-heat are 
 your most powerful protectors in nature, and that these defenses are 
 destroying every moment myriads of the worst enemies of mankind. 
 Do not neglect these allies. Use them every day. Never be without 
 them. 
 
 But do not forget that these natural germicides — sunlight and sun 
 heat — can not destroy germs instantly. Their action takes time — ^min- 
 utes, hours or days. So we must not depend upon these protective 
 agents alone. We must do our part to protect ourselves. After, all 
 has been said, it remains true that the germs of typhoid, tuberculosis, 
 syphilis, lockjaw, influenza, boils, abscesses, gangrene, hookworm, 
 amebic dysentery and many other diseases may be lurking here and 
 there in dark, damp, warm, and dirty places, and sometimes in the 
 dry and dusty places that lie near our homes, our places of work, our 
 restaurants, and our places for play. The fly that travels from the 
 
 110 
 
sewer may carry infectious excrement from a typhoid patient to the 
 food on your table. The dirty hands of the careless milkman may 
 transmit scarlet fever from his children to you by way of the milk you 
 buy from him. Your drinking water may bring you typhoid, and the 
 dust in the air may bring you influenza. We can not leave the matter 
 of our defense against disease to nature alone. We must do, our share. 
 We must help defend ourselves and our communities against disease. 
 
 IV 
 
 SOME OF THE NATURAL DEFENSES SUPPLIED BY THE 
 
 HUMAN BODY 
 
 The Surface Defenses of the Human Body (the Walls of the City) 
 
 The Skin. — ^We know that very few disease organisms can gain 
 access to the tissues through the normal healthy skin. Pathogenic 
 organisms can enter only through scratches, punctures or other de- 
 structive wounds. The young hookworm is a noteworthy exception. 
 
 The Mucous Membranes. — Many organisms live and produce upon 
 the warm, moist mucous surfaces of the alimentary canal, the respira- 
 tory canal, and other natural openings and channels of the human body 
 connected with the exterior. But it seems to be true that most of 
 those organisms are unable to pass through the mucous membranes 
 unless some injury has occurred to make an opening through which 
 they can enter. For example, the mouth-breather, the child or man 
 with nasal obstruction, chronic nasal catarrh, adenoids or tonsils, is 
 permitting an injury to the lining of his air passages so that disease 
 organisms may more easily enter. In this way dirty gums, sore gums, 
 and decayed teeth help pathogenic organisms in their battle against 
 your health. Constipation and indigestion are making microscopic open- 
 ings in the intestinal wall that defends you against your enemies. 
 
 The Natural Secretions are Often Your Protectors. — ^The glands of 
 the eyes secrete a fluid — the tears — ^which is continually washing the 
 surface of the eyes and is carried away through a canal into the nos- 
 trils. The secretions of the nose, throat and lungs mechanically exer- 
 cise a cleansing effect upon these mucous walls. We excrete this 
 material when we expectorate. The secretions of the eyes, the nose, 
 the mouth, and the throat have a mildly antiseptic action. The gastric 
 juice has a somewhat stronger antiseptic influence. 
 
 Ciliary Movement. — ^The passages of the nose, throat and larger air 
 passages are covered with small hairs which filter the inhaled air, and 
 
 111 
 
which, at the same time, gently, slowly, but unceasingly push the 
 moisture, the excretions, the foreign bodies, germs, etc., on and out 
 of the respiratory tract. This ciliary action is present in other parts 
 of the body. 
 
 Remember, then, your skin and your mucous membranes protect 
 you from disease. Take care of them. Keep them in health. Do all 
 you can to help them in defending you. Keep your skin clean and 
 healthy. Keep your teeth clean. Keep them from decay. Keep your 
 gums clean. Watch your digestion. * Don't allow yourself to become 
 constipated. 
 
 Remember, too, that the glands of the eyes and the cilia of the 
 air passages are working to keep you well. You must do all you can 
 to help them. Keep your eyes clean. Keep your nasal passages free. 
 Remove abnormal growths of the nose and throat. A healthy nose and 
 throat is a defense against disease. 
 
 V 
 
 THE INTERNAL DEFENSES OF THE BODY 
 
 While the germs of the disease are on the skin or on the mucous 
 membranes of the eyes, the respiratory or the digestive tracts, they are 
 really outside the human body. If they gain access to the tissues 
 through injuries of the skin or the mucous membranes, there are still 
 other agents present within the tissues themselves that are active in 
 your defense against disease. The most important of these defenses 
 may be described as follows: 
 
 The Phagocytes. — (o) Principally the white blood corpuscles. The 
 action of these cells may be observed under the microscope. Such ob- 
 servation shows that one of these cells will ingest a bacterium and 
 slowly dissolve it. A single white cell may, in a short time, be seen to 
 destroy a number of bacteria. Under normal conditions there are be- 
 tween S,ooo and 8,000 white blood corpuscles in a single cubic milli- 
 meter of human blood. In some diseases this number is very greatly 
 increased, and there may be 40,000, 50,000 or more, rarely over 100,000 
 per cubic millimeter. (&) There are other circulating cells of the body 
 which have this phagocytic action, (c) Significance of phagocytosis as 
 a defense against disease. 
 
 Bacteriolysis. — (Destructive action of blood serum and tissue juices 
 upon bacteria.) When typhoid bacilli are placed in normal human 
 blood serum and observed under the microscope, it is soon noted that 
 the bacilli gradually dissolve. This process is called bacteriolysis. 
 
 112 
 
Human blood has a bacteriolytic effect upon the typhoid, anthrax, colon, 
 dysentery, cholera, and probably other bacteria. 
 
 Remember: Phagocytosis and bacteriolysis are processes by means 
 of which the tissues of the body may destroy bacteria and thus protect 
 themselves from disease. 
 
 Inflammation as a Defense Against Disease. — When a number of 
 bacteria gain access to the tissues at any given point, there is normally 
 an inflammatory reaction at that point. The features of the reaction 
 which interest us are: (i) The increased blood supply which brings 
 phagocytes and bacteriolytic serum to act on the invading organisms; 
 (2) there is a proliferation of the local and circulating tissue cells which 
 on the one hand produces phagocytes and which on the other hand 
 builds a wall of cells about the invading organism. The story of in- 
 flammatory reaction is longer than I have time to relate. But these 
 several facts serve to illustrate its protective character. 
 
 VI 
 
 ACQUIRED IMMUNITY 
 
 So far in our discussion we have been concerned mainly with factors 
 in what is called natural immunity. We have been considering the 
 bodily defenses that are always present in the normal healthy individual. 
 These defenses are frequently overcome by disease, and pathogenic 
 organisms then establish themselves in the tissues of the body as in 
 pneumonia, tonsilitis, diphtheria, and so on. Under these conditions the 
 body usually acquires a new internal defense which enables it to de- 
 stroy the invading pathogenic bacteria and expel them. We then say, 
 "The disease has run its course. He is well." Sometimes this ac- 
 quired defense is so strong that it becomes permanent. Men do not 
 have smallpox a second time. We call this defense against disease 
 "active acquired immunity." 
 
 The mechanism of this process by means of which the animal body 
 is able to organize a new and powerful defense against disease is one 
 of the wonders of physiology. I can do no more than point out to you 
 a very few of the more important facts, but I would urge you to go 
 deeper into this marvelous story if ever the opportunity arises. 
 
 When an infecting agent, like a pathogenic bacterium, establishes 
 itself in the tissues, it appears to have an irritating influence upon some 
 or possibly all the fixed and circulating cells of the body^This irritat- 
 ing or stimulating influence may be due to soluble chemical excretions 
 or secretions given off by the living pathogenic organism, or it may be 
 
 113 
 
due to soluble chemical particles arising from the disintegration of the 
 dead bodies of the invading pathogenic organisms. These chemical 
 bodies are carried about by the blood stream and are thus brought into 
 contact with the various tissue cells in all the organs of the body. And 
 then a remarkable thing happens. The irritation of these tissue cells 
 seems to stimulate some, possibly all of them, to produce specific anti- 
 bodies M^hich destroy the infecting organism or neutralize the toxic 
 products of its activity. 
 
 We call the soluble chemical agents that cause the tissue cells to 
 produce these antibodies "antigens." An antibody which neutralizes a 
 toxifi we call an "antitoxin." A toxin is an antigen which causes the 
 production of an antitoxin. An antigen which causes the production of a 
 lysin we call a "lysogen." We know a number of well-established groups 
 of antigens and their corresponding antibodies. For our purposes the 
 most important of these are the toxins, the lysogens, and the opsogens, 
 and their antibodies, the antitoxins, the lysins and the opsonins. 
 
 The toxins are antigens and are soluble poisons usually produced 
 by pathogenic bacteria. The toxins of diphtheria and of lockjaw are 
 poisons of terrible power. Each has an antitoxin. 
 
 The lysogens are antigens which cause the tissue cells to produce 
 lysins. Typhoid bacilli produce lysogens. When they are present in 
 the tissues they cause the appearance of lysins which dissolve and destroy 
 typhoid bacteria. Lysins that destroy bacteria are called bacteriolysins. 
 
 The opsogens are of great importance and are, in addition, unique in 
 their mode of action. The opsogens cause the appearance or produc- 
 tion of opsonins. The opsonins are important because without them 
 the white blood corpuscles do not exercise their powers of phagocy- 
 tosis. 
 
 Remember: When disease organisms establish themselves in the 
 tissues they act as general tissue cell irritants. Under the influence of 
 this general irritation the cells of the body produce anti-bodies which 
 destroy the invading organisms or neutralize the poisons which those 
 organisms produce. In this manner the cells of the human body re- 
 spond to the call "to arms" and defend themselves from destruction 
 through disease. 
 
 VII 
 
 ACQUIRED IMMUNITY— CoM^JMM^rf 
 
 Source of Antigens. — ^Antigens are soluble protein bodies concerning 
 which much yet remains to be learned. The antigens that interest us 
 are those that are formed by pathogenic organisms. 
 
 114 
 
Extra-cellular Antigens. — We know that some antigens are released 
 by such organisms in their excretions and secretions. Antigens given 
 off in this manner may be called extra-cellular antigens. Several of the 
 toxins given off by the diphtheria bacillus are extra-cellular antigens. 
 Toxins of this sort are frequently called ectotoxins or exotoxins. 
 
 Intra-cellular Antigens. — It seems to be true, too, that many patho- 
 genic organisms contain poisonous substances that are structurally parts 
 of those organisms and are released only when those organisms die and 
 become disintegrated. These intra-cellular poisons then go into solu- 
 tion and may then act as antigens. Such antigens may be called intra- 
 cellular antigens. The existence of antigens from this source has not 
 been proven but there is ample indication that there is such a source. 
 
 We may summarize our statements on the sources of antigens by 
 saying that the antigens manufactured in infectious diseases are given 
 off in the secretions or excretions of living pathogens or they are dis- 
 solved out of the dead bodies of such organisms. 
 
 Sources of Antibodies. — Metchnikoff has voluminous evidence that 
 the antibodies are products of the white blood corpuscles and other 
 phagocytes. Ehrlich supports the view that the connective tissue cells 
 are the chief sources of the antibodies. It is probably true that anti- 
 bodies are manufactured by all active tissue cells under varying cir- 
 cumstances. 
 
 Active and Passive Acquired Immunity 
 
 Acquired Immunity May Be Active or Passive. — The animal (or 
 man) that is protected by antibodies of its own manufacture is pro- 
 tected by an active acquired immunity — or rather by an immunity 
 which it has acquired actively. 
 
 Passive Acquired Immunity. — On the other hand, when an animal 
 (or man) is protected by antibodies which have been transferred to it 
 from some other animal, in the tissue cells of which those antibodies 
 were manufactured, we say that animal has been protected by an im- 
 munity which it acquired passively. 
 
 Active acquired immunity is the defense which an individual manu- 
 factures within his own tissues to save him from a specific infection. 
 Passive acquired immunity is the defense which an individual may ac- 
 quire through the injection into his tissues of defenses manufactured 
 by the tissues of some other animal. The factors in immunity acquired 
 actively by one animal may, therefore, be used passively by another 
 animal. 
 
 Our surface defenses and certain of our internal defenses operate 
 to prevent our becoming sick. The skin, mucous membranes, the 
 
 lis 
 
cleansing and antiseptic secretions, the cilia, the phagocytes, the lysins, 
 and other less well-known agents of natural immunity participate in 
 this defense. 
 
 The antibodies are the internal defenses which we organize to save 
 us from destruction when our natural surface and internal defenses 
 have proven insufficient to protect us from invasion by pathogenic 
 organisms. Recovery from infectious disease depends upon this ac- 
 quired immunity. Death comes when the acquired immunity (i.e., army 
 of antibodies) is not strong enough — quantitatively or qualitatively — 
 to overcome the invading pathogenic organisms and their poisonous 
 antigens. 
 
 This acquired internal defense is remarkable in many respects, (o) 
 It is a specific defense. The antibodies manufactured for defense 
 against the poisons of diphtheria will not offer any defense against the 
 poisons produced by the bacillus of typhoid fever or the treponema of 
 syphilis or from any other source, (b) This acquired defense may last 
 for a very short time and then disappear as in diphtheria. It may leave 
 behind it an increased susceptibility to the pathogenic organism against 
 which it was developed as in influenza or pneumonia. It may leave a sen- 
 sitiveness which enables the tissue cells to manufacture new antibodies 
 against the same disease more rapidly than before the first attack as in 
 cholera. It may last a long while as in smallpox or measles. 
 
 VIII 
 
 ANTIGENS AND ANTIBODIES IN ACTION 
 
 As found in an attack of diphtheria. Diphtheria is a common dis- 
 ease. Over 1,200 persons died of this disease in New York City in 
 1918. There were over 11,000 cases in this city in 1918. It is caused 
 by the diphtheria bacillus. This pathogen most commonly locates itself 
 in the throat. When the bacillus of diphtheria establishes itself in the 
 human throat, if conditions are favorable, it reproduces very rapidly, so 
 that in a few hours there may be many millions of new bacilli. Each 
 one of these living organisms takes its food from the tissues in which it 
 is located. This tissue is the mucous membrane of the throat. All of 
 its excretions and secretions are deposited in that same tissue. When 
 the organism dies its body disintegrates and its chemical structure dis- 
 solves in the fluids in which it has been living. These soluble chemical 
 products of the life and death of the diphtheria bacillus are carried by 
 the blood and lymph circulations to every organ, every tissue, and 
 
 116 
 
every tissue cell of the human body in which the bacilli have been per- 
 mitted to grow. 
 
 Several of the soluble chemical products of the life and death of the 
 diphtheria bacillus may be noted as follows: 
 
 Toxins. — The bacillus produces several toxinsi. The chief toxin 
 is known as the diphtheria toxin. As a matter of fact, this "toxin" 
 is a group of toxins, some of which are less poisonous than others. 
 (Rosenau defines a toxin as "a specific poison elaborated by bacterial 
 metabolism." The common use of the term gives it a much looser 
 definition as a poison of microbic source.) The toxin of diphtheria is 
 particularly poisonous. One cubic centimeter of a filtered bullion 
 culture (about the contents of a small-sized thimble) contains enough 
 poison to kill 2,000 average-sized guinea pigs. Before the days of anti- 
 toxin treatment of diphtheria this toxin destroyed from 20 per cent, 
 to 50 per cent, of all the children infected with the diphtheria bacillus. 
 
 Antitoxins. — The toxin of diphtheria acts as an antigen stimulat- 
 ing the tissue cells (the phagocytes — MetchnikoflF; the connective tissue 
 cells — Ehrlich) to produce antibodies known as antitoxins. Recovery 
 from diphtheria depends upon the neutralizing of the toxin of the 
 diphtheria bacillus by this antitoxin. These antibodies (the anti- 
 toxins) are factors in active acquired immunity. They are nowadays 
 supplied the individual by the physician and thus offer a passive ac- 
 quired immunity. 
 
 Since the introduction of the antitoxin treatment of diphtheria, 
 death from that disease has been greatly reduced. "Bayoux makes the 
 statement, based upon an analysis of 230,000 cases, that the death-rate 
 of diphtheria before antitoxin was 55 per cent., and that since the 
 advent of the serum it has fallen to 16 per cent." (Osier's Modern 
 Medicine, first edition. Vol. II, page 340.) 
 
 The earlier the antitoxin is used the more certain is its action. 
 This is shown in the following statistics: 
 
 REPORT OF THE STATE BOARD OF HEALTH, MASSACHUSETTS, 1902 
 
 In 1433 cases, antitoxin given 1st day on which case was seen, mortality 7.9% 
 
 In 3284 
 In 2654 
 In 1684 
 In 864 
 In 1242 
 
 2d 
 
 ft t( ft 
 
 3d 
 
 (( (( tt 
 
 4th 
 
 tt (( u 
 
 Sth 
 
 a 11 it 
 
 6th 
 
 " (and later) 
 
 6.2% 
 
 9.0% 
 
 12.9% 
 
 IS.9% 
 
 17.6% 
 
 Lysogens and Lysins. — It seems to be well established that there 
 are antigens produced by the diphtheria bacillus which cause the tissue 
 cells to produce specific bacteriolysins. We do not know how im- 
 
 117 
 
portant the bacteriolysins of diphtheria are, but we beheve that they 
 take a more or less effective part in the defense of the body against 
 the diphtheria bacillus — that is, in recovery from diphtheria. 
 
 Opsogens, Opsonins and Phagocytes. — The soluble chemical products 
 of the life and death of the diphtheria bacillus contain an antigen which 
 is called an opsogen. This antigen when distributed in the blood stream 
 causes certain of our tissue cells to manufacture a specific opsonin for 
 the diphtheria bacillus. The specific opsonin for the diphtheria bacillus 
 attacks this bacillus in some, at present, unknown way, and causes that 
 organism to become susceptible to the phagocytes (white blood cells), so 
 that these phagocytes will then engulf diphtheria bacilli and destroy 
 them. We are justified in believing that the opsogen of diphtheria is 
 of great importance in its productive relation to the opsonin of diph- 
 theria and, therefore, to the specific phagocytosis of diphtheria. The 
 number of phagocytes (white blood cells) in the blood is greatly in- 
 creased in the majority of cases in diphtheria. This increase is well 
 marked by the third day of the disease. The number of white cells 
 may then have increased from 3,000 to 4,000 per cubic millimeter to 
 such enormous ntmibers as 38,000 per cubic millimeter (Billings), or 
 46,000 (Morse), or 75,000 (Bonchut), or 148,229 (Felsenthal). (See 
 R. C. Cabot, Qinical Examination of the Blood.) These phagocytes 
 may each take up from 30 to 50 bacilli. 
 
 Possibility of there being a production of unknown antigens by the 
 diphtheria bacillus with consequent unknown antibodies produced by 
 the human tissue cells. 
 
 There may be other extra-cellular antigens which we have as yet 
 been unable to identify. Their antibodies are, of course, not known 
 There may be intra-cellular antigens of the diphtheria bacillus which 
 are dissolved and released into the blood stream when the dead bacillus 
 is destroyed either by lysins or through phagoc)^ic digestion. 
 
 Possibility that the human tissues produce "antigens" which cause 
 the diphtheria bacillus to produce "antibodies." The human antibody 
 is produced for defense against certain germs. It seems to be true 
 that the germs may produce antibodies of their own which protect them 
 against the human being. 
 
 Aggressins. — It often happens that the bacillus of diphtheria shows 
 an unusual virulence. This may be due to the fact that it is stimulated 
 to produce active defenses against its human host. Those defenses are 
 called aggressins. The indications are that living, virulent microbes ex- 
 crete or discharge substances which are not toxins proper but which, 
 nevertheless, have an inhibitive or "anti" action upon the cells of the 
 organism. (Adami.) "It may, indeed, be suggested that the ag- 
 
 118 
 
gressins are to the bacterial organism what the opsonins are to the 
 animal." (Adami.) And so while the tissue cell is manufacturing 
 specific defenses against the diphtheria bacillus, the bacillus is manu- 
 facturing specific defenses against the cell. Each one is producing 
 chemical bodies which are antigens to the other and antibodies for 
 itself. 
 
 Summary 
 
 (a) The bacillus of diphtheria injures and destroys human life with 
 the following agents (antigens): (i) Toxins; (2) lysogens; (3) 
 opsogens; (4) aggressins; (5) various unknown, extra-cellular and 
 intra-cellular products. 
 
 (b) The human body may be defended against the diphtheria 
 bacillus, (i) Actively, by specific (a) antitoxins, (b) bacteriolysins, 
 (c) opsonins and phagocytes, (d) anti-aggressins, (e) various other 
 unknown antibodies. (2) Passively, by (a) antitoxin manufactured 
 in another animal — usually a horse— and injected into the circulation. 
 (3) Neither the active nor the passive defense remains long after the 
 disease has been cured. 
 
 Conclusion 
 
 (a) Our natural immunity protects many of us so that we never 
 have diphtheria. It is not strong enough in some persons to protect 
 them and as a result we have from 11,000 to 12,000 cases a year in 
 New York City. 
 
 (b) Our powers of active acquired immunity have been able in the 
 past to save from death only from 50 to 80 per cent, of all persons in- 
 fected with the diphtheria bacillus. 
 
 (c) Our powers of active acquired immunity, assisted by the im- 
 munity we have been able to secure from commercial antitoxin 
 (passive acquired immunity), have been able to save from death from 
 84 to 93 per cent, of the human beings who have had the benefit of 
 this combined defense. It is believed that a very early use of diph- 
 theria antitoxin would save life in nearly every case. 
 
 IX 
 
 PERSISTENT IMMUNITY 
 
 The antibodies which we have discussed under diphtheria and lobar 
 pneumonia produce only a transient immunity. Repeated infections 
 with diphtheria bacilli or with the various strains of pneumococci are 
 common. The immunity produced in defense against these organisms 
 
 119 
 
lasts for a short time only. The immunity produced in bronchitis, 
 tonsilitis, and common colds, is transient. In some cases one attack of 
 disease seems to predispose the individual to subsequent attacks. This 
 is especially true of lobar pneumonia, influenza, erysipelas, bronchitis 
 and malaria. 
 
 A more lasting immunity occurs after the following diseases : Small- 
 pox, yellow fever, measles, whooping-cough, scarlet fever, cerebro-spinal 
 meningitis, infantile paralysis, typhoid fever, typhus fever, chicken-pox 
 and mumps. In these infections the tissue cells produce antibodies 
 which may remain in the blood and tissue juices for longer periods of 
 time. It is more probable that in these cases the cells continue produc- 
 ing specific antibodies for months or years after recovery. We have 
 not yet learned the details of the campaign of offense and defense in 
 these various infections. We feel safe in deciding that it is a campaign 
 in which antigens and antibodies participate in the various charac- 
 teristic ways already pointed out in these lectures. We have, there- 
 fore, a general understanding of these methods of warfare, though we 
 do not know all the details of any specific campaign. 
 
 The Use of Antibodies for the Protection of the Community Against 
 
 Disease 
 
 Our knowledge of immunity has shown us various ways in which 
 we can aid the individual to recover from certain diseases and with 
 which we can protect the individual and the community from certain 
 epidemics. The use of passive acquired immunity for the reduction of 
 mortality from diphtheria has been discussed above. 
 
 Immunity Against Smallpox. — The immunity produced by vaccina- 
 tion against smallpox is an active immunity developed by a mild disease 
 — cowpox — against cowpox, and also against the very much more 
 serious disease, smallpox. Such vaccination causes vaccinia (or cow- 
 pox) in the human. The human being who has had vaccinia is abso- 
 lutely protected thereby against smallpox for a period of from two to 
 seven years. The experience of over one hundred years offers con- 
 vincing proof of the pronounced difference in the mortality and mor- 
 bidity from smallpox in the vaccinated and the unvaccinated. The 
 following table from Schamberg shows that, among thousands of cases 
 of smallpox occurring in cities all over the world, the death-rate from 
 smallpox has been from five to sixteen times greater among the un- 
 vaccinated than among the vaccinated: 
 
 120 
 
DEATH-RATE FROM SMALLPOX AMONG VACCINATED AND UNVACCINATED IN VARIOUS 
 
 COUNTRIES * 
 
 Death Rate per 
 
 Total Number , 100 Cases ^ 
 
 Place and Time of Ohservation of Cases Among the Among the 
 
 Observed Unvaccinated Vaccinated 
 
 France, 1816-1841 16,397 16.125 1. 
 
 Quebec, 1819-1820 2 27. 1.66 
 
 Philadelphia, 1825 140 60. 0.00 
 
 Canton Vaud, 1825-1829 5,838 24. 2.16 
 
 Verona, 1828-1829 909 46.66 S.66 
 
 Milan, 1830-1851 10,240 38.33 7.66 
 
 Bresleau, 1831-1833 220 53.8 2.11 
 
 Wurttemberg, 1831-1835 1,442 27.33 7.1 
 
 Carniola, 1834-1835 442 16.25 4.4 
 
 Vienna Hospital, 1834 360 51.25 12.5 
 
 Carinthia, 1834-1835 1,626 14.5 0.5 
 
 Adriatic, 1835 1,002 15.2 2.8 
 
 Lower Austria, 1835 2,287 25.8 11.5 
 
 Bohemia, 1835-1855 15,640 29.8 5.16 
 
 Galicia, 1836 1,059 23.5 5.14 
 
 Dalmatia, 1836 723 19.66 8.25 
 
 London Smallpox Hospital, 1836-1856 9,000 35. 7. 
 
 Vienna Hospital, 1837-1856 6,213 30. S. 
 
 Kiel, 1852-1853 218 32. 6. 
 
 Wurttemberg (no date) 6,258 38.9 3.5 
 
 Malta (no date) 7,570 21.07 4.2 
 
 Epidemiological Society Returns (no date) 4,624 23. 2.9 
 
 * Extract from papers prepared in 1857 by Sir John Simon, Medical Officer of 
 the General Board of Health of England, and at that time laid before Parliament 
 with reference to the History and Practice of Vaccination. Published in first Report 
 of the Royal Commission on Vaccination, 1889, Appendix 1, p. 74. (From Preven- 
 tive Medicine and Hygiene, by Rosenau, p. 29.) 
 
 The United States authorities vaccinated 3,515,000 persons in the 
 PhiHppine Islands during the fewr years of their control without a single 
 death from the vaccination itself. The discomfort and injury that 
 sometimes follow vaccination is due to carelessness in the treatment 
 of the vaccination sore. If such sores are treated aseptically — as all 
 wounds ought to be treated — they remain innocent and harmless. 
 
 Immunity Against Rabies. — The Pasteur treatment of rabies de- 
 velops an active immunity in the individual by repeated short interval 
 infections with attenuated (weakened) organisms of rabies. Of 54,620 
 persons treated early at twenty- four Pasteur Institutes, less than 8 per 
 cent, died of hydrophobia. In Hungary, between 1880 and 1885, 5,899 
 persons were bitten and 4,914 received the Pasteur treatment. Two 
 per cent, died among those treated. About 14 per cent, of all persons 
 bitten by rabid dogs and who are not given the Pasteur treatment die 
 of hydrophobia. 
 
 Immunity Against Typhoid. — Immunity against typhoid fever last- 
 
 121 
 
ing from three to five years is produced by the injection into the tissues 
 of emulsions of dead typhoid bacilli. Vaccination against typhoid fever 
 is now practiced in various armies, numerous hospitals, and by many 
 wise individuals. The results have been universally satisfactory. In 
 continental United States, in 1908, one person in every two hundred 
 had typhoid fever. In our Spanish-American War, out of 107,000 
 troops, 20,000 had typhoid fever. In 191 1 anti- typhoid vaccination was 
 given 12,801 soldiers at San Antonio, Texas. Only two cases de- 
 veloped. One had not been vaccinated and the other had been infected 
 before vaccination. In the small city of San Antonio at that same time 
 there were 49 cases of typhoid fever with 19 deaths. The incidence of 
 typhoid fever in the British Army in India is 1.7 per 1,000 among the 
 vaccinated and 5.3 among the non-protected. (Before the Great War.) 
 If the American Expeditionary Force (2,000,000 men) had not been 
 vaccinated against typhoid fever and if the same rate of infection with 
 typhoid had occurred as did occur in our Spanish-American War there 
 would have been 384,113 cases and 29,266 deaths from typhoid in our 
 American Expeditionary Force. 
 
 This protective treatment of typhoid fever has apparently very little 
 danger attached. Sometimes fever and discomfort follow such "vacci- 
 nation," but when they are the results of the vaccination they are never 
 serious. 
 
 Protective methods of treatment like these have been or are being 
 devised for pneumonia, tetanus, cholera, bubonic plague and other 
 diseases. 
 
 It is obvious that the products of immunity reactions are of the 
 greatest value in the protection of individual and public health. Im- 
 munity is more than a defense which the individual manufactures un- 
 consciously for his own protection. It is now a protection which may 
 be intelligently guided, directed and reinforced for personal and com- 
 munity benefit. 
 
 The market is full of serums for the prevention and treatment of 
 disease. It is always unwise to try new medication until its value has 
 been established by scientific medical authority. 
 
 X 
 
 DEFENSE OF HEALTH THROUGH HYGIENE 
 
 General Laws of Personal or Individual Hygiene 
 
 Everything that lives is capable of good health, poor health, or dis- 
 ease. In general, the physiology of animal life and the physiology of 
 
 122 
 
plant life are the same and the laws that govern the health (physio- 
 logical efficiency) of all forms of life, simple and complex, are much 
 the same. Under these laws, the health of every living thing is de- 
 pendent upon (i) the remedy and correction of physical defects; (2) 
 adequate nourishment; (3) the effective removal of waste products; 
 (4) normal exercise of normal functions; (s) recreation, play and rest, 
 and (6) the avoidance of injury. No policy of personal health control 
 can be successful if any one of these requirements is neglected. Wise 
 habits of exercise will not lead to good health if the individual has bad 
 habits of rest. The man that exercises wisely and rests wisely but pays 
 no attention to a mouth full of decayed teeth can not expect to be in 
 the best of health. 
 
 Furthermore, these same laws apply in a general way to the health 
 problem of every living cell, whether of animal or vegetable origin. 
 Some animal and plant organisms are very complex, others are relatively 
 simple. The ameba is a simple one-celled animal. The same general 
 laws of health govern the one cell of the ameba and each of the many 
 millions of cells of which the individual human is made. Each one of 
 those cells is an individual requiring the repair and correction of 
 physical defect, nourishment, exercise, the removal of wastes, rest, and 
 protection. A great army of our tissue cells are grouped together to 
 form our voluntary muscles. Millions of other cells are combined and 
 organized into our brain and nerves. A host of bone cells form the 
 skeleton. Myriads of other special cells make the skin. The stomach 
 and intestines are lined with an infinite number of gland cells which 
 secrete the juices with which we digest our food. The heart is a bundle 
 of specialized muscle cells. These and other specialized cells in your 
 body and mine are living together in a great community obeying the 
 same laws of repair, nourishment, exercise, rest, and protection. 
 
 The large tissue masses that form our voluntary muscles are made 
 up of great numbers of muscle fibres. Each fibre is a delicate, com- 
 plex thread of tissue. The longer fibres may measure an inch in length ; 
 the diameter may be as little as one five-hundredth of an inch. Each 
 fibre is a distinct individual. It receives food from the blood fluids 
 with which it is surrounded. It builds its own structure out of this 
 "food." From this same supply it manufactures and stores up the 
 chemical substance or substances with which it does its work. When 
 there is work to be done these stored-up chemicals become active and 
 in some marvelous way the fibre is made to shorten and the muscle 
 contracts. These chemical events are accompanied by the formation of 
 chemical products or wastes which would poison the fibres, and other 
 tissues too, if those wastes were not quickly removed or neutralized. 
 
 123 
 
These wastes pass from the fibres into the lymph and venous blood 
 streams which drain the muscles and are neutralized by agents in the 
 blood; or they are carried by the blood to the excretory organs, chiefly 
 the lungs and kidneys. When all the health habits of the muscle fibre 
 are good habits the fibre will be healthy, efficient and strong. If it 
 does no work or takes no exercise it will degenerate and atrophy. If it 
 is bathed in a sluggish lymph or blood stream that is never stirred up 
 by exercise, it will be poisoned by the injurious chemical products of 
 its own vital activities. If it has no rest, it will be unable to repair its 
 structural injuries or replace its functional losses. Any of these bad 
 habits of muscle-fibre hygiene may be sufficiently injurious to make the 
 fibre weak and unhealthy. 
 
 The same description applies with but little variation to all the tissue 
 cells of the human body. 
 
 XI 
 
 DEFENSE OF HEALTH THROUGH HYGIENE— Continued 
 
 From what has been said it is evident that the general problems of 
 personal health — ^the problems of resistance and defense of the human 
 body against disease — are problems of repair, nourishment, excretion, 
 exercise, recreation, play, rest, and protection. 
 
 The defense of the individual through the repair and correction of 
 physical defects has been discussed with the contributory causes of 
 disease. 
 
 The protection of the individual from the various causes of disease 
 and injury has been discussed with the agents that injure health. 
 
 Defense through adequate nourishment. Every tissue cell and every 
 organ must be adequately nourished in order that the human being of 
 which it is a part may be in resistant health. Adequate nourishment 
 depends on (o) the digestibility of the food; (h) its composition; (c) its 
 preparation; (d) the amount eaten; (e) conditions under which the food 
 is eaten; (/) habits of mastication; (g) condition of the digestive tract; 
 (A) the after-meal habit of the individual. 
 
 The Digestibility of Food. — Experience has taught us that the fol- 
 lowing foods are usually not easily digested : Fried foods and all greasy 
 foods ; corned beef and cabbage ; soft, hot breads, rolls, and cakes ; very 
 sweet foods ; uncooked bananas. On the other hand, we know that one 
 individual may digest easily a food that another can not digest at all. 
 It follows, then, that each individual must learn by experience what 
 his digestive possibilities and limitations are. Some humans thrive on 
 corned beef and cabbage; others are unable to handle milk. 
 
 124 
 
The daily dietary should contain a mixture of protein, fatty and 
 carbohydrate food, with normal saline constituency, fruit, and water. 
 Protein food is found in meats, fish, eggs, milk, cheese, and some vege- 
 tables, such as peas, and beans. Carbohydrate food is furnished in 
 larger quantities by the various cereals and vegetables. Bread is our 
 chief source of carbohydrate food. Fat is found chiefly in butter, meats, 
 and oils. The salts present in meats, fish, vegetables, cereals, and water 
 are ordinarily adequate to meet the needs of the tissue cells. We habitually 
 salt many of our foods in order to make them more palatable. In 
 doing this we at the same time furnish saline "food" to the tissue cells. 
 Fruit foods and water as a "food" need no further comment here in 
 this connection. 
 
 A food of relatively easy digestibility and containing ample nourish- 
 ment may be made difficult of digestion through careless or unwise 
 preparation. Fried food is more difficult of digestion than less greasy 
 food. The cooking may make the food tough, leathery, or hard, and 
 therefore, not easy to masticate. Poor cooking produces soggy, sticky 
 food that is unpalatable and hard to digest. The aim of cooking should 
 be to destroy the organisms present in the raw food; to make the food 
 more digestible through the action of heat on the food, and to produce 
 a pleasing, appetizing result. 
 
 The amount of food one should eat varies with age, occupation, 
 weight, and general condition. The very young and the old need less 
 food than the robust, active adult. The miner needs more food than 
 the stenographer; the big man more than the small man; and the well 
 man more than the sick man. Under ordinary circumstances it is un- 
 wise to limit the diet to one sort of food. It should be a mixture of 
 the several varieties of food. There should not be an excess of pro- 
 tein. Milk, eggs, and cheese furnish a safer protein food than do the 
 meats because they contain a lesser amount of the purin bodies. These 
 bodies add to the labors of the kidneys and the liver. 
 
 The conditions under which food is eaten have a great deal to do 
 with its digestion and, therefore, with its nutritional service. Disa- 
 greeable emotions depress or stop the secretion of digestive juices and 
 the movements of the digestive tract. Agreeable emotions, especially 
 those associated with food, encourage and stimulate such secretions and 
 movements. Attractive table service, appetizing odors, sightly foods, 
 pleasant company, and general conversation are conditions that help 
 digestion and lead to better nourishment. 
 
 Food that is eaten slowly and thoroughly chewed is more easily and 
 rapidly digested than that eaten in chunks. Leisurely eating with 
 effective mastication is a logical accompaniment with the conditions of 
 
 12S 
 
good cheer discussed in the preceding section. One can not secure 
 favorable meal environment and good digestion if he hurries to his 
 meals, through his meals, and from his meals. 
 
 The problems of nourishment are complicated in all cases in which 
 gastric or intestinal indigestion exists. Such indigestion is frequently 
 the result of mistakes made by the individual. The treatment is usually 
 concerned with the quality of the food, its digestibility, its composition, 
 preparation, quantity eaten, conditions under which it is eaten, and the 
 after-dinner habits of the eater. Nervous irritability is perhaps the most 
 common cause of indigestion. 
 
 The after-meal activities of the individual have much to do with 
 the digestion of his food. Heavy muscular exercise at such a time is 
 accompanied by a cessation of all digestive movements. Disagreeable 
 emotional states bring on the same results. Each meal should be 
 followed by an interval of quiet, pleasant relaxation, or at most, only 
 light exercise. The appropriate duration of this period must vary witR 
 different individuals and at different times with the same individual. 
 
 XII 
 
 DEFENSE OF HEALTH THROUGH HYGIENE— Continued 
 
 Defense through excretion. The health of every tissue cell depends 
 further upon its relief from the influence of chemical products of its vital 
 activities and the chemical products of the vital activities of other tissue 
 cells. Muscular exercise is the most powerful agent concerned in the 
 more rapid and effective removal of wastes. This result is accomplished 
 through the effect of muscular exercise on the movement of the blood 
 stream, and on the respiratory activities of the lungs. The secretions, 
 excretions, and wastes from the tissue cells finally leave the body by way 
 of (a) the respiratory tract, {b) the skin, (c) the bowels, {d) the genito- 
 urinary tract. The excretory activities of the lungs and the kidneys are 
 the most important. The regulation of these functions: (a) The lungs 
 should be well ventilated with clean, fresh air; (&) the kidneys are 
 likely to do their work better and with less injury to themselves when 
 one drinks six or eight glasses of water a day and eats meat only in 
 moderation; (c) the bowels should move naturally and effectively at 
 least once a day; {d) and a moderate sweating with regular bathing 
 and clean underclothing are likely to keep the skin in a healthy con- 
 dition. Regular and reasonable habits of muscular exercise and bathing 
 give us our best method of regulating these various excretory functions. 
 
 The health of every tissue cell and, therefore, the health of every 
 
 126 
 
organ and of every human being depends further on the exercise of the 
 normal function of the tissue cell. Eyes that never see lose the power 
 of vision. Children that never hear do not learn to talk. Nerve cells 
 that are not used do not develop but rather deteriorate. Muscles that 
 do not work grow small and weak. We exercise most of our tissue 
 cells and organs to some extent at least because we have to. The heart 
 does its work regardless of what we think about it. We can't help 
 breathing. We feel, see, hear, taste and smell, and thus exercise the 
 organs concerned, without any deliberate plan for their exercise. The 
 exercise of the nerve cells concerned with mental activity has become 
 one of the responsible burdens of society. It is through the wise exer- 
 cise of these cells that healthy, educated minds are produced, and it is 
 for this purpose that schools have been established and various systems 
 of education applied the world over. 
 
 The muscles need exercise as much as the nerves do. They are too 
 often neglected with injury to themselves and with injury to the gen- 
 eral health of the whole body. Regular, interesting, muscular exercise 
 should be a part of the daily routine in every human life. The bene- 
 ficial effects of such muscular activity are far-reaching and most valu- 
 able in their influences on health. Through general muscular exercise 
 we are able to affect the nourishment, excretion, and exercise of prac- 
 tically the whole great community of tissue cells that form the human 
 body. The effects of exercise may be summarized as follows: 
 
 (a) An immediate, transient, local increase in the blood supply of 
 the muscle. 
 
 (b) An immediate, transient, local increase in the lymphatic and 
 venous drainage of the muscle. 
 
 (c) An immediate and transient increase in the heart rate, blood 
 pressure, and rate of respiration. 
 
 (d) An immediate and transient increase in the superficial circula- 
 tion. 
 
 (e) A later, more lasting increase in the size, strength and func- 
 tional endurance of the exercised muscle. 
 
 (/) A later, more lasting decrease in the length of the exercised 
 muscle. 
 
 (g) A later, more lasting increase in the size and strength of the 
 tendons, ligaments, sheaths, bones, and joints directly associated in 
 exercise. 
 
 (h) A later, more lasting increase in the size and efficiency of the 
 nerve cells in the exercised motor centres. 
 
 ( i) An improvement and perfection of old neuromuscular co- 
 ordinations. 
 
 127 
 
(/) The establishment of new neuromuscular coordination with the 
 possibility of developing new parts for the afferent and efferent nerve 
 impulses. 
 
 {k) An increase in the size, strength, functional endurance and 
 efficiency of the heart. 
 
 (/) An improvement in the regulation of the vasomotor balance. 
 
 {m) An improvement in the blood and lymph circulation. 
 
 (m) An increase in the strength, endurance, and coordination of the 
 musculature of respiration. 
 
 (o) An improvement in the depth and the rhythm of the thoracic 
 and diaphragmatic movements governing the ventilation of the pul- 
 monary alveoli, and augmenting the speed of the general lymphatic and 
 venous circulation. 
 
 (/>) An improvement in the operation of the heat- regulating 
 mechanisms. 
 
 {q) A perfection of the mutual neuromuscular coordinations asso- 
 ciating cardiac, circulatory, pulmonary, and vasomotor activities. 
 
 (r) An increase in general katabolic activity. 
 
 (j) An increased circulation of the products of the chemical activi- 
 ties of all the tissues and organs associated directly and indirectly in 
 physical exercise. 
 
 (^) A larger hormone effect of these products (among them carbon 
 dioxide, acid potassium phosphate, sarcolactic acid, ammonia, creatin, 
 and the endogenous purin bases). 
 
 (m) An increase in the elimination of carbon dioxide by the lungs; 
 of water and carbon dioxide by the skin; of uric acid and creatin by 
 the urine. 
 
 {v) A desire for rest after exercise, and a desire for sleep at the 
 end of the day. 
 
 {w) An improved appetite, better digestion, more food in the blood 
 for the tissues, a greater demand for food by the tissue cells (a be- 
 nignant circle). 
 
 {x) An increase in the anabolic activities of all the tissues concerned 
 directly and indirectly in exercise, with, therefore, a general structural 
 and functional benefit. 
 
 (y) A gain in weight or in increased growth, or both, continuing 
 until the metabolic equilibrium is re-established. 
 
 {z) A perfection of the physiological efficiency of the whole organ- 
 ism, with consequently 
 
 (aa) A better development of the powers of potential and active 
 immunity. (Storey in Hare's Modern Treatment. Vol. i, p. 192.) 
 
 128 
 
XIII 
 
 OUR DEFENSES AGAINST FATIGUE 
 
 All living things require appropriate and adequate periods of rest. 
 Every active moment in the cells, tissues and organs of the human 
 body is a moment in which the living cells use up their stores of energy 
 and subject themselves to structural wear. Every passive moment is 
 used by these same cells for recuperation and repair. Wherever there 
 is life there must be chemical change, with the formation of various 
 chemicals, some of which are appropriately called waste products 
 (fatigue products). If life is to continue there must be a restoration 
 of the chemical substances used and a removal of the wastes formed. 
 We find everywhere that nature has established resting periods of rest- 
 ing stages in which to counteract the effects of activity, that is, of 
 fatigue. Rest is nature's treatment of fatigue. 
 
 There are three types of fatigue, which may be designated as (i) 
 normal fatigue, (2) acute fatigue, and (3) chronic fatigue. 
 
 Normal fatigue or general fatigue is a summation of the normal 
 daily fatigue of all the cells of the body. We rest, we sleep, in order 
 to rest our muscle cells, our nerve cells, our gland cells, all of our tissue 
 cells. Normal fatigue brings on a desire for rest and sleep. Fatigue 
 that is not relieved by rest and sleep is not normal fatigue. Such 
 fatigue is a symptom of poor health and is usually the result of bad 
 habits of hygiene. If one is wise in his daily habits of health, if his 
 habits of nourishment are good, if his habits of exercise are reason- 
 able, if he takes good care of his excretions, if his habits of rest are 
 right, he will accomplish his day's work with no left-over fatigue 
 burden from yesterday and will pass no such burden onto to-morrow. 
 Such a man is "fit" to-day because he lived right yesterday. He can 
 depend on himself to-morrow because he is taking care that his tissue 
 cells are properly fed, cleaned, exercised, rested and protected to-day. 
 His fatigue is normal and transient because he is a normal, healthy 
 human being. 
 
 If a muscle is made to lift a weight rapidly it soon tires. After a 
 short interval of rest, a few seconds or minutes, perhaps, the muscle 
 recovers and is able to do quite as much work as it did before. The 
 trained athlete falls exhausted at the end of the hundred-yard dash. 
 In a few minutes he is ready for another race. If the hod-carrier or 
 the bricklayer or the coal-heaver speeds up his pace he soon tires. If 
 he then rests he soon recovers. These are samples of acute fatigue. 
 We may have acute fatigue of the heart, the lungs, of the eyes or the 
 
 129 
 
ears, or any other active organ, which can be relieved by appropriate 
 rest. Acute fatigue is often accompanied by injury when the activity 
 causing the fatigue is sustained too long. This is especially true when 
 the active organs are weak, malformed, or otherwise out of condition. 
 
 Chronic fatigue is brought on by careless health habits which pre- 
 vent the removal of the fatigue effects of one day's work before the 
 next day's work is undertaken. If one rests or sleeps too little there 
 will not be sufficient time for the repair of injuries, the restoration of 
 losses, and the removal of waste products. If one's nourishment is in- 
 adequate from any cause inside or outside the body, there will be in- 
 sufficient material in the blood for restoration and repair. If the ex- 
 cretory activities are inadequate the accumulation of waste products 
 (fatigue products) in the blood will subject the tissue cells to con- 
 tinuous injury and there will be no real rest. If one takes no exercise 
 the processes of cell nourishment and cell excretion will be inadequate. 
 Thus the persistent influence of a habitual neglect of any one of these 
 health requirements makes it difficult or impossible for the tissue cells 
 to recover from the losses that occur during each day's work. Under 
 the influence of these bad health habits normal fatigue becomes ab- 
 normal fatigue, acute fatigue comes on more easily and is more likely 
 to be harmful. Each day, then, inherits a fatigue injury from the day 
 before and each day receives a health injury from the day before. The 
 worker then finds himself "out of condition." He is always tired. The 
 morning brings him a dark-brown taste and the world is colored yellow. 
 His brain is dull. His head aches. He makes mistakes in his work. 
 His efficiency is lowered. Sooner or later his health is broken and his 
 job is gone. 
 
 Chronic fatigue comes with poor health habits. Chronic fatigue, 
 poor health and poor morals are frequently associated. We sometimes 
 discover fine character in association with the irritable disposition, bad 
 breath and acne that comes with chronic fatigue, but we are not sur- 
 prised if those symptoms are accompanied by various petty vices or 
 even a few of grosser dimensions. Somehow we do not look for 
 happy homes, well-trained children and satisfied parents when chronic 
 fatigue has loaded the father or mother with a burden of mental worry, 
 nervous indigestion and insomnia. 
 
 The stenographer or clerk whose monotonous days of close applica- 
 tion are followed by nights of excited search for compensating pleasures 
 are too often willing to sacrifice moral standards in that search. The 
 occurrence of misconduct, low morals, petty vices and gross vices in 
 company with fundamentally bad hygiene and chronic fatigue is com- 
 mon. There may be no scientific relationship, but the association is 
 
 130 
 
there. The fatigue and health factors are in bad company and we are 
 very liable to judge facts as we judge people — ^by the company they 
 keep. 
 
 The lessons we have learned from the truant and unruly boy, the 
 records of cases in our juvenile courts, reform schools and peniten- 
 tiaries, the stories of our nervous patients, our insane and our suicides, 
 all teach us that there is an intimate relationship between fundamentally 
 bad hygiene, chronic fatigue and mental and moral irregularities, mis- 
 conduct, and crime. 
 
 He that carries a heavy mental or physical labor and fails to lead 
 a rational physiological life is not necessarily a criminal; he need not 
 be immoral; he may support his load of fatigue and bad hygiene with 
 moral success. He may be only tired, irritable, nervous and dyspeptic. 
 But such men do not as a rule make the best husbands, the best fathers, 
 nor the best citizens. Such men and women can not be relied upon to 
 choose wisely between right conduct and wrong conduct. Their habits 
 of relaxation and rest often bring no relaxation and no rest. The 
 clouded judgment of poor health and chronic fatigue blurs clear vision 
 and makes the choice of legitimate recreation difficult. The irritability, 
 the restlessness, the dissatisfaction that come at the end of the fatiguing 
 day, as a result of fundamentally bad hygiene, have led many a man 
 and many a woman to search for recreation, for change and for pleasure 
 where the recreation is a further drain, where the change is for the 
 worse, and where the pleasure is immoral. 
 
 And so I would urge you most seriously to obey these several laws 
 ot health. Exercise wisely. Rest wisely. Give proper consideration to 
 the importance of clean, healthful recreation and amusement. And I 
 would insist that these important health habits should be combined with 
 the wise health habits of nourishment, and excretion, and with an in- 
 telligent treatment of all injurious physical defects. A policy of per- 
 sonal health control which develops reasonable habits along these various 
 lines is a policy which obeys the laws of all nature and must inevitably 
 lead to a full realization of the health possibilities of the individual con- 
 cerned. 
 
 Finally, I would point out to you the fact that you and I are de- 
 pendent on the community in which we live in much the same way and 
 for much the same reasons that our tissue cells are dependent upon us. 
 If we supply these citizens of our bodies with the food they need, if we 
 look after the removal of their excretions, if we give them reasonable 
 exercise and rest, if we repair their injuries and protect them from 
 harm, we are supplying thei^^with the necessities of life. In the same 
 way we, the citizens of another community — a community of humans — 
 
 131 
 
depend on the social forces under which we live for our necessities. 
 An army of human beings connects us with the garden, the dairy, and 
 the farm, bringing us the food we must have. A myriad of laborers 
 of all sorts provide us with the water we need. The work of many 
 men is responsible for the removal of our excretions and wastes. A 
 great group of teachers exercises the minds of our children so that they 
 may grow in mental efficiency. Our institutions, municipalities, and 
 commercial units are tending more and more to provide adequate op- 
 portunities for our normal • physical exercise, recreation and rest. A 
 band of public and private servants remedy our physical defects and 
 protect us from disease, injury and violence. 
 
 XIV 
 
 CARE OF SPECIAL ORGANS 
 
 I. The shin is very likely to show the effects of malnutrition, de- 
 fective excretion, lack of exercise, imperfect rest, and local injury. 
 The care of the skin, then, involves the care of the general health, pro- 
 tection from mechanical, physical, chemical or parasitic injury. It 
 further involves more specially, regular habits of exercise and bathing. 
 
 The sweat glands of the skin should be regularly active. Recrea- 
 tional physical exercise is the most attractive and on the whole the most 
 effective means of securing this result. Such exercise should be fol- 
 lowed by a bath. Bathing is a health habit of great importance; first, 
 because it is necessary to cleanliness; and, second, because it is an 
 effective means for the exercise of the muscular and nervous mechan- 
 isms concerned in the control of the blood supply to the skin — ^the ex- 
 ercise of the vasomotor mechanism in the skin. 
 
 One should bathe enough to keep clean. This may call for a bath 
 a day, particularly in the summer time. The bath should not be of long 
 duration, especially if the water is hot. The finish of a bath should be 
 cool. A cold bath that is not followed by a warm glow on the skin is 
 a bath to be avoided. A cold or cooler finish to the bath leaves the 
 blood vessels of the skin stimulated and active, and, therefore, better 
 able to protect the organisms against drafts and cold. Under such cir- 
 cumstances the skin is more likely to be a healthy skin and perform its 
 various functions — excretory and others — effectively. 
 
 Some skins are sensitive to soap, and other cleansing fluids; even 
 water itself is an irritant with some people. These rare cases call for 
 the expert advice of a skin specialist. 
 
 132 
 
XV 
 
 CARE OF SPECIAL ORGANS— Continued 
 
 2. Care of the Muscles. — Recreational muscular exercise is one of 
 our most important health habits. For various reasons it may be safe 
 to state that it is our most important health habit because of its far- 
 reaching influence upon the health habits of all the other organs of the 
 body. 
 
 The best time for physical exercise is late in the morning or during 
 the latter part of the afternoon. Most of us, however, must take our 
 recreational exercise when we get the chance. 
 
 One should not exercise vigorously on a full stomach. There should 
 always be an interval of comparative quiet after meals. 
 
 Exercise is more beneficial if taken out of doors with pleasant sur- 
 roundings. Indoor exercise is better than no exercise. 
 
 The best exercises are those that are interesting. 
 
 Exercise should be regular. It should be sufficiently vigorous to 
 stir up the circulation, increase the rate of breathing, and induce sweat- 
 ing. It should be followed by a bath and a change of underclothing 
 if some sort of a uniform is not worn during the period of exercise. 
 
 3. Care of the Nerves. — ^A wise care of the nervous system involves 
 other factors nowadays than those that operate in our educational 
 systems. One's problem of "nerves" may be more difficult because of 
 a heritage that has made him susceptible to nervous derangement. But 
 with or without such a legacy it is important to protect one's "nervous 
 balance" with wise health habits. The stability of the nervous system 
 depends very largely on reasonably regular habits of daily life — habits 
 of protection, repair, nourishment, excretion, exercise and rest. Nervous 
 instability with poor nervous health may follow such influences as the 
 misuse of alcohol ; various infections, notably syphilis ; certain metabolic 
 diseases such as diseases of the thyroid gland and gout; abnormal 
 modes of life; local injuries to the brain; suggestion; auto-suggestion; 
 psychic contagion ; strong emotions often repeated ; disturbance of sleep ; 
 obsessing sexual images and thoughts; and excessive sexual activity. 
 There is an alarming increase in mental and nervous disease in these 
 modern times due to our high tension life, our various dissipations, 
 neglect of regular living, and heredity. 
 
 133 
 
XVI 
 
 CARE OF SPECIAL ORGANS— Continued 
 
 Care of the Vasomotor System. — The care of heat- regulating organs 
 of the body is secured through (a) regular exercise, {b) bathing, (c) 
 clothing, and {d] the ventilation and heating of the buildings in which 
 we live. 
 
 (a) Regular physical exercise accompanied by sweating and fol- 
 lowed by a bath which is terminated by a dash of cold or cool water 
 is a procedure that does much to exercise the vasomotor system and 
 put it in efficient condition; consequently, such habits as these make 
 us less susceptible to "colds" and other respiratory affections. 
 
 {b) A cool or cold sponging of the neck and shoulders on rising in 
 the morning or a cool or cold shower or tub bath at that time followed 
 by a brisk rubbing of the skin with a coarse towel will improve the 
 action of the heat-regulating mechanisms of the body. Some individuals 
 can not stand cold bathing. If one is blue and cold after his bath and 
 does not react he should not attempt such habits. 
 
 (c) Clothing should be worn for comfort. If the room temperature 
 is between 64° and 68° F. the underclothing should be as light as that 
 worn in summer. One will do better to depend on heavy clothing — 
 overcoats, high overshoes, and gloves — when he leaves a warm room 
 for the cold exterior in the winter, than to perspire in the house be- 
 cause of heavy clothing and a high room temperature and then meet 
 the outer cold with damp underclothes and a poorly trained vasomotor 
 system. 
 
 The underclothing and the outer clothing should be porous. Rubber 
 clothing and tightly woven fabrics do not permit ventilation througfi 
 their textures. They lead, therefore, to excessive surface heat and 
 consequent perspiration without evaporation and drying. 
 
 XVII 
 
 CARE OF SPECIAL ORGANS— Continued 
 
 Care of the Kidneys. — The kidneys are the chief excretory organs 
 of the body. Their labors are increased if the other organs of excre- 
 tion are inactive. One protects his kidneys when he keeps his skin 
 active and his bowels open. If one drinks too little water, his urine 
 will be concentrated, acid, irritating, and reduced in amount. Six or 
 eight glasses of water a day will dilute the urine and save the kidneys 
 
 134 
 
in the normal individual. Alcoholic drinks, excessive meat diet, too 
 much sugar, and rhubarb are influences that injure the kidneys. 
 
 Care of the Bowels. — The bowels should move effectively at least 
 once each day. A glass or two of water before breakfast; a diet in- 
 cluding cereals, milk, coarser bread, vegetables and fruits; regular 
 habits of general exercise, and regular habits of defecation, will keep 
 the bowels free and regular. It is unwise to depend on medicines. 
 The habit is the thing. 
 
 XVIII 
 
 CARE OF SPECIAL O'RGA.'iiS— Continued 
 
 The care of the reproductive organs is a matter of supreme im- 
 portance from the point of view of heredity and healthy offspring. 
 
 Gonorrhea does more to make men impotent and women sterile than 
 any other — ^perhaps more than all other causes combined. Gonorrhea 
 is avoidable. 
 
 Syphilis is the most important infectious disease in its destructive 
 influence on the germ cells of men and women, and syphilis is avoid- 
 able. 
 
 Alcohol is the most common cause of injury to the germ cells. 
 Drinking is a habit. 
 
 There are other poisons of lesser importance that might be men- 
 tioned in this connection, such as lead poisoning and poisoning with 
 the nitrate of mercury. 
 
 Any influence that injures the germ cells in man or woman is an in- 
 fluence that leads to sterility, early death of offspring, or to bad 
 heredity. 
 
 One's problem of health, then, brings him an obligation not only to 
 himself but also to the lives of his offspring, for whose health and 
 happiness or for whose misery and pain he may be responsible. He 
 must protect himself and his family, his children and his children's 
 children by leading a reasonable, continent, sober life. 
 
 XIX 
 
 CARE OF SPECIAL ORG A'HS— Continued 
 
 Care of the Eyes. — The eyes are frequently infected at the time 
 of birth. A great deal of blindness is due to neglect of the eyes at that 
 time. It should be an unvarying rule that the eyes of all babies be 
 treated with nitrate of silver or argyrol within a few minutes after 
 birth. Either of these two salts of silver will destroy the organisms 
 that are the common causes of ocular inflammation. Such treatment 
 
 135 
 
should be administered only under the direction of the expert nurse or 
 physician. 
 
 Eye infections may be spread through the use of the common towel, 
 facecloth, handkerchief, or napkin. One should always use his own towel, 
 his own handkerchief, his own washcloth, and never the towels, or cloths 
 of others. 
 
 Mild irritations of the eyeball and eyelids are common at all ages. 
 They sometimes become serious. Such irritations may be prevented or 
 cured by washing the eyes two or three times daily with a 2 per cent, 
 solution of boric acid in warm water. The application is best made 
 with an eye-cup or a pipette. 
 
 Intense light causes eye strain. Infants and young children should 
 not be permitted to expose their eyes to the direct rays of the sun or 
 of artificial light of high candle-power. Habits of eye protection from 
 such injury should be taught early in life. 
 
 One should not read with his eyes bared to direct rays of light. In 
 reading, writing, or any other close visual application the light rays 
 should come from the rear of the individual or they should be so 
 diffused as to give adequate illumination without any points or areas 
 of intense, brilliant light in the field of vision. Illumination of vary- 
 ing intensity soon tires the eyes. Long lines, close print, small type, 
 faint impressions, thin letters, ragged, blurred or decorative type, in- 
 definite contrast between print and page; indistinct contrast between 
 color of ink and color of page; glazed or shiny paper; uneven sur- 
 faces (books that do not open flat) ; moving or vibrating surfaces 
 (street-car reading), and excessive or inadequate illumination are 
 factors in the production of ocular fatigue, eye strain, and defective 
 vision. 
 
 Individuals with uncorrected defects of vision are naturally more 
 susceptible to visual fatigue than are persons with normal eyes. Pro- 
 longed reading, writing, or other visual activity often leads to fatigue 
 and eye strain even in normal eyes. 
 
 Defects of vision should be corrected with great care. Glasses 
 should be prescribed and fitted by experts. It is important to get the 
 right lenses. It is equally important to get the right frames and fit them 
 to the eyes. A poorly fitted mounting or frame will destroy the useful- 
 ness of good lenses. The glasses should be so held as to enable the 
 wearer to look directly through the centre of the lenses. His line of 
 vision should be at right angles to the surface of the lens at its central 
 area. Glasses that tilt to one side, frames that are askew, nose bridges 
 that lower the lens so that the wearer sees through the tops of his 
 glasses, are factors that destroy the value and usefulness of lenses. 
 
 136 
 
XX 
 
 CARE OF SPECIAL ORGANS— Continued 
 
 The Care of the Ears. — It is unwise to introduce hard, pointed in- 
 struments into the external canal of the ear. The drum is a very 
 delicate membrane and such procedure may cause it injury and lead 
 to infection. But the more serious problems of ear hygiene are con- 
 nected with the hygiene of the nose and throat. Ear disease and loss 
 of hearing are in the great majority of cases caused by the extension 
 of disease from the nose or throat to the middle ear by way of the 
 Eustachian tube which leads from the nose and throat to the middle ear. 
 
 The habit of sleeping on the stomach is a measure for the prevention 
 of a drainage of fluids from the nose and throat into the middle ear. 
 Babies should be taught to sleep in this position for this reason if for 
 no other. 
 
 It is unsafe to exert much air pressure in blowing the nose. If the 
 nostrils are reasonably free they may be cleared one at a time by blow- 
 ing through one while the other is held closed. 
 
 The hygiene of the nose and throat involves the repair of defects 
 in those air passages and the treatment of their chronic affections. As 
 has been stated before, all obstructions to nasal breathing should be re- 
 moved, adenoids and tonsils should be taken out, and all reasonable 
 measures taken to place the nose and throat in normal condition. Such 
 treatment ought to be undertaken only by the experienced, conscientious 
 and trustworthy specialist. The mere presence of a defect is not always 
 a sufficient reason for its removal. 
 
 The individual will do well to gargle his throat regidarly (or at least 
 when he notes the presence of irritation) with a solution of a pinch of 
 table salt in half a glass of warm water. Such a solution has about the 
 salinity of the tears and serves as a soothing wash. It may be used 
 also for douching the nasal passages, but fluids should not be forced 
 into the nose. If the nasal passages are washed with a stream from a 
 syringe or by snufiing there is danger of forcing, the fluid into the 
 passage to the ear. 
 
 XXI 
 
 CARE OF SPECIAL ORGANS— Continued 
 
 The Hygiene of the Teeth. — All decayed teeth and all dead roots 
 and all root abscesses should be given expert dental attention. The 
 teeth should be cleaned after each meal by brushing them gently 
 with a soft tooth-brush. The brush should be applied with a ro- 
 
 137 
 
tary motion. An unirritating tooth-powder is of service in the morn- 
 ing brushing. A mild salt solution — a pinch of salt in half a glass 
 of warm water — may be used at night. 
 
 The spaces between the teeth are cleaned best by drawing threads 
 of dental floss through them. 
 
 It is impossible, however, for one to keep his teeth free from tartar 
 and green stain without the help of the dentist. Once or twice a year 
 a competent dentist should clean the teeth so that all accumulations of 
 tartar and green stain may be removed from the exposed surface of 
 the teeth in front, on the sides, and behind. 
 
 Sore gums are less likely to appear when the teeth are kept clean, 
 but when the gums do become sore their treatment is a problem de- 
 manding expert dental service. 
 
 The teeth should be examined at least once a year by a competent 
 dentist. All dead roots and all teeth in which the nerves have been 
 killed should be examined by the X-ray. These examinations will fre- 
 quently discover abscesses connected with the buried roots. Proper 
 treatment of such cases often leads to a cure of rheumatism, lumbago, 
 backache, headache, and a large list of other ailments whose relation 
 to "local abscesses" is only recently understood. 
 
 XXII 
 
 CARE OF SPECIAL ORGANS—Continued 
 
 The Care of the Heart and Blood Vessels. — The heart is a muscle 
 and like all muscles it does its best work and maintains its best health 
 while it is regularly exercised. But like all other muscles, it may be 
 given too much exercise. Furthermore, the amount and kind of exer- 
 cise that should be given the heart depends on its condition and on the 
 condition of the more important organs to which it supplies blood. The 
 proper exercise for a sick or crippled heart should be determined by 
 an expert advisor. It should be remembered here that the rational 
 prescription of general exercise must take into account not only the 
 condition of the heart and blood vessels, but of the arteries, the lungs, 
 kidneys, nervous system and other major organs. When there is no 
 such trouble with the heart or other important organs ordinary recrea- 
 tional exercise should be taken. When there is a limitation from these 
 sources, the exercise given may be regulated on the basis of the in- 
 fluence on heart rate, blood pressure and respiratory rhythm. It is easily 
 possible to give beneficial exercise to a seriously crippled heart, and not 
 increase its activity beyond the safe limit of its strength. This result is 
 
 138 
 
accomplished through massage, passive exercise, and slow movements 
 against little or no resistance. 
 
 If the heart receives too little exercise it grows weak and flabby. 
 Its fibres degenerate. The result is an inefficient organ susceptible to 
 injury and disease. 
 
 The heart should not be exercised while the individual is running a 
 temperature. Extra labor at this time may lead to heart disease and 
 heart injury. This is particularly true in the presence of rheumatic 
 fever, diphtheria, scarlet fever and other infectious diseases. 
 
 Acute infections such as "colds" in the head and throat, tonsilitis, 
 and other active infections, even if no fever is present, should be recog- 
 nized as good reasons for not making any increased demands on the 
 heart at the time. 
 
 The hygiene of the heart includes also the removal of all foci of 
 chronic infection in any other organs of the body. We know that 
 heart affections may be caused by infectious material transferred to the 
 heart by the blood from decayed teeth, dead teeth and dead roots, dis- 
 eased gums, diseased tonsils, sore throats, and other areas of chronic 
 infection. The health of the heart then is dependent on the general 
 health of the body, and the care of the heart means also the care of the 
 other organs of the body. 
 
 The poisons produced during the activity of general infectious dis- 
 ease may lead to a degeneration of the heart muscle. The resulting 
 weakness of the heart makes it necessary that the heart be given no 
 relatively heavy work to do until the period of recovery is safely over. 
 
 Alcohol is a very common source of heart injury "When taken regularly 
 or in excess. The alcoholic heart is characterized by what is called 
 "fatty degeneration." 
 
 In conclusion it may be said that heart exercise is essential to heart 
 health; that prolonged heart rest means heart degeneration; that the 
 prevention of heart infections is accomplished through heart rest during 
 acute infections elsewhere in the body and through the successful treat- 
 ment of the chronic infections of the other organs, and that heart weak- 
 ness due to the poisons of febrile disease and such poisons as alcohol 
 calls for greater care in heart exercise until recovery is complete. 
 
 The care of the arteries is intimately associated with the care of the 
 heart. It may be stated, in addition, that the arterial walls harden with 
 age, so that the health problems of older men and women are largely 
 the problems of hardened arteries (arterio-sclerosis). This hardening 
 of the arterial walls is hastened by various avoidable diseases, notably 
 syphilis; by various dissipations, notably alcoholism; and by excessive 
 labor. 
 
 139 
 
XXIII 
 
 CARE OF SPECIAL ORGANS— Continued 
 
 The lungs and the upper air passages are Chiefly organs of nourish- 
 ment and of excretion. Through these organs the blood receives its 
 supply of oxygen from the air which it carries to every living cell in 
 the body. Through these same organs the blood discharges a large part 
 of the carbon dioxide which it receives as waste (fatigue products) 
 from every living tissue cell. 
 
 Lung power, respiratory efSciency, or respiratory endurance is a 
 product of rational respiratory exercise. The lungs of inactive sedentary 
 life are relatively of small capacity and limited efficiency. They fatigue 
 easily and are frequently diseased. The outdoor school, the fresh air 
 school, the open-window school, the porch bedroom, out-of-door Ufe, 
 regular respiratory exercise, muscular activity that induces respiratory 
 activity, are various sources of respiratory exercise where value to 
 lung health in particular and tissue health in general is now widely 
 recognized. 
 
 The health and therefore the efficiency of the lungs are injured by 
 any influence that restricts the free play of the chest wall or the 
 diaphragm. A tight belt, waistband, vest, or tight suspenders, stooping 
 posture, flat chest, spinal curvature, and funnel chest, are exarhples of 
 such influences. 
 
 Lungs that are supplied constantly with dusty air are very likely 
 to become diseased. Such lungs are usually tubercular. The dust may 
 be ordinary dust. It may be factory dust, shoddy, metal filings, emery 
 powder, crushed rock, cement. It may be mine dust, quarry dust, mill 
 dust. The result is quite the same. Smoky, sooty air and air that con- 
 tains gases and chemical fumes leads to respiratory damage. 
 
 XXIV 
 
 CARE OF SPECIAL ORG ANS— Continued 
 
 The Bones Form the Framework of the Body. — This framework 
 serves for the attachment and support of other organs. Some of the 
 bones, notably those of the head and spinal column, protect important 
 and delicate organs. Other bones are levers which under the dominion of 
 the voluntary muscles enable us to move about or to move objects about 
 us. The marrow of the bones manufactures most of the formed ele- 
 ments in the blood — ^that is, the blood corpuscles. 
 
 The most important early consideration in the hygiene of the bones 
 
 140 
 
is their nourishment. Bones that are poorly fed are weak and un- 
 healthy. Undernourished children are "rickety." Their bones may be 
 underdeveloped, deformed and crippled. The undernourishment of the 
 child may be due to the inability of the child to digest its food or to a 
 lack of nourishment in the food it receives. A baby that can digest 
 miik easily starves on soft-boiled eggs and roast beef. 
 
 Constant pressure may cause abnormal bony changes, particularly 
 in early life when the bones are plastic. Tight shoes produce misshapen 
 feet. Tight clothing makes small chests. The mail-carrier is liable 
 to have a low shoulder and a crooked spine. The very heavy man 
 will probably have flat feet. 
 
 Posture tends to produce fixed bony positions. Habitual stooping 
 of the shoulders leads to round shoulders, and flat chest. Persistent 
 efforts to stand in correct posture eventually fixes the good posture as a 
 habitual position. Habits of. posture, standing or sitting, active or 
 passive, tend to impress themselves on the shape of the bony skeleton. 
 The pressure of such habits records itself permanently on the bones. 
 Good habits of posture should, therefore, be established in early life. 
 
 The common injuries to bones are breaks (fractures) due to 
 mechanical causes. These injuries are usually the results of careless- 
 ness and are ordinarily avoidable. Failure to take intelligent care of 
 broken bones not infrequently leads to incapacitating deformity after 
 the break has healed. 
 
 XXV 
 
 CARE OF SPECIAL ORGANS— ConHnued 
 
 The joints of the skeleton make bony movements possible. A poor 
 joint or a stiff joint limits or destroys movement in the bones and 
 muscles directly concerned. Such a joint limits more or less com- 
 pletely the normal exercise of the tendons, ligaments, nerves, and blood 
 vessels that supply the joints, bones, and muscles concerned. It is evi- 
 dent then that the health of joints involves the health of other im- 
 portant organs. 
 
 The most important health habit for the joints of the skeleton is 
 exercise. The movable joints must be moved or they will lose their 
 freedom and possibility of motion. A joint that remains in one posi- 
 tion for a few days becomes stiff. If the position is maintained long 
 the joint grows rigid and motion is impossible. 
 
 The joints, like the bones are affected by mechanical pressure from 
 tight clothing or by habits of posture. The mobility of the joints be- 
 tween the ribs and spinal column may be limited by tight corsets or 
 
 141 
 
vests ; the mobility of the hip joints by tight skirts ; of the joints of the 
 feet by tight shoes, and the joints in general by the postural habits of 
 sedentary inactivity. 
 
 The common infectious diseases of joints are acute rheumatism and 
 gonorrheal rheumatism. The first may be avoided, to some degree at 
 least, through good hygiene of the teeth and throat. A large number 
 of cases of acute rheumatism or rheumatic fever begins with an attack 
 of tonsilitis. Others come from infections of the teeth roots. Chronic 
 local infections in these and other organs may be preliminary to infec- 
 tion of the joints and heart. 
 
 Gonorrheal rheumatism is a joint disease that is usually consequent 
 on a gonorrhea of venereal origin. A life of physical uselessness may 
 be the penalty for contracting an avoidable gonorrhea. Sometimes that 
 penalty falls with relentless cruelty on the innocent victim of a faith- 
 less and guilty mate or parent. 
 
 Dislocations and strains are commonly due to mechanical injury. 
 
 XXVI 
 DOMESTIC HYGIENE 
 
 Domestic hygiene is the regulation of home and family sanitation 
 and hygiene in the health interest of each individual within the family. 
 The problems of domestic hygiene include: 
 
 (o) The location of the house with wise reference to sunshine, 
 weather exposures, soil and drainage, good air, neighborhood nuisances 
 such as smoke, gases, fumes, soot, dust (commoner industrial), offensive 
 odors, garbage, sewage, noise, and dangerous industries, and safety from 
 fire and disease causes and disease carriers. 
 
 (b) Protection of the home from cold in the winter and heat in 
 the summer, through an effective heating plant and sufficient oppor- 
 tunity for ventilation. 
 
 (c) Adequate natural illumination through window surface and out- 
 side exposure and sufficient artificial illumination through oil, gas, or 
 electricity. 
 
 (d) Safe and sufficient water supply. 
 
 (e) Effective garbage removal and sewage disposal. 
 (/) An adequate supply of clean, nourishing food. 
 
 (g) An attractive preparation of food and a pleasing table service. 
 
 (h) Cheerful, happy home life. 
 
 ( *) Wise instruction of children in the practice of health habits — 
 habits of health information (safe literature, reliable lectures and 
 demonstrations, regular health examinations and advice) ; habits of 
 
 142 
 
bodily care (hygiene of the eyes, teeth, skin, etc.) ; habits of health 
 protection (avoidance of the agents that injure health and of pathogen 
 carriers) ; and habits of constructive hygiene for bodily growth, organic 
 development, and functional perfection (products of wise habits of 
 nourishment, adequate excretion, reasonable work, conditioning exer- 
 cise, satisfying recreation, happy play, and sufificient rest). 
 
 (;') Sane preparation for parenthood. 
 
 (k) Reasonable plans for home defense against the causes and 
 carriers of disease from within and from without. 
 
 XXVII 
 
 COMMUNITY HYGIENE 
 
 The successful acquisition and conservation of human health in- 
 volves an education, a material resource, and a legislative and execu- 
 tive power which the single individual does not possess. Such in- 
 formation, resource and power may reside in the community. The 
 individual must look to the community of which he is a part for 
 better health opportunities, wiser health education and more effective 
 health protection than he himself can provide. 
 
 The community can call on experts to plan its defenses against 
 disease and its campaign for health. It can command the financial 
 resource necessary for the scientific construction, adequate equip- 
 ment, effective maintenance and expert administration which such 
 plans may involve. It has the authority to establish and enforce laws 
 necessary for the success of those plans for the public welfare. 
 
 Community hygiene is concerned with: 
 
 (i) The Health Education of the Community. — (a) The mother 
 that teaches her child good habits of nourishment, excretion, exer- 
 cise, rest, and self-protection is giving her child a more valuable and 
 important health education than it can ever secure anywhere else or 
 in any other way. (b) The school that succeeds in teaching health 
 habits to boys and girls is furnishing the community with more 
 efficient women and men and is providing healthier fathers and 
 mothers for future and better homes, (c) The health educational 
 schemes of various community organizations, societies, business firms, 
 churches, colleges, libraries, and civic departments accomplish much 
 in their influence on general health intelligence, (d) Our knowledge 
 of the causes of disease, the carriers of disease, and our defenses 
 against disease is the result of a very great amount of careful, pains- 
 taking, scientific investigation, and is largely an accumulation of re- 
 
 143 
 
cent years. There is much that we do not know. We can not hope 
 for perfect protection against disease until science has taught us how 
 to secure that protection. A substantial encouragement of the 
 scientific study of the causes, carriers and defenses against disease 
 should be a part of the settled defensive policy of every community. 
 
 (2) The repair and treatment of physical defects through (0) 
 the medical inspection of school children, {b) the maintenance of public 
 clinics, medical and dental, and (c) the support of public hospitals for 
 mental as well as for medical and surgical cases. 
 
 (3) Protection from injury through (a) the building code, {h) 
 The sanitary code, (c) Fire laws and fire protection, (c?) Traffic 
 regulation — speed laws. {e) Regulation of dangerous occupations. 
 (/) Regulation of nuisances — smoke, odors, fumes, gases, {g) Iso- 
 lation, suppression, destruction or removal of disease causes and 
 carriers (covered by sanitary code. State laws, etc.) {h) Effective 
 school hygiene. 
 
 (4) Community nourishment through (o) infant feeding. (&) 
 School lunches, {c) Community charities, {d) Community water 
 supply. 
 
 (5) Disposal of excretions through (o) sewage systems. (&) 
 Street cleaning, (c) Regulation of stables, yard privies, pigpens, 
 poultry yards, etc. 
 
 (6) Community recreation and exercise through (o) public parks. 
 (b) Playgrounds. (c) Drives, {d) Recreation centers; and {e) 
 public baths. 
 
 (7) Community rest through (a) regulation of hours of labor; 
 
 (b) suppression of unnecessary noise; (c) time limitation of sleep- 
 disturbing activities. 
 
 The common agents concerned with community hygiene here in 
 New York City are: (a) The schools; (b) the Board of Health; 
 
 (c) the various commissions on water supply; (d) the Tenement 
 House Department; (e) the Street Cleaning Department; (/) the 
 Police Department; (g) the Fire Department; (h) the Department 
 of Charities and Correction; (i) the city hospitals and clinics; (;') 
 the Department of Sewers; (k) the Park Department; (/) the Port 
 Quarantine Station; (m) Board of Ambulance Service; (w) Com- 
 mission of Public Parks; (0) Bureau of Public Baths; (/>) Recrea- 
 tion Commission; and a great number of societies, associations, and 
 enterprises organized voluntarily within the community. 
 
 Every community enterprise that increases the public health, de- 
 creases community disease and delays death. Every such enterprise 
 brings added resource to the community in terms of greater happi- 
 
 144 
 
ness, larger efficiency, and increased productivity. When our citizens 
 are more healthy, when they are sick less, when they get well faster, 
 and when they live longer, they are worth more to themselves, their 
 families and their community. Every community investment that 
 leads to such results is an economy that more than pays for itself in 
 terms of everything that is worth while — from a reduction in crime, 
 insanity, illiteracy, and vagrancy to an increase in culture, morality 
 and thrift, and from a lower tax-rate to a higher idealism. 
 
 XXVIII 
 
 INTER-COMMUNITY HYGIENE 
 
 Inter-community relations, as between towns, cities, States, or 
 nations, involve and emphasize certain special problems in hygiene 
 and sanitation associated with trade, commerce, transportation and 
 other means of inter-community exchange, communication, or con- 
 tact. It is obvious that the chief concern in this special field of 
 hygiene is with inter-community carriers of disease. 
 
 (o) The aerial transmission of disease from one community to 
 another. There is probably no aerial transmission of infectious dis- 
 ease of great community importance. Mosquitoes are known to 
 have been carried seventy miles by the wind. We have, however, gases, 
 odors, fumes, smoke carried through the air from one community 
 to another. Insect and bird life is no respecter of "city limits" or 
 State boundaries. Flies, mosquitoes, gnats — our present information 
 concerning the carriers of disease has not implicated birds. Noises. 
 
 (b) Inter-community water-carriers. The drinking water of one 
 community may be infected from the sewage of another. The fish 
 in common waters may carry disease from one community to another, 
 e.g., fish tapeworm, oysters. 
 
 (c) Railroads as inter-community carriers of disease. Railroad 
 accidents, sanitation of trains, dining-car garbage, sewage from 
 toilets, expectorations in and from cars, cattle trains, manure, dis- 
 eased animals. 
 
 (d) Safety and sanitation of street cars, ferry boats, passenger 
 vessels, and freight vessels. 
 
 (e) Safety and sanitation and regulation of inter-community 
 vehicular traffic. 
 
 (/) Sanitation of cargoes; prevention of the importation of dis- 
 eased animals and diseased animal products; rats; fleas; perishable 
 foods. 
 
 145 
 
(g) Regulation of human carriers; port quarantine; border 
 quarantine; inter-city quarantine. 
 
 {h\ Inter-community education; societies, congresses, commissions. 
 
 ( i) Inter-community laws ; Federal laws in the United States ; 
 international laws. 
 
 XXIX 
 
 SUMMARY 
 
 Our community health defenses have decreased sickness and death 
 from pathogenic organisms enormously during the last century. But 
 we have evidence that our individual health defenses have not been 
 well cared for and that as a consequence here in the United States 
 the death-rate from diseases of decay has recently been growing 
 steadily higher in the various age periods. In America our hearts, 
 blood vessels, and kidneys wear out earlier and more rapidly than in 
 England, France, and Norway. Our habits of individual hygiene are 
 generally poor in this country. It seems that we begin to pay the 
 penalty for our earlier neglect noticeably soon after we reach the 
 age of forty. We find ourselves then in poor health or our re- 
 sponsible friends bury us years before the appropriate time. 
 
 No one can safely estimate the losses we sustain each year in 
 productivity, working time and life itself because of our poor and 
 inadequate health habits, and particularly because of the early neglect 
 of those habits. Our efficient citizenship loses extravagantly and 
 enormously from this source. Our armies are weakened by myriads 
 of men thrown into the military discard because of poor health. 
 
 If when your time comes you belong to the discard in peace or in 
 war it is likely to be your own fault. If your health habits are 
 poor, if your health influence upon your community is not constructive, 
 you will be a liability, and in most cases you will be so because of 
 your own blind carelessness. Your family, your people and your 
 country need the best health there is in you, and they have a right to 
 expect you to give your best. 
 
 Your obligation and your responsibility as an individual, and 
 your obligation and your responsibility as a part of the community 
 in which you live, will always be the same. Each requires, and that 
 justly, that you make every reasonable effort to prepare yourself 
 physically, mentally and morally for the exigencies of life and to in- 
 fluence your community to defend the health of its citizens with all 
 its resource of brains and money. 
 
 146