Cornell TDiniversit^ Xibrar^ OF THE IRew l^orft State College of agriculture (k^'^m Mi. Cornell University Library RT 67.P84 Hygiene and sanitation; a text-bool< for n 3 1924 003 473 273 The original of tliis bool< 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/cu31924003473273 HYGIENE AND SANITATION A TEXT-BOOK FOR NURSES BY GEORGE M. ERICE, M.D. idthor of **a hand-book on sanitation;" "tenement house inspectiokj' "epitome of hygiene and public health;" director, joint board of sanitary control; director op investigation, new york state factory commission LEA & FEBIGER PHILADELPHIA AND NEW YORK 1913 e.v. Entered according to the Act of Congress, in the year 1913, by LEA & FEBIGER, in the OflRce of the Librarian of Congress. All rights reserved TO LILLIAN D. WALD THE PIONEER OF PUBLIC HEALTH NURSING IN THE UNITED STATES AND THE FOREMOST ADVOCATE FOR THE Extension of the scope of THE nurse's WORK THIS BOOK IS DEDICATED IN APPRECIATION AND RESPECT PREFACE The last decade has seen a wonderful expansion of the function of the trained nurse and a great broaden- ing of the scope of her usefulness. No longer are her duties limited to the simple care of the sick. The nurse has become a priestess of prophylaxis. Her work in preventive medicine has become invaluable, She has become an important factor in social, in municipal, and in public health work. No one at present denies the great utility of the nurse's work in the school, in the factory, in the social part of dispensary work, in the milk stations, in the preventive work undertaken by life insurance companies, and in many other public health activities which have been opened to her. In all these activ- ities a fundamental knowledge of the principles of hygiene and public health is necessary for intelligent work and usefulness. This book is an attempt to give the nurse a knowl- edge of the elements of hygiene in its various branches. Disputed points and too detailed instructions on minor points have been avoided. Rules for the care VI PREFACE and treatment of diseased persons have been omitted, as these are taught to the nurses in their regular curriculum in the training school. It is hoped that the book will be useful to the nurse in the discharge of her manifold duties. G. M. P. New York, 1913. CONTENTS CHAPTER I INTRODUCTION TO THE STUDY OP HYGIENE Definitions — Foundations of Modem Hygiene — Conser- vation of Human Resources — The Role of the Nurse in Prophylaxis . 17 CHAPTER II THE HYGIENE OP HABITATIONS Housing and Health — Light and Illumination — Air — Ventilation — Heating — Water Supply — House Drainage — Plumbing — Plumbing Pipes and Fixtures — House Waste Matters — House Cleaning — Disinfection . . 24 CHAPTER III THE HYGIENE OP POODS A'ND FOOD SUPPLY Foods — Food Preparation, Diet, and Preservation — Cereals, Nuts, Fruits, and Vegetables — Meat and Meat Supply — Milk and Dairy Products — Milk Composition and Characteristics — Milk Products — Milk Adulteration and Preservation — Milk Inspection and Testing ... 98 CHAPTER IV THE HYGIENE OP SCHOOLS AND OP SCHOOL CHILDREN The School Child— The School Building— The Care of the Child in School — Excerpts from OfBcial Instructions to Nurses . . ...... 162 vm CONTENTS CHAPTER V THE HYGIENE OF OCCtTPATIONS Occupation and Health — Industrial Factors Influencing Health — Specific Occupational Dangers — Industrial Better- ment .... . . . 190 CHAPTER VI THE HYGIENE OF MUNICIPALITIES Growth of Cities and Health — Control of Public Supplies — Disposal of Waste Matters — Control of Offensive Trades and Public Nuisances — Control and Prevention of Spread of Infectious Diseases 212 CHAPTER VII PEKSONAL HYGIENE Prevention of Constitutional Diseases — Increase of Vital Resistance — Personal Hygiene of the Child — Personal Hygiene of the Aged — Care of the Sick — Sick Room . 222 HYGIENE CHAPTER I INTRODUCTION TO THE STUDY OF HYGIENE Hygiene is the oldest and the youngest of all sciences. Hygiene is the oldest of all sciences because the preservation of life and health is an instinct born in the animal, and the common endeavor of human beings to preserve their health and to prolong their lives is as old as human society and dates from the beginning of manldnd. Hygiene is the youngest of all sciences because it could only become a science when physiology, bac- teriology, and vital statistics had been firmly estab- lished upon a scientific basis. Definitions. — Hygiene is the science and the art, the theory and the practice, of the preservation and the promotion of human health and life. The aim and function of hygiene are the prevention of disease, the prevention of premature death, and the promotion of normal health in human beings. Tbere are a number of branches of hygiene. 2 viii CONTENTS CHAPTER V THE HYGIENE OF OCCUPATIONS Occupation and Health — Industrial Factors Influencing Health — Specific Occupational Dangers — Industrial Better- ment ... .... ... 190 CHAPTER VI THE HYGIENE OP MUNICIPALITIES Growth of Cities and Health — Control of Public Supphes — Disposal of Waste Matters — Control of Offensive Trades and Public Nuisances — Control and Prevention of Spread of Infectious Diseases 212 CHAPTER VII PERSONAL HYGIENE Prevention of Constitutional Diseases — Increase of Vital Resistance — Personal Hygiene of the Child — Personal Hygiene of the Aged — Care of the Sick — Sick Room . 222 HYGIENE CHAPTER I INTRODUCTION TO THE STUDY OF HYGIENE Hygiene is the oldest and the youngest of all sciences. Hygiene is the oldest of all sciences because the preservation of life and health is an instinct born in the animal, and the common endeavor of human beings to preserve their health and to prolong their lives is as old as human society and dates from the beginning of mankind. Hygiene is the youngest of all sciences because it could only become a science when physiology, bac- teriology, and vital statistics had been firmly estab- lished upon a scientific basis. Definitions. — Hygiene is the science and the art, the theory and the practice, of the preservation and the promotion of human health and life. The aim and function of hygiene are the prevention of disease, the prevention of premature death, and the promotion of normal health in human beings. There are a number of branches of hygiene. 2 18 INTRODUCTION TO THE STUDY OF HYGIENE Hygiene may be personal or public, municipal, State, and federal. We may also distinguish particular branches of hygiene, such as the hygiene of housing, food, of school, of industry, etc. Personal hygiene is the science and the art of the preservation and the promotion of iyidimdual health and life by the prevention of constitutional diseases and by the increase of the vital force and resistance of the human body. Public hygiene is the science and the art of the preservation and the promotion of public health by the prevention of environmental causes of disease, and by the improvement of such conditions common to many persons and communities. Sanitary science is the theoretical part of hygiene. It is based upon the investigations of the influence of environmental conditions upon the health and life of human beings, and has for its aim the study of these conditions and their effect upon the health and life of man. Sanitation is the sum total of practical measures undertaken for the preservation of pubUc health. Sanitary art is the practice of public hygiene, the erection of public works for the improvement of public health. Sanitary law or pubUc health law or State medicine are terms applied to the rules, regulations, and laws prescribed by States or municipalities for the conduct of individuals and communities, with the aim to pre- serve and promote public health. Prophylaxis is the study of prevention and preventive measures for the preservation of human life and health. FOUNDATIONS OF MODERN HYGIENE 19 Foundations of Modem Hygiene. — ^Modern hygiene is founded principally upon three sciences: sanitary science, bacteriology, and vital statistics. Sanitary Science. — ^Men have always known their dependence upon the soil upon which they dwell, the air which they breathe, the water which they drink, the food which they eat, the houses in which they live, and the many other external factors by which their life and well-being are so profoundly influenced. It is scarcely more than threescore years that sanitary science, the science of the environmental factors, has been firmly established and the direct causative influence of the various external factors has been fully shown. Chad wick, Farr, Pettenkoffer, and others were the first to establish the effects of soils, waters, foods, clothing, and the general environment of man. Only when the influence of thes^ factors had been demonstrated could hygiene enter the rank of modern sciences. Bacteriology. — ^The greatest impetus toward the establishment of modern hygiene has been given by bacteriology. Pasteur, Koch, and a host of their followers discovered the hidden causes of many diseases which were destroying innumerable human beings, and made possible the prevention of disease by studying and discovering the means of fighting these destructive agents. Vital Statistics. — Sanitary science or bacteriology alone would not have shown their great worth in the struggle of mankind against unfavorable environ- mental conditions had not the science of vital sta- tistics previously been established. 20 INTRODUCTION TO THE STUDY OF HYGIENE Vital statistics may be termed "Public Health Book-keeping." As in economic and financial under- takings it is impossible to determine the exact state of affairs and progress without a system of book- keeping, so it would be impossible to determine the state of public health, its decline and fall, or rise and progress, without vital statistics. By the means of vital statistics the number of persons of various ages, sex, nationality, etc., living in a given period in a given place may be determined, and the actual and natural increment of population, the birth rate, marriage rate, death rate, etc., in a given year, period, or locality may be learned. Vital statistics also show the general morbidity rates, the rates of specific diseases, the probable duration and the expectation of life. Since vital statistics have become an established science among civilized nations, the waste of human life from the various causes and the progress of sanitary endeavor by the efforts of personal, municipal, and public hygiene have become evident. Conservation of Human Resources. — ^The function of hygiene is the conservation of human resources and the prevention of the waste of human life, of which there is still a lamentable and deplorable waste from preventable causes. Upon examining the recorded causes of death in any given community, it is found that only a very small percentage of deaths (less than 2 per cent.) is due to old age. The other 98 per cent, of all deaths are caused by disease and pestilence, by violence and war, by sin and crime. CONSERVATION OF HUMAN RESOURCES 21 Infectious diseases still destroy millions of innocent infants and children. The lives of thousands of adults are still being destroyed by typhoid, tuberculosis, and many other diseases of adult life. Pneumonia, nephritis, and other constitutional diseases are still the causes of innumerable deaths. Many, if not all, of these are largely preventable. Great as is the waste of human life at present, this is incomparably less than in the past. Great sanitary progress has been made during the last and present centuries. The average length of life has been considerably lengthened, the mortality rates have decreased, and many diseases which were among the worst enemies of mankind have either entirely disappeared or their ravages have been materially lessened. The length of life has increased over 100 per cent, during the last few centuries, the progress having been greatest during the nineteenth century. During the sixteenth century the average length of life was from eighteen to twenty years, during the eighteenth century it was a little over thirty years, while at the end of the nineteenth century it reached thirty-eight to forty years. The general mortality rate in London per thousand inhabitants in the year 1680 was 50; in 1780, 40; in 1905, 15.1. In Berlin the rate from 1751 to 1780 was 39.34 per thousand inhabitants; from 1841 to 1870, 28.78; from 1871 to 1900, 26.22. In urban America (white) this rate from 1804 to 1825 was 24.6; from 1826 to 1850, 25.7; from 1864 to 1875, 25.4; from 1876 to 1888, 22.9; and from 1889 to 1901, 21. In New York the rate was 25.99 in 1886, 16.52 in 1908, and 14 in 1912. 22 INTRODUCTION TO THE STUDY OF HYGIENE There has been a great reduction in the mortality from certain diseases like smallpox, yellow fever, diphtheria, cholera, typhoid fever, and malaria. Dur- ing the eighteenth century 50,000,000 people died of smallpox in Europe; in 1900 there were but 3500 deaths from it in the United States. Since 1793 the United States has had 500,000 cases of yellow fever, resulting, it is estimated, in about 100,000 deaths. Since the discovery of the species of mosquito which transmits the causative factor, and the practical preventive measures to which this has led, the cases of yellow fever have been greatly reduced. In Havana there were 4420 deaths from this cause in the eight years from 1891 to 1898, while in the eight years from 1899 to 1906 they numbered but 465.1 The reduction of the mortality rate from typhoid fever has also been great but not yet as marked as that of yellow fever, cholera, and smallpox. Statistics also show a reduction of mortality from other diseases and a consequent saving of human life. Further Possible Prevention of Disease. — ^Though much has already been accomplished in the prevention of disease and in the conservation of human life, a great deal more may be done by proper sanitary measures and hygienic control. According to the calculations of Professor Fisher, "the length of life could easily be increased from forty-five to sixty years, a prolongation of fifteen years. This would result in a permanent reduction in the death rate of about 25 per cent. The principal reduc- ' Report on National Vitality. THE ROLE OF THE NURSE IN PROPHYLAXIS 23 tions would come from the prevention of infantile diarrhea and enteritis (over 60 per cent.), broncho- pneumonia (50 per cent.), meningitis (70 per cent.), typhoid fever (85 per cent.), tuberculosis (75 per cent.), deaths by violence (35 per cent.), pneumonia (45 per cent.), so that the estimate of fifteen years as prolongation of life is a safe minimum without taking into account possible future discoveries in medicine or the cumulative influence of hygiene." The Role of the Nurse in Prophylaxis. — Among those combating disease and death there are few whose work is so far-reaching and whose endeavors are so valuable, or whose work is as important in prophyl- axis as that of nurses. Since Florence Nightingale demonstrated the need and value of the nurse in war, an even more emphatic demonstration has been made of the nurse's value in peace. Not only as an aid to the physician, but also by her own work in prophylaxis, has she become one of the most impor- tant conservators of human life, and her role in the prevention of disease and premature death cannot be overestimated. Within a comparatively short time the number of nurses in the United States has been increased to many thousands. At present the nurse is found not only at the sick-bed in the individual home, but also in the tuberculosis clinics, in factories and workshops, in department stores, in tenement house departments, health departments, and in a great many private as well as public institutions. There is no doubt that her field of work and usefulness will be still further expanded until it will embrace all human activities. CHAPTER II THE HYGIENE OF HABITATIONS Among the factors I of external environment there are few which play so important a role in the life of man as his habitation. Housing conditions are power- ful factors in the preservation of human life and the prevention of disease. It has been statistically proved that the death rate as well as the disease rate of populations is greater in cities than in the country. The density of popula- tion according to area and congestion in localities and overcrowding in houses, bear a direct influence upon death and disease rates. Dr. Farr has shown that death rates increased from 14 per 1000 when there were only 86 persons per square mile, to 26 per 1000 where there were 3399 persons per square mile. According to Dr. Anderson, of Dundee, the death rate in one-room apartments per 1000 was 21.4, in two rooms 18.8, in three rooms 17.2, and in four rooms 12.3, showing a gradual de- crease in death rate with the decrease of overcrowding. There is also an intimate connection between tuber- culosis mortality and morbidity and housing conditions. LIGHT AND ILLUMINATION Natural Light. — Sunlight is essential to the growth of animal and vegetable life; it acts beneficially upon NATURAL LIGHT 25 health, stimulates the metabolism of the body, assists in the oxygenation of the blood. Sunlight is also a powerful germicide and disinfectant; it kills low organisms, fungi, and moulds, is capable of destroying tubercle bacilli within a short time, and is, therefore, indispensible in human habitations. Habitations without direct sunlight are damp, cold, and unhealthy. The amount of natural light within a house depends on: 1. The location and aspect of the house. 2. The sources of light. 3. The location and size of the openings through which it penetrates. 4. The character of windows and of surfaces within the house. Direct rays of the sun give more light than the re- flected lights from adjacent surfaces, walls, trees, etc. Greater light is obtained through horizontal openings on top of the house than from windows in vertical walls. The intensity of light within a house depends on the character of the window glass. There is a loss of light of 50 per cent, through milk glass, 10 per cent, through double glass, and 8 per cent, through plate glass. Prism or ribbed glass, by distributing and reflecting the rays of the light evenly through the room, increases the amount of light. The window area of a room should not be less than 10 per cent, of the floor area; one square foot of glass surface should be allowed for every 70 cubic feet of interior space. Piers between windows should be narrow; window tops should extend to the ceiling, or 26 THE HYGIENE OF HABITATIONS at least to within 6 inches of it. Plate glass is best for transmission of light, unless prism glass is used. Smooth, light, or white colored surfaces of inner walls and floor and ceilings increase the amount of reflected light. Artificial Light. — ^Artificial illumination in the house is obtained from electricity, or from oils, alcohols, water gas, coal gas, and acetylene gas. The value of artificial illumination is judged by its intensity, quality, heat production, amount of impurities, safety, and cost. Electric light may be very intense; ordinary incan- descent bulbs are of 16 to 32 candle power; the recently introduced Tungsten lamps give a more intense light at less cost. Acetylene gas may produce a very intense and brilliant light of from 20 to 160 candle power. The intensity of other lights depends on their material, the character of the burners, etc. Welsbach lights are made of mantles impregnated with earthy silicates, which become incandescent upon slight heating. They give from 60 to 120 candle power. All illuminants, except electricity, produce much heat and give off some impurities, such as carbon monoxide, carbon dioxide, sulphur compounds, am- monia compounds, smoke, soot, and moisture. Acetylene Gas. — ^Acetylene gas (C2H2) is produced by mixing water with calcium carbide, and during this process much heat is evolved. Special generators are manufactured for the production of the gas, and, contrary to the current opinion, there is little danger from explosions, as calcium carbide is not explosive ARTIFICIAL LIGHT 27 either by heat or by concussion. The pipes used for ordinary gas illumination may also be used for acety- lene lights, but the tips of the burners must be smaller. The light is intense, steady, white, and cheap, and is well adapted for houses in rural communities, or, whenever there are no central plants, for the manu- facture of electricity or coal gas. Coal Gas. — Coal gas is' made by heating bituminous coal in air-tight vessels. During this process the compounds of hydrogen and carbon are transformed into other gaseous and solid products. The refined gas contains about 50 per cent, of hydrogen, 35 per cent, of marsh gas, 6 per cent, of carbon monoxide, and 9 per cent, residue. Water Gas. — ^Water gas is manufactured from anthracite coal, steam, and petroleum by a compli- cated process. The refined product contains 30 per cent, of carbon monoxide; 35 per cent, of hydrogen; 20 per cent, marsh gas, and 15 per cent, residue. Because of the greater amount of carbon mon- oxide, water gas is more dangerous to life and health than coal gas. The inhalation of even small amounts of water gas is injurious. Large amounts may become fatal because the carbon monoxide combines with the hemoglobin of the blood and forms an insoluble compound. Coal gas and water gas are manufactured in central plants, from which they are conducted through iron tubes and pipes under the streets into houses, and through a network of smaller iron pipes throughout the houses. The gas-service pipes are made of best wrought iron with malleable iron fittings. The house 28 THE HYGIENE OF HABITATIONS service should be provided with main and secondary stop-cocks, and meters to measure the amount of gas consumed. The gas-service system must be perfectly air-tight, should be exposed and readily accessible, and should be tested for air-tightness by appropriate tests before use. Gas fixtures are of various shapes and values. The intensity of illumination greatly depends on the char- acter of the burner. Argand and Welsbach burners are the best. Excessive intensity of light is controlled by shades and globes. AIR The conditions of the air within houses is one of the most important factors with which the hygienist must deal. Air is a compound gas consisting of several gases. Its chemical composition is as follows: nitrogen, 78.09; oxygen, 20.94; argon, 0.94; carbon dioxide, 0.03; with traces of other gases, helium, kryton, neon, xenon, and hydrogen. The quantity of nitrogen is constant, while the quantities of oxygen and carbon dioxide vary accord- ing to different conditions. In the outside air the variation of carbon dioxide is between 0.03 in the very purest mountain air to 0.04 in the air of city streets. The amount of oxygen does not vary much in the outside atmosphere. Air, like all gases, diffuses itself through space, and its weight is due not only to its chemical constituents. IMPURITIES IN AIR 29 but also to its physical condition, especially to its temperature and humidity. The lower the temperature of the air the heavier it is. Warm air is lighter than cold air. As the temperature of the air at some places is much lower than at other places this difference causes variations in weight and produces a general motion of air through space, a motion which is often perceptible, and, when rapid, is _ known as wind. Air also contains a certain amount of water in the form of moisture. The amount of moisture depends upon the temperature of the air. The higher the tem- perature the greater is the amount of moisture that the air can absorb. When air is saturated with mois- ture, that is, when it contains all the water it can absorb, the excess of moisture is deposited in the form of dew; it has reached then what is known as the "dew point." The utmost amount of moisture which air may contain without reaching the dew point is called absolute humidity. The difference in the amount of moisture which air at a given temperature may actually contain, and that which it must contain in order to reach absolute saturation, is called relative humidity. Impurities in Air. — ^Air may contain certain impurities. These may consist of dust of mineral, metal, vegetable, or animal origin, or of various gases, the most common of which are carbon dioxide (CO2), carbon monoxide (CO), etc. There are many sources of these impurities, such as artificial illumination, artificial heating, dust matter from outside or from the inside of the house, dust and debris from the various processes and work 30 THE HYGIENE OF HABITATIONS carried on within the house. Perhaps the most impor- tant source is the presence of animals within the house. The air which an animal takes in with every breath differs greatly from the air which this same animal expires. The air that a grown-up person expires contains but 16.03 of oxygen and about 0.6 of carbon dioxide. Its proportion of moistiu-e is • also much larger than that of the inspired air. About 4 per cent, of oxygen is lost with every breath an adult person inspires, and this is extracted from the outside air. The amount of carbon dioxide expired is proportion- ately about one hundred times that which is inspired. In the outside air the inequalities due to this consump- tion of oxygen and addition of carbon dioxide and moisture are speedily adjusted by the motion of the air and diffused through space. If outside air is excluded, it is evident that the amount of air within a given space will be sufficient for a person's respiratory functions only for a compara- tively short time; that is, so long as the oxygen in the air does not fall below a certain minimum or the carbon dioxide rise above a certain maximum. Going beyond in either direction causes the air to become irrespirable. The famous "black hole of Calcutta," in which many persons perished for lack of air, is a noteworthy example of the dangers which result from excluding a sufficient supply of fresh air. The Influences of Impurities in the Air upon the Health. — Some of the impurities within the house may have no deleterious effects. Others, in the form of dust, etc., may become injurious when their quantity is too large or when they are of a poisonous nature. INFLUENCES OF IMPURITIES IN THE AIR 31 Certain germs and bacteria may be found in the dust, and other impurities in the air may also become dangerous to health. Of the gaseous impurities, carbon monoxide (CO), from leakage of illuminating gas or from processes of combustion, is very dangerous, as even a small quantity of this gas is poisonous to human beings. The amount of carbon dioxide (CO2) in the air is of considerable importance. While it has been demon- strated that carbon dioxide even to the extent of 4 or 5 per cent, may not be very harmful, there is abundant proof that much smaller quantities are not without injurious influences. Certain organic emanations from animal and human beings have been claimed to be toxic in character and the injurious influence of air which is fouled by the presence of a large number of persons in rooms has been attributed to them. Other investigators, however, assert that the rise in temperature and the increase of humidity which result from overcrowding are the factors responsible for injurious effects, such as listlessness, headache, dulness, vertigo, and loss of appetite. It is definitely known that the constant inhalation of the air in crowded rooms causes anemia, lack of resistance to colds and infectious diseases, and pre- disposes so markedly to pneumonia and tuberculosis that these two last diseases have been called "house diseases." The invigorating influence of hfe in the open air is well known and is greatly relied upon in the modern treatment of tuberculosis. 32 THE HYGIENE OF HABITATIONS VENTILATION By excluding the outside air by means of walls, ceil- ings, and floors, artificial conditions are created. Houses are habitable only as long as some provision is made for the exchange of air from the outside to the inside, and vice versa. The room air which becomes impure must be replaced by a supply of fresh air from without. This interchange of air is called ventilation. The quantity of air which each individual needs depends on a great many conditions beside the air space within tiie house and the rate of influx. The older hygienists based their calculations on the carbon dioxide content and determined the amount at 3000 cubic feet of air per hour. They regarded the carbon dioxide contents of the room air as an index to the general purity and held that whenever it exceeded 0.06, the room air was bad. Natural Ventilation. — ^The main factor in ventilation is not so much the amount of space in the house as the amount of air which enters by various means. Air is a gas, and as such diffuses through space. As most of the materials of which houses are constructed are porous, a certain amount of air enters and leaves through the walls, floors, and ceilings. A certain amount also passes through the cracks, crevices, and other slight openings which are found in even the best constructed houses, near the windows, doors, etc. The motion of air due to differences of temperature and consequently of weight is also an important factor in ventilation. The colder outside air tends to flow into NATURAL VENTILATION 33 the house while the warmer hghter air in the rooms tends to flow out of the house. The greater the differ- ence in temperature the greater the exchange of the air. There is, therefore, some ventilation in every house: (1) Through the porosity of the building materials and the diffusion of the air through these materials, and (2) through various openings due to faulty con- struction, etc. Chimneys also contribute largely to the interchange of air and form flues through which the warm air passes. When the wind blows over the openings of the chimneys it creates a suction or aspiration and large quantities of air are drawn out. The occa- sional opening of doors and windows also serves to allow the influx of outside air and the flowing out of the room air. The value of windows for ven- tilation depends of course upon their use. In ordinary houses, not inhabited by too many persons, these means of ventilation may be sufiicient for all practical purposes. These various methods are grouped under the term natural ventilation. There are also other means by which a larger and more frequent exchange of air is produced. These are openings made in the windows, in the walls, in the floor, or in the ceiling and the roof. They are termed air inlets or outlets, according to their position. Those at the lower part of a room usually serve as inlets for the cold air, while those at the upper parts usually serve as outlets for the warm air. Sometimes the upper sash of a window is movable and tilted so as to allow the air to come in and out, or the glass panes are sliding or in the form of movable 3 34 THE HYGIENE OF HABITATIONS louvers, or the whole glass pane swings on a pivot. Circular openings sometimes are made in the glass pane and are either left open or fitted with a perforated sheet-metal circle revolving with the inflow and outflow of the air. The lower sash may also be raised and have a board placed beneath, thus allowing the air to get in upward through an opening between the upper and lower sashes. The walls may also assist in ventilation by special devices consisting either of perforated bricks, or boxes made to fit in the wall, with openings allowing the inflow of air. Such open- ings may also be made in the ceilings and roofs. There are innumerable devices all serving as means of ven- tilation in ordinary houses. They are probably suffi- cient under all normal conditions. Mechanical Ventilation. — ^This means removal of the air from the room or introduction of air into the room by mechanical means. There are two methods : vacuum and plenum. The best method is that carried on from a central location and is a combination of the plenum or pro- pulsion method with the vacuum or exhaust method. The air from the room is exhausted by mechanical means and is removed through a system of openings and tubes, and at the same time fresh air from without is mechanically introduced through tubes and openings. The advantages of mechanical ventilation are many, for they permit control not only of the quantity and velocity of the air brought into the room, but also its temperature, moisture, and purity. The tempera- ture of the air before it is introduced may be regulated by passing it over heated or cooled coils. The amount MECHANICAL VENTILATION 35 of moisture may also be regulated and the dust or impurities may be extracted by passage through filtering media. Mechanical means of ventilation are employed especially in schools, factories, theatres, and other public places where large numbers of persons gather within a room. Parkes and Kenwood summarize the essential and practical points of ventilation as follows: "1. When air is heated, it expands and tends to rise; when air is cooled, it contracts and tends to fall, "2. Cold air tends to enter a room and to move about very much as water would; and this holds true so long as the temperature of the fresh air remains lower than that in the room. "3. The extent of inlet provision is not quite of the same importance as that for the exit, of foul air; for if foul air is extracted in sufficient quantities, fresh air will enter somehow to replace it, as by skirtings, crevices in doors or windows, or even through brick- work in walls. "4. While the inlet provision for fresh air should average 24 square inches for each individual, several small inlets not too near each other are preferable to one large one; and the provision of inlet areas somewhat larger than those of exit tends to minimize draughts. "5. Inlets should be as low in the room as possible — i. e., just above the floor (so as not to raise the dust) — if the outside air is warm or has been warmed prior to entry; but at a height of five feet or more if the out- side air is cold; otherwise unpleasant draughts are experienced. As a further protection against unpleas- 36 THE HYGIENE OF HABITATIONS ant draughts when cold air is admitted, the incoming air should be directed upward; while hot air, since it tends to rise, should be directed downward. "6. If possible, outlets should be so placed that vitiated air is drawn toward them before mixing with the general air of the room. " 7. The tendency for fresh air to take a direct course to the outlets must be overcome by judicious selection of the positions of inlets and outlets. "8. Methods of ventilation devised to ventilate crowded premises are generally inefficient unless the incoming air can be warmed in winter to about 60° Fahrenheit, for efficient ventilation by cold air connot be tolerated, and there is a great tendency among workers to close all ventilating inlets. "9. With less than 250 cubic feet of space for each person, ventilation can never be satisfactory without the aid of mechanical force. " 10. The source of incoming air should be considered. It should not be borrowed from adjoining rooms, but taken directly from the outside. One great advantage of the more expensive mechanical system of ventilation is the fact that sufficient air can always be obtained from a source that is known and selected. "11. Ventilation dependent on the extraction of foul air is more convenient and satisfactory than that in which propulsion is mainly relied upon; but the purity of the air is not provided for so easily. " 12. Warmed air forced into a room should be raised only to a temperature sufficient to prevent a feeling of cold (about 60° Fahrenheit). More highly heated air is often felt to be overdry and unpleasant." METHODS OF REGULATION OF TEMPERATURE 37 HEATING The human body may be accustomed to bear great variations in external temperature providing the change from one extreme to the other is not too sudden and providing the equilibrium of the body temperature is maintained by proper clothing, food, and muscular exercise. In most parts of this country during a large part of the year the temperature of the air within the rooms and houses would be too low for comfort and health if it were not raised by artificial means. There are certain hygienic demands for heating houses which may be formulated as follows: 1. There must be an equable temperature within the house and the heating apparatus must therefore be easily regulated. 2. The heating must be continuous so that there is no sudden fall of temperature during night. 3. The heating should not add any impurities to the air in the form of dusts, smoke, or gas. 4. The temperature of the room should be between 58 and 70° Fahrenheit, with a relative humidity of 40 to 60 per cent. 5. The heating processes should be simple and free from dangers of explosion, etc. 6. The heating should be inexpensive and accom- plished with as little effort on the part of the dweller as possible. Means and Methods of Regulation of Temperature. — As a rule, no attempts are made to regulate the tem- peratures of our rooms by artificial means during 38 THE HYGIENE OF HABITATIONS summer. Some lowering of the temperature may be gained by preventing insolation, by window curtains, blinds, etc., by revolving electric fans, and by opening windows and doors. • The heating of rooms is accomplished by burning certain materials called fuels. These fuels are of many kinds, such as straw, corn-stalks, dry peat, wood, bituminous and anthracite coal, coke, oil, gas, etc. Heating may be local or central. In local heating the fuel is burned in the room to be heated. In central heating the fuel is burned in a central location and the heat is conveyed into the rooms by means of air, water, or steam. Local Heating. — ^The fuel is burned in special re- ceptacles, either open, called grates, or closed, called stoves. Orates. — ^The form of radiant heat represented in the various open grates is probably one of the oldest methods of house warming known. A large percentage of the heat, some say 88 per cent., is totally lost. The greatest objection, however, is that the heat evolved is distributed unequally, that considerable drafts are created, and that while a grate fire may look cheer- ful, it is neither comfortable nor adequate. There are improved forms of grates in which a greater com- bustion of fuel is accomplished and in which some of the objections to open grates are overcome. Stoves. — Stoves made of brick or glazed tile are extensively used in European countries. In the United States cast- and wrought-iron are used almost exclu- sively. Iron heats and cools very rapidly and is apt to become overheated. The use of stoves is often CENTRAL HEATING 39 very convenient, but is inevitably accompanied by ashes and dirt, and the need of carrying coal and wood to the stoves. The air of rooms heated by ordinary stoves is apt to be overdry and overheated. Heating with Gas. — ^Theoretically, gas is an ideal fuel for heating rooms and houses. Whenever it is employed the gas stoves must be provided with flues leading to chimneys for the disposal of deleterious gas. Heating by means of gas logs and asbestos flakes is much preferable to the heating of the sheet metal stoves. Electricity. — ^This is undoubtedly one of the best methods of heating, and the only objection against it is its cost. Central Heating. — ^The central heating of small dwellings by means of hot-air furnaces is very exten- sively used in the United States. As ordinarily made the hot-air furnace is a stove, usually placed in the cellar and enclosed by a sheet-metal jacket at some distance from the stove. The space between the stove and the jacket contains air, which is brought from the outside of the house by a tube or cold-air box. This air within the jacket is naturally heated by the stove, and, rising, is conducted by means of sheet- metal pipes or ducts into the various rooms of the house. The cold-air box should be made of metal and its entrance should be screened to prevent the introduction of dust. The hot-air ducts should be ample and have as few bends as possible. The advan- tages of hot-air furnaces are their low initial cost of installation, the absence of radiators occupying space within the room, and the improved ventilation by 40 THE HYGIENE OF HABITATIONS the introduction of warm air. The objections are that they often produce superheated air which is too dry and that the air often contains dust, coal gas, and smoke. Hot-water Heating. — In this most simple form of heating a water receptacle is heated in a central loca- tion within the house, usually the cellar. This recep- tacle is connected with an ascending pipe leading to the upper part of the house, whence a descending pipe returns the water to the original receptacle below. In each room there may be several coils of pipe radiators connected with the ascending or descending pipes. The water in the receptacle or heater rises and circu- lates through the ascending and descending pipes and radiators. The temperature of the water in the system is never very high and is below boiling point. The heat may be kept up continuously. This is the best system of house heating, especially for houses not above three or four stories in height. The objec- tion to hot-water heating is the cost of installation. The consumption of coal in hot water heating is comparatively small. Steam Heating. — In this system the pipes are filled with steam under low or high pressure instead of hot water. The steam-heating plant needs expert attend- ance, a large consumption of coal, and cannot be well regulated so as to give constant heat. As soon as the heat in the boilers is reduced below the production of vapor the pipes and radiators are suddenly cooled off. There is, therefore, usually a marked difference be- tween day and night temperatures of steam-heated rooms. An annoying concomitant of a steam-heating WATER AND HEALTH 41 system is the noise and hammering within the pipes due to the steam meeting with the condensed water from cooled-off radiators. This "water hammer" is met very often. There are a number of different systems of steam heating. The advantages of steam heating are that houses may be heated with a comparatively small installa- tion expense, or even from a central location outside of the house, and also that houses of any size may be heated to any temperature desired. The objections to steam-heating systems are the need of specially trained caretakers, the undue heat of the steam pipes and radiators, the usual stoppage of steam ait night, and the comparatively high cost in fuel consumption. Temperature Regulation. — ^The degree of heat in the rooms is measured by thermometers; the degree of relative humidity or moisture in the air is measured by various hygrometers. In houses provided with a mechanical system of ventilation and heating the temperature of the room may be regulated by thermo- stats and the relative humidity by humidostats. WATER SUPPLY Water and Health. — Water is essential to human life. Nothing in the organic world can exist without water; it is a component of everything in the vegetable and animal kingdom. Sixty-three per cent, of the weight of the human body is water. Without water life can be sustained only for a very short period. Hence, the importance of a water supply in human habitations. 42 THE HYGIENE OF HABITATIONS Water is needed not only for drinking purposes, but also for cooking the food, for washing the body, for laundry purposes, for cleaning utensils, and for many other household purposes. The .quantity of water needed for the various household purposes varies according to the habits of the individual and the degree of civilization. Thirty gallons of water per capita per day is a very conservative estimate while a greater supply is beneficial. Water, chemically pure, consists of two volumes of hydrogen and one part of oxygen. As water is a great solvent it is very rarely, if ever, found chemically pure; it contains various ingredients with which it has come in contact. Some of these are harmless, but the presence of others in drinking water may be harmful. The impurities found in water, which may have some influence upon man, may be gases, minerals, organic matter, and microbes. The gases are those which are a component part of air, oxygen, and carbon dioxide. Water dissolves most of the minerals with which it may come in contact, and among those found in water are the following: chlorides, calcium, magnesium, iron, sulphur, and many others. The organic matter may be of vegetable or of animal origin. Microscopic plants, vegetable fungi, detritus of vegetable life, as well as the products of decomposi- tion in vegetable life, are abundantly found in water. Substances of animal origin found in water include minute insects, infusoria, the ova of insects, some minute parasites, suspended animal debris, products of decomposition, disintegration, and putrefaction. WATER AND DISEASE 43 The most important constituents of water from the hygienic point of view are the microbes or repre- sentatives of germ hfe, bacteria, bacilli, etc. The millions of bacteria usually found in water are harmless, as a rule, but there may be some which may become a menace to health and life. These germs are called pathogenic. They may cause the specific diseases of typhoid fever, cholera, dysentery, diarrhea, and other similar disorders. They get into the water by various routes and means, but most commonly through pollu- tion with animal sewage and decomposed organic matter. Besides the impurities enumerated already, water may also contain certain poisons which it has dissolved during its course over or under the ground. The most important of these are copper, lead, zinc, arsenic, and sulphur. Water and Disease. — ^The physical impurities, such as the debris of vegetable, animal, and mineral matter, which are often found in water, may be dangerous to health, because of the disturbances they cause in the digestive tract. The degree of danger depends upon the quantity, composition, etc. The chemical impurities are found in the form of dissolved metals or gases, and include sulphur, lead, arsenic, and other toxic elements in greater or lesser quantities. The ingestion .of water containing such substances may become dangerous to health according to the amount and toxicity of these ingredients. Certain parasites and their ova are also found in water. Among these are the ova of tapeworms, roundworms, and especially of hookworms. The 44 THE HYGIENE OF HABITATIONS terrible scourge of "hookworm disease" in the Southern States is undoubtedly transmitted by means of water containing the ova. There is no doubt whatever that typhoid, cholera, and dysentery have been, and are frequently caused by the drinking of water containing the germs of these infectious diseases. Indeed, these have been properly named the "water-borne diseases." The presence of typhoid, cholera, and dysentery germs in water, as well as the direct transmission of such diseases through the agency of water, has been clearly demonstrated. There are also abundant data which show a marked decrease in the prevalence of such diseases whenever precau- tions for the prevention of contamination or for puri- fication of contaminated water are taken. Good water should be clear, free from sediment and suspended matter, colorless, odorless, aerated, of a pleas- ant taste, cool, and soft. It is judged by its palata- bility, degree of hardness, turbidity, the amount and character of organic contamination, the presence or absence of metallic poisons, and the number and character of the bacteria present. All palatable water is not necessarily wholesome, nor is a water bad merely because it may be unpalatable. The taste of water depends upon the temperature and upon the presence of air and carbonic acid. As carbonic acid may be due to organic decomposition, water may be organically contaminated and still taste pleasant; on the other hand, chemically pure distilled water has an insipid taste. The hardness or softness of the water depends upon the presence or absence of carbonate of lime, or of SOURCES OF WATER SUPPLY 45 the sulphate and chloride. Temporary hardness is caused by the presence of carbonate of lime (chalk), which is driven off by boiling; permanent hardness depends upon the chlorides, sulphates, salts of mag- nesium, etc., and cannot be removed by boiling the water. Hard water, on boiling, precipitates the salts upon the side and bottom of the vessels, and thus prevents the proper cooking and softening of certain vegetables; hard water also prevents the formation of lather and the dissolving of soap in washing clothes. Except for these effects it is questionable whether hard water is otherwise injurious. Sources of Water Supply. — ^There are three main sources of water supply for habitations: (1) rain water; (2) surface water; and (3) subsurface water. Rain Water. — Rain water is the purest of all waters, unless it is contaminated by the impurities in the air during its fall, or by the vessels in which it is stored. Rain water is not very palatable because of lack of aeration, but is very good for cooking and laundry work because of its softness. The quantity of rain water depends upon the amount of the rainfall, the periodicity of the fall, and the area of the collecting vessels. As a constant source of water supply rain water cannot very well be depended upon, and in cities in which the surface air is apt to be much contaminated, rain water is not without dangers because of the impurities it gathers during its fall. In farm houses and rural communities the collection of rain water as a supplementary source may be of benefit, provided care is taken that the tubs, barrels, tanks, or cisterns wherein it is collected are clean, free 46 THE HYGIENE OF HABITATIONS from impurities, and kept covered after the collection of water. As to the wholesomeness of the waters gained from various sources, the following table from the report of the British River Pollution Commission is of value. {1. Spring water. Very palatable. 2. Deep well water. 3. Upland surface water. Moderately palatable. Suspicious ( ^- ^^°''^^ ^^"^ ^^*«'- I 5. Surface water from cultivated land. Palatable, Dangerous ( ^- ^^^^^ ^^*^'' ^^^ "^^^^e. I 7. Shallow well water. Surface Water. — Surface waters, like ponds, lakes, and streams, are not a very good source for water supplies, because they are easily contaminated with sewage and other organic materials which are so abundant upon the soil, especially about or near human habitations. They are principally collections of the drainage of the very much polluted surface soil and may contain any dangerous impurities, like the germs of typhoid fever and others. Large and swift rivers and very large lakes are sometimes used as a source of water supply, but even these are apt to be dangerous unless the water is taken far from the shore or is purified before use. Subsoil Water. — ^A large proportion of the water falling upon the ground in the form of rain or snow slowly sinks into the soil through its porous strata until it finds a stratum which is impermeable. It then collects and forms underground water reservoirs, which are at a greater or lesser distance from the SOURCES OF WATER SUPPLY 47 surface, and can be reached by digging deep enough into the ground. During its percolation into the ground the water is filtered and loses some of its impurities, but in pass- ing through the various soils it may take up certain minerals with which it comes in contact and these become suspended or dissolved in it. The underground water basins lie sometimes at a very great depth. The water therein is in constant motion in a vertical or horizontal direction, and as the pressure is sometimes great the water may crop out at some surface in the form of springs. The water in such springs, when at a proper temperature and free from minerals, is palatable and wholesome. Sometimes these springs have considerable mineral ingredients dissolved, and are at high temperature, owing to the character of the earth's crust which the water traverses. They are then called "hot" or "mineral" springs. The deep-lying underground waters may be reached by driving wells into the ground into the lower im- permeable stratum. Water from deep wells of this kind is very good. The water from shallow wells or those dug into the first near-surface-lying underground water basin is apt to be impure, because such wells usually tap a subsoil water, which is gained by surface drainage from localities largely contaminated with organic matter, manure, and sewage. The privies and cesspools near habitations almost always drain their liquid contents into' the sources from which shallow wells get their water, and many epidemics of typhoid and other diseases have been 48 THE HYGIENE OF HABITATIONS traced to the use of polluted shallow well water. Shallow wells are also called dug wells to distinguish them from deep and artesian wells, which are commonly bored or driven. Wells must be dug at considerable distances from houses and stables, and at places where no surface impurities can drain into them. They should be lined with brick and cement, or with glazed tiles set in cement, and also fitted with proper covers to prevent the falling in of filth from the outside. The water is drawn from the well in buckets or pails either worked by hand, windlass, or by means of suc- tion pumps or other mechanical devices. Aqueducts. — ^For the supply of large towns with their millions of population immense water-supply works are needed. Their construction and the supervision of the water area must be in charge of engineers. House-water Supply. — ^Where there is a town-water supply system, houses are supplied from the street mains; the size of the street mains depends upon the water pressure and the number of houses to be supplied. The branch house-water supply pipes coming from the street mains should not be less than three-quarters inch for small houses and from one and a half to two inches for larger houses. The house pipes are connected with the street pipe by "corporation taps." There should be a stop-cock under the sidewalk, and also one on the service pipe at the entrance to the cellar. Street mains are made of galvanized iron; some of the house pipes may be made of lead. The materials and workmanship of all water pipes must be of the best, and they should be protected from freezing whenever exposed. PURIFICATION OF WATER 49 Whenever the pressure of the street mains is insuffi- cient to hft the water to the height of the upper stories of a house, storage tanks or cisterns must be provided upon the roof. These tanks are commonly made of cedar or cypress wood, are round in shape, and should rest upon a solid foundation, preferably upon iron beams. When located within the house the tanks are metal lined. All tanks should be provided with suit- able covers, also with overflow pipes and water-waste protecting valves. The overflow pipe may be dis- charged, onto the roof, or lead down into the cellar and discharged into a sewer-connected, properly trapped, water-supplied open sink. In order to lift the water to the highest story, some mechanical means, such as pumps, driven by gas, steam, or electricity, may be necessary. Hot-water Supply. — Modern houses are not only provided with hot water, but provisions are also made to supply the house with hot water, necessary for bathing, washing, and cleansing purposes. The hot-water supply is derived in most houses from boilers of copper or iron, connected with the kitchen range. In larger houses special hot-water furnaces and boilers may be provided, from which the hot-water pipes go to every fixture in the house. The heating of water by means of electricity is practicable wherever there is electric power within the_ house. A simple device to heat water in a vessel is by means of elec- trically heated metal coil placed in the vessel. Purification of Water. — ^The large amount of impurities, some of them very dangerous to the health and life of the consumers, which are commonly found in drinking 4 50 THE HYGIENE OF HABITATIONS water, render the problem of water purification an important one from a sanitary standpoint. Water purification should be twofold, public and private. Whenever the water supply is collective, public, and on a large scale, the community at large should provide for proper water purification. Whether there is a public water-purification plant or not, every individual household should provide some means of local water purification. Methods of Domestic Water Purification. — Water may be purified for domestic use by sedimen- tation, boiling, distillation, chemical means, and by filtration. Sedimentation. — ^Water may be freed from its coarser particles of impurities of sand and dirt by letting it stand in a vessel from twelve to twenty-four hours. This may also free the water from such organic matter and impurities as are held in suspension, without, however, clearing it of the impurities held in solution. Boiling. — ^AU living organic matter and germs are destroyed by raising the temperature of water to the boiling point and by keeping it at that temperature for a certain time. This is the cheapest and most available method of purification, and is also the most efficient. The objection against boiled water is the insipid taste which results from the expulsion of air and carbon dioxide by the process of boiling. The pleasant taste of the water may be restored to boiled water by aeration, or by charging it with carbonic acid gas. Distillation. — ^This is the surest and best means of removing all impurities. It kills all germs, including PURIFICATION OF WATER 51 all of the spores, and gives an absolutely pure water, which when aerated or charged with carbon dioxide is very palatable in addition to being pure. The objec- tion to distillation of water for domestic purposes lies in the necessity for a proper apparatus; but the time seems to be approaching when every house will be furnished with water-distilling apparatus just as it is at present furnished with a cooking range and hot- water boiler. The apparatus to be of value should be simple in construction, easily operated, durable, strong, and readily cleansible. It should furnish an adequate supply of water for all domestic purposes with little trouble and at small cost. Such an ideal apparatus has not as yet been invented, but there are a number of devices which approach it and may safely be used. Chemical Means. — ^The settling of turbid water may be hastened by the addition of a few grains of alum (not more than six grains to the gallon). The addition of small quantities of potassium perman- ganate has a destructive effect upon organic matter. Addition of tea leaves, and other vegetables contain- ing tannin, is said to reduce the danger from organic impurities, but this is problematic. Other chemicals, like borax and boracic acid, copper sulphate, etc., have been advocated, but when used in too small quantities they are of little or no value; when used in larger quantities they may become as dangerous to health as the impurities which they are intended to destroy. Water Filtration. — ^Water may be purified by filtration, i. e., by letting the water pass through 52 THE HYGIENE OF HABITATIONS some material which is capable of retaining some or all of the contained impurities. The value of a water filter depends upon the following factors: 1. The character of the filtering medium and its ability to retain and remove from the water as many impurities as possible. 2. The thoroughness of the process and its rapidity. 3. The ready cleansing of the filtering media and its ready disinfection. 4. The simplicity, cheapness and accessibility of the filter. It is claimed for some filters that they are able to remove all the organic impurities from the water, as well as the bacteria, but this is not yet proved. It is certainly true only of a very few filters upon the market, and of those only when they are new. When- ever water is suspected of containing pathogenic bacteria, dependence upon filters may become danger- ous to health, and distillation is the only sure way of securing purity of drinking water. The materials which are used for filtering water are sponges, wool, asbestos, sand, stone, porcelain, infusorial earth, spongy iron, magnetic carbide of iron, charcoal, etc. Sponges, wool materials, and asbestos cannot very well be depended upon; at best they act but mechanically, easily get dirty, and are difficult to clean. Sand and porous stone will arrest suspended matter; they may even remove some of the organic matter. It is doubtful whether all organic impurities and microbes can be removed by them. Charcoal is a very good filtering medium in some respects. Animal and not wood charcoal is used. ICE 53 Animal charcoal is prepared from calcined crushed animal bones, and may be used in block form or in the form of a powder. Charcoal removes coloring matter and considerable organic matter from water, but does not remove all organic impurities. Charcoal used for filtering must be frequently recalcined. Unglazed porcelain is used for filtering purposes and is quite effective in removing water impurities, pro- vided the filtering porcelain is frequently cleansed, as the impurities are apt to become clogged. Infusorial earth is used in the Berkefeld filter. It is pressed in the form of hollow tubes. The water passes under pressure through the fine pores of the filter and gains access to the tap. It is claimed for this filter that when new it will remove all organic matter and bacteria from the water. The filter is made in various forms and sizes and may be attached to the house-sink faucet. The filtering tube must be removed frequently, sometimes more than once a day, and the dirt accumulating upon the surfaces washed off, otherwise the filtering process becomes slower and slower and stops when the pores of the tubes become clogged. Ice. — ^The use of frozen water in the form of ice is very extensive, and when used for drinking purposes there is the same danger of organic impurities as in ordinary unfrozen water. As most of the ice used is obtained from the surface of lakes, ponds, and rivers subject to organic contami- nation the use of ice may become very dangerous. It is best to use ice only as a cooling medium, without melting it for drinking purposes. Ice may be made 54 THE HYGIENE OF HABITATIONS from distilled or boiled water, and is then free from impurities. It has been shown experimentally that freezing does not kill all the bacteria in the water. Ice-chests and refrigerators have become a household necessity. They are commonly made of wood, hard wood is best, with mineral packing in the double wall to insure non-conductivity. Within the refrigerator is lined with metal or porcelain or enamelled iron. Some refrigerators are kept cold by means of electricity without the use of ice. The waste pipes from the ice-box should never con- nect directly with the plumbing of the house, but should discharge into the sewer-connected, properly trapped, water supplied, open sink. The waste pipe is sometimes provided with a flap valve to prevent the entrance of warm cellar air. HOUSE DRAINAGE Sewage and its Disposal. — One of the most important needs in connection with human habitations is the disposal of the organic matter and sewage due to the presence of the inhabitants. The average adult passes about 3 ounces of solid and about 40 ounces of liquid excreta, which when multiplied by the number of house dwellers forms a large amount of organic detritus. This organic matter if left exposed for some time begins to decompose and undergo putrefactive changes, evolving foul gases and odors during the process. The solid excreta may also contain a large number of germs, some of which, such as the germs of cholera, typhoid, intestinal disease, and others, are PRIVY VAULTS 55 pathogenic. The organic excreta and detritus are embraced under the general term of "sewage," and unless there is proper and effective disposal they become not only disagreeable and unpleasant because of the foul odors and gases, but also dangerous to life and health. Methods of Sewage Disposal. — ^The principal methods of ultimate disposal of sewage are the following: cremation, chemical precipitation, land irrigation, disposal into rivers, lakes, and seas, and the various modern bacterial, septic, and biological methods. The immediate disposal of sewage from the houses may be dry or by means of water. In isolated houses without water supply, and with a few house dwellers, the means of disposal of sewage is by pails, earth closets, privy vaults, and cesspools. When there is a water-supply system the sewage may be carried out through a system of plumbing pipes and fixtures, and be disposed of in cesspools or through land irrigation. Pail System. — ^The pail system is by means of the simple expedient of gathering the solid excreta into tight pails or receptacles and then removing the contents when the pails are full. The " earth closets" were introduced by the Reverend Moule, and at one time were used extensively in the United States. Privy Vaults. — Privy vaults are in extensive use in this country, in rural communities, villages, farms, and in some cities which are not sewered. There are a large number of them in the outlying boroughs of New York and the outskirts of other cities. 56 THE HYGIENE OF HABITATIONS The privy vault, as ordinarily constructed, is a liole in the ground, over which there is a raised plat- form, with a seat, the whole covered with some sort of a shed. The privy is always a nuisance, because of its proximity to the house, of the foul odors emanating from it, the flies and insects it attracts, the contamina- tion of surrounding soil, and the possible pollution of near lying wells and water-courses. This pollution of the water and of the soil is the greatest objection against privy vaults. These privies remain in the same place so many years that the soil beneath them becomes a veritable sewage lake from which contamination of the surrounding soil and of the water supply nearby results. The diseases which may be due to such soil pollution are typhoid fever, hookworm dysentery, tapeworm, etc. In the South the terrible ravages of the hookworm disease are due mainly to soil pollution and unsani- tary privies. The principal parts of a privy are the shed, the seat, and the receptacle into which the excreta are dropped. The shed in a sanitary privy should be made of tightly fitted boards, with windows properly screened and doors well closed in order to prevent insects and flies from gaining access. The seat should be so arranged as to be convenient for use, and should be free from contamination of excreta. The receptacle or the place into which the excreta are dropped should be more than a mere hole in the ground, from which the liquids percolate into the surrounding soil, and in which the excreta remain and decompose; it should be made water-tight by being lined with cement or some non- PRIVY VAULTS 57 absorbent material. The excreta when dropped into this water tight receptacle will remain there and must be removed from time to time. A still better method is to place in such water-tight receptacles a tight portable pail which is hung on a hook from the seat. The excreta are dropped directly into the pail, which may be removed as soon as it fills, and the contents cremated or disinfected, the pail cleansed, washed, and disinfected, and returned to its place. For the purpose of removing these pails and cleaning the vault beneath the privy each part of the privy should be made with a sling cover so as to be accessible. Cesspools. — ^These may be used when the house is provided with fixtures and pipes to carry the sewage out, and to collect it in a cesspool at a point distant from the house. The so-called "leeching" cesspools, which are not water-tight and allow liquids to drain into ground, are open to the same objections as privy vaults. When cesspools are water-tight they must be emptied at periodical intervals or provided with automatic ejectors and siphon apparatus to dis- charge their contents. The best mode of discharge is by means of a system of intermittent filtration, or subsoil irrigation. The sewage is emptied into earthenware pipes with open joints, which lie several feet under ground and radiate in different directions, through land to be irrigated. The liquid sewage drains into the ground at the joints and is effectively disposed of, enriching the land. The Water-carriage Method. — This method is now extensively used in cities and towns where sewers are built. It is the best means of disposing of the liquid 58 THE HYGIENE OF HABITATIONS and sewage contents of houses and streets. The sewage from the sewers is either collected and led to the ulti- mate disposal works, or is carried into sea and water courses. There are two methods of sewering houses by water carriage. In the combined method not only sewage proper is carried away through the plumbing pipes and the street sewers, but also all other waste waters, and especially all rain water collected from the roofs. In the separate system the rain water is disposed of by means of separate pipes, and the sewers proper carry away only the liquid and solid waste matters from the house itself. In the separate system the pipes are smaller, and thus decrease the expense of the plumbing; in the combined system the pipes must be large enough to discharge the sometimes enormous amounts of storm water. The combined system is the one used more extensively. Street sewers are constructed by the municipalities, and are made of brick, earthenware, and iron. Every house connects with the street sewer by separate house sewers. PLUMBING Materials. — ^The plumbing system of the house consists of receptacles (or as they are termed "fix- tures") which receive the various forms of house waste, and of pipes connected with these fixtures, by means of which the waste matter is carried into the street sewer. As the pipes carry waste water and at times considerable quantities of gas the materials PLUMBING JOINTS 59 from which the pipes are manufactured must be strong, durable, and water- and gas-tight. The earthenware or "clay" pipes which were for- merly extensively used for house drains and house sewers are objectionable. They are obsolete now, and most municipalities have prohibited their use within the house and limited them to the short lengths needed for house sewers, outside of houses, when they are laid on rocky or solid ground. The only advantage of earthenware is its cheapness; but on the other hand its brittleness is such that it is impossible to make gas-tight drains to withstand any long and constant use. Earthenware houfee drains are veritable channels of filth, emitting foul and offensive odors. Lead. — ^Lead is quite extensively employed in the manufacture of piping. It has some advantages in its ductibility, but the pipes are heavy, expensive, and easily injured by nails driven into them, by being gnawed through by rats, etc. The use of lead is limited to short lengths of pipe, to branch waste pipes, and to small-caliber water pipes. Iron. — ^The material which is almost universally used for pipes is iron; it has all the advantages of cheapness, hardness, durability, and tightness. Brass. — ^Brass, nickel, and other hard metal pipes might be used were it not for the expense. Glass is a good and appropriate material for piping, and when its manufacture is perfected it will probably be used extensively. Joints. — The proper joining of the several lengths of pipe used in the house is of great importance, as other- wise, the system cannot be made gas-tight. Earthen- 60 THE HYGIENE OF HABITATIONS ware pipes are joined by means of cement. Lead pipes are joined by means of solder-wiped joints. Cast- iron pipes are joined by means of lead-calked joints. Wrought-iron and brass pipes are joined by screw joints. Lead pipes are joined to iron pipes by means of brass ferrules. Pipes. — ^The plumbing system within the house consists of several pipes — vertical and horizontal. Vertical Pipes. — ^The vertical pipes are the following: The Rain Leader. — ^This carries down the rain water from the roof into the house drain. The Waste Pipe. — ^This carries down the waste water from kitchen sinks, wash-basins, laundry tubs, etc. The Soil Pipe. — ^This is connected with the water closets and, usually, with the bath tubs, and carries down the sewage and waste from these. Horizontal Pipes. — The House Drain. — ^This is the principal horizontal pipe. It connects with all the vertical pipes and carries away the whole house-waste matter into the street sewer. House Sewer. — ^This name is applied to the short length of drain a few feet outside of the house founda- tions, which leads to the connection with the street sewer. It is really a part of the house drain. Sizes. — ^The sizes of the various pipes should corre- spond with the amount of waste matter they are supposed to carry. There is no advantage in making the pipes too large; smaller pipes are apt to be better flushed than larger pipes. A two-inch soil pipe with only two or three fixtures attached to it ought to be suflScient for a private dwelling. The New York SEWER AIR 61 rules require a four-inch pipe in tenement houses where five or more sinks are used. Three- and four-inch soil pipes are adequate in private dwellings, five-inch pipes are required in tenement houses with five or more water closets. Branch waste pipes vary from one and one-half inch for basin and laundry tubs to two-inch pipes for other fixtures; branch soil pipes should not be less than four inches in diameter. House drains and house sewers are from four to six inches in diameter, according to the number of fixtures in the house. The six-inch drains, invariably demanded by municipal authorities, are sometimes entirely too large to be properly flushed. Sewer Air. — The materials of which pipes are made should be perfectly water-tight, to prevent any leakage of the sewage and waste fluids. The pipes should also be gas-tight, because the gases generated within the pipes are believed to be undesirable for the inhabi- tants of the rooms in which the plumbing pipes are situated. The plumbing system connects the house with the street sewer, and the same pipes which serve to rid the house of liquid waste and sewage matter become reciprocally, a direct means of entrance for the air and gases in the street and house sewers to the house and rooms. Is this desirable? There is still a great deal of misapprehension of the common terms sewer gas and sewer air. The popular idea of sewer gas is that it is a distinct gas, something like illuminating gas, which is found only in sewers and plumbing pipes, and that its inhalation is harmful to a great degree. There are some, indeed, who believe 62 THE HYGIENE OF HABITATIONS that sewer gas is capable of producing, certain diseases like typhoid fever, diphtheria, etc.; and not so long ago a prominent sanitary inspector asserted that she traced several cases of tuberculous meningitis to defec- tive pipes under sinks. This theory that sewer gas causes various diseases was once upheld by noted sanitarians, and seriously advocated by Drs. Simon, Richardson, Gorfield, and others equally prominent. As a matter of fact, later research and scientific investigation have shown that there is no such gas as sewer gas. What is termed sewer g^s is but sewer air, and there is no more reason to term the air in a room "room gas" than the air of sewers "sewer gas." The sewer air may at times be as pure, and more so, than the air of rooms, and, at other times, it may contain the same or more impurities than room air. The impurities ordinarily found in sewer air are an excess of carbon dioxide, carbon monoxide, illuminating gas, sulphuretted hydrogen, marsh gas, ammonia, and other gases found wherever decomposition and putrefaction takes place; there may also be found a large number of bacteria and various microorganisms. This composition of air which at times may be found in sewers, while not liable to directly cause various diseases, is certainly not desirable as an additional mixture to the air in our rooms, air which, without any additions, is rich in impurities. There is no doubt that the inhalation of impure sewer air is in- jurious to human beings, in the same manner as is the inhalation of any impure air, and, therefore, it is imperative to prevent the incoming of air from sewers into the house and rooms. LOSS OF SEAL IN TRAPS 63 Traps. — As there is a direct connection of the rooms with the sewer in the house-plumbing system, the problem is how to disconnect the house from the sewer and at the same time leave the plumbing system to perform its functions? The problem is solved by means of traps. A trap is a bend in a pipe, so constructed as to retain a certain amount of water. This water is called seal, and serves as a barrier to the backflow of air from the sewer into house pipes. Traps are especially con- structed' with the object that water should always remain in them, and thus cut off communication be- tween sewer and house. The house is disconnected from the sewer by the main trap on the house drain. This serves as the prin- cipal barrier to the inflow of sewer air into the house, but there are also additional traps on the branch pipes under each and every fixture, which serve to prevent the bad air in the house pipes from coming into the room from and through the fixtures. " Thus there are a main trap, th^ house-drain trap, and a multitude of fixture traps. The traps are made in various forms, and have innumerable names and shapes, but all are intended to serve the same purpose. There are also a number of mechanical traps with various devices for strengthen- ing the action of the trap as a seal. Of course, as everywhere in plumbing, the simpler the contrivance the better it is. The most commonly used traps are the "running trap" on the house drain and the " S" traps on fixtures. Loss of Seal.^-The traps can be depended upon only as long as their seal, i. e., the water in them, is 64 THE HYGIENE OF HABITATIONS intact; but if, for any reason, this seal is broken or "lost," it is evident that the trap becomes useless. There are a number of causes, such as evaporation, momentum, capillary attraction, siphonage, and, perhaps, back pressure, through which a trap may lose its seal and thus become ineffective as a barrier to sewer air. Loss by Evaporation. — ^The water in a trap may evaporate if the fixture over the trap is not used for a long time; hence, house dwellers may find the houses they left for the summer full of bad air on their return, owing to the loss of seal. This evaporation can only be prevented by frequent use of the fixture, or by filling in the traps, before leaving and closing up the house, with some oil or other non-evaporable material. Loss by Momentum. — ^Loss of seal by momentum is due to negligence in pouring into a fixture a large amount of water, suddenly and forcibly, so that the momentum is insufficient to empty the trap as well. This can be prevented only by care. Loss by Siphonage. — ^A more important loss of seal occurs through siphonage. The water in the trap or seal is suspended between two columns of air, and is influenced by any and all currents of air on either side of the seal. A discharge of water from a large fixture connected with a vertical pipe acts like the drawing of a cork or piston through the pipe, i. e., it creates a vacuum behind it, causes great suction, and draws out, or "siphons" out, any water which may be in the trap. By "siphonage" is therefore meant the emptying of the seal of the trap by the aspiration of the water VENT PIPES 65 in the trap, as a result of the downward rush of water in the pipes with which the trap is connected. This siphoning of traps is a frequent occurrence in large houses in which the water from fixtures in the top floors has a distance to travel and falls with great momentum. Every discharge of a water closet on a top floor will siphon out the seal of the traps of sinks and wash-basins on the lower floors. Loss by Back Pressure. — There is also what is called "back pressure." By this two conditions are under- stood: in the one there is actual forcing back of the water in a trap by the backflow of water. This happens in house-drain traps during big rain storms when the street sewers are overflooded, and part of the overflow backs up into house drains where it may force back the water of the main trap. This may also occur during a rise of tide in houses near the shore. What is ordinarily understood by back pressure, however, is the absorption of foul gases by the water in a trap from the air in the pipes. As the water is exposed continuously to the gases in the pipes this absorption goes on all the time, and thus the gases may enter the room through the water in the traps. Vent Pipes. — ^The prevention of the siphonage of traps, as well as of back pressure, has occupied the minds of many plumbers, and various means have been employed to remedy the evil. A number of mechani- cal traps have been invented, but they all have the one fatal defect, that they are cumbersome and do not prevent the evil they intend to remedy. Actual backing up of water in main traps can be prevented by the tide valves. There are a number of 5 66 THE HYGIENE OF HABITATIONS these on the market, and most of them serve their purpose well. The back pressure, which consists of the absorption of gases by the water in traps, can very well be pre- vented by a good ventilation of the pipes. This is readily accomplished by the ordinary extension of the vertical pipes above the roof and by the fresh-air inlet. The siphoning of traps in houses of two and three stories, in which the fall of water is not so heavy and i the momentum consequently not so great, can be pre- vented by the "non-siphoning" traps. It is only in large houses, tenements, factories, etc., that the problem of siphonage demands the installa- tion of a new system of pipes called "vent-" or "back- air" pipes. These run vertically through the houses, and by their branches join all the traps near their crown and thus furnish a column of air for the water seal in the traps. This air prevents siphonage because it is more easily withdrawn during the aspiration process than the heavier water in the traps. The vent-pipe system serves also as an additional means of ventilating the whole pipe system. The objection against the venting pipes is the additional expense. While most municipalities strictly demand vents in all houses, there is reason, to believe that the practice of installing a special vent system will not last very long, especially in private dwellings. At present the tendency is toward simplification of the pipe system of the house. In the so-called "one-pipe system" of plumbing the vent pipe is omitted, and siphonage is prevented by the installation of "non- siphoning" traps. HOUSE DRAIN PLUMBING PIPES AND FIXTURES The plumbing system consists of the various fix- tures, such as sinks, wash-basins, laundry and bath tubs, and the water closets. All these fixtures lead into the three main vertical pipes within the house, viz., waste and soil pipes, with the vent pipes accompanying them. All the vertical pipes in turn lead into the horizontally running main house drain which connects with the street sewer through the short house sewer. House Drain. — ^The house drain is the main pipe. It receives all the drainage from the vertical pipes in the house and carries it to the street sewer. The house drain is not level, but has a pitch or fall, in order to assist the velocity of the flow of its con- tents. The rate of fall should not be less than half an inch to the foot, although some municipalities allow a fall of a quarter an inch to the foot. The rate of the fall depends also on the diameter of the pipe. The position of the drain under the house should be above the cellar : on the cellar floor, or under the ground. There is the greatest objection to the placing of any plumbing pipe out of view, especially a pipe of the importance of the house drain. The general practice of hiding the house drain under the cellar floor is very bad, as it conceals the frequent defects of construction, joints, etc., and is likely to cause great damage to the cellar and foundations by saturating them with offen- sive effluvia before the defects are detected. When the house drain runs above the cellar it should be 68 THE HYGIENE OF HABITATIONS properly supported, either by brick piers, or by suitable hangers to the wall. When it runs on the cellar floor the house drain should rest in specially constructed concrete or cement beds, and in trenches with proper beds for the hubs. The house drain is separated from the house sewer by the main house trap, which is situated near the inside house wall. It should be provided with hand holes for cleansing purposes, and with tide valves when there is a possibility of back pressure by tide or storm. These hand holes should be closed by brass screw ferrules. The fresh-air inlet is a cast-iron pipe about four inches in diameter. It enters the house drain on the house side of the main trap, and extends to the outer air at or near the curb, where as a rule it terminates in a receptacle covered by an iron grating in the sidewalk. This form of fresh air inlet is almost always ineffective, because the iron grating and the fresh-air box are com- monly full of rubbish and dirt. The extension of the fresh-air inlet pipe several feet above the ground, properly protected by a wire basket or otherwise, and placed at a distance of at least fifteen feet from windows, is preferable to the ordinary fresh-air box. The Soil and Waste Pipes. — ^The soil pipes receive the sewage from the water closets, and the bath tubs, which are commonly located in the water-closet apartments. The soil pipe is made of heavy cast iron, with lead- calked joints, and is three or four inches in diameter in small houses and five inches in tenement houses and larger buildings. The soil and waste pipes should THE SOIL AND WASTE PIPES 69 never be built in the walls, but should be exposed throughout their whole length, so that they can be inspected at all times and that defects may be seen as soon as they occur. If the pipes are gas-tight there is no reason to fear their exposure. With proper bronzing or painting they need not be artis- tically more objectionable than exposed steam pipes. Specially built shafts in which the pipes are some- times placed must be made wide enough to allow entrance, inspection, and repairs. The waste pipe is the pipe to which sinks, laundry tubs, and basins are connected. It is of heavy cast- iron with lead-calked joints, and varies in diameter from three to four inches. Waste and soil pipes should not end in the house, but should be extended open above the roof, at least two feet above every coping. As the extension must be at least four inches in diameter, two- and three-inch waste-pipes will have to be increased to four inches in the extension pipe above the roof. Pipes of larger diameter should run above the roof. Branch soil and waste pipes run from the various fixtures to the main soil and waste pipes, join with "Y" branches and are of lead when less than four inches in diameter and of iron when four inches and above. Branch waste pipes from basins, sinks, and tubs are usually one and a half inches and two inches, branch soil pipes of water closets are three inches and four inches (in New York not less than four inches). The traps on the branch soil and waste pipes are not more than 2 feet from the fixture, and are provided with a screw cap for cleansing purposes. 70 THE HYGIENE OF HABITATIONS Vent pipes and branch vents are of iron. The size of main vent pipes depends upon the number of fixtures with which they are connected. The main vents either run above the roof or join the vertical pipes above the fixtures. Rain leaders serve to collect the rain water from the roof. They are made of galvanized or cast iron, or of sheet metal. The vertical pipe only is trapped at its base before connection with the house drain. The ostensible purpose of this trap is to prevent* sewer air from escaping the rain leader and entering the rooms near the windows of which the rain leader runs. As the trap of the rain leader is frequently empty, owing to evaporation during draughts or freezing during winter, and as the rain leader is situated outside of the house, there does not seem much reason for its being trapped. Fixtures. — Sinks, wash-basins, laundry and bath tubs are made of various materials. From a sanitary point of view the worst material is wood, which was formerly much used; zinc or copper lining is not much better; somewhat better is cast iron. The more modern fixtures are invariably made of enamelled iron, which is smooth, durable, and sanitary in all respects. Por- celain fixtures are more expensive, but their advantage over enamelled iron when properly made is small. Bath tubs are commonly in the same room with water closets. They are connected with the soil pipes several feet below the water-closet connection, and if not vented the traps are apt to be siphoned by the discharge of the water closets. The overflows from bath tubs and basins should be MODERN WATER CLOSETS 71 connected on the inside of the trap on the same fixture. Standpipe overflows are preferable to fixed ones. Refrigerators should not be directly connected with the plumbing system of a house, but their waste pipes should be made to discharge into properly trapped, sewer-connected, water-supplied open sinks. The sediment pipes of kitchen boilers should be con- nected with sink traps on the inlet side, and should be provided with faucets. It is still better not to connect them with the pipes. All fixtures should be separately trapped, except that one trap is permitted for several, not more than three, laundry tubs, and one line. WATER CLOSETS Water-supplied fixtures of some sort or other for the receiving of fecal matter have been in use for many years. Unfortunately the type of the fixtures which have been extensively used until lately, embodied many defects which made them unsanitary. Of the older fixtures it is sufficient to name the so-called " pan water closet," the "plunge closet," the "school sink," the "long hoppers," the "wash-out closet," etc. Modem Water Closets. — ^These are made of baked clay or porcelain, with an enamelled and smooth surface, trapped and bolted in one piece, and so arranged that the excreta drops into the receptacle, always containing water, from which the soil is properly flushed out and the whole cleaned out every time it is used. The value of these fixtures depends not only upon their shape, 72 THE HYGIENE OF HABITATIONS but also upon the methods of their flush and the abun- dant supply of water. Formerly the water closets were flushed directly by a pipe connected with the fixtures. This, however, was found to be defective by reason of the insufficiency of the volume of water furnished. The method used at present is the flushing of these fixtures by means of a separate flush tank placed at least four to six inches above the fixture. These tanks hold from three to five gallons of water, are connected with fixtures by flush pipes of one and a half inch in diameter, and are emptied by the pull of a chain. In some public places these tanks are so arranged that they automatically discharge their con- tents at certain intervals. The added cost of the flush tanks has caused various devices to be invented, with the view of eliminating their installation. There are a number of efficient "flushometers" which are used for this purpose. Water-closet Apartments. — The undesirability of placing the water closets in the yard has already been mentioned. It is unnecessary to add that the water closets should never be placed in cellars. There are also grave objections against water closets in halls, which are frequently found in tenement houses. In office or public buildings there is perhaps no reason why the water-closet apartments should not be located in a separate compartment in the hallways, but in tenement houses this is objectionable on account of the neglect of the fixture if responsibility is divided and each tenant has not his own separate fixture. Wherever the fixture is placed, there are several requirements which ought to be absolutely adhered WASTE MATTER: RUBBISH AND GARBAOE 73 to; these are the following: sufficient space, plenty of natural light by adequate window space opening into the outer air, provision for artificial light, provision for heating in cold weather, smooth and non-absorbent walls and ceilings, a floor of cement, concrete, slate, tile, or any other non-absorbent and readily cleansible material. If in addition there is a separate entrance from the private hallway, and the apartments are placed at some distance from bed rooms and living rooms, the least objectionable, most advantageous location and construction of these necessary though sometimes offensive conveniences is obtained. HOUSE WASTE MATTERS Waste Matter : Rubbish and Garbage. — ^A large amount of various waste matter found in the house, such as newspapers, rags, wool, and cloth remnants, pieces of clothing, rags, detritus of wood, stone, and other articles; also remnants of foodstuffs, cooked and uncooked meats and vegetables, etc. Some rubbish may be harmless, but it may become a vehicle and carrier of dust, dirt, and possibly patho- genic germs. Remnants of cloth and rags may be saturated with organic matter, and contain insects and parasites, as well as ill-smelling and foul organic matter. Garbage, consisting of remnants of foodstuffs, is apt to putrefy and decompose, to attract insects and rats, to emit foul odors, and it may contain dangerous microorganisms. 74 THE HYGIENE OF HABITATIONS Waste Water and Sewage. — ^This consists of the water used in washing dishes, clothes, vegetable and animal food, and in cleaning; of waste water from baths, etc., and, also, of liquid and solid excreta. In houses provided with modern water-carriage plumbing systems most of the waste water and sewage is effectually disposed off by being carried away into the house and the street sewer and flushed by copious discharges of water. Whenever houses are without a system of plumbing, accumulation of the waste mat- ters may become dangerous to health on account of decomposition and foul odors and the presence of microorganisms. Gases and Poisons. — ^The character of the various gases and poisons which may be found in houses vary, but the most common are the following: carbon dioxide, coal gas, carbon monoxide, illuminating gas smoke, "sewer gas;" and of the poisons the most common are arsenic, lead, antimony, etc. Carbon Dioxide. — Carbon dioxide is a constituent of the air in the proportion of 3 or 4 volumes in 10,000 volumes, but in some ill-ventilated rooms the amount of carbon dioxide may reach from 20 to 50 times the normal amount. There is comparatively little danger to health from carbon dioxide unless it is present in excessive quantities. Carbon Monoxide. — Carbon monoxide is a constit- uent of illuminating gas and comes into the house from various defects in the gas pipes and fixtures through which the gas may escape. The inhalation of even minute quantities of illuminating gas is injurious, and may cause headache, anemia, etc. The inhalation POISONS 75 of large quantities may cause death by suffocation, as the carbon monoxide combines with the hemoglobin of the blood. The escape of illuminating gas is also a frequent cause of fires and explosions which endanger property and life. Carbon monoxide is also given off by imperfectly burning illuminants, by charcoal burning, and by imperfect heating arrangements and imperfect combustion of coal, as well as by iron stoves which are allowed to become red hot. Smoke and Coal Gas. — Imperfect combustion of wood and coal produces smoke and coal gas. Their presence is also due to faulty chimneys, back draughts from flues, partial closing of dampers, etc. Smoke causes inflammations of the conjunctiva, headaches, nausea, ill-feeling, vomiting, and in large quantities suffocation. Sewer Gas. — ^As already indicated, what is com- monly called "sewer gas" is only the air in sewers and plumbing drains and pipes. It may be entirely free from any deleterious matter, but frequently contains various gases, such as ammonia compounds, marsh gas, sulphuretted hydrogen, etc., which arise from the decomposing organic matter within the pipes. The efiluvia escape through defects in the plumbing system, and their harmfulness depends upon their quantity and character. Poisons. — ^Wall paper colored with poisonous dyes is the most common source of the various poisons which may be found in the air of rooms. Minute particles of the wall paper floating in the air, the rubbed- off coloring matter adhering to dust, and scraped-off debris from painted surfaces may all contain arsenic, antimony, lead, and other poisons. Numerous cases 76 THE HYGIENE OF HABITATIONS of arsenical poisoning by wall paper have been reported, and in some countries, notably France and Germany, the use of arsenic for coloring wall paper is prohibited by law. Lately, Nephe tried to prove that poisoning by arsenical paper is not due to the dry dust,, but to the volatile organic arsenical compound produced in the moisture present by the action of certain moulds on the paste used to attach the paper. The presence of lead may be due to the dust from lead-painted walls and surfaces. Dust and Dirt. — Dirt and dust may be organic or inorganic, coarse or fine, and generally consist of fragments and particles of earth, soil, clay, stone, brick, wood, lime, plaster, hair, wool, animal and vegetable matter, ashes, pulverized excreta of animals and insects, dried sputum and discharges of the healthy and sick, pollen of flowers, pulverized wool, cotton and silk fabrics and clothes, moulds, fungi, and sapro- phytic and pathogenic germs. The street and the outside of the house contribute a large part of the house dirt and dust. Some of it gains access through open windows and doors or other ' openings, but most of it is brought in by the dwellers on their clothes, skirts and shoes. It is, of course, useless to preach against the common habit of not discarding in the house the shoes worn in the streets and fields. These shoes carry manure, organic refuse, moist and dried excreta of man and animals, moist and dry discharges from the sick and well, sputum of consumptives, and millions of germs. Why such receptacles, laden with germs of disease, should not be left behind when coming into our " sweet DUST AND DIRT 77 homes," as is done by the "benighted" Orientals, is a question the answer to which is vainly sought. It is also useless to decry the equally unhygienic habit of women of wearing trailing skirts which drag along and sweep up the pavements of the streets and sidewalks as well as the gutters, gathering the rich harvest of the same dangerous matter and bringing it into the house. The house itself is a source of dirt and dust. Frag- ments of walls, floors, and ceilings, various objects like furniture, plants, flowers, also the various processes carried on within the house, such as sewing, cooking, lighting, heating, etc., all furnish their quota of the dirt falling upon the various surfaces of the house, and of the dust floating around in the air and settling upon various objects. The most important source of dirt and dust is of course man himself. Dirt and dust are brought in by persons upon their clothes and bodies. Considerable filth is due to the discharges from animals and human beings, and a very large part of the house dirt is due to the filthy habit of expectoration. In his booklet on Diist and its Dangers, Dr. Prudden expresses himself in the following forcible manner about expectoration. "The spectacle of the well-dressed, filthy brutes, whom natural selec- tion has most unkindly left but a few degrees higher than their congeners in the sty, wallowing in their expectoration, about certain hotels and theatre en- trances, may well impress the sensitive onlookers with the colossal task which nature undertook when she set to work to evolve man, and the lamentable 78 THE HYGIENE OF HABITATIONS failures which are so often but half-concealed in fashionable attire." The Dangers of House Dust. — The character, the quantity, the sources of the dirt and dust as well as the individual susceptibility and healthy condition of the house dweller are all determining factors in the amount and intensity of the danger to health and life. The inhalation of dust is injurious to the mucous membrane of the nose and throat, and may cause inflammation and catarrh of the respiratory tract. Dust consisting of the scales from the skin of persons suffering from measles and scarlet fever is apt to produce the same disease in healthy persons coming in contact with it. The greatest danger from dust comes from the patho- genic germs which adhere to it. They come from the dried sputum, skin scales, and other discharges of infected persons which contain the specific microbes of various specific diseases. The dust containing tubercle bacilli from the sputa of consumptives, the dust containing the germs of typhoid fever from dis- charges of typhoid patients, and the other micro- organisms from the many infectious and contagious diseases are of course very dangerous and capable of producing those diseases in healthy persons, either by inhalation, or by ingestion through food. That such infectious germs are abundantly found within the house has been proved by the experiments and investigations of many hygienists. In many houses, especially those which are damp, there are found a number of low moulds, mites, and fungi, some of which are dangerous to health. Among DOMESTIC AND OTHER ANIMALS 79 the most important of these is the fungus of "dry rot," " Hausschwamm, or Merihus Lacrymans," which is found in damp houses. The organic matter which is abundantly found in the dirt and in the superimposed layers of dust upon all surfaces within the room is dangerous to health because of the putrefaction and decomposition going on within it, because of the foul and disgusting odors emanating from it, and also because of the various pathogenic germs which may be found in it. When horse manure is a part of the organic dirt of the house it may contain tetanus bacilli, which may lead to infection with that dread disease. Also abundant organic matter, especially in dark and damp places, attracts rats and insects. Domestic and Other Animals. — Keeping domestic animals within the house is apt to become a source of danger. The common pets are dogs, cats, birds, and more rarely, rabbits, squirrels, monkeys, etc. The sources of danger to health from the animals are (1) in their excreta, (2) from the parasites living upon them, (3) from the dirt and germs which they may carry in upon themselves from outside, and (4) from the diseases with which the animals them- selves may be afiBicted. Among the diseases of domestic animals which may be transmitted to man are ringworm, favus, scabies, tetanus, anthrax, glanders, actinomycosis, "psittacosis" (a pulmonary disease of parrots), in- fluenza, diphtheria, plague, etc. Rats are not exactly domestic animals, but they may infest houses and become a veritable pest. Their 80 THE HYGIENE OF HABITATIONS presence is favored by the construction of the house, which leaves a hollow space between the walls and floors and by the food and drink which tempt these voracious animals. Rats have been proved to be very dangerous as carriers of and transmitters of plague, and probably other diseases. Their excreta deposited in foodstuffs may cause intestinal infection in man. Fleas and other parasites of rats may be carried to the human inhabitants and may infect human beings with plague and other diseases with which the rats may be afflicted. Insects. — ^Houses harbor a number of uninvited guests, who not only make the lives of their host miserable, but may even become a source of grave danger. Besides rats and mice, the most disagreeable of the uninvited guests and pests are the various insects with which some or most of the houses are teeming. These insects are the following: roaches, water-bugs, beetles, centipedes, spiders, lice, fleas, bed-bugs, and last but not least the mosquito. The very presence of these insects is disagreeable, either on account of their repulsive looks, or of their odors, or because of their bites. Moreover, the mode of feeding of most of these insects is objectionable to the human dwellers, who themselves are the hosts that furnish the sustenance. Relation of Insects to Disease. — ^Furthermore, most of the insects may become agents in the trans- mission and carrying of disease. The mode of propa- gation of disease by insects is by (1) transmission, (2) direct inoculation through their bites, and (3) by becoming the intermediate hosts of some infectious germs. HOUSE CLEANING 81 Transmission.— There is little doubt that insects can transmit disease germs by means of their bodies, legs, wings, etc., which may come in contact with the food, clothes, and skins of human beings. Thus, they dis- seminate disease directly from one person to another. Flies, on account of their prevalence and their habit of coming in contact with excrementitious materials outside of the house ' and with the food and drink inside of the house, are the most active agents in disease dissemination. Inoculation. — ^That certain insects by their bites inoculate human beings with the germs of diseases from which they themselves suffer has been surmised by many scientists for a long time, but definite proof of this has only lately been obtained in the matter of the transmission of plague in which the role of fleas, bugs, and rats is prominent. Intermediate Hosts. — Some insects become the inter- mediate hosts of certain specific and dreaded infectious parasites, which must pass through an intermediate stage in insects before they develop into full-grown parasites capable of infecting human beings. The mosquito which has been proved to be the cause of malarial and yellow fever, diseases which count their victims by hundreds of thousands, is a notable example. HOUSE CLEANING The presence in the house of so many and such varied impurities so dangerous to health and life, makes the problem of their prevention, their removal, and their destruction an important task. 6 82 THE HYGIENE OF HABITATIONS The war waged by the house dweller against all kinds of impurities must be remorseless, constant, thorough, and exhaustive, for if but a short armistice is granted the enemies of mankind are likely to get the upper hand and increase to an extent which makes their final dislodgement most difficult if not impossible. The methods of warfare against house impurities are threefold, aiming at (1) the prevention of the admission of filth, organic matter, etc.; (2) cleaning and removing impurities from the house; (3) the destruction of infectious materials. Prevention. — ^To prevent the accumulation of waste matter, paper, rubbish, etc., such stuffs should imme- diately be collected in closed receptacles and cremated. This may be done in ordinary stoves, ranges, and fur- naces, or in special furnaces for the purpose, which should be more extensively introduced. It will sur- prise some housewives to learn how easily they may get rid of most of the house waste, as well as the garbage, in a well-constructed fiu-nace, and how much this assists in keeping the house clean. Waste water and sewage are disposed into the plumb- ing system with which each house should be provided. In rural communities in which no sewer system is pro- vided the sewage and house-waste water may also be sent into a house-plumbing system, which empties into cesspools, or, better, into land irrigation. When no system of house plumbing exists, all waste water may be sent through rubber pipes into the kitchen garden, and the solid sewage may be collected in earth closets and used later as fertilizer. The removal of the sources of danger coming PREVENTION 83 from various deleterious gases and poisons consists in the proper construction of the house, its sanitary conveniences, and its proper maintenance. Ground air from the cellar may be prevented by a thorough isolation of the house foundation from the soil by means of damp-proofing materials, and also by a proper ventilation of the cellar. Leaks from illuminating gas pipes and fixtures may be prevented by a proper and good construction of the pipes and fixtures, and by periodical inspection and care, also by periodical and frequent tests of the whole system. This also applies to the plumbing pipes and plumb- ing fixtures. The pipes and fixtures must be properly constructed, all joints made gas-tight, the whole system frequently inspected, and periodical tests made to detect defects and leaks. Handholes of traps and screw caps of traps should be uncovered and the traps cleaned out, and all sink and wash-basin traps and pipes cleaned once in a while by solutions of caustic soda or potash. Smoke and coal gas may be kept from entering houses by a proper construction of the heating and cooking stoves and furnaces, by the skill in feeding them with proper fuel, by the care of chimneys, flues, and dampers. The best prophylaxis against arsenic and lead and other poisons in the house is the disuse of papers and paints containing those poisons as ingredients and the substitution of papers and paints free from toxic elements. There is really no justification for the use df any materials of which some ingredients may become dangerous to the house dwellers. 84 THE HYGIENE OF HABITATIONS The prevention of dirt and dust within the house is one of the most important sanitary measures. With proper care in construction and maintenance there is no reason why it should not be possible to make houses dustless and dirtless. With the installation of an ideal system of mechanical ventilation it is possible to eliminate all the dust coming into the house through windows and openings. These may then remain closed, and all incoming air may be filtered and passed through appropriate materials which will intercept all dust and leave the incoming air pure and dustless. Until the question of discarding the shoes worn outside, before entering into a house, and the even more difficult one of women's skirts is settled, some substitute prophylactic measures must be provided, such as special vestibules in houses, with some mechan- ical means of cleaning shoes and brushing off skirts. There is no inherent difliculty in the construction of such mechanical cleaners, and their installation would do infinite good and prevent much harm. Other means of preventing dirt and dust are the proper hygienic construction of house interiors, and the elimination of certain dust- and dirt-gathering objects within the house. The elimination from the house of all dust-gathering objects is absolutely necessary. Thus carpets, rugs, curtains, soft stuffs, upholstered furniture, wall paper, and all other dust- gathering and retaining materials and objects must be removed and kept out if the house is to be rendered dustless. Moulds, germs, mites, fungi, and bacteria will also PREVENTION 85 disappear from the house if these preventive measures against dust and dirt are universally adopted. The additional precaution of keeping the house dry and well-aired will further diminish the presence of these impurities by removing the conditions of life favorable to their growth and development. The keeping of domestic animals within the house is incompatible with hygienic housekeeping. The ordinary precautions of bathing and washing them and of consulting veterinarians in case of sickness may diminish the dangers, but will not entirely eliminate them. The prevention of the rat and mice pest is a more difficult problem, for these animals do not wait for an invitation to enter houses. The solid construction of walls and floors, the proper construction, lighting and ventilation of cellars and pantries, the immediate cremation of all garbage and organic matter used by them as food, the absolute cleanliness of kitchens, the keeping of food in tight receptacles, the use of rat traps, and periodical inspection and cleaning of house are some of the methods of preventing the living of rats and mice in the house. If these measures fail, war-like methods, like poisoning and periodic fumigation with sulphur, must be adopted. The prevention and eradication of house insects is no less difficult. Beetles, water-bugs, cockroaches, spiders, and similar insects may be eliminated from the house by the following means : by measures against house dampness and the maintenance of the dryness of the kitchen floors, walls, and cellars; the construction of floors and walls without cracks and crevices; the 86 THE HYGIENE OF HABITATIONS absence of any hiding and dark places for the habitat of insects; the frequent inspection, periodic and thorough cleaning of all rooms, and, especially, of those in which the presence of the insects is noticed; the dusting of surfaces where some of these insects live, with borax, boracic acid, or some other antiseptic and germicide; and finally, as in the case of rats and mice, periodic fumigation. Fleas and lice can be eliminated by the absence of domestic animals, by removing carpets and similar objects, and by the absolute cleanliness, in body and clothes, of the inhabitants. The elimination of the noxious bed-bug is difficult. It needs eternal vigilance on the part of the house- keeper; it needs absence of cracks in walls and floors, the more extensive use of light, airy, single, metal bedsteads and light, easily handled mattresses; it needs periodic inspection, thorough cleaning, and occasional fumigation. The elimination of the fly demands proper screening of windows and doors; covering of all foodstuffs with wire-mesh covers; the keeping of kitchens and dining- rooms in a proper and clean condition free from scraps of food, garbage, and organic matter; and constant warfare by cleaning, disinfection, fumigation, etc. The ravages of the mosquito must be prevented by draining all marshes and standing water near human habitations and towns, and the destruction of their larva by the use of kerosene oil. In addition the same precautions are employed as for flies. Means and Methods of Cleaning. — ^The common methods of house cleaning are wrong in principle^ MEANS AND METHODS OF CLEANINO 87 faulty in their execution, and futile in their efforts. The common dry method of cleaning of the housewife and servant is by means of the broom, brush, duster, and feathers. These instruments instead of cleaning the house, raise the dust, flap around the dirt, dis- turb quietly lying matter, and disseminate infectious material otherwise harmlessly resting in peace. It is remarkable that centuries of progress have not helped to evolve a more rational and sanitary method of house cleaning. The common wet method of clean- ing is not much more efficacious. The scrubbing of floors, spilling of pails of water upon floors and surfaces, soaking the woodwork, rendering it damp and mouldy, are not ideal methods of cleaning, likely to assist in the elimination of dirt and house insects. The carpet sweeper and dry-rag duster may be included among abominations in house cleaning. Undoubtedly the best method of cleaning is by means of the vacuum cleaners. Some of these are portable and operated by hand power or by electricity; others are installed in the house as a whole system with tubes and piping to all rooms, and special arrange- ments which make the exhaustion of dirt and dust a matter of little difficulty. No greater evidence of the enormous amount of dirt found in the carpets and rooms of houses is needed than the barrels and barrels of dirt which these vacuum cleaners collect. The only objection against them is their expense, but with their universal introduction this may become smaller. The other rational method of cleaning is by going over all the walls of rooms and the objects in the 88 THE HYOIENE OF HABITATIONS rooms with damp rags, thus removing the dust and dirt; occasionally some mild antiseptic, such as turpen- tine, carbolic acid, or a weak solution of corrosive sublimate, should be used. In house cleaning it is of the utmost importance to make the process thorough, regular, and periodic. Houses and rooms must be cleaned daily, weekly, monthly, and a special cleaning must be given every three months at the end of the seasons. The following instructions, written by Prof. T. M. Prudden, and disseminated in leaflets by the New York Department of Health, are of interest as to proper methods of house cleaning: "Sweeping and Dusting" "When you sweep a room, raise as little dust as possible, because this dust when breathed irritates the nose and throat and may set up catarrh. Some of the dust breathed in dusty air reaches the lungs, making parts of them black and hard and useless. If the dust in the air you breathe contains germs of consumption (tubercle bacilli) which have come from consumptives spitting on the floors, you run the risk of getting consumption yourself. If con- sumptives use proper i spit-cups and are careful in coughing or sneezing to hold the hand or handker- chief over the nose and mouth so as not to scatter spittle about in the air, the risk of getting the disease by living in the same room is mostly removed. "To prevent making a great dust in sweeping, use moist sawdust on bare floors. When the room DISINFECTION 89 is carpeted, moisten a newspaper and tear it into small scraps and scatter these over the carpet when you begin sweeping. As you sweep, brush the papers along with the broom and they will catch most of the dust and hold it fast, just as the sawdust does on the bare floors. Do not have either the paper or the sawdust dripping wet, only moist. "In dusting a room, do not use a feather duster, because this does not remove the dust from the room, but only brushes it into the air so that you breathe it in; or it settles down and then you have to do the work over again. Use soft, dry cloths to dust with, and shake them frequently out of the window, or use slightly moistened cloths, and rinse them out in water when you have finished; in this way you get the dust out of the rooms. In cleaning rooms you should re- member that dust settles upon the floors as well as on the furniture, and is stirred into the air which we breathe by walking over them. You can easily re- move all this dust in rooms which have bare floors, in houses, store.s, shops, schoolrooms, etc., after the dust has settled, by passing over the floor a mop which has been wrung out so as to only be moist, but not dripping wet." DISINFECTION Definitions. — Disinfection is the absolute destruction of pathogenic germs or the morbific agents. A disinfectant is an agent capable of destroying pathogenic germs. A germicide is the same. 90 THE HYGIENE OF HABITATIONS Sterilization is the absolute destruction of all organic life, whether infective or not; it is, therefore, more than disinfection which destroys the germs of infection only. Antiseptics are agents capable of inhibiting patho- genic germs without totally destroying them; a dis- infectant must be an antiseptic, but an antiseptic need not be a disinfectant. Asepsis is the absence or exclusion of bacteria. An insecticide is an agent capable of destroying insects; it is not necessarily a disinfectant, nor need a disinfectant be an insecticide. A deodorant is a substance which neutralizes or destroys unpleasant odors; it is not a disinfectant. Disinfectants are divided into three principal groups — physical, chemical, and gaseous. Physical Disinfectants. — Low Temperatures. — • Low temperatures are not regarded as disinfectants, as they do not destroy bacteria, but only inhibit their action and growth. Sunlight. — Sunlight is a good disinfectant, provided the infective materials and the gerxas are directly exposed to the rays of the sun. The germ-destroying action of the light is thought to be due to the ultra- violet rays. Some germs are killed by a very short e3cposure to the direct rays of the sun. Tubercle bacilli are killed by direct sun rays within ten to twenty minutes, depending on the media in which they are located. Electric and other artificial light is said to have some germicidal action, but it is very slight in comparison to sun rays. Desiccation. — Desiccation is like cold, an anti- septic but not a germicide. While bacteria must have PHYSICAL DISINFECTANTS 91 moisture as a condition of their life and growth, desic- cation will not always kill them; especially is this the case with the spore-bearing germs. Koch proved that the spore-bearing bacteria lose their viability after complete drying, but complete drying is very rare. Heat. — Of the physical disinfectants, heat is the most valuable, the most reliable, and the one most commonly employed. Heat may be applied as a disinfectant in several modes: By burning, baking, boiling, and steaming. Burning. — Burning is applicable only to materials and objects which are so greatly infected as to make any other destruction of infective agents difficult or impossible, or it may be applied to infected materials which are of so little value as not to pay for the ex- pense of any other method. It is not always easy to destroy certain infected materials by burning. Some objects, like mattresses, etc., infected with cholera or typhoid excreta, require a very high degree of heat, possible only in special furnaces, for the total and absolute destruction of all germs, and unless the ob- jects are totally consumed and turned to ashes the process cannot be regarded as complete. Dry Heat. — Some spore-bearing bacteria are able to withstand very high degrees of dry heat (140 C). This method is only applicable to objects that are not injured or destroyed by dry heat, such as metal and glass and like materials. Boiling. — ^Most bacteria are killed at temperatures much below the boiling point of water, and boiling for half an hour destroys most spore-bearing bacteria. 92 THE HYGIENE OF HABITATIONS Boiling is, therefore, a very valuable and efficient as well as inexpensive method of destroying in- fective agents and materials. It is applicable to all objects which are not injured by the process, such as underwear, some kinds of clothing, textile fabrics, etc. Steam. — This is the most valuable and elEcient disinfecting method. Steam kills all bacteria at once, while the most resisting spores are destroyed within a very short period-; steam is also very penetrating, and may be applied to a great many objects without injuring them. Steam may be applied in a small way in convenient Koch and Arnold sterilizers for domestic disinfection, and in a large way for large objects in institutions and hospitals by special apparatus. Steam for disinfecting purposes is used in two forms — either as saturated streaming steam, or as super- heated steam under pressure. While streaming steam may be sufficient for certain objects and infected materials, the penetrating qualities of superheated steam used under pressure, and the fact that such steam leaves disinfected objects dry, makes the latter method more valuable and efficient. Streaming steam is used in the disinfection of objects by the Arnold disinfector as well as by the Koch apparatus. For disinfection by steam under pressure special apparatus, called autoclaves, are used. Chemical Disinfectants. — Certain chemicals are cap- able of destroying pathogenic bacteria which come into contact with them. The chemicals may be used in solid or liquid form or as gases. The disinfectant qualities depend on the character of the chemical constituents, the form in CHEMICAL DISINFECTANTS 93 which they are used, and the material in which the infective agents and germs are lodged. The objections to chemical disinfectants are that most of them, to destroy infective agents, must be used in solutions so strong that they likewise injure the object to be disinfected; and furthermore, that they must be thoroughly mixed with infected objects and come into direct contact with the infective germs, for otherwise their action is not destructive. It is exceedingly difficult to disinfect properly certain infected objects like cholera and typhoid discharges, unless the chemicals are very thoroughly mixed with every particle of the discharges, and this is very difficult. Carbolic Acid. — ^This is a good antiseptic, but a comparatively weak germicide. Carbolic acid is not applicable to disinfection of material infected with spore-bearing bacteria, as its action upon spores is very feeble. It has been recorded that some anthrax spores can withstand a forty days' immersion in a 5 per cent, solution of carbolic acid (Rosenau). Non- spore-bearing bacteria are killed in a solution of carbolic acid of from 3 to 5 per cent. Carbolic acid has little penetrating power. It is largely used in solutions of 2 to 5 per cent, for washing floors, walls, wooden surfaces, small objects, etc. Its range of usefulness is wide, because it is not injurious to most objects. Cresols. — Creoline and lysol are the most commonly used as disinfectants of this group, although others, like saprol, etc., may be employed. The cresols are more powerful disinfectants than carbolic acid, and are used for about the same objects. 94 THE HYGIENE OF HABITATIONS Corrosive Sublimate. — ^Bichloride of mercury is a valuable disinfectant, and is used in solutions of from 1 to 2000 to 1 to 500. In the stronger solutions it kills germs rapidly, but because it unites and forms insoluble compounds with albuminous matter, corrosive sublimate loses much of its disinfecting property when used for infective agents mixed with much or- ganic matter. According to Rosenau, corrosive sub- limate kills spores in solutions of 1 to 500 after e^^osure for one hour; solutions of 1 to 1000 destroy non- spore-bearing bacteria within a half hour at ordinary temperatures. As an antiseptic, corrosive sublimate is used in medical and surgical practice in solution of 1 to 2000 to 1 to 10,000. Lime. — In the form of chlorinated lime, or of Labarraque's solution, it is a good disinfectant for excreta, and is used for disinfecting privy vaults, cesspools, cellars, etc. It is efficient only when it is freshly prepared. A number of other chemicals are used as disinfectants, although their range of usefulness is limited and they are not commonly so employed. Of these chemicals, mention may be made of potassium permanganate, ferrous sulphate, zinc chloride, copper sulphate, borax, boracic acid, and a number of others. Gaseous Disinfectants. — Gaseous disinfectants are more valuable than other disinfectants, because of their penetrating power and the possibility of reach- ing surfaces and places which are inaccessible to ordin- ary liquid chemicals. Of the gaseous disinfectants employed, the most important one is formaldehyde, which has lately superseded the once very popular sulphur dioxide disinfection. Among the other gaseous CHEMICAL DISINFECTANTS 95 disinfectants sometimes used are chlorine, bromine, and hydrocyanic acid, but these have been discarded almost entirely because of their toxic nature and their questionable effects on bacteria. Sulphur Dioxide. — Sulphur dioxide is a powerful germicide and a good surface disinfectant; its disad- vantages are (1) that it is not very penetrating, (2) that it does not destroy spore-bearing bacteria, (3) that it damages textile fabrics, (4) that it bleaches vegetable colors, and (5) that it injures and tarnishes metals. It is also poisonous to those handling it, causes injury to the mucous membranes of the eyes and nose and throat, and leaves a very disagreeable odor, clinging to materials for a long time. Several methods of sulphur disinfection are employed. The pot, candle, or liquid form, also the furnace. About five pounds of sulphur are used for every 1000 cubic feet of space to be disinfected. Moisture and heat increase the penetrating qualities of the gas and the value of disinfection. An exposure of twenty-four hours is necessary for thorough disinfection, and as the gas is very diffusible, precautions must be taken effectively to close all windows, doors, and cracks, crevices, and other apertures found in the room. Sulphur disinfection is preferable wherever surface disinfection is needed and where there are few articles which would be 'damaged by it, also wherever in- secticide action is demanded. Formaldehyde Gas. — ^Formaldehyde gas has very largely superseded sulphur dioxide as a disinfectant. Its main value is that while it is a good germicide it does not destroy fabrics and injure objects, and also that it is non-toxic. Formaldehyde also is only a 96 THE HYGIENE OF HABITATIONS surface disinfectant, and its penetrating qualities are not very great. Bacteria are killed immediately by formaldehyde on direct exposure, and spores within an hour. It kills dried organisms as well as those in a moist state. Formaldehyde is not an insecticide. For domestic disinfection formaldehyde is generated by spraying liquid formalin (which contains 40 per cent, of the gas) or by heating paraform pastils or powder, also by means of generators or lamps. Other methods of evolving formaldehyde in disinfection which are used in large house and hospital disinfec- tions are by means of large generators or lamps, or in specially constructed autoclaves under pressure, or in retorts without pressure. Disinfection of Rooms, etc. — Practical disinfection is a process which needs scientific precision and atten- tion to details. It must be adjusted to the form and nature of infection and the infected materials and objects, each of which may need a different method of handling and disinfection. The disinfection of rooms and infected materials differs according to the disease; various methods must be employed after tuberculosis, typhoid fever, yellow fever, diphtheria, scarlet fever, etc. Boom Air. — ^The room air needs no disinfection, for whatever germs may be found in the dust of the air in a room will settle upon the surfaces whenever the room is closed and left undisturbed. Bjoom Walls. — ^The room walls if covered with paper may be efficiently disinfected by thorough rubbing with stale bread. Painted surfaces of walls and ceilings may be disinfected by washing with .3 DISINFECTION OF ROOMS 97 per cent, solution of carbolic acid or a 1 to 500 solu- tion of sublimate of mercury. Floors and other sur- faces of rooms may also be conveniently scrubbed with hot water and a solution of carbolic acid or sublimate, or one of the cresols. Carpets, rugs, etc., may be efficiently disinfected by a strong solution of formalin, by gaseous disinfection with formaldehyde, or steam under pressure. Curtains, hangings, etc., within the rooms are disinfected with formaldehyde, and may also be washed in boiling water. Wooden bedsteads may be washed with a 3 per cent, carbolic solution or a 5 per cent, formalin solution. Bedding, linen, etc., may be disinfected by steam, by formalin, and also by formaldehyde. For the successful disinfection of rooms with a gas it is necessary to close all openings, cracks, and crevices, key-holes, etc., completely, and especially the crevices about windows and doors. This is done by means of cotton, or better, by means of gummed paper strips. Raising the temperature of the room assists disinfec- tion. The room is then closed and all openings and crevices are sealed with gummed paper, and the room is left for at least twenty-four hours. Excreta, sputum, feces, and other discharges of infected persons must be gathered and collected in special glass or porcelain vessels and disinfected by means of the various chemical disinfectants like lime, cresols, carbolic acid, copper sulphate, and formalin. Whatever disinfectant is used it must be thoroughly mixed with the discharges so as to penetrate them through and through, and it must also be used in large quantities and in very strong solution. 7 CHAPTER III THE HYGIENE OF FOODS AND FOOD SUPPLY FOODS " Food is that which, when taken into the body, builds tissue or yields energy." Everything is, therefore, food which may be used for the purpose of replacing the wear and tear of the cells of the body, or of supplying heat and energy to the body, or of storing up such energy for future use. The sources of human food are the vegetable, mineral, and animal kingdoms. Certain minerals and a large number of cereals, roots, vegetables, fruits, and nuts are used, either in their natural state or specially prepared and somewhat modified by art and science. The flesh of a large number of animals is used as human food, when specially prepared and modified by man. All food contains, beside nutrients and waste matter, a greater or smaller percentage of water. Chemical Composition. — In their final analysis all foods contain the elements, carbon, hydrogen, oxygen, nitrogen, sulphur, sodium, potassium, calcium, mag- nesium, etc. Most of the foods, however, are when taken into the body derived from the organic world; the only foods taken from the inorganic world are mineral matter and water. USE AND VALUE OF EACH FOOD COMPONENT 99 The firs^ subdivision of food is therefore into organic and inorganic. The mineral substances used for food are sodium, potassium, magnesium, chlorine, sulphur, phosphorus, iron, silica, fluorine, iodine, etc. The water and mineral substances used for food are taken either in their natural state or in combination with organic foodstuffs. Organic foods are divided into two main groups, nitrogenous and non-nitrogenous. ■Kj-. f T> i. • f White of eggs, curd or casein of milk, Nitrogenous < Protein < , T \ . . ■ ^ , I. I lean meat, gluten of wheat, etc. „ ., r Carbohydrates: sugar, starch, etc. Non-nitrogenous i -c, . • , ° ,, I Fats: animal, vegetable. The Relative Use and Value of Each Food Component. — Each of the food components is essential to life. A certain amount therefore of each must be used in order to sustain and continue life. Water. — ^The human body consists of two-thirds of its weight of water. The body loses water con- stantly through the lungs, skin, and excretory ducts. The amount of the daily loss of water depends upon many factors, and is estimated at from 2000 to 3000 grams. There is, therefore, needed a considerable amount of water for daily use, and this is partly fur- nished by the water which is a component of nearly every food, and partly by the water consumed with or in addition to the food. Mineral Matter. — ^The body contains a quantity of mineral matter which is found in the form of ashes when the body is burned. The minerals which have 100 THE HYGIENE OF FOODS AND FOOD SUPPLY been enumerated are found in the body and are also needed as food for the formation of bone and as an aid to digestive processes. It is claimed that the lack of certain inorganic matters, especially acids, is capable of producing the disease called "scurvy," which is found among sailors and others who are deprived of foods containing those acids. Protein. — ^The muscles, the blood, the lymph, and other parts of the human body and organs contain a large percentage of protein or albumin matter. There is a constant loss of these protein cells in the body metabolism, and consequently a need to repair and replace this loss. This is accomplished by the ingestion of foods which have a certain percentage of protein in their composition. All animal foods contain a large proportion of proteins, while vegetables with a few exceptions contain but a small proportion of protein. The chemical composition of protein matter depends upon its source. Thus there are. different varieties of protein matter, such as the albumins, globulins, albuminoids, nucleo-albumins, peptones, etc. Carbohydrates and Fats. — The heat and energy of the body use up certain elements, such as oxygen, carbon, and hydrogen, and these must be replaced by food. The carbohydrates and fats supply this need. Fats and carbohydrates are to some extent inter- changeable. The principal elements of food which furnish the carbohydrates are the sugars and the starches, which digestive processes convert into sugars. The fats are found in foods in the form of fat and oil. There is considerable fat in animal food, but only a ESTIMATES OF FOOD VALUES 101 relatively small percentage of carbohydrates. Many vegetables contain starches and sugars in large quantities. Estimates of Food Values. — In the metabolism of the body the use of food produces energy and heat. This heat may be measured and serves as criterion of the heat and food values. The measure of heat is in "calories." A calorie is the amount of heat required to raise 1 kilogram of water, 1° C. It has been found that: 1 gram of protein gives 4 . 1 available calories 1 gram of carbohydrate gives 4.1 " " 1 gram of fat gives 9.3 " By the aid of this table it is possible to calculate the fuel value in calories per certain weight of food, for instance, 100 grams. For instance the composition of milk is protein 3 per cent., sugar 5 per cent., and fat 4 per cent. The number of calories represented by 100 grams of milk will be as follows: Protein, 3 X 4.1 = 12.3; fat, 4 X 9.3 = 37.2; carbo- hydrates, 5 X 4.1 = 20.5. Total = 70 calories. Dietary Standards roB Man in Full Vigor at Moderate Mdsctjlar Work (Langworthy) Protein. Energy. Condition. Gram. Calories. Food as purchased .... .115 3.800 Food as eaten 100 3.500 Food as digested 95 3.200 The following table of the composition of various food materials and their fuel value in calories per 102 THE HYGIENE OF FOODS AND FOOD SUPPLY pound is taken from the charts prepared by C. F. Langworthy, Food E3q)ert of the United States Department of Agriculture: Food. it Is 1 I 1 ■S S! Carbohy- drates. Per cent. 4 I I'll o.Sa Whole milk 87.0 3.3 4.0 5.0 0.7 310 Skim milk . 90.6 3.4 0.3 5.1 0.7 165 Buttermilk 91.0 3.0 0.5 4.8 0.7 160 Cream 74.0 2.5 18.5 4.5 0.5 865 Whole egg 73.7 14.8 10.5 1.0 700 Egg white . 86.2 13.0 0.2 0.6 265 Egg yolk . . 49.5 16.1 33.3 1.1 1608 Cream cheese . . 34.2 25.9 33.7 2.4 3.8 1950 Cottage cheese 72.0 20.9 1.0 4.3 1.8 510 Lamb chop 53.1 17.6 28.3 1.0 1540 Pork chop . 52.0 16.9 30.1 1.0 1580 Smoked ham 40.3 16.1 38.8 4.8 1940 Beef steak 61.9 18.6 18.5 1.0 1130 Dried beef 54.3 30.0 6.6 9.1 840 Cod . 82.6 15.8 4.0 1.2 325 Salt cod . . . 53.5 21.5 3.0 24.7 410 Smoked herring 34.6 36.4 15.8 13.2 1355 Oyster . 86.9 6.2 1.2 3.7 2.0 235 Mackerel 73.4 18.3 7.1 1.2 645 Olive oil • > 100.0 4080 Bacon . 18.8 9.4 67.4 4.4 3030 Beef suet . 13.2 4.7 81.8 0.3 3510 Butter 11.0 1.0 85.0 3.0 3410 Lard 100.0 4080 Com . 10.8 10.0 4.3 73.4 1.5 1800 Wheat 10.6 12.2 1.7 73.7 1.8 1750 Buckwheat 12.6 10.0 2.2 73.2 2.0 1600 Oat 11.0 11.8 5.0 69.2 30.0 1720 Rye . 10.5 12.2 1.5 73.9 1.9 1750 Rice 12.0 8.0 2.0 77.0 1.0 1720 White bread . 35.3 9.2 1.3 53.1 1.1 1215 Whole wheat brea d . 38.4 9.7 0.9 49.7 1.3 1140 Oat breakfast fooc 1 84.5 2.8 0.5 U.5 0.7 285 Toasted bread . 24.0 11.5 1.6 61.2 1.7 1420 PREPARATION OF FOOD AND DIET 103 Food. i S Carbohy- drates. Per cent. ii' booa values in calories per pound. Corn bread 38.9 7.9 4.7 46.3 2.2 1205 Macaroni . 78.4 3.0 1.5 15.8 1.3 415 Sugar . 100.0 1860 Molasses . 25.1 2.4 69.3 3.2 1290 Stick candy 3.0 96.5 0.5 1785 Maple sugar 16.3 82.8 0.9 1540 Honey . 18.2 0.4 81.-2 0.2 1520 Parsnip 83.0 1.6 0.5 13.5 1.4 230 Onion . 87.6 1.6 0.3 9.9 0.6 225 Potato 78.3 2.2 0.1 18.4 1.0 385 Celery .... 94.5 1.1 3.4 1.0 85 Shelled bean, fresh 58.9 9.4 0.6 29.1 2.0 740 Navy bean, dry . 12.6 22.5 1.8 59.6 3.5 1600 String bean, green 89.2 2.3 0.3 7.4 0.3 195 Corn, green 75.4 3.1 1.1 19.7 0.7 500 Apple . 84.6 0.4 0.5 14.2 0.3 290 Dried fig . 18.8 4.3 0.3 74.2 2.4 1475 Strawberry 90.4 1.0 0.6 7.4 0.6 180 Banana 75.3 1.3 0.6 22.0 0.8 460 Grapes 77.4 1.3 1.6 19.2 0.5 450 Raisins . 14.6 2.6 3.3 76.1 3.4 1605 Grape juice . 92.2 0.2 7.4 0.2 115 Canned fruit . 77.2 1.1 0.1 21.1 0.5 415 Fruit jelly . . 21.0 78.3 0.7 1455 Walnut 2.5 16.6 63.4 16.1 1.4 3285 Chestnut . 5.9 10.7 7.0 74.2 2.2 1875 Peanut . 9.2 25.8 38.6 22.4 2.0 2500 Peanut butter . 2.1 29.3 46.5 17.1 5.0 2825 Cocoanut . 3.5 6.3 57.4 31.5 1.3 3125 Preparation of Food and Diet. — ^By diet is understood the quantity, quality, and kind of food taken in by the person daily. There are a great many factors determining the value of the average person's diet. The main factors are as follows: 104 THE HYGIENE OF FOODS AND FOOD SUPPLY The person: Age, weight, physical condition, race, condition of rest. The food: Chemical composition, physical condi- tions as to form, volume, consistency, percentage of edible and inedible parts, temperature, etc. General conditions: Climate, temperature. It is difficult to make hard and fast rules for dietetic standards. Human beings adjust themselves easily to different kinds and forms of food, and during health, as a rule, do not suffer much except when they take either too much or too little food, are fed exclusively on one food or on food which lacks some of the necessary nutrient ingredients. A prolonged and constant overuse or underuse of certain principles of food is bound to cause patho- logical conditions and is the cause of certain diseases of digestion and metabolism. The form and consistency of food is of much impor- tance, for food must be in such condition as to be readily digested. Many foods must be mechanically ground by the teeth; some are chemically acted upon in the mouth by the processes of mastication. This not only prepares the food for the stomach by softening and dividing it into small particles, but also aids much in the conversion of starches of vegetables and cereals into sugars. There is still much controversy as to the value of an exclusively vegetarian diet, as well as to the com- parative percentage of the protein and carbohydrate elements needed for persons. For the average healthy person a mixed diet of animal and vegetable food is probably the most appropriate, and the amount of PREPARATION OF FOOD AND DIET 105 the protein matter must be somewhat Hmited, much depending upon the physical condition and habits of the person. The cost of food depends also upon very many factors. Often it is not the most costly food that is the most useful or nourishing as some of the causes of the high cost of food are its rarity, difficulty of obtaining it, the manner of preparation, the place where it is sold, and the matter of taste. For physical subsistence, cereals, vegetables, nuts, fish, and flesh of animals furnish all the necessary nutrient qualities, and some among these are of comparatively low cost, their nutritive value being, however, quite as great if not greater than that of the more costly foods. Raw, Cooked, and Prepared Foods. — Some cereals, a large number of vegetables, most of the fruits, a number of nuts, and some forms of animal foods may be taken in their natural state. The flesh of animals is seldom used raw, although the fat is often so used, and in some climates the flesh also is eaten raw. The process of cooking foods greatly improves the consistency and form of most foods, develops the flavors, increases the digestibility, improves the taste, and generally enhances the value of food for human beings. Much of the increased digestibility and value of the food depends upon the various forms or pro- cesses of cooking. The food may be heated (pasteurized at 160° F. for ten minutes) . This process destroys certain patho- genic germs, softens the food, and is valuable for the preparation of milk, for the cooking of soft-boiled eggs, etc. 106 THE HYGIENE OF FOODS AND FOOD SUPPLY Boiling, stewing, steaming, baking, roasting, and fry- ing are some of the various modes of subjecting foods to heat. The value of each process depends more or less upon the kind of food and various other conditions. In stewing, the food is cut into small pieces and put in cold water and heated slowly. This is an economic method of preparing certain meats and vegetables. Boiling is a more rapid process in which the food is put into hot water and kept at a boiling temperature. Certain foods, especially fruits and cereals, are more tender and digestible when prepared by means of steaming. The food is placed in a double pot, the water is boiled in the lower part, and the food in the upper part is subjected to the steam formed by the heat. Baking and roasting are processes by which the food is exposed to the direct radiation of heat in open or enclosed stoves. Frying is a form of roasting in which the food is placed in a pan and. fried in fat. Boiling and frying somewhat toughen the fibers of the food and render it less digestible than the other processes. Care, Storage, and Preservation of Food. — ^All foods when left exposed for some time undergo a process of deterioration and decomposition. This is due to the breaking up of organic tissue into its simple com- ponents, and finally into its primary elements, the decomposition being due to the action of micro- organisms. The majority of the microorganisms which cause the breaking up of the tissue of the foodstuffs are harmless. The deterioration of food is also due to various moulds, yeasts, and other vegetable and CARE, STORAGE, AND PRESERVATION OF FOOD 107 animal germs which are found almost everywhere. In order to prevent the deterioration of foodstuffs, the action of the destroying germs must be inhibited or stopped. Foods that are overripe or underripe, that have fungi, parasites, or worms in them, or that lack pro- tective coverings, usually undergo more rapid decom- position. Certain foods when in a process of decom- position develop chemical poisons which cause serious disturbances in those eating the foods. These, are sometimes called ptomain poisoning. In order to care, store, and preserve foods in the house, certain conditions are necessary: (1) A sound conditipn of the food; (2) dry air: moisture is abso- lutely necessary to decomposition, and its presence favors the growth and development of low organic and bacterial life; absence of moisture is a preventive against decomposition; (3) absence of flies and insects: certain insects injure the food and also bring to it germs which aid in decomposition; all foods must be examined and covered to prevent the access of these insects. It is best to have all foods covered or wrapped in protective coverings so as to prevent their injury from outside agents. Temperature. — A low temperature, even below the freezing point, does not kill bacteria, but it stops and inhibits their further growth. At a temperature of 40 to 45° F. the growth of germs is greatly retarded, and this is the best temperature at which to keep and store foods. Food in houses is stored in separate rooms, pan- tries, cellars, or ice chests. Wherever it is stored 108 THE HYGIENE OF FOODS AND FOOD SUPPLY care must be taken to have an equable temperature, below 45° F., and as far as possible each food should be separated and kept apart from other foods. Drying. — The method of drying foods in order to preserve them is efficient in proportion to the thorough- ness of the process. Drying is adaptable to meats, cereals, seeds, and some fruits. The drying is done either in the sun or on fires. Some foodstuffs may be preserved for a long time. Salting and Pickling. — Salting and pickling are partly chemical and partly physical methods of food preservation. Salt prevents decomposition by reason of its antiseptic qualities and by its absorption of moisture. This method is applicable to meats and fish. Fish are also preserved in brine or salt solution. Pickling is the keeping of food, such as fish, certain vegetables, and fruits, in vinegar. These processes harden to some extent the fibers and diminish the digestive qualities of the food. Smoking. — ^The method of food preservation by smoking is really a combination of several methods, drying, salting, and chemical. It is said that the creosote in the wood smoke to which the food is ex- posed serves as an antiseptic. Certain meats and fish are preserved by smoking. This hardens the fibers and makes them less digestible. High Temperature. — Foods may be preserved by subjecting them to high temperature. This destroys all microorganisms and prevents the decomposition of the food. The heating of the food to 140° F. from ten to fifteen minutes is called pasteurization. Heating to the boiling point and subjecting the ADULTERATION 109 food to this heat for one-half hour or longer is called sterilization. It effectively destroys all micro- organisms, even the spore-bearing bacteria. Canning. — Many foods may be preserved for in- definite periods of time by sterilization with heat and by subsequent storage in hermetically closed tin or glass receptacles. Many kinds of meats, fish, fruits, and vegetables are at present preserved by the process of canning. The food is cut in appropriate forms and placed in tin cans of various sizes. It is then covered with hot water and boiled. The cans are covered except for a very small opening at their tops, and subjected to a high degree of heat in steam boilers for the period of an hour or longer. When taken out the opening is sealed with solder, and after the cans have again been subjected to heat, they are taken out, cooled, labelled, and stored. In this condition they may be kept for very long periods. If the food in the cans is not properly sterilized and if decomposition subsequently sets in, the carbonic acid gas developed in the cans causes a bloating or bulging out of the top or bottom of the can, which indicates that the food has undergone some decom- position. Such cans should be rejected. Adulteration. — By adulteration is meant the "alter- ing" of the normal composition and constituency of the food. Food adulteration is accomplished in various ways: (1) By mixing with the food some foreign substance to reduce, lower, or injure its quality and strength; (2) by the entire or partial substitution of an inferior substance; (3) by the entire extraction of a portion of valuable substance from it; (4) by the sale no THE HYGIENE OF FOODS AND FOOD SUPPLY of imitations leading the consumer to purchase articles he never intended to buy; (5) by the sale of food, in part or wholly, of a diseased, decayed, or decomposed substance; (6) by coloring, coating, polishing, or pow- dering the food, thus concealing its poor quality, or making it look better than it is; (7) by introducing into the food a poisonous constituent, or any ingredient likely to be harmful to the consumer. Adulteration may be harmful, fraudulent, or acci- dental. Harmful adulteration includes all those which are either directly harmful by the addition of injurious substances, by the decomposed or unwholesome state of a part or the whole of the food, or by the dilution or extraction of some nutrient part of the food, thus rendering it less nutritious. Under fraudulent adul- terations are classed all those which do not directly or indirectly harm the consumer, except in deceiving him and making him pay more than he would normally have paid. There is much adulteration of foods in commerce and trade. The Federal Food and Drugs Act makes stringent provisions against adulteration and mis- branding, and much has been done by the (govern- ment to insure the purity of foods and the honesty of their adulteration. Much more, however, remains to be done. The methods of adulteration of foods are many and change from time to time. Cereals, Nuts, Fruits, Vegetables. — ^Vegetable foods are classified by Harrington as follows: 1. Farinaceous seeds: (a) Cereals: wheat, rye, barley, oats, corn, buckwheat, rice. (6) Legumes: peas, beans, lentils. CEREALS, NUTS, FRUITS, VEGETABLES 111 2. Farinaceous preparations: Sago, tapioca, arrowroot. 3. Fatty seeds : Nuts, almonds, cocoanuts, walnuts, peanuts, chestnuts, etc. 4. Vegetable fats: Olive oil, cotton-seed oil. 5. Tubers and roots: Potato, artichokes, carrots, turnips, parsnip, beets, etc. 6. Herbaceous articles: Asparagus, cabbage, cauli- flower, sprouts, lettuce, spinach, beet tops, dandelions, leeks, onions. 7. Fruit products used as vegetables: Tomato, cucumber, squash, pumpkin, egg-plant, vegetable marrow. 8. Fruits: Apples, pears, peaches, apricots, plums, cherries, oranges, etc., berries, bananas, figs, lemons, etc 9. Fungi: Edible mushrooms, truffles. 10. Saccharine preparations: Cane sugar, maple sugar, honey, molasses, etc. This classification includes most of the vegetable foods. The chemical compositions and calorie values of some of these have been given in the table on pages 102 and 103. Cereals. — Cereals contain a large percentage of starch, a considerable percentage of protein, some mineral matter, and extractives. Some of the cereals, like rice, contain more starch, while others, like oats, contain less starch. The cereals are an indispensable part of human diet. While most of the cereals may be eaten raw, dried, or specially prepared in the seed, the common use of most of them is in the form of ground flour mixed with water and baked. The proper making of edible bread is a domestic art 112 THE HYGIENE OF FOODS AND FOOD SUPPLY long monopolized by women, although at present in the ^cities this domestic art threatens to be lost, as most of the bread is baked in special bakeries. Legumes. — The legumes are valuable foods. They contain not only a large portion of starch, but also a high percentage (22 per cent, to 25 per cent.) of proteids, and thus are said to be good substitutes for meat foods. Farinaceous Preparations. — Most of the farinaceous preparations contain a large percentage of starch. Nuts. — Nuts are valuable on account of their large content of protein and large percentage of oil. • Vegetable Oils. — ^The vegetable oils are valuable foods and are used as substitutes for animal fats. Tubers. — ^Among the tubers, potatoes deserve their reputation as a valuable food and furnish much of starch which the human organism needs. Roots. — The roots contain a considerable part of sugar, and with herbaceous articles serve as food adjuncts especially for preparations in cooking other foods. Fruits. — Fruits contain a large percentage of water, sugars, acids, and very little protein matter. Saccharine Preparations. — The use of saccharine preparations is very general. They possess valuable food properties in that they furnish heat energy, but they are used more for the agreeable taste. They are likely to be used in too great quantities; thus causing oversupply of this principle of food, and digestive fermentation. Beverages. — ^A certain amount of water is a part of almost all foods. Some is taken in its pure form, and HYGIENE OF MEAT FOODS 113 large quantities are consumed in the form of various beverages, like tea, coffee, beer, cider, soda, etc. Some of these contain a greater or smaller quantity of sugar and acids, others contain certain alkaloids, which have found favor, and others contain a certain percentage of alcohol. Whether such beverages are needed is a disputed question. Some advocate their use, others deny that they possess any beneficial properties. The overuse of most of them, especially those containing a large percentage of alcohol, un- doubtedly endangers the health. Condiments. — ^This term designates certain articles which are used, not for their food value of which they have none or very little, but for the flavor they impart to food and the stimulation they give to the appetite and digestion. Among the principal condiments are vinegar, salt, spices, pepper, mustard, etc. MEAT AND MEAT SUPPLY Hygiene of Meat Foods. — ^The hygiene of meat foods may be considered according to the following sub- divisions: Bangers to Health. — Infection by entozoa, bacteria, toxins, and ptomains. Etiology. — Diseases of the animals, conditions of the animals, postmortem- changes, postmortem infection, adulteration. Prophylaxis. — Hygiene of the food animals: meat inspection, ante mortem and post mortem; hygiene of place and persons; preservation, sanitary supervision of manufacture, etc. 8 114 THE HYGIENE OF FOODS AND FOOD SUPPLY Dangers to Health. — ^The dangers to health from the ingestion of flesh foods are due to infection by entozoa, infections by bacteria, and to the action of toxins and ptomains. Parasitic Diseases Due to Meat. — ^These are due to (1) infection by tapeworms, (2) infection by trichina, (3) infection by echinococci. Tapeworm. — ^The two principal species of tapeworm found in man which are due to meat infection are the Taenia saginata and the Taenia solium; the former is due to infection by "measly" beef, the latter by "measly" pork. The Cysticercus cellulosse is the larval form of the Tsenia solium. It appears in hogs in the shape of minute bladder worms, encased in little cysts which are found in the intestines, muscular fibers, brain, liver, and other parts, and especially under the tongue, where it may readily be recognized. The cysticercus is derived from the segment and egg of the Tsenia solium, which are passed from the human intestine, ingested by the hog, and on reingestion by man develop again into tenia. The Cysticercus bovis is the larval form of the Tsenia saginata of man, 'and is found in the intermuscular fibers and connective tissue of cattle. Trichina. — ^The Trichina spiralis is a parasite found mostly in the muscular fibers of pork, in the form of minute spiral-form worms, which are encapsulated, but may be recognized with the naked eye as white specks. The ingestion of pork infected by trichina causes: in man the acute disease called "trichinosis," which is due to the presence of the trichina in the TOXINS AND PTOMAINS 115 muscular fibers. Its symptoms resemble those of typhoid fever. The disease is often fatal. Echinococcus. — Echinococcus sometimes infects sheep, and, rarely, cattle. The infected meat causes in man the hydatid diseases. Originally the infection comes from Taenia echinococcus found in dogs. Meat Infection by Bacteria. — Pathogenic bacteria may be found in the flesh of animals, and such infected flesh on consumption is capable of producing disease. The pathogenic bacteria may originate in the diseased condition of the live animals suffering from the in- fectious diseases, or they may gain entrance into the meat of healthy animals through infection by contact, etc., after killing. The diseases of animals infectious to man which are caused by pathogenic bacteria and which, it is claimed, may be transmitted through their meat to man, are the following: tuberculosis, pleuropneumonia, foot and mouth disease, cattle plague, anthrax, glanders, malignant edema, erysipelas, actinomycosis, typhoid fever, cholera, pyemia, septicemia, tetanus, sheep-pox, Texas fever, etc. Toxins and Ptomains. — Certain meat causes, on in- gestion, toxic symptoms. These symptoms are due to toxic substances in the meat or to bacterial products of decomposition called "ptomains." The symptoms resemble those of severe gastro-intestinal inflammation, and may be fatal. The Bacillus botulinus has been regarded as the cause of some of the toxic influences of certain meats. The virulence of the intoxication by meat differs according to the condition of meat, the manner of 116 THE HYGIENE OF FOODS AND FOOD SUPPLY preparation, the quantity ingested, and the individual idiosyncrasies of the victim. Intoxication is most frequently caused by the eating of "prepared meats," such as chopped meats, sausages, canned, "potted," and "deviled" meats, etc. Causes of the Unfitness of Meat for Food. — ^These may be: (1) The diseases of animals; (2) the unfit condition of living animals; (3) postmortem changes; (4) infection of the meat by persons or by places of manufacture, sale, etc.; (5) adulteration. Diseases of Food Animals. — ^The diseases of food ani- mals, which render their meat totally or partly unfit for food, have already been enumerated. Condition of Food Animals. — ^The conditions of the food animals, which may render their meat unfit for food, are the following: 1. The death of the animals from age, disease, or accident. 2. Moribund conditions from injury, drugs, over- work, fright, overdriving, etc. 3. Immaturity: unborn calves and lambs and ani- mals in the first few weeks of life, are unfit. 4. Artificial conditions and treatment of the car- casses by blowing up (blown veal), coloring, etc. Postmortem Changes. — ^The temperature, moisture, and substances of the slaughtered carcass make a a favorable medium for the development of micro- organisms which swarm in the meat or may gain access later. The resulting decomposition and organic changes necessarily cause the ipeat to deteriorate and render it unfit for food unless bacterial action is inhibited by placing the meat in a condition CHARACTERISTICS OF GOOD MEAT 117 t rendering the development of bacteria and putrefaction unfavorable. The rapidity of deterioration depends on the condition of the animal from which the meat was obtained, the cleanliness of the process of preparation, and the place in which it is kept. Infection by Persons and Places. — In addition to the foregoing sources of deterioration, meat may be directly infected with pathogenic and other bacteria by the persons who handle it and take part in slaughtering, skinning, dressing, cutting, manufacturing, packing. Food may also become infected in the various places through which the meat must pass in the pro- cess of manufacture. Adulteration of Meat. — Meat adulterations may con- sist in: 1. The addition of foreign substances reducing, lowering, or injuring the quality of the food. 2. Partial or entire substitution of an inferior substance. 3. Extraction of some of the valuable substances from the meat. 4. Coloring, coating, or otherwise changing the appearance of the food, concealing its poor quality or making it appear better than it is. Characteristics of Good Meat. — Good meat is uniform in color, neither too red nor too pale, firm and elastic to the touch, moist but not wet; it does not pit nor crackle on pressure, and has a marbled appearance. It is free from unpleasant odor, its juices redden litmus paper slightly. The fat is firm and does not run. Beef is bright red, more marbled than any other meat. Veal is pale and less firm to the touch. Mutton 118 THE HYGIENE OF FOODS AND FOOD SUPPLY is dull red, firm, and its fat white or yellowish. Horse meat is coarse in texture, dark in color, without layers of fat in the muscles; the fat is yellowish and runs down in drops when the carcass is hung up, and has a peculiar Sweetish odor and taste. Preservation of Meat. — Postmortem putrefactive changes due to the development of bacteria can be prevented: (1) By rigid asepsis and the cleanliness of those who handle the meat and by careful attention to sanitation in the places in which meat products are prepared. This prevents the bacteria from gaining access to the meat. (2) By the storage of meat under conditions that are unfavorable to the life and devel- opment of bacteria. These are cold, dryness, and condimental or partly chemical preservations. (3) By destruction of all the bacteria, i. e., by sterilization of the meat by heat. Cold Storage. — Cold storage of meat does not kill bacteria, but inhibits their growth, and keeping meat in cold storage or freezing may preserve it for a long time. The common opinion that meat may be kept in cold storage indefinitely without injury is wrong, for meat certainly deteriorates if it is kept at a low temperature for more than two or three months. On thawing, frozen meats deteriorate very rapidly, and they have been known to produce toxic symptoms on ingestion. As an auxiliary means of preservation for not too prolonged periods cold is a valuable preservative. Drying. — Drying of meat is an old method of pre- serving it, and may be a valuable means of preserving the meat fibers; but they should be rendered very dry, PRESERVATION OF MEAT 119 or in the form of powders. Drying may be accomplished in the sun, and is very slow, or it may be done artifi- cially. Its usefulness is necessarily limited. Condimental Preservation. — Condimental preserva- tion of meat consists in preserving it by the aid of salt, sugar, vinegar, and other condiments, either in dry form (with salt) or by the wet process (pickling in vinegar, etc.). These condiments do not kill the bacteria, but they effectively stop putrefaction and may preserve certain meats for long periods. Smoking. — Smoking meat renders it not only com- paratively dry but also impregnates it with the creosote of the smoke, which serves as a valuable means of preservation of certain kinds of meat. None of the above methods of preservation destroy parasitic ova, or all the pathogenic germs which may be in the meat, and all except cold render the meat less digestible, and somewhat alter its texture, appear- ance, and taste. Chemical Preservatives. — ^The use of chemical pre- servatives, such as borax, boracic acid, sulphite of soda, and others, is very reprehensible, and is justly prohibited by federal and municipal sanitary legislation. The objections against chemical preservatives of any food may be summed up as follows : 1. All chemicals used for preservation are more or less toxic, and their ingestion injurious to health, especially if habitually used. 2. By the use of chemical artificial preservatives inferior meats and products, and meat which is partly decomposed may be so disguised as to be sold as fresh and unspoiled products. 120 THE HYGIENE OF FOODS AND FOOD SUPPLY Heat. — Heat preservation of meat is the only effective and absolutely reliable method of preserva- tion, because it kills and destroys all entozoa and patho- genic germs, and thus renders the product sterile and absolutely safe. For domestic use the sterilization of meat is accom- plished by roasting, baking, or boiling for from fifteen minutes to an hour. For commercial purposes the pro- cess of meat preservation should include (1) destruction of all germs by heat, and (2) enclosure of the product in hermetically closed sterile vessels in which further infection is prevented, thus permitting the food pro- duct to be preserved for indefinite periods. This process of meat preservation consists of "canning," and is accomplished in the following manner: (1) By selection of appropriate meat; (2) cutting it into appropriate pieces; (3) parboiling or exposing the meat in hot water under the boiling point for ten to twenty minutes in order to shrink it and lessen its bulk; (4) the parboiled meat is placed in cans or tins filled with salted soup or liquid and the cover is soldered on, except for a small aperture for the escape of air; (5) the cans are then placed in boilers or steamers and subjected to high heat for an hour or two; (6) the openings left in the cover of the can are closed and the cans are again subjected to a steam bath for an hour or more according to the character of the product. Sanitary Supervision, Prevention of Adulteration of Meat. — ^The strict sanitary supiervision of all the various processes through which meat passes from the initial to the final product is absolutely necessary in order to render the food supply free from dangerous contami- POULTRY AND GAME 121 nation and infections. Adulteration by substitution, palming off inferior products for superior ones, and adulteration with foreign ingredients, as well as by artificial preservation by means of chemicals, may be prevented only by a rigid, thorough, scientific, and prompt municipal and federal inspection by qualified and competent medical officers. Poultry and Game. — ^The flesh of all domestic fowls, such as chicken, turkey, geese, duck, and of some wild fowls, is used for human food. Vacher' gives the following characteristics of healthy poultry and poultry meats: "Healthy poultry are active, bright, dry in the eyes and nostrils; their feathers are glossy -and elastic, and the combs and wattles are firm and of brilliant red. Age is indicated by duskiness of comb and gills, dulness, fading, and brittleness of feathers, raggedness of feet and size of claws. Good poultry should be firm to the touch, pink or yellowish in color, fairly plump, should have a strong skin, and a fresh, not disagreeable odor. Stale poultry loses firmness, becomes bluish in color, green over the crop and abdomen; the skin readily breaks, and the bird has a disagreeable odor." "Drawn" or "undrawn" are terms used to indicate the removal or presence of the internal organs of poultry offered for sale. Undrawn poultry decomposes sooner on account of intestinal putrefaction. Cold- storage undrawn poultry may become dangerous to health by its deterioration. As poultry can be obtained at all times there is no good economic reason why it 1 Food Inspector's Handbook. 122 THE HYGIENE OF FOQDS AND FOOD SUPPLY should be placed in cold storage for long periods, and the practice is reprehensible. The custom of keeping poultry or game for a certain time until it is "ripe," or "gamey," and partly decomposed, is dangerous to health. Forced feeding does not seem to produce any "patho- logical conditions in poultry, and even the " fatty liver" of forcibly confined and fed geese in the much prized delicacy "pSte de foie gras" does not seem to affect the gourmand injuriously. Live poultry is subject to many and various diseases, which render the meat unfit for use, and the necessity of rigid antemortem inspection is apparent in this as well as in other meats. Fish Foods. — ^A large variety of- sea and fresh-water fishes are used for food. Fish are allowed to die by being deprived of oxygen. Fish should be used in season, should be fresh, firm, and elastic to the touch. Fresh fish may be recognized by the rigidity due to rigor mortis, the freshness and red color of the gills, the moist, clear eye, and not disagreeable odor. Frozen fish is not palatable, and decomposes very rapidly on thawing. Many cases of poisoning, includ- ing ptomain poisoning from eating stale fish, are on record. The eating of certain shellfish, crabs, lobsters, and oysters is at times fraught with danger to health, and many cases of wholesale poisonings have been reported. Oysters sometimes are purveyors of typhoid fever, when they are grown near large towns in waters that are much contaminated by sewage containing typhoid germs. The danger from oysters is the greater in that they are very often eaten raw. IMPORTANCE OF THE MILK INDUSTRY 123 Fish are preserved by smoking, drying, salting, pickling, and also by canning.' The sanitation of the establishments where fish are prepared for canning should be the same as that for the manufacture of meat products. MILK AND DAIRY PRODUCTS Importance of Milk as a Food. — Of all the various foods used by human beings milk is the most important. Milk contains all the elements of food necessary for the nutrition of man, and it contains these elements in a right proportion. Milk is the only food of millions of infants and children deprived of the breast; it is the principal food of the sick, of invalids and convales- cents, and it is a part of the food of all people at all times. Importance of the Milk Industry. — According to the United States Agricultural Department there were in January 1, 1910, in New York State alone 1,800,000 milch cows. New York City alone consumes about 2,000,000 quarts of milk daily. There are nearly 1,000,000,000 gallons of milk sold every year in the United States, and the amount of capital invested in the dairy industry exceeds $1,000,000,000. The great importance of milk and milk products as a food and the magnitude of the milk industry make it of paramount importance that they should reach the consumer in as clean and as pure a state as possible. This, however, is almost impossible for the following 124 THE HYGIENE OF FOODS AND FOOD SUPPLY reasons: (1) Distance, (2) time, (3) the nature of the product, and (4) contamination. Distance. — In the milk supply of cities the distance of the producers from the consumers is necessarily great. New York City obtains its milk supply from about 44,000 farms located in six States and within a radius of 400 miles from the city. Time. — ^The city consumer of milk hardly ever gets it less than twenty-four hours old, and often thirty- six and forty-eight hours elapse between milking and consumption. Nature of Product. — ^Milk being an opaque animal secretion voided at a temperature of the body is easily contaminated with all kinds of impurities difficult of detection. Sources of Contamination. — ^These are very numerous. They may be the cow, the food and water she drinks, the stable, barnyard and surrounding of the cow, the pails, cans, and various utensils used by the farmer, milkers, and handlers of the milk, and a great many other things. Character of Impurities. — ^The impurities which are found in milk may be divided under two large groups : Dirt and bacteria. Dirt. — By dirt is meant everything found in milk which is foreign to its composition and is not milk, which "is matter out of place." The dirt may be mineral, vegetable, or animal. The mineral dirt con- sists mostly of dust, sand, clay and earthy particles, also of certain preservative salts used for increasing the keeping qualities of milk. Vegetable dirt is com- posed chiefly of particles of hay, straw, grain, seeds. CHARACTER OF IMPURITIES 125 flowers, etc. The animal dirt, which is abundantly found in milk, is mostly hair, feathers, manure, insects, flies, ova of parasites, etc. The amount of dirt found in milk is in direct ratio to the care taken in the production of milk. It is often very large. Most of the dirt may readily be seen at ' the bottom of vessels after milk has been left standing for some time; it may also be readily obtained by the action of the centrifuge. Bacteria in Milk. — ^The most important impurities found in milk are bacteria. Bacteria are minute vegetable microorganisms, invisible to the naked eye, but discernible under the microscope, and are found everywhere. Bacteria are of various shapes, some round, others spiral, rod shape, etc., and are found clinging to soil, dust, dirt, rubbish, excreta, discharges, etc. They develop very rapidly under favorable conditions, millions of them growing out of one colony. The importance of bacterial life lies in the fact that to it solely is due the process of putrefaction and decomposition, and the disintegration of all organic matter. Besides their putrefactive action bacteria may also play a more important role in the causation and trans- mission of disease. Within the last several decades it had been definitely demonstrated that many diseases, the true causes of which were hitherto unknown, were directly due to the action of certain bacteria which upon gaining entrance into the human body cause certain patho- logical lesions resulting in certain groups of symptoms 126 THE HYGIENE OF FOODS AND FOOD SUPPLY which we call by names of various diseases. These diseases are usually called "infectious," because they are caused by bacteria and may be transmitted from one person to another. A large number of infectious diseases are known to be transmitted from one person to another by means of food and especially milk. Disease Bacteria in Milk. — A large number and many varieties of disease bacteria may and often are found in milk. The sources of the disease germs are the cows, their surroundings, their food and drink, the persons handling the milk, and the utensils in which it is kept, as well as the air with which it may come in contact. Besides the disease germs themselves milk may be contaminated by the common germs of putrefaction. These do not cause disease by themselves, but they may produce toxic elements in the milk which may harm the consumers and cause certain gastro-intestinal disturbances and "ptomain" poisoning, often with fatal results. The infective bacteria which may be transmitted by milk are those of the following diseases : diphtheria, scarlet fever, measles, tuberculosis, cholera, typhoid fever, dysentery, cholera infantum. A number of other infectious diseases have also been transmitted by milk, as has been demonstrated at various times. Milk and Infants' Diseases and Infant Mortality. — The prevalence of gastro-intestinal diseases among infants and children, especially during the summer MILK AND DIPHTHERIA AND SCARLET FEVER 127 months, is well known. Out of a total of 105,553 deaths of infants in the United States during 1905 not less than 39,399 were due to gastro-intestinal diseases. The difference in death rate between breast-fed children and those fed on cows' milk in the New York Infant Asylum in 1902 was very great: 7.47 per cent, in the former to 63.14 per cent, for the latter. The record of Rochester, N. Y., where Dr. Goler inaugurated a vigorous campaign on behalf of clean milk for chil- dren, proves conclusively how a supply of purer milk will reduce not only the infant mortality during the summer months, but also the general death rate throughout the year. In New York City the death rate of children under five years was reduced from 96.2 per 1000 during the whole year and from 136.4 during the three summer months in 1901 to 55 per 1000 during the whole year and 62.7 during the summer months in 1906. This reduction is undoubtedly largely due to the cleaner milk which is at present supplied to the city and especially to the use of the Straus pasteurized milk among the poor classes of the city. Milk and Diphtheria and Scarlet Fever and Measles. — It is not difficult to understand how milk may be readily contaminated by the germs of these dreaded children's diseases. The farmer's children, or the children or employees of the milk dealers and sellers, may suffer from one of these diseases and by their proximity to the milk, during acts of coughing, spitting, sneezing, or by the scaling of the skin, may contaminate the open cans of milk with the infective germ and thus transmit the disease to other children and people. A 128 THE HYGIENE OF FOQDS AND FOOD SUPPLY large number of scarlet fever and diphtheria epidemics have been directly traced to infected milk. Milk and Typhoid, Cholera and Dysentery. — ^The in- fective germs of the various diarrheal diseases, like typhoid, cholera asiatica, and cholera infantum, as well as of dysentery, are found in the discharges from the bowels of infected persons. These discharges may cling to the hand, clothes, etc., of those who handle milk, and thus gain access to the milk in which these infective germs find a very favorable medium and are capable of developing and increasing in very large numbers. The most frequent way in which the germs of these diseases gain access to the milk is through water. The discharges of infected patients are often deposited upon the exposed ground, or in shallow privy vaults, cesspools, etc., from which they are washed off, seep through the ground, and gain access to the rivers, lakes, ponds, or wells which serve as sources of water supply on farms. The typhoid bacillus has been demonstrated in milk and its vitality is so great that it retains its life for long periods. Hesse reports finding typhoid germs in sterilized milk after four months' time. According to Whipple (quoted by Ward) "it has been estimated that in the United States at the present time about 40 per cent, of the typhoid fever in cities is caused by water, 25 per cent, by milk." Water infected with typhoid fever germs may also be used as a washing fluid for milk utensils, or it may at times be used an an adulterant. Milk and Tuberculosis. — ^Tuberculosis may be trans- mitted through milk because the tubercle bacilli MILK AND TUBERCULOSIS 129 which are the cause of the disease may be and are often found in milk. Hess found that 16 per cent, of the New York city milk supply contained tubercle bacilli, and according to the investigation of others the presence of the germs causing tuberculosis has been clearly demonstrated so as to be beyond dis- pute. Where do the tubercle germs which are found in milk come from? There is no doubt that some of these germs may come from accidental contamination from the outside. It is easy to see how persons who are afflicted with the disease may while handling the milk infect it with tubercle bacilli by coughing, spitting, sneezing; or the germs may be found in the dried dust floating around dairies, or on the hands and clothes, etc., of the persons handling the milk. There are also strong reasons for believing that a large or a considerable number of the tubercle germs found in milk are derived from the cow herself. Un- questionably a very large percentage of milch cows suffer from tuberculosis. According to many observers the average percentage reaches at least 25 per cent. This means that one cow in every four is affected. The disease is scattered over the entire country and there is hardly a herd that is completely free from its ravages. The question whether a tuberculous cow gives milk containing tubercle germs has been decided affirma- tively, at least insofar as it is now definitely known that cows suffering from advanced tuberculosis which involves the udder yield tuberculous milk. 130 THE HYGIENE OF FOODS AND FOOD SUPPLY COWS' MILK Definition. — Milk is the lacteal secretion obtained by the complete milking of one or more healthy cows. Composition. — Milk consists of water in which cer- tain solids are dissolved or suspended. The relative proportion of the solids to the water varies from 11 to 14 per cent., to 89 to 86 per cent., with an average composition of 13 per cent, solids and 87 per cent, of water. Solids. — ^The milk solids consist of sugar, fat, proteids, and minerals. Milk also contains a certain amount of ferment, gas, and bacteria. Milk Sugar (Lactose). — ^Lactose is a sugar peculiar to milk, found in milk only, and differing somewhat from sugrose, dextrose, and other sugars. Milk sugar is less sweet, less soluble, less subject to acid fermenta- tion, has a specific gravity of 1.53, is soluble in 6 parts of cold and 2.5 parts of boiling water; undergoes lactic acid fermentation readily, but alcoholic with difficulty (Blyth). The average percentage of milk sugar in milk is about 5, varying but slightly from this. Milk Fat. — ^Milk fat consists of the glycerides of various fatty acids, volatile and non-volatile. It is found in the milk in the form of an emulsion consisting of very numerous minute fatty globules held in sus- pension in the whole milk. The milk fat is the most variable part of the milk constituents. Its proportion varies between 2 and 6 per cent., with an average of 4 per cent. COMPOSITION OF MILK 131 Proteids and Albuminoids. — ^The proteid matters in milk consist of about 80 per cent, of casein and 20 per cent, of other albumins, such as lacto-albumins, protein, nuclein, etc. The casein is the principal and most valuable pro- teid matter. Casein is coagulated by acids, by gastric juice, by rennet, and by a variety of other substances; it is not precipitated or coagulated by heat which does coagulate the lacto-albumins. The proportion of pro- teid matter in milk is less variable than that of fat. Its average is 3.25 per cent. Mineral Matter. — ^Milk contains various minerals in minute quantities. Milk ash shows the presence of potash, soda, lime, magnesia, chlorine, iron, certain acids, etc. The percentage of mineral matter in milk averages 0.75. Composition of Average Milk Water 87 per cent. Solids 13 per cent. Sugar 5.00 per cent. Fat . 4.00 per cent. Proteid 3.25 per cent. Mineral . 75 per cent. 13 . 00 per cent. Ferments and Gases in Milk. — Milk contains a number of ferments or enzymes (diastose, galactose, etc.) which are peculiar to every species of animals, and have some function in the digestion and nutritive qualities of the milk. Milk when fresh also contains some gases, such as oxygen and carbon dioxide, due to the air it contains. Later the pressure of carbon dioxide may be due to fermentation. 132 THE HYGIENE OF FOODS AND FOOD SUPPLY Appearance, Color, and Reaction. — Normal milk has a white or slightly yellowish color; it is opaque, has a pleasant characteristic odor, and a sweetish taste. The reaction of milk is "amphoteric," i. e., slightly acid to litmus and alkaline to turmeric. The reaction becomes more acid with the advance of lactic acid fermentation; when milk becomes decomposed it develops ammonia and becomes alkaline in reaction. Specific Gravity. — ^The weight and density of milk are greater than of water, inasmuch as most of the milk solids are of a relatively greater weight and density than water. The heavier and denser solids are the milk sugar, the proteid matter, and the mineral matter. Milk sugar, specific gravity 1.55, proteids 1.20 (Rubner). The only ingredient of milk which is lighter and less dense than water is the milk fat (0.92). If a liter of water at- 60° F. (15° C.) weighs 1000 grams, a liter of milk at the same temperature will weigh from 1.028 to 1.032. The specific gravity of average milk is usually 1.029, with variations from 1.028 to 1.032. Milk without fat (skim milk) will have a much greater specific gravity, for the lighter part is with- drawn. The specific gravity of skim milk ranges from 1.035 to 1.040, according to the more or less thorough removal of the fat. The specific gravity of milk is increased by low temperature, by the addition of solids, and by the subtraction of fat. It is decreased by high tem- perature, by the addition of water, and by the addition of fat. COLOSTRUM 133 Variations. — ^Not only the quantity but also the quality and the relative amounts of the various milk ingredients vary greatly. Some of these factors on which the variation depends are the breed of the cow, age, kind, health, condition, care, food, drink, housing, treatment, climate, time of year, time of day, period of lactation, season, weather, and many others too numerous to mention. Most of the variations pro- duced by these factors are normal and are expressed in the relative quantity of milk produced, or the relative proportion of its various ingredients. Among the most important variations in milk are those which are found in colostrum, fore-milk, and the strippings. Colostrum. — ^For a certain period before and for several days after parturition the milk secreted by the cow differs materially in composition from normal milk. While most cows "dry up" or cease to give milk in the last months or weeks of pregnancy there are some which continue to produce milk until the last days of pregnancy. During the ten days or two weeks before calving and from three to five or six days after the milk derived from cows is called "colostrum," or commonly "bee stings." Colostrum differs in composition from normal milk in that it contains a relatively smaller percentage of water (about 75 per cent.), relatively less milk sugar and milk fat, and relatively more proteid matter, not in the form of casein but of lacto-albumin. To the latter it owes its property of coagulation by slight heat, a distinctive characteristic of colostrum. Colos- trum also contains a considerable number of blood corpuscles and of the so-called "colostrum corpuscles." 134 THE HYGIENE OF FOODS AND FOOD SUPPLY The color of colostrum is distinctly yellowish and reddish, the taste peculiarly sweetish, and the odor specific. The ingestion of colostrum, especially when heated, is relished by a number of persons, although it has been known to cause gastric disturbances. The mixing of colostrum with the rest of the milk, or its sale, is forbidden by most municipalities. Fore-milk and Strippings. — ^There is a considerable difference in the relative amount of milk fat in the few streams of milk derived at the beginning of milking from that of the few streams of milk derived at the end of the milking. The first milk, called fore-milk, contains sometimes less than 1 per cent, of fat, while the last, called strippings contains sometimes over 5 per cent. Abnormal Milk. — Milk is sometimes abnormal in color, composition, etc., and the sale of such milk is usually forbidden. Milk may be abnormal in color, distinctly red, blue, yellow, violet, etc. These abnormal colors of the milk are due to contamination with specific bacteria, which produce the changes in color. The odor and taste of milk may also be abnormal. Thus milk sometimes is distinctly bitter or has the taste of garlic, onions, turnips, cabbage, etc.; it may bear some of the characteristic odors of strong vege- tables, etc. Milk may also have a distinctly fermenta- tive and " swilly" taste. Most of these deviations from the normal are due to the food ingested by the cow. The bitter taste may be due to bacterial action. Milk may be abnormal in its consistency and become "slimy," "ropy," and viscous. In this condition it CREAM 135 will not churn, nor will the cream separate, but other- wise it does not seem to be very harmful. The condi- tion is due to the action of certain bacteria. Ropy milk is said to be a favorite article of food in Norway and elsewhere, and may be artificially produced by immersing the stem of "butterwort" in milk (Blyth). MILK PRODUCTS A consideration of milk production and inspection is incomplete without reference to the most important products which are a part of the milk industry. The milk products are the following: cream, skim milk, butter, buttermilk, cheese, whey, condensed and evap- orated milk, milk powders, kumiss, kefir, etc. Cream. — Cream is the fatty portion of milk. It has the same composition as milk except that the percent- age of fat is very much larger. The percentage of cream in milk may vary from 6 to 50 or 60, and depends upon the process of obtaining it from the milk. The average amount of butter fat in cream is 20 per cent.; the United States standard is 18 per cent. Production of Cream. — Cream is found in milk, in suspension, in minute globules of varying size. It is separated from milk by two processes: the gravity method and by aid of the centrifuge. Separation by aid of gravity is the oldest known process of gaining cream. It is based upon the fact that the suspended fat globules are of a lesser specific gravity than milk and rise to the surface when the whole fluid is left at rest. The common method is to pour the newly drawn milk into vessels and let them 136 THE HYGIENE OF FOODS AND FOOD SUPPLY stand for a period of twenty-four to thirty-six hours. The cream rises to the siu-face and appears as a yellowish layer, and may be accordingly removed from the milk. Gravity methods may be divided into two, the shallow pan and the deep vessel setting systems. Cream is also separated by centrifugal force in special "separators," which remove all fat except 0.1 per cent., which is left in the skim milk. This is an effective process of separation. Skim Milk. — ^Skim milk is milk from which all or part of the cream has been removed. The amount of fat remaining in skim milk depends upon the methods of separation and the thoroughness by which it is done; it may vary from less than 0.1' per cent, to more than 1 per cent. Skim milk has a white and somewhat bluish color, a high specific gravity varying from 1.035 to 1.040. Because of the proteids and casein it contains skim milk is a highly nutritious and valuable food. The sale of skim milk is prohibited in many cities, not because of any harm that it may do, but mainly on account of the ease with which it is substituted for whole milk and the difficulty of detecting the adulteration. The casein may be sep- arated from the skim milk and used for commercial purposes, or it is used for the extraction of its milk sugar. Certain forms of cheese are largely made of skim milk. Blended Milk. — ^This term is applied to a modified milk in which one or more of the components of milk is increased or diminished so as to furnish a modified milk with definite desired stated percentages of certain of the milk coinponents. It is largely used for infant BUTTER 137 foods, and manufactured according to formulae pre- scribed by physicians. Milk Powders. — ^These are used chiefly as infant foods and are prepared by complete slow evaporation of the water of the milk. As a rule the powders are mixed with some sugar and cereal products. Condensed Milk. — Condensed milk is a milk from which a large part of the water has been extracted by slow evaporation. It is a very important article of commerce. Most of the condensed milk sold contains about 70 to 72 per cent, of water with 28 to 30 per cent, of milk solids, to which cane sugar is added to increase the keeping qualities. Some thickeners may also be used to give the condensed milk more "body." The condensed milk is sterilized and sold in hermetically sealed tin cans. When mixed with water it has a sweet cooked taste. Butter. — ^Butter is the milk fat of the milk gathered into a mass and separated from the milk or cream by the process of churning. Beside the milk fat which it contains in the proportion of 80 or more per cent., butter also contains water and minute quantities of the other ingredients of milk. Butter is commonly made of cream which is for this purpose ripened or made to undergo a process of lactic acid fermentation which is supposed to give the butter its valued "flavor." A "starter" made of buttermilk or sour cream is used to produce the "ripening." Butter is produced by churning or agitating the cream with paddles or spoons, in vessels, tubs, or barrels. These may be revolved by hand or machine power. The particles of fat adhere together and form distinct 138 THE HYGIENE OF FOODS AND FOOD SUPPLY grains which are worked over, the buttermilk is re- moved by several washings of water, and the whole turned into a mass by working and pressing together. The process of butter-making requires "attention to temperature and other factors, upon which the flavor and quality of the butter depend. Some salt is added to the butter. Buttermilk. — Buttermilk is the residue left after butter is made from milk or cream. It contains all the ingredients of milk except fat. It contains millions of lactic acid germs, and is a valuable food for man and animals. Cheese. — Cheese is "the solid and ripened product made by coagulating the casein in the milk by means of acids or rennet." Cheese is made of whole milk which has undergone some lactic-acid fermentation. It is then coagulated or rendered into two parts: one an insoluble semisolid composition consisting of the casein and fat, and the other of water (92 per cent.), of nearly all the sugar, of the albumin and the mineral matter. The in- soluble part is then pressed out of the water and worked over by pressing and cutting, as well as by the addition of certain ferments, until the desired flavor and texture of the finished product is obtained. Cheese may be made of whole milk, of skim milk, and of milk to which cream has been added. The "rennet" which is added and used for the coagulation of the milk is an extract made from the fourth or digestive stomach of a young calf fed on milk. There are many varieties and forms of cheese, depending upon the kinds of milk, temperature of MILK STANDARDS 139 fermentation, degree of acidity, manner of coagulation, kind of rennet, process of ripening, the specific "ripen- ing" bacteria used, etc. The Hquid portion which is left after the insoluble part has been removed in the process of cheese-making is called whey. It consists mostly of water, but contains small quantities of albuminous matter and the sugar and most of the mineral matter of the milk. Whey is used for the extraction of milk sugar, and is also a valuable food for domestic animals. The casein of the milk which is extracted from skim milk is also used for various purposes in the commercial manufacture of sizing for paper, etc. Standards. — ^The relative composition of milk and some of its products given above are only the aver- age composition, found after an examination of a great number of samples of milk, etc., with large variations in the relative composition. In order, however, to guard the welfare of the public and prevent substitution, adulteration, and selling inferior grades of products, municipalities. States, and the federal government have instituted certain minima of compositions or standards below which milk and its products must not go and must not be sold to the public. The following are the United States Standards for milk, etc. Solids Solids. Fat. not fat. Water. Per cent. Per cent. Per cent. Per cent. Milk . 11.75 3.25 8.5 88.25 Skim milk 9.25 Condensed milk . 28.00 7.00 ... 72.00 Cream 18.00 Butter 82.50 Cheese . 50.00 140 THE HYGIENE OF FOODS AND FOOD SUPPLY The New York State standard for milk was 12 per cent, solids and 8 per cent, water until 1910, when it was lowered by act of Legislature to 11.5 per cent, of solids and 88.5 per cent, of water. The New York city standard for milk is 12 per cent, solids, of which 3 per cent, must be milk fat. Other States and cities have slight variations from these standards. "Standards are based upon data representing ma- terials produced under American conditions and are fixed as such that a departure from above or below the minimum limit they prescribe is evidence that such articles are of inferior quality. The limits fixed as standards are not necessarily the extremes authentically recorded for the article in question, such extremes being due to abnormal conditions as a rule." (Wiley.) Official Definitions. — ^The following are the official definitions of milk and its products according to the United States Department of Agriculture: MUk. — ^Milk is the fresh, clean lacteal secretion obtained by the complete milking of one or more healthy cows, properly fed and kept, excluding that obtained within fifteen days before and ten days after calving. Blended Milk. — ^Blended milk is milk modified in its composition so as to have a definite and stated percentage of one or more of its constituents. Skim Milk. — Skim milk is milk from which a part or all the cream has been removed. Condensed or Evaporated Milk. — Condensed, or evaporated milk is milk from which a considerable portion of water has been evaporated. MILK ADULTERATION 141 Buttermilk. — Buttermilk is the product which re- mains when butter is removed from milk or cream in the process of churning. Cream. — Cream is that portion of milk, rich in milk fat, which rises to the surface of milk on standing, or is separated from it by centrifugal force. Butter. — Butter is the clean, non-rancid product made by gathering in any manner the fat from fresh or ripened milk or cream into a mass, which also con- tains a small portion of the other milk constituents, with or without salt. Cheese. — Cheese is the sound, solid, and ripened product made from milk or cream by coagulating the casein thereof with rennet or lactic acid with or without the addition of ripening ferments and seasoning. Whey. — ^Whey is the product remaining after the removal of fat and casein from the milk in the process of cheese-making. Kumiss. — Kumiss is the product made by the alco- holic fermentation of cows' or mares' milk. Kefir. — Kefir is a product made by a specific yeast fermentation of milk. MILK ADULTERATION Milk is adulterated in several ways: (1) By addi- tion of water; (2) by subtraction of cream; (3) by both addition of water and subtraction of cream; (4) by addition of coloring matter, thickeners, and certain harmless substances; (5) by addition of skim milk; (6) by addition of chemicals as preservatives. 142 THE HYGIENE OF FOODS AND FOOD SUPPLY Addition of Water. — ^This is one of the most prevalent methods for the adulteration of milk. It is so easy, apparently difficult of detection, and changes the ap- pearance and general physical quality of the milk so little that it is often resorted to by dishonest dealers and producers. The addition of water to milk reduces its quality by diluting it, and the whole mass is less nutritious and has fewer food ingredients than normal milk. This is a harmful adulteration because it reduces the quality of the milk, and when fed to children proves injurious to their health. It is also a fraudulent adulteration because it substitutes an inferior product for the same price that the superior would sell for. Extraction of Cream. — ^The extraction of cream, or what is called "skimming," is also a frequent mode of milk adulteration. It is perhaps even more in vogue among dealers than simple watering, because it is so much more profitable and difiicult to detect. A forty- quart can of milk which sells for $1.60 will bring the dealer but 16 to 20 cents of additional profit when he adds four or five quarts of water to the can. If, how- ever, the dealer removes two quarts of cream of the six or seven which the can contains he gains the price of the two quarts of cream (40 to 60 cents) less the price of the two extracted quarts, which amount to only 8 cents. This shows that the skimming of milk is a very profitable procedure, even when it is but partial. Indeed, a great deal of the milk in cans, which is sold at the markets and by grocers for a low price, is more or less skim milk. Skimming and Watering. — Skimming of milk makes it heavier by subtraction of the fatty or lighter portion, COLORING MATTER IN MILK 143 thus increasing its specific gravity and density. A skim milk will read from 32 to 38 on the Quevenne lactometer and from 110 to 118 on the Board of Health lactometer, according to the amount of cream taken off. In order to disguise this higher specific gravity and to reduce it, dealers who make their own tests add sufficient water to reduce the density of the skim milk, so as to make the readings on the lac- tometer about the normal, and thus try to deceive the inspector who relies too much on the lactometer examination alone. Skimming, as well as skimming and watering, reduces the nutritive quality of the milk and is a harm- ful as well as a fraudulent adulteration. Addition of Skim Milk. — ^The addition of skim milk to normal milk reduces the quality of the whole milk and is harmful as well as fraudulent. One of the principal reasons for the prohibition of the sale of skim milk in some cities is the tendency of dealers either to sell skim milk for whole milk, or to reduce whole milk by the addition of the skimmed. Addition of Coloring Matter and Other Harmless Ingredients. — ^The addition of coloring matter is mostly practised to disguise the poor appearance of skim or watered milk and make it look richer. The coloring matter most commonly used is a vegetable coloring "annatto." The other colors used belong to the coal-tar family (azo-colors) and are harmful in comparsoin to coloring with "annatto," which is harmless.' Their detection is possible only by chemical tests. Sodium bicarbonate is sometimes added to milk 144 THE HYGIENE OF FOODS AND FOOD SUPPLY which is beginning to turn sour, in order to disguise the acid taste. In small quantities the additipn of soda is harmless, but the procedure is dishonest in that its purpose is to palm off milk which is acid for fresh milk. Thickeners are very seldom put into milk, more frequently into cream and condensed milk. Addition of Chemicals. — See p. 152. MILK PRESERVATION Milk Deterioration. — ^The milk, secretion of normal cows remains in a normal state for a comparatively short period, and important changes occur very soon. If left undisturbed at the normal house temperature fresh milk shows some physical changes within six to twelve hours, and by this time it has also passed through certain chemico-biological changes. The physical changes are limited to the separation of the fat globules and the separation of the cream layer at the upper portion of the vessel containing the milk. There is also a reduction of the temperature of the milk from that at which it was voided to the temperature of the room. The other changes which occiu- are a souring which is slight at first and later increases. If milk is left at the same temperature for longer periods a distinct coagulation or curdling develops, owing to the hardening and separation of the casein. At the same time there is some gas formation and a bitter taste in the milk may become noticeable. All these changes are included in the term "deterioration" of CAUSES OF DETERIORATION OF MILK 145 milk. These phenomena are only the outward and noticeable changes; the real physical, chemical, and biological changes are, of course, more complex, and cannot be so easily detected. To what are these changes in the milk due? Causes of Deterioration. — ^The separation of the cream is easily accounted for by the comparative lightness of the fat globules which coalesce and rise to the top. The other noted changes are due to the micro- organisms. A perfectly sterile milk, that is, one abso- lutely free from bacteria, has never been obtained. Microorganisms are found in the ducts of the teats and udder of the cow and even milk obtained by cannula already contains a certain number of germs. Immediately after secretion the milk begins to be contaminated with numerous germs from the air in the stable, the hands of milkers, the udder and teats of the cow, the surfaces of strainers, pails, etc., so that by the time the milk is taken out of the stable it contains a very large number of bacteria. The number of bacteria usually remains stationary for a few hours owing to the so-called "germicidal" power which the milk possesses at this initial stage of its existence outside of the cow. Sooner or later, according to the condition of temperature, the bacteria begin to develop and multiply, so that after a certain time they are so numerous as to be counted by the million in the cubic centimeter. The number of the bacteria is not the most important factor, but their importance lies in the kinds of the multiplying germs. The bacteria which get into and develop in milk are of several kinds. 10 146 THE HYGIENE OF FOODS AND FOOD SUPPLY In the first place there is the group of germs named "lactic-acid" bacteria. By acting upon the lactose they convert it into lactic acid and thus favor the gradual souring which on reaching a certain stage causes coagulation of the casein with consequent curdling of the milk. Another group is composed of the "gas-forming" or "aerogenous" bacteria which are said to cause the gas formation in deteriorated milk. The butyric- and proteid-decomposing bacteria may also develop simultaneously with the lactic-acid germs. There are numerous other germs which may at the same time act upon the milk. The lactic acid bacteria are important because they cause the souring of the milk and its subsequent curdling. As far as health and food value are concerned, lactic-acid for- mation is not necessarily a harmful process. The ingestion of even very large quantities may not be harmful to health; indeed, in many cases it is even beneficial. Buttermilk and whey contain enormous quantities of the lactic-acid germs, but are drunk with profit to health. They also possess another beneficial action in that they counteract other more harmful bacteria. While lactic-acid fermentation is active and at its height, it is germicidal to other bacteria, which cannot develop in an acid medium. It may, therefore, be said with truth that the lactic-acid fermentation process is not per se a harmful process. The gas-producing, the butyric- and proteid-decom- posing germs are of more importance to health, because they are of harmful character. They produce putre- faction and decomposition, they develop a bitter taste and foul odors, and may also produce certain toxins. BACTERIAL GROWTH IN MILK 147 which may become very harmful to those ingesting the fluid. Conditions Favoring and Retarding Bacterial Growth in Milk. — In view of the rapidity of the growth and the various character of bacteria, it is important to note the conditions which favor and retard their growth and development. Generally, low temperatures, very high temperatures, absolute dryness, and certain chemicals are unfavorable to the, life and growth of germ life. Moisture and a temperature between 60° and 100° F. on the other hand are very favorable. Dryness. — Moisture is necessary for germ life, and bacteria develop very slowly, if at all, in a dry medium. It is, of course, difficult to obtain absolute dryness, which alone is inimical to bacterial life, but if milk is dried and kept in the form of a powder it may be pre- served for some time, although this applies more to milk powder from skim milk than to powdered whole milk, as the cream is said to become rancid if in powder form. Low -Temperature. — By low temperature is ^meant any temperature 50° F., and below, to freezing point. A low tenperature does not destroy, but stops growth and development of bacteria. Their number remains the same, but they are in stunned form, always capable of doing mischief, even under these conditions. Thus it is known that typhoid fever bacilli may be alive for long periods even in ice or frozen milk, and such milk may, therefore, produce the disease. While bacteria do not grow in frozen milk, they do grow in milk kept at temperatures between 34° and 50° F., but only 148 THE HYGIENE OF FOODS AND FOOD SUPPLY very slowly. The varieties which grow at these low temperatures are not the lactic-acid bacteria, but those which are likely to do harm if the milk is kept too long at these temperatures. Milk kept at tempera- tures between 34° and 50° F. may be preserved for several days to a week and more, the lower the tem- perature the longer. The milk will not become sour, but it may become unfit for use because of the develop- ment of the other bacteria and their products. Mean Temperatures. — ^The effect upon milk kept at temperatures between 50° and 100° F. varies accord- ing to the degree of temperature and depends upon the kind of bacteria which the temperatures favor in growth and development and multiplication. Various bacteria have a different and varying point of thermal death, as well as a temperature at which growth and development are most abundant. Lactic- acid bacteria for instance develop most rapidly at a temperature of 60° to 70° F., at which they multiply more quickly than any other species. As their devel- opment is inimical to the growth of other germs, milk kept at 60° to 70° F. will sour and contain lactic- acid bacteria to the exclusion of almost all others. At higher temperatures between 80° and 100° F., the lactic- acid bacteria do not always gain a predominance, but often others, especially the gas-producing bacteria, gain the upper hand and then in addition to the acid bacteria the milk contains other less desirable germs. High Temperatures. — High temperatures, i. e., tem- peratures above 100° F., are inimical and unfavor- able to the life and growth of bacteria, and the various bacteria have their own thermal death-point. Some MILK PRESERVATION BY COLD 149 are destroyed at temperatures of from 120° to 140° F. kept up for a certain period; to destroy others requires for an hour or more a temperature above the boiling point of water. Except for a few species, bacteria cease growing when the temperature is raised above 100° F. and begin to die when it is above 120° to 140° F., according to time of exposure to heat. At higher temperatures the bacteria are more quickly destroyed and in less time. Bacteria which bear spores are the most difficult to kill, and sometimes must be subjected to a very high temperature for a long time before they are destroyed. Most of the active germs, including the pathogenic bacteria of most common diseases, like typhoid, diphtheria, and tuberculosis, are killed at temperatures of 140° F. kept up for twenty minutes, and at higher temperatures kept up for less time. Chemicals. — Certain chemicals are inimical to bac- terial life and growth, although the number of these chemicals applicable to milk is, comparatively, very small (see page 152). Milk Preservation by Cold. — ^As previously indicated, cold, i. e., a temperature of from 32° to 50° F., does not destroy the germs in milk but merely inhibits and stops their growth and multiplication and thereby keeps the milk from being soured and decomposed. The length of time for which milk may be preserved by cold depends upon the number and the kind of germs originally in the milk before its temperature was reduced. It may vary from twenty-four hours to a week; frozen milk has been known to keep for longer periods, and is an article of commerce in Siberia and other northern countries. While the souring of 150 THE HYGIENE OF FOODS AND FOOD SUPPLY the milk is undoubtedly postponed, it is not certain that its decomposition by other bacteria is avoided. Thus milk kept under low temperatures may keep sweet, and yet at the same time develop dangerous qualities. The main advantages of cold as a preserva- tive are that it does not change the appearance and composition of the milk, and is valuable as an aid in preserving clean milk for a moderately short time. It must always be remembered that none of the germs are killed by cold temperatures and that the patho- genic bacteria may be as active as in warmer raw milk. Infected milk is, therefore, a dangerous milk to drink while raw, even if kept in a cool state. Cold is only a valuable aid in milk preservation, nothing more. Milk Preservation by Sterilization. — Sterilization is the only method by which it is possible to make abso- lutely certain that milk contains neither bacteria nor their spores. It is the only method of preservation which rids milk of pathogenic bacteria. Sterilization is defined as the "heating of milk to the boiling-point of water and above for a time sufiicient to destroy all organic life and all bacteria and their spores." Complete or absolute sterilization cannot be accom- plished unless the milk is heated well above the boiling point — 220° to 240° F. — in autoclaves or sealed chambers under steam pressure for a prolonged time, varying from one-half to two hours. This is the only means which assures complete destruction of all spores and pathogenic spore-bearing bacteria, like those of tetanus, etc. Simple boiling is also sometimes called sterilization. While this kills most germs and even a MILK PASTEURIZATION 151 few spore-beaang germs, it does not make certain that all spores have been killed. The objections to sterilization of milk, complete as well as incomplete, by boiling, are that certain changes are produced in milk by the heat. The effects of boil- ing and sterilization are as follows: 1. Change in color due to the browning or carameli- zation of the lactose. 2. Change in taste, the milk receiving a different cooked taste. 3. The destruction of all lactic-acid bacteria, fer- ments, enzymes as well as all other germs in the milk. 4. Coagulation of the albuminoid matter in the milk. The sum of these changes is that the milk is not only less tasty, but is much less digestible and fit for food. For infant-feeding it has been found not appropriate, and some observers claim that it may cause scurvy and rickets. Milk Pasteurization. — ^The word "pasteurization" has been so much used and misused that it is about time to discard it entirely, for it has no intrinsic meaning and simply confuses the minds of those who use it promiscuously. Pasteur's name is applied to a process which is carried out variously, and not always with scientific accuracy. The official definition of the term is " the heating of milk to a degree of heat suffi- cient to kill all most active germs;" in general, the word is applied to any kind of heating of milk short of boiling. It is obvious that until a definite attempt is made to define the degree of heating and the time of heating and the exact procedure, the term will embrace various 152 THE HYGIENE OF FOODS AND FOOD SUPPLY meanings according to the whim and methods of each commercial or other concern using it. As Rosenau (in Bulletin 41) truly says: "We should protest against a word which means a generality." And as he further remarks the two main dominant factors that control the temperature and time at which the milk should be pasteurized are (1) "the thermal death-points of pathogenic bacteria, and (2) the fer- ments in the milk." The aim and purpose of so-called pasteurization is (1) to kill all most active bacteria, especially pathogenic, (2) to leave the "ferments" unaffected, and (3) to change the milk as little as pos- sible in its general appearance, taste, and digestibility. There is as yet no unanimity of opinion as to the degrees and time at which these conditions are reached. Accord- ing to Rosenau a heating of milk for twenty minutes at a temperature of 140° F. absolutely destroys the tubercle bacilli, typhoid, diphtheria, dysentery, cholera, and other germs, but not all the necessary and valuable ferments in the milk. Not only the bacteria but their toxins, especially those of diph- theria and tetanus, are likewise destroyed at such a heating. There are, however, certain spore-bearing bacteria and bacterial toxins which remain un- affected at these temperatures. These spore-bearing germs are fortunately rare. Chemical Preservation. — The difficulty of keeping milk sweet for a shorter or longer time after milking, led to the use of chemical preservatives. Among those formerly used are borax, boracic acid, salicylic acid, peroxide of hydrogen, and formalin. At present the use of any chemicals for milk preservation is CHEMICAL PRESERVATION OF MILK 153 strictly forbidden, although it is still more or less practised in secret. Borax and boracic acid were used in quantities of ten grains to the quart of milk. , When used either singly or in combination they may preserve the keeping quality of the milk for twenty-four to forty-eight hours. Salicylic acid is a more powerful preservative, but its bitter taste makes it unfit for use except in very minute quantities. Formalin, which is a 40 per cent, solution of formaldehyde, is a powerful disinfectant. Even very small quantities can greatly enhance the keeping qualities of milk. One part of formalin in 50,000 of milk, or about one teaspoonful to a forty-quart can of milk, will keep the milk sweet for from twenty-four to forty-eight hours. The ob- jections to chemical preservation are the following: 1. The chemicals referred to are even in minute doses injurious to health. As they are injurious to adults, it is apparent that they must be even more harmful when ingested by delicate or sickly infants for whose use most of the milk is intended. 2. They change somewhat the digestibility of the milk. This is notably the case with formalin, which hardens the proteid matter. 3. A continuous and steady use of those chemicals will result in gastro-intestinal disturbances and intoxi- cation, especially in children. 4. The use of chemicals, once permitted, even in minute doses, is bound to produce carelessness on the part of producers who will rely more upon the keeping qualities of the chemical than upon the cleanliness of production. 154 THE HYGIENE OF FOODS AND FOOD SUPPLY 5. As soon as chemical preservation of clean and good milk is allowed, it will be impossible to prevent the use of chemicals in the case of bad, old, and partly spoiled milk, and this increases the danger of the use of milk. The use of harmless preservatives has also been urged. Among these are peroxide of hydrogen, oxygen, and carbon dioxide. Peroxide of hydrogen is used in the amount of about two ounces to the forty- quart milk can. It destroys most of the bacteria and at the same time disappears itself in the form of free oxygen. The use of hydrogen peroxide has not been tried extensively. The chemical is comparatively ex- pensive and its value as a preservative is problematic. Oxygen has been advocated as a disinfectant in milk; it is perfectly harmless and escapes after destroying the germs. The expense and the lack of proper appar- atus, have so far made this process impracticable. Carbon dioxide is said to destroy most germs in the milk when used under pressure of 75 pounds; the gas is harmless, does not change the character of the milk, and may be removed by aeration. This process is being exploited by a commercial concern, but its scientific and practical value still remains to be demon- strated. MILK INSPECTION AND TESTING Methods of Examination and Testing. — ^The methods of examining and testing milk for the different impuri- ties it may contain, and detecting the adulterations PRECAUTIONS IN EXAMINING MILK 155 to which it is often subjected, are physical, chemical, and bacteriological. Physical Examination. — By the physical examina- tion are determined the appearance, color, odor, and specific gravity of the milk, together with the varia- tions from the normal. Chemical Examination. — ^This determines the exact amount of solids in the milk, also the exact percentage of each solid in the fluid. Bacteriological Examination. — ^This determines the number of bacteria in the milk and the presence or absence of pathogenic bacteria. Precautions. — ^The precautions to be taken in the examination of milk are: (1) That the milk is thoroughly mixed; (2) that it is not partly frozen; (3) that the milk to be tested has not been partly churned or partly separated from its cream; (4) that it is not partly or wholly coagulated. In order to make proper tests, fair samples of the milk must be taken from a given quantity of the marketed milk, and precautions must be observed in the manner of taking samples, so as to obtain a fair and just sample of the whole quantity instead of only a small part of the fluid. For this a thorough mixing of the milk is necessary in order to give it uniformity. Partly frozen milk will not give a good test, because the frozen part represents the watery part of the milk, and the rest of the milk will show a richer fluid and a higher percentage of solids. Milk which has been partly churned and has butter 156 THE HYGIENE OF FOODS AND FOOD SUPPLY granules floating in it, or milk from which the cream has been wholly or partly separated, will naturally not give the normal percentage of fat in the fluid; thus the sample of the milk taken may not be a fair sample of the whole fluid. A milk which has been partly or wholly coagulated will not give a fair sample for testing because of the separation of the whey and solids. Before samples are taken, milk which is partly frozen must be thawed, so that the whole fluid becomes uniform; milk which has been partly churned and contains butter granules floating in it must be heated, so that these granules melt; milk which has been partly or wholly coagulated must be treated with alkalies sufficient to dissolve the coagulum; a milk which has been partly separated from its cream must be thoroughly mixed and made uniform. In mixing milk care must be taken not to stir it too violently, so as to churn the milk or to mix it with air. The best means of mixing milk and of getting a uniform mixture is by pouring it from one vessel to another. Physical Examination. — The physical examination of milk is of very great importance, and may give valuable information to the inspector. The color of the milk, its opacity, its resistance to the immersion of a lactometer, its adherence to the instrument, the visibility of the instrument through the glass test-tube, are all valuable indications in the hands of an experi- enced inspector. Milk which is bluish in color, which allows the lactometer to sink with little resistance, which runs down the instrument in thin bluish streaks, which hardly adheres to the instrument, and which PHYSICAL EXAMINATION OF MILK 157 is so little opaque that the instrument is readily seen through the test-tube, is a milk which is poor in solids and which is probably either skimmed or watered, or both skimmed and watered. Cream Gauge. — Milk is often tested by the cream gauge, pioscope, and lactoscope. The cream gauge is simply a graduated glass test-tube in which the milk to be tested is allowed to stand for twenty-four hours. At the end of this time the amount of the cream, as indicated in the yellowish layer on top, is read off. A good milk usually shows about 14 per cent, of cream. In order to facilitate the better separation of the cream, the milk is mixed with an equal amount of water and the resulting layer of cream is multiplied by two to show the actual amount of cream in the milk. The milk in the gauge should be put in a cold place, which favors the separation of the cream. This is a test upon which not much reliance can be placed. Pioscope. — The pioscope (Heeren) is a small inge- nious instrument to test the quality of milk by its opacity and color. The instrument consists of a small rubber disk with a small depression in its centre, and of a glass plate painted in segments of varying shades of color representing the color of cream, rich milk, normal milk, poor milk, skim milk, watered milk, etc. The inspector takes a drop of the milk to be tested and places it in the central depression of the hard rubber disk, covers it with the glass plate, and compares the opacity and color of the milk with the various segments in the circle. In the hands of an experienced inspector this is a fairly trustworthy test. 158 THE HYGIENE OF FOODS AND FOOD SUPPLY Ladoscope. — ^The lactoscope (Feser) also tests the milk by its opacity. The instrument consists of a graduated glass cylinder, in the centre of which, at the bottom, is fixed a small white rod with several black lines on its face; 4 c.c. of the milk to be tested are put into the cylinder, making the black lines on the rod invisible through the opacity of the milk. The test consists in carefully measuring the amount of water needed in the cylinder to render the fluid transparent, and to make the black lines upon the rod visible. It is obvious that the poorer the quality of the milk the less water will it be necessary to add to the cylinder in order to make the mixture transparent; and, on the contrary, it will be necessary to add more water the richer the milk. The in- strument is, graduated and shows the amount of estimated fat in the milk according to the number of the cubic centimeters of water added. Specific Gravity. — ^The testing of milk by its specific gravity is the test most frequently employed, and is very valuable in conjunction with the general physical examination of the milk. The specific gravity of milk depends on the solids in the fluid. Of these solids, sugar and the proteids are heavier than water, while the fat is lighter. The specific gravity of average normal milk is 1.029, and ' may vary in normal milk between 1.029 to 1.032. The specific gravity is calculated at 60° F. Milk which has been skimmed, i. e., from which a part of the whole of the cream has been separated, will show an increased specific gravity, because the absence of the fatty portion will make it denser and PHYSICAL EXAMINATION OF MILK 159 heavier. A milk which is diluted with water will show a decreased specific gravity because it is made thereby much less dense and thinner. Quevenne Lactometer. — ^The testing of milk with the Quevenne lactometer is based upon the relative specific gravity of the milk. This lactometer is grad- uated from 15 to 40, the scale reading as in ordinary hygrometers and showing the corresponding degree of specific gravity. A good milk (at 60° F.) will read 32 upon this lactometer, showing a specific gravity of 1.032, and average standard milk will read 29. A watered milk will read less than 29, according to the amount of water (0 being water), while a skimmed milk will read more than 32 up to 40, according to the amount of cream subtracted. Lactometer of the Health Department of New York. — ^This instrument, extensively used in many places in the United States, is a larger instrument and is graduated differently from the Quevenne lactometer. According to this instrument it is assumed that 1.029 is the lowest permissible specific gravity for standard milk. The 29 degrees are divided into 100 subdivisions from the top figure (showing the reading of water at 60° F.) to 100, which corresponds to 29 on the Quevenne instrument, or to the specific gravity of 1.029 on the ordinary hygrometer. The lactometer is graduated from to 120. According to the Board of Health lactometer a poor market milk will read 100, a good rich milk will read between 100 and 110, a skimmed milk will read between 110 and 120, while a watered milk will read under 100, the amount of water added being indicated by the reading, i. e., 10 per cent, of 160 THE HYGIENE OF FOODS AND FOOD SUPPLY water has been added if the lactometer reads 90°, 25 per cent, if 75°, etc. This instrument is the most convenient for use, as the stem is longer and the degrees may be read more readily, and also the exact amount of the probable addition of water may be more readily calculated. As the lactometric readings are calculated at 60° F., corrections must be made for any difference in the temperature of the milk above or below 60° F. When the difference in the temperature is very great it is best to reduce or increase its temperature to within 10° of 60°. The correction for the temperature is the 0.1 degree of the Quevenne lactometer for every 1 degree of temperature, and 0.3 degree of the Board of Health lactometer for every 1 degree of temperature above or below 60°; added to the reading when the temperature of the milk is above 60° F., and sub- tracted from the reading when the temperature of the milk is below 60° F. The usual rough correction for the Board of Health lactometer is 4° on the lac- tometer for every 10° on the thermometer, added or subtracted, according as it is above or below 60° F. As the specific gravity of milk is increased by skim- ming and decreased by watering, some milk dealers first subtract a certain amount of cream, thus in- creasing the specific gravity and lactometer reading, and then add sufficient water again to decrease the specific gravity and lactometer reading to about normal, so as to deceive the inspector and give an adulterated milk a normal reading on the instru- ments. The only recourse of the inspector is then to' compare the physical appearance of the sample CHEMICAL EXAMINATION OF MILK 161 of milk with normal milk, when there will appear the difference in the color, opacity, and density of the fluid. Chemical Examination. — ^The chemical tests of milk consist in the examination to discover the exact percentage of solids, and the amounts and per- centage of each component solid. The usual tests are those of weighing and evaporation for the exact amount of solids, and the Babcock test for the deter- mination of the amount of fat in the milk. For the complete chemical and bacteriological tests of milk the student is referred to special works on the subject. 11 CHAPTER IV THE HYGIENE OF SCHOOLS AND OF SCHOOL CHILDREN THE SCHOOL CHILD By compulsory education the State forces children between the ages of six and twelve or fourteen to be sent to and to be kept in school for the greater part of the day during six or eight years. These years are the most important in life. They represent a period of formation, growth, and development. Having compelled the child to remain in school during this most important period, it is the duty of the State to take care not only of the mental growth and development of the child, but also of its moral and physical condition and development. Not long ago it was deemed sufficient for the State to provide means and teachers for the cram- ming of the child's intellect with rudimentary knowledge of the elementary sciences. At present, broader ideas prevail. The child is the greatest asset of the State. The child's mental and moral develop- ment and growth go hand in hand with its physical growth and development. The school influences not only the child's mental growth, but also has a profound effect on its physical well-being. No care of the school INFLUENCE OF AGE AND GROWTH OF CHILD 163 child is therefore complete that does not take into consideration the physical condition and the bodily growth of the child as well as the prevention of the evil influences of school and school life upon its health. What are the influences of school and school life on the physical well-being of the child? These influences may be grouped as follows: 1. The influence of the school and the school room. 2. The influence of the age and growth of the child. 3. The influence of the methods of teaching and of the mental training given. 4. The influence of the herding together of a large number of children. The Influence of the School and School Room. — No per- son of tender age may remain for six or seven hours a day during six to eight years in a place without being profoundly influenced by the condition of the place. The hygiene of schools begins, therefore, in the proper construction and care of school-houses and school rooms. The Influence of Age and Growth of the Child. — ^The child when it enters school at the age of six years weighs on the average forty-three to forty-five pounds, and its average height is forty-three to forty-four inches. When the child leaves school at fourteen years of age its average weight is one hundred pounds and its average height five feet. During this period the physical being of the child undergoes remarkable transformation; it is extremely sensitive to external influences, and its health must be carefully nurtured and promoted. It is imperative, therefore, to supervise strictly the personal hygiene of the child, its nutrition, 164 HYGIENE OF SCHOOLS AND OF CHILDREN tion, clothing, dentition, physical development, etc. Mother and school are bound to take care not only of the child's unripe mind, but also of its unripe and growing body. This is accomplished by physical examinations of the child on its entering school, by supervision of and provision for its proper feeding, by the guiding of its muscular exercises, by providing baths, playgrounds, etc. The eyes of the children need very careful attention. The light of school rooms, as well as the distance of the desks from the slate-boards, etc., must be properly adjusted, so that no harmful effects to the eyes ensue. One of the diseases which are so frequent among school children is myopia. It is a disease directly due to school life, to study, to defective light and illumination, to improper positions, faulty seats and desks, defective methods of writing, too small print, and too much eye-strain generally. Children who come to school with some degree of weak vision grad- ually develop more pronounced near-sightedness, which increases in each grade of school. Thus in one New York school the percentage of myopics in lower grade 8 was 8 while in the higher grades it was 20.2. The teeth of the children very often suffer from various defects and diseases, and these lead to certain malformations of the mouth, improper breathing, improper mastication, and improper development. With the ignorance prevailing among many classes of the population, it is impossible to depend upon the parents for the proper care and treatment of the irregularities of dentition, and the school through its TEACHING AND MENTAL TRAINING 165 dental surgeons should take care of this important field of hygiene. There are certain diseases of the bone, rickets, deformities of the spine, etc. The latter, especially, are due to improper positions in school and may be prevented by taking proper care of the children within the school, by the adjustment of seats and desks, and by strict supervision on the part of the teachers of the positions and attitudes of the children during school work. One of the most important defects among a large class of children is malnutrition. This is often due not so much to the lack of sufficient food as to the ingestion of improper food. Recent investigations have also shown that a great many children come to school breakfastless, and that many of them content themselves but with a very slight lunch, often con- sisting of ingredients insufficient for nutrition and im- proper for digestion. It is absurd to endeavor to teach the child and to train its mind while its body suffers from lack of nourishment. A healthy mind can exist only in a healthy body. It is the duty, therefore, of the school to provide for the proper feeding of the school children during school hours. This feeding should be given at a nominal cost to those who can afford it, and without any cost whatever to those children whose parents cannot afford the expense. Influence of Teaching and Mental Training. — ^The methods of teaching and the subjects taught have an important influence, not only upon the mind, but also upon the body of the child. The unscientific and irrational methods of teaching as yet prevailing in 166 HYGIENE OF SCHOOLS AND OF CHILDREN many schools do much harm to the mind, injuriously influence the nervous system of the child, and do harm to the physical condition of the body. The prepara- tion 'of a child for useful future citizenship does not mean the stuffing of his mind with useless book knowledge, to be forgotten as soon as out of school. The methods of teaching should be rather a training of the growing brain and mind, to gather for itself useful facts and to garner knowledge for its own use. The old hot-house methods of child culture are rapidly giving way to new natural methods of mental training. Especially harmful to the child's nerves and physique are the present systems of competitive examinations, and the obsolete methods of punishment, etc. The Influence of Crowding a Large Number of Children in the Schools. — ^This is the greatest evil of school life and the greatest danger to the health and lives of school children. A child in school comes in close bodily contact with other children, with a consequent possi- bility and probability of catching and spreading infec- tious diseases. The infectious diseases of school life may be grouped as follows: Diseases of the Eyes. — Conjunctivitis, blepharitis, pink eye, granular conjunctivitis, or trachoma. Diseases of the Skin. — Pediculosis, ringworm, scabies, impetigo, favus, molluscum contagiosum. General Infedioiis Diseases. — Rotheln, measles, scarlet fever, diphtheria, typhoid, mumps, whooping cough, chickenpox, etc. The diagnosis of the various infectious diseases is within the province of the medical inspectors of schools. THE SCHOOL BUILDING 167 The exclusion of the children is made under the recom- mendation and order of these physicians. The school nurses should have, and usually do have, a general knowledge of the initial symptoms of the various infectious diseases. This medical instruction is given to the nurses in their medical curriculum, and may, therefore, be omitted here. THE SCHOOL BUILDING The school is a place where children of tender age remain daily for long hours. The physical, mental, and moral conditions of the children during their school life is. partly influenced by their sojourn in the school building. The preservation, therefore, of the health of the children demands that the school building be constructed and maintained in the best sanitary condition. The sanitation of the school building should begin before its construction. The site for the school build- ing shduld be selected from among the best in the town or city. The soil should be dry, porous, well-drained. The location should be distant from factories, markets, boiler shops, saloons, elevated railroads, and other establishments which for one or more reasons may become offensive and be a nuisance to the school. It is advisable to surround the school building with playgrounds and, if possible, with a public park. . There should be very little economy practised in the purchase of the site for the school building and in the 168 HYGIENE OF SCHOOLS AND OF CHILDREN construction of the building itself. Except in very small localities no school building should be of frame construction. Brick, stone, or reinforced concrete should be used. The school building should be limited in height and should not contain more than four or five stories, preferably fewer. The school building- should be constructed of fireproof materials and its inner trim should be made fireproof. The cellar and the lowest story should be dry, well lighted and ventilated. They may be used for the location of boilers, machinery, etc., but should not be used for workshops, gymnasia, or any other similar purposes. There should be plenty of entrance and exit doors at frequent intervals. These should be broad, light, and fireproof, and should be sufficient to empty the building within a very short time in case of fire or panic. The size of school buildings is best limited. It is better to construct three buildings for two thousand children each than one building to accommodate six thousand children. The walls, floors, and ceilings should be sound-proof and also proof against dust, damp, and vermin. Some buildings demand a minimum of thirty square feet of floor space for each child. The surfaces of walls and ceilings within the school should be smooth so that dust cannot adhere to them, should be easily washable, and painted with bright tints. The subdivision of the school-house into school VENTILATION AND HEATING OF SCHOOLS 169 rooms should be made by solid partitions if possible, reserving one floor with movable partitions for general assembly rooms, etc. The rooms should not be less than thirteen feet in height. The usual size of a school- room is thirty by twenty-five feet. Lighting. — ^The window area of school houses should not be less than one-fourth of the floor space. The top of the windows should be as near the ceiling as possible and should reach to about four feet from the floor. The best white glass, or preferably plate, should be used for the panes. The prevention of glare should be con- trolled by appropriate shades from the top and the bottom of the windows. Electric lights should be used for artificial illumination. Ventilation and Heating. — ^There has been much controversy as to the proper methods of ventilation for school buildings. There is no doubt whatever that school buildings, with the large number of children in the school rooms, cannot be ventilated properly by natural means, or by means of windows or openings in the windows, walls, , or ceilings. There cannot be too much fresh air introduced into the school room. Provision should be made for artificial mechanical ventilation in all school buildings. The installation of a proper mechanical ventilating plant is an engineering problem, the solution of which should be given only to most competent persons. The combined plenum and vacuum systems are the best for school ventilation. By this method the foul air from the room is exhausted through outlet openings in the school room, and the fresh air is introduced into the room through inlet openings in the same. 170 HYGIENE OF SCHOOLS AND OF CHILDREN The advantage of this system of ventilation is that it may be combined with a system for heating and cooling the air which is introduced into the room. In the winter the air introduced through the tubes may be warmed by passing over steam coils, while in summer the air may be cooled by passing through a cold chamber. Even in very small school buildings no local heating should be used. A hot-water heating plant may be cheaply installed even in small buildings. The com- bined heating and ventilating system must also make provision for proper regulation of temperature by thermostats. Water Supply. — An ample supply of pure water should be had in every school room and there should be no need for the pupils to go long distances to obtain a drink. Sanitary drinking fountains are the best and all common cups should be prohibited. The filtering plant for the water supply of the school should be installed in a central location where it can be watched and kept clean. There should be toilet accommodations of the best type on every floor of the building. The water closets should be provided with automatic flush so as to be self-cleansible. Provision should also be made for wash rooms, shower baths, swimming tanks, etc. Cleaning. — ^The utmost care should be taken to keep all surfaces in the school room clean, and a routine daily, weekly, and periodical cleaning system should be adhered to. The obsolete method of cleaning by SCHOOL CLEANING AND SANITATION 171 the feather duster or dry rag should be abolished. Whenever possible, vacuum systems should be installed in every school room. The school furniture and other surfaces should be cleaned daily with damp, clean rags. School Furniture. — ^The desks, seats, platforms, and black-boards should be properly constructed, and the desks and seats of the pupils should be made so as to be adjustable to the size of each child in order to prevent it from assuming improper attitudes while at work. The depth of the school room should not be too great and the distance of the rearmost pupil from the platform should not exceed twenty feet. It is best not to have the seats and desks attached to the floor, but to make them movable. Some improved substitute is needed for the dust- creating chalk used on slate black-boards. The Supervision of School Cleaning and Sanitation. — The common method of leaving all questions in regard to the care of the school building, rooms, and furniture to the janitor is entirely wrong. Each school should be supervised in its care and cleanliness by a trained school nurse who should have the supervision over janitors and cleaners, and whose duty it should be to make daily and hourly inspection of all parts of the school and to see that each part is properly cleaned and taken care of. The appointment of such a supervising school nurse for the cleaning and sanitation of the school building would be of great benefit to the sanitation of the school and would greatly improve the health of the school children. 172 HYGIENE OF SCHOOLS AND OP CHILDREN THE CARE OF THE CHILD IN SCHOOL The purpose of keeping the child in school from the age of six to fourteen and more is not only to give the child a mental training and education for use in its adult life, but also to promote the physical development and growth of the child into a healthy and useful citizen capable of holding his own in the struggle for existence. The mental and moral training of the child is given into the hands of teachers and principals, whose duty it is to devise and institute a proper system of intel- lectual activity and education and to give to the child the foundations of knowledge as well as a moral training. The various systems of teaching and of mental training, the selection of the courses, and of the teachers to guide the mental and moral training of the child, are in the province of mental hygiene and of the science of pedagogy. The school has also a certain influence upon the health and life of the child and is the place where very often certain infectious diseases are communicated from child to child. A duty of the school authorities, therefore, is to prevent as much as possible the spread of these diseases. These functions — -the care of the health of the school child, the promotion of its normal growth and development, the prevention of general and especially of contagious diseases — are recognized as included in the hygiene of schools and have been intrusted to the school physician and to the school nurse. These have, therefore, the following functions: PHYSICAL CULTURE OF SCHOOL CHILDREN 173 1 . To care for and promote the health of their charges. (a) By recording their condition, growth, and development. (b) By their physical culture by means of exer- cises, bathing, proper playing, and ath- letics. (c) By care for their cleanliness in person, body, clothes, etc., the teaching of personal hygiene (d) ■ By care for the feeding and proper nutrition of the children. 2. To prevent disease among the school children. (a) By the detection and correction of physical defects. (b) By the detection, correction, and treatment of the general diseases of childhood. (c) By the detection and prevention of the spread of infectious diseases. Record of Condition, Growth, and Development. — Each child on its entrance to school should be sub- jected to a medical examination, and a proper record of the condition of its health be kept, with periodic reexaminations at stated intervals. Such records, preferably kept on individual cards, give a valuable indication of the gradual growth and development of the child, and would also be valuable for the physi- cian, for the teacher, and for the child itself. Physical Culture by Means of Exercises, Bathing, Proper Playing, and Athletics. — It is not sufficient to examine a child and keep it in school, giving it mental instruc- tion. It is absolutely necessary to guide the physical culture of the child by subjecting it to moderate and 174 HYGIENE OP SCHOOLS AND OF CHILDREN appropriate exercises, to frequent bathing, by giving it proper playgrounds, athletic exercises, contests, etc. At present no school should be regarded as complete that does not have its proper facilities for play and exercise, or that lacks sufficient shower baths, swim- ming tanks, and other bathing facilities. Care for Personal Hygiene. — Cleanliness in Person, Body, Clothes, etc.— The personal hygiene of the child must be thoroughly supervised. The child during its school hours is entirely under the control of the school authorities, and should be taught how to take care of itself, how to be clean in body, how to take care of its clothes, hands, hair, etc. For this purpose the supervision by trained nurses is most valuable. Care for the Feeding and Proper Nutrition of the Child. —A subject which has lately been given much attention is the improper feeding of school children during school hours. The advocates of the proper feeding of school children recommend the establishment of food stalls and restaurants within the schools, and the furnishing of proper food to all children at a nominal price or free of charge to those who are unable to bear the cost. The Detection and Correction of Physical Defects in the Child. — School children may also be given partly into the care of nurses and be partly under the supervision of medical school inspectors. Certain minor accidents, such as wounds, abrasions, etc., which may occur within the school, should be immediately attended to by the nurse in charge, in order to prevent wound infection or complications. There should, therefore, be stationed in every school a nurse or nurses, who should furnish the first aid to those who need it. GENERAL DISEASES OF CHILDHOOD 175 The detection and correction of the physical defects of children is partly accomplished at the various medical examinations of the child as well as by a routine daily inspection by the school nurse. Mouth breathing, adenoids, and enlarged tonsils may easily be detected and should be referred to the family physician for proper treatment, and if not properly treated should be corrected by the school physician. Other defects of the nose, ear, or bones may easily be detected on inspection and should be referred to physicians for treatment and correction. The care of the teeth and mouth is a very important prevention of disease. There should be a periodical and frequent examination of the teeth of school chil- dren and the defects should be corrected and treated by the family physician, or if neglected by parents and family physicians, the treatment should be in the hands of school dentists. Education in Hygiene. — There should be thorough, periodic, and intelligent instruction in hygiene in every grade of the school. By means of charts and models, and, if necessary, moving pictures, the anatomy of the human body may be made intelligible to the child, and physiology made a fascinating study. Instruction in hygiene should be made a special study, and should be systematically carried on from the beginning of school life until graduation. The Detection, Correction, and Treatment of the General Diseases of Childhood. — ^This should be the duty of the school nurse and the school physician. Malnutrition, anemia, and malformation of the bones can easily be detected. Means should be sought to prevent their 176 HYGIENE OF SCHOOLS AND OF CHILDREN further progress and development. If the child is properly examined and inspected daily the symptoms of various diseases may be detected, the child sent home with proper instruction, and subjected to early treatment which saves a great deal of trouble and consequent suffering. The Detection and Prevention of the Spread of Infectious Diseases. — ^The most important duties, however, of the nurse and physician are the detection of contagious diseases. As has already been noted, there are besides the general contagious diseases, such as diphtheria, scarlet fever, measles, typhoid, etc., a number of eye and skin diseases which are very communicable, and which are spread from one child to the other in the congested school rooms. The system of medical school inspection which has been introduced into most of the schools in large cities in the United States was instituted primarily with the purpose of controlling contagious diseases in the schools. At present, however, the system of medical school inspection is supplemented by the system of inspection and supervision by nurses. FUNCTIONS AND DUTIES OF SCHOOL NURSES The following excerpts from the official instructions of the Health Departments of Rhode Island, Mas- sachusetts, and New York City will give an idea of the functions and duties of school nurses, and should be studied by those who are especially interested in this subject: MEDICAL INSPECTION OF SCHOOL CHILDREN 177 Instructions to Childeen. Do not spit if you can help it. Never spit on a slate, floor, or sidewalk. Do not put the fingers into the mouth. Do not pick the nose or wipe the nose on the hand or sleeve. Do not wet the finger in the mouth or wet them with the lips. Do not put money into the mouth. Do not put pins into the mouth. Do not put anything into the mouth except food and drink. Do not swap apple cores, candy, chewing gum, half-eaten food, whistles, or bean blowers, or anything that is put into the mouth. Keep your face and hands clean; wash the hands with soap and water before each meal. Medical Inspection 1. The repeated and systematic inspection of all school chil- dren for the purpose of early recognition of contagious disease. 2. Exclusion from school attendance of all children affected with an acute contagious disease. 3. Subsequent control of the case with isolation of the patient, and disinfection of the living apartment after termination of the illness. 4. Control and enforced treatment of, contagious eye and skin diseases with the purpose of diminishing the number of children excluded from school attendance. 5. Knowledge of unreported cases of contagious disease among school children at home. 6. Complete physical examination of each school child with reference to the existence of any untreated physical abnormality. 7. Education of the parents as to the necessity of obtaining proper medical care for untreated physical defects. 8. Provision of facilities for the treatment of contagious eye and skin diseases and non-contagious physical defects occurring in school children. 12 178 HYGIENE OF SCHOOLS AND OF CHILDREN Inspection for the Detection of Cases of Contagious Diseases morning inspection 1. Each nurse visits each school in her charge before ten o'clock each morning, unless otherwise authorized, and inspects in a room set apart for this purpose all children referred by the teachers as cases of suspected contagious disease. 2. Children manifesting any signs or symptoms of disease which might prove to be of an acute contagious nature, such as smallpox, diphtheria, scarlet fever, measles, chickenpox, whooping cough, or mumps, are referred by the nurse to the principal. The principal thereupon sends the child home. Cultures are taken by the nurse in every case of sore throat. All such children are sent home by the principal upon the advice of the nurse, who forwards the culture tube with the essential data to the nearest culture station in the borough where the culture was taken. The following day a report is sent to the nurse regarding the bacteriological diagnosis made from the culture. If the Klebs-Loeffler baoiUi are not found, the nurse notifies the child to return to school; if they are found the case passes under the control of the Division of Contagious Diseases for further isolation and control. The name and address of each child recommended for exclu- sion from school by the nurse is telephoned by the latter to the borough office of the division, together with a statement of the possible nature of the case. The case is immediately referred to a medical inspector of the division, who visits the home and makes the diagnosis. If the child is not suffering from a contagious disease it is notified to return to school and is given an official certificate to that effect. If a confirmatory diagnosis of contagious disease is made the patient is isolated, the apartment placarded with a notice of the character of the disease, and the case immediately reported to the Division of Contagious Diseases, which thereafter assumes supervision and control. The children are instructed to report to the nurse at the opening of school on the following morning. At this time, if they show evidence of treatment, they are allowed to remain in school but are required to report to the nurse at regular INSTRUCTION AND TREATMENT OF CHILDREN 179 intervals, and unless evidence of continued treatment is shown, are excluded from school attendance until the disease has dis- appeared. When no treatment has been obtained the following is the method of procedure: (a) Cases excluded: 1. Contagious eye diseases with symptoms of acute inflammation or discharge. 2. Contagious skin diseases with extensive lesions. 3. Pediculosis with Mve pediculi. (6) Cases allowed to attend school while under treatment by a private physician, dispensary or the school nurse. 1. Acute conjunctivitis. 2. Pediculosis (with no live pediculi). 3. Skin diseases, including ringworm of scalp, face, or body; scabies, favus, impetigo, moUuscum con- tagiosum. 4. Trachoma cases are instructed as to the necessity for treatment and are required to report to the nurse at regular intervals, but are never treated by the nurse. Methods of Instruction and Treatments pediculosis Children affected with pediculosis are assembled in groups and instructed by the school nurse as to methods of home treat- ment. Each child is given a copy of the following circular of instruction. Instructions to Parents on the Care of Children's Hair and Scalp Children affected with vermin of the head are excluded from school. The following directions will cure the condition: Mix one-half pint of sweet oil and one-half pint of kerosene oil. Shake the mixture well and saturate the hair with the mixture. Then wrap the head in a large bath towel or rubber cap so that the head is entirely covered; the head must remain covered from six to eight hours. (Tincture of larkspur may be used instead of oil mixture. The directions for use are the same.) 180 HYGIENE OF SCHOOLS AND OF CHILDREN After removing the towel, the head should be shampooed as follows: To two quarts of warm water add one teaspoonful of sodium carbonate. Wet the hair with this solution and then apply Castile soap and rub the head thoroughly about ten minutes. Wash the soap out of the hair with repeated washing of clear warm water. Dry the hair thoroughly. Nits. If the head is shampooed regularly each week as above described, it will cure and prevent the condition of nits. Another Method of Exterminating Pediculi Capitis The following method is employed by Whitfield in the case of female children in whom treatment is made difficult by the length of hair. The patient is laid on her back on the bed with the head over the edge, and beneath the head is placed a basin on a chair so that the hair lies in the basin. A solution of 1 iu 40 phenol is then poured over the hair into the basin and sluiced backward and forward until the whole of the hair is thoroughly soaked with it. It is especially necessary that care should be taken to secure thorough saturation of the hair over the ears and at the nape of the neck, since these parts are not only the sites of predilection of the parasites, but they are also apt to escape the solution. The rule Whitfield gives is that this sluicing shall be carried out for ten minutes by the clock. At the end of the ten minutes the hair is lifted from the basin and allowed to drain, but is not dried or even very thoroughly wrung out. The whole head is then swathed with a thick towel, or better, a large piece of common house flannel, which is fastened up to form a sort of turban and the head is allowed to remain like this for an hour. It can then be either washed or simply allowed to dry, as the phenol, being volatile, quickly disperses. At the end of this period every pediculus and, what is more important, every ovum is dead, and although the ova are left on the hair they win not hatch and no relapse will take place unless expo- sure to fresh contagion occurs. Incidentally any impetiginous scabs are softened so that they come away easily and allow any ointment which is used for tke cure of this complication to be applied easily. In cases in which there is no impetigo no further treatment is necessary. These children report to the nurse at least once each week and are then examined for evidence of treatment. If persistent TREATMENT EMPLOYED BY SCHOOL NURSE 181 neglect is shown, the nurse visits the home and instructs the parents in the methods to be employed. Further neglect is followed by exclusion from school a(ttendance. Tbachoma Trachoma is never treated by the nurse. Children so affected are instructed as to the necessity for treatment, as per foUdwing instructions: Instructions to Parents Regarding Trachoma Trachoma is a contagious disease of the eyelids. If left untreated it is very dangerous to the eyesight. It first attacks the inner surface of the eyelid, later it spreads to the eyeball itself and causes loss of sight. In the beginning the eyes may be red and watery, and they may, from time to time, contain matter, but often for a long time there are no symptoms that the person notices, and the disease is frequently first discovered by the doctor. It is very diflBcult to cure trachoma, and it is the more difficult the longer the disease has lasted. For this reason trachoma should be detected as early as possible. It is contagious when secretion, that is to say "matter," is present. This secretion is for the most part conveyed by means of towels, wash cloths, and hand- kerchiefs, and persons with trachoma should always be careful that their towels, wash cloths, and handkerchiefs are used by themselves. It is, therefore, not on the street that trachoma is transmitted from one person to another, but most generally in the home, and it is therefore in the home that the greatest precautions should be taken. Children who have trachoma are not allowed to attend school imless they are regularly treated. Methods of Treatment Employed by the School Ntjbsb in CONTAGIOTTS EyE AND SkIN DISEASES Favus : Ringworm of Scalp Mild cases: Scrub with tincture of green soap and cover with flexible collodion. Severe cases: Scrub with tincture of green soap, paint with tincture of iodine, and cover with flexible collodion. 182 HYGIENE OF SCHOOLS AND OF CHILDREN Ringworm of Face and Body Wash with tinctvire of green soap and cover with flexible collodion. Scabies Wash with tincture of green soap and apply sulphur ointment. Impetigo Remove crusts with tinctiu'e of green soap and apply white precipitate ointment (ammon. hydrarg.). Molluscum Contagiosum Express contents: Apply tincture of iodine on cotton-covered toothpick. Conjunctivitis Irrigate with solution of boric acid. Pediculosis Saturate scalp and hair with a mixture of equal parts of kerosene and sweet oil. Next day wash with a solution of potassium carbonate (one teaspoonful to one quart of water), followed by soap and water. RotTTiNE Inspection 1. At the beginning of each term each medical inspector makes a routine class-room inspection of each child in the schools under his charge. Thereafter the nurse makes a continuous routine class inspec- tion of each child in the schools under her charge, following the same procedure. The inspector stands with the back toward the hght from a window and the children pass in line in front of him. The condi- tion of the eyehds, throat, skin, and hair of each pupil is observed. The inspector or nurse does not touch the child, but the latter is instructed to puU down the eyehds, open the mouth, show the hands, and in the case of girls lift up the back hair. Wooden tongue depressors are furnished by the department, and a sepa- rate one is used for each child when such use is indicated. No NON-CONTAGIOUS PHYSICAL DEFECTS 183 tongue depressor is to be used more than once, under any cir- cumstances. 2. All cases of disease found are recorded on a special class index card, with the data in appropriate columns. A card or cards is made out for class room, and the index kept in an acces- sible place in each school. Further data regarding each case is recorded on this class index card. Code numbers are used to indicate the kind of disease. 3. AU contagious diseases found are dealt with as described under the heading "Morning Inspection." 4. When a child is foimd to be affected with a marked form of physical defect, the particular defect is noted and the child referred to the medical inspector for a physical examination. 5. AU children ordered under treatment are referred to the school nurse are thereafter controlled as described under the heading "Morning Inspection." Emebqency Cases In the absence of the inspector aU emergency cases are treated by the nurse in the school whenever other treatment is not available. Such cases are thereafter referred to the parents for future care. The Diagnosis and Coebection of Non-contagious Unteeated P^^ysical Defects 1. The medical inspector visits each school under his juris- diction for two successive days. A regular schedule is main- tained, and the principals of the schools are thus informed of the dates of the inspector's visits. The principals are requested to instruct the children to report, in small squads, to the inspector for physical examination. 2. Examinations are made in the following order: First: Children entering school for the first time. Second: Children especially referred by the principals or teachers. Third: Children belonging to the class to be graduated. Fourth: In the regular course, beginning with the children of the lowest grades, and proceeding to the higher grades in regular order. Fifth: Classes of the same grade are examined in regular order in each school of the group. 184 HYGIENE OF SCHOOLS AND OF CHILDREN 3. Each child is thoroughly examined for the following condi- tions: Defective vision. Defective hearing. Defective nasal breathing. Hypertrophied tonsils. Tuberculous lymph nodes. Defective teeth. Malnutrition. Pulmonary disease. Cardiac disease. Chorea. Orthopedic defects. 4. A complete record of each physical examination is made on a special form. If a child is normal the inspector sends such a report to the borough office of the division. If abnormalities are found, the record form is given to the school nurse. A dupUcate record of each child's condition is placed on file with the child's school record, thus affording to the educational authorities the fullest information in regard to the child's physical condition, and enabling them to take advantage of this informa- tion in adjusting the individual curriculum. The nature and results of the treatment obtained for each defect are thereafter noted upon this school record form by the nurse. The inspectors and nurses are required to cooperate to the fullest extent with the principals and teachers, giving to them all possible data in relation to the children found to be physically defective, and to offer suggestions in the way of school adjust- ments which may tend to correct the existing defects. TtTBERCXrLOSIS Suspected cases of pulmonary tuberculosis are brought to the attention of the medical inspector. (a) During morning and routine inspection. (6) Diu-ing routine physical examinations. (c) By the school nurse. (d) By the principal or teachers. The teachers and nurses are instructed to refer to the inspector any child showing symptoms of loss of weight, lassitude, fever, or cough. CARE OF THE MOUTH AND TEETH 185 All children showing such symptoms are immediately examined by the inspector, who forwards a report of his tentative diag- nosis. If, in his opinion, the child is affected with tuberculosis, the report is forwarded from the Division of Child Hygiene to the Division of Communicable Diseases. The latter division sends to the home of the child a diagnostician who makes a more thorough and complete physical examination. A specimen of the sputum is also obtained. The child is allowed to remain in school pending the receipt of the report of the examination from the Division of Communi- cable Diseases. If the report shows the presence of tubercle bacilli in the sputum, the school miedical inspector is notified to exclude the child from school, and thereafter the case remains under the control of the Division of Communicable Diseases, the child being regularly visited by a nurse from that division and placed in a day camp, school, or sanatorium whenever possible. Instrtjctions to Parents Rbgaeding the Care op the. MoTJTH AND Teeth The physical examination of school children shows that in many instances the teeth are in a decayed and unhealthy condition. , Decayed teeth cause an unclean mouth. Toothache and disease of the gums may result. Neglect of the first teeth is a frequent cause of decay of the second teeth. If a child has decayed teeth, it cannot properly chew its food. Improperly chewed food and an unclean mouth cause bad diges- tion, and consequently poor general health. If a child is not in good health, it cannot keep up with its studies in school. It is more likely to contract any contagious disease, and it has not the proper chance to grow into a robust, healthy adult. // the Child's Teeth are Decayed it Should be Taken to a Dentist at Once The teeth should be brushed after each meal, using a tooth- brush and tooth powder. 186 HYGIENE OF SCHOOLS AND OF CHILDREN The following tooth powder is recommended: 2 ounces powdered precipitated chalk. i ounce powdered castile soap. 1 dram powdered orris root. Thoroughly mix. This prescription can be filled by any druggist at a cost not to exceed fifteen cents. The child should take the tooth-brush and powder to the school and receive instructions from the nurse as to their proper use. Defective Vision The relative number of children with defective vision has been reduced from 13.1 per cent, in 1909 to 10.6 in 1911. When the parents are unable to pay for glasses, the cases are referred to the various rehef organizations of the city. There are, how- ever, a considerable number of cases in which the child presents a certificate from private physicians or dispensaries, stating that the child is under treatment for defective vision, but when no evidence other than some form of "eye lotion" or "eye drops" has been prescribed. In 1911 this class of cases amounted to 14,122, as opposed to 8218 where glasses had been obtained. The department has no legal authority to demand that glasses shall be provided in these cases; it accepts only at its face value the evidence that other treatment has been obtained. Defective Nasal Breathing and Hyperthophied Tonsils As these defects are so closely associated in their occurrence, and have ahnost similar harmful effects upon the child, they may be considered together. Next to defective teeth they stand as the most predominant of the physical defects of the children examined. In the physical examinations as made in schools it does not seem practical to enter into the complicated methods of exami- nation necessary and essential to the proper diagnosis of the presence of adenoids. The wide difference of opinion still existing among the medical profession as to the readily demon- strable stigmata for a positive diagnosis without exploration or visual examination of the nasopharyngeal vault has opened an avenue for conflicting diagnosis and criticisms. It is, there- CARE OF THE NOSE 187 fore, the policy of the division to have the inspector determine if the child can breathe readily and freely through the nasal passages, and call the attention of the parents to the objective symptoms which point to obstruction of the nasal passages, classifying such cases under the general term of "defective nasal breathing." The cause of the nasal occlusion is left for the family physician to determine. The report of physicians have shown conclusively that in this class of cases adenoid growths were present in the majority of instances. The number of such cases found has decreased from 18.7 per cent, in 1909 to 11.8 per cent, in 1911. While not abating all possible efforts to induce parents to have children so affected placed under competent medical care, the nurses during their visits to homes have directed particular attention to correcting the unsanitary home conditions and the unhygienic methods of living that have such a direct bearing upon the production of these defects. The examination for hypertrophied tonsils is made by direct natural hght, and individual wooden tongue depressors being used in each case. A gratifying decrease is shown in the number of cases now found as compared with the conditions three years ago — from 22 per cent, in 1909 to 15 per cent, in 1911. Whenever a child is found to have any abnormal condition of the nose and throat, a copy of the following circular is given to the child to take home to the parents: Insthtjctions to Parents Regakding the Care of the Nose The physical examination of school children shows that in many instances they breathe through the mouth because they cannot breathe properly or sufficiently through the nose. This may be due to bad habits in regard to keeping the nose clean, or, in a majority of instances, to a growth which is known as "adenoids" and which stops up the back of the nose. In either case the air is not breathed through the nose, and the child becomes what is known as a "mouth breather." Constant breathing through the mouth causes the child to become pale, restless in its sleep, and dull in its actions. The child often speaks as though it had a cold in the head. Fre- quently there is an almost constant discharge from the nose. 188 HYGIENE OF SCHOOLS AND OF CHILDREN Mouth breathing renders a child especially liable to contract tuberculosis and other infectious diseases; in fact, the child has very little resistance to disease of any kind. Every child should be. given a handkerchief, and be taught to thoroughly blow the nose several times each day. If, after doing this regularly, the child is stiU unable to breathe properly through the nose, it is probable that an adenoid growth is present. Such children should be taken to the family physician or to a dispensary for further advice and treatment. Do not wait too long in the hope that the child will outgrow the conditions, for the effect of adenoid growths persisting throughout childhood may injure the person for life. Have your child's throat and nose examined one month after measles, scarlet fever, or diphtheria. Defective Hearing The whispered voice at twenty feet is used as a test. Under the necessary restrictions of school physical examinations it is not probable that either this or the watch test is an accurate determination of this defect. There is also another factor which contributes toward the unreUabiMty of the diagnosis. Owing to the large number of foreign-born children in the schools, many of whom have but a sUght acquaintance with our language, ignorance, confusion, or apparent stupidity may be often mis- taken for impairment of hearing. Even with these chances of error in diagnosis, however, it is evident that the number of children whose power of hearing is below the normal is suffi- ciently large to warrant their segregation in special schools or classes, where they may have the advantage of a form of instruction suited to their abnormal condition. Such provision has been made to a hmited extent. Malnittbition The wide difference of opinion as to what may or may not be classified as malnutrition results in great uncertainty as to the number of such cases that may be recorded. Practically all of the physical defects have an associated anemia and a degree of mahiutrition. This is particularly true in the poorer or tenement districts of the city where the living conditions are MALNUTRITION IN SCHOOL CHILDREN 189 particularly detrimenl^al to the health of children. Racial characteristics, as altered by the new environment of our alien population and a vast array of factors, too numerous to be discussed here, bear more heavily in their unwholesome effect upon the children than they do upon the adult population. Mahiutrition, dependent upon some concurrent physical defect which tends toward readjustment to the normal when the primary defect has been cured, is not considered as malnutri- tion, per se, so that the cases hsted are those where the condition exists as an entity and where active remedial measures, directed toward that condition, are essential to place the child in normal health. Whenever possible, such children are referred by the inspector or nurse to the open-air classes. Whenever school lunches are provided arrangements are made to include these children. Excellent results have been obtained by these methods, but they are not available for the greater number of children suffer- ing from this condition. The greater part of the adjustment must be done at home. In each case a survey is made of home conditions and the routine of the child's Hfe. The nurses visit the homes and instruct the mothers as to the hygiene of the home and the proper adjustment of the child's Hfe in regard to sleeping, play, study, out-of-door Mfe, and diet. When ignor- ance is the causative factor, excellent results have been achieved, but poverty is a more difficult problem. With the cooperation of the various social service and relief agencies of the city, this element is partially removed in many instances. CHAPTER V THE HYGIENE OF OCCUPATIONS OCCUPATION AND HEALTH The functional activity of organs in the normal way is a physiological condition of health; the disuse, more or less prolonged, of any organ is, as a rule, followed by atrophic changes. While the normal pur- suit of occupation is therefore a condition of health, pursuit of most occupations in the present industrial system is often followed by certain pathological changes in the human body. It is certain that the health of workers is profoundly influenced by the kind of occupation they pursue, and that their very letagth of life is determined by their particular occupation. Occupation is a potent factor in the determination of human longevity. If the period of infancy and childhood and the hours devoted to sleep are deducted from man's life the greatest part of it is spent in industrial activity and is necessarily largely influenced by the occupation engaged in. The relative number of those who die while in pur- suit of their occupations bears an important relation to the healthfulness of the occupations. Mortality statistics clearly prove this contention. When the mortality of members of various trades is compared, a great difference in the rate of death per thousand OCCUPATION AND HEALTH 191 is found. This difference frequently embraces long periods, large numbers, and many different countries, showing a uniformity in the increase of mortality rates of the members of one trade over the mortality rate of members of another trade. It is shown, for instance, according to Ogle's tables, from the experience of Great Britain, that clergymen have the lowest death rate, next to them gardeners and farmers, while members of trades like bakers, tailors, liquor dealers, file makers, and others suffer from a much higher mortality rate. The mortality rate of clergymen is therefore put as 100 in the follow- ing table as a basis for comparison. Mortality Occupation. rate. Clergymen 100 Gardeners . 108 Farmers 114 Bakers . . 172 Tailors . . 189 Glass-workers 214 Liquor dealers . . 274 File makers . 300 The United States mortality tables also show that the mortality rate per thousand of engineers and surveyors was 8.2; tailors, 11.8; printers, 12.1; car- penters, 17.2; cigar- and tobacco-workers, 18.7; and millers, 26.6. Thus it is found that the mortality rate of members of one trade is much higher than the rate for workers in another trade, and if the causes of the increased mortality are sought for, it is usually found that there are some specific dangers in the occupation which shows the highest rate of mortality. 192 THE HYGIENE OF OCCUPATIONS Morbidity. — Not only the length of life of the workers is determined by their occupation, but also their state of health during life. If a physical examination of the workers in one trade is made, and the results are compared with those of a similar physical examination in another trade, a difference in the morbidity rate according to certain factors existing in each occupa- tion is usually found. The experience of various sick benefit insurance societies in Germany, Austria, and other continental countries in which state insurance exists, show a great difference in the rate of disease among the workers in different occupations. A recent medical examination undertaken by the New York State Factory Investi- gating Commission of 2283 persons, in the tailors', bakers', tobacco, and furriers' trades, has shown a large percentage of members of these trades suffering from one or more diseases. Tuberculosis. — ^The most frequent disease in indus- trial life from which the members of various trades suffer is tuberculosis. Indeed, tuberculosis has been named an industrial disease. All statistics confirm this statement; They show that tuberculosis as a cause of mortality in active workers between the ages of twenty-five and forty-four is responsible for from one-third to one-half of all the deaths. According to statistics of the Prudential Insurance Company of America presented at the International Congress of Hygiene and Demography in 1912, tuberculosis was shown to be the cause of death of 35.5 per cent, of all occupied males between the ages of fifteen and twenty- four. Among farmers the rate at the same age was 33.1 ; DISEASES OF OCCUPATION 193 among clerks, 45.9 per cent.; among glass-workers, 48.1 per cent.; among stone-workers, 47.8 per cent.; among plumbers, 42.1 per cent.; among printers, 49.5 per cent.; .cigar makers, 45.5 per cent.; tailors, 48.6 per cent.; textile-workers, 47.5 per cent. Hoffman has shown the great mortality among workers in dusty trades also. According to Somerfeld, the miortality of Berlin workers in non-dusty trades was 2.39 per thousand, while in dusty occupations it was 5.42 per thousand. Diseases of Occupation. — There are a number of diseases which are peculiar to certain occupations, and they have been therefore called industrial diseases. Among these diseases beside tuberculosis, which has been already referred to, the following are the most important: 1. Respiratory Diseases. — ^The term pneumonokoni- osis is applied to an affection of the lungs due to the deposit of dust among its cells. Miners, charcoal drivers, metal and glass polishers, stone- masons and plasterers, and other workers in especially dusty trades are apt to have the dust lodge in their lungs, where it causes a special fibroid disease which eventually is followed by an infection with tubercle bacilli and frequently leads to death. Pneumonia, bronchitis, and emphysema are also found frequently among workers. They are due to exposure, difference in temperatures, and other factors in the occupa- tion. 2. Nervcms Diseases. — ^Among the nervous diseases which are frequently found among workers are those due to overstrain, tension, extremes of heat, shocks, 13 194 THE HYGIENE OF OCCUPATIONS and other untoward occupational factors. There are also certain nervous diseases due to the overstrain of particular organs; the most common of these are writer's cramp, telegraphers' spasm, etc. 3. Diseases of the Eyes. — Among the principal eye diseases are eye-strain, nystagmus, and other affections due to excessive light, heat, overuse, overstrain, and accidents. 4. Infectious Diseases. — ^A number of infectious dis- eases are due to infection by materials which are handled by the workers. The most important of these are anthrax, which is often found among workers with hides and cattle, ankylostomiasis, and others. 5. Other Diseases. — ^There are also a number of diseases of the digestive tract, of the skin, and of other organs, due to the various factors in various occupations. Summary. — ^The effects of industries on health may be summed up as follows: 1. Sudden death due to accidents, falls, burns, explosions, etc. 2. Total or partial disability from the same causes. .3. Sudden deaths from acute intoxications by poisons, fumes, and gases. 4. Deaths from chronic intoxications by the same elements. 5. Deaths due to infectious material in indus- tries. 6. Diseases due to direct action of dangerous ele- ments in trades. 7. Diseases due indirectly to industries and occu- pations. PERSONAL FACTORS 195 INDUSTRIAL FACTORS INFLUENCING HEALTH There are a number of factors in industry and various occupations which influence the health and bring about occupational diseases and the comparative shortening of the lives of industrial workers. They may be grouped as follows: 1. Personal factors. 2. Work place. 3. Working conditions. 4. Specific occupational dangers. Personal Factors. — ^The personal character of the worker, his fitness for the occupation which he selects, his industrial training, his capital of bodily health and mental training, his vital resistance, his age and sex, all are important factors determining the influence of the work upon the worker. The greater the sum of health with which the worker starts out at the beginning of his career the more efficient will be his work, and the less likely will it be that he will suffer from the adverse conditions incident to his work. His susceptibility and vital resistance depend partly on his physical health and partly on individual idiosyncrasies. There are, for instance, those who are less susceptible to certain poisons than others, enjoying a certain immunity against the effect of infec- tions and poisons to which others quickly succumb. The proper selection of a trade according to fitness is very important. A feeble individual selecting a trade which requires strenuous physical exertion will suc- cumb sooner to the effects of the trade than a robust worker. 196 THE HYGIENE OF OCCUPATIONS Age. — ^The age at which work is begun is also of great importance. There are nearly 2,000,000 children under the age of sixteen employed in the various occupations in the United States. That the developed organism is unable to withstand the sti;ains of continuous and prolonged muscular or other exer- tion is obvious. The mind and body of a child under sixteen should be carefully nurtiu-ed and not allowed to be subject to physical or mental strain for long periods. In normal society there should be no econ- omic cause for parents of children under sixteen to need the wages of the child workers or to impose the burden of economic independence upon the physically unripe child. The effects of labor on children may be summed up as follows: 1. Injury to the weaker organism. 2. Interference with their growth and physical development. 3. The production of special and other bone defor- mities. 4. The lowering of vital resistance and the predis- posing of the body to disease. 5. The stunting of mental and moral development. 6. The physical, moral, and mental degeneration. 7. The shortening of life. The Labor of Women. — Under the present economic conditions a large number of women are employed in gainful occupations, and form a most important part of the industrial population. There is hardly a trade or industry in which women do not participate. The question what effect, if any, occupation has upon women has been studied by many investigators, THE WORK PLACE 197 and certain conclusions have been reached which are at present universally accepted. These conclusions regarding women's labor may be summed up as follows: 1. That there are certain forms of labor, especially those requiring great physical exertion, which should not be followed by women because of their compara- tive physical weakness. 2. That women cannot bear with impunity as long hours of labor as men; that, therefore, the hours of labor should be shortened, and should not exceed eight per day. 3. That there are certain periods each month during which women should not be allowed to work at all, because they are in a semipathological state. 4. That women who bear the burden of pregnancy and childbirth should not be allowed to work during these periods. .5. That night work is injurious to the health of women. 6, That those women who are burdened with the care of children or of a household should not be ex- pected to participate in industries to the same extent as those who are free from these burdens. 7. That owing to the greater susceptibility of women to certain industrial poisons, they should be excluded from work in all indu.stries in which these poisons are produced. The Work Place. — ^The place where the work is carried on has a great influence upon the health of the worker. The effect of the factory or workshop upon the health of the worker depends upon its proper construction, upon the fire protection, the pro- 198 THE HYGIENE OF OCCUPATIONS vision for light and illumination, adequate ventilation, proper heating, the drainage, plumbing, and general sanitation of the place. At present much work is done at home, especially by women and children. The injurious effects of "home work" or "sweat-shop work" are due partly to the unsanitary conditions under which the home-workers are compelled to work, and partly to other causes, such as the tendency in home work for small children to participate, the longer periods of the work at home, the danger that the home will be infected by the dust and manufactured materials brought into it, or that the materials will carry in- fection from the home. A great many of the factory buildings are entirely un suited to the purpose of manufacture and are unfit for the workers. The existence of so many unfit factories is a cause of a great many of the evils of the modern factory system. The dangers from fire in factories and workshops, as they are ordinarily constructed, are very great. These dangers are due to: 1. The congestion of factories in certain areas. 2. The too great height of many buildings in large cities. 3. Faulty internal construction. 4. Bad internal arrangements. 5. Too many workers on each floor. 6. Insufficient exits. 7. Improper exits. 8. Insufficient fire-escapes. 9. Inadequate means of extinguishing a fire and of preventing panic. THE WORK PLACE 199 Another of the great dangers in many industrial establishments is due to the improper safeguarding of machinery. It has been estimated that there are nearly 1,000,000 accidents to workers in the United States every year, and that several hundred thousand persons are disabled, while many thousands are killed outright, through accidental injuries in factories. Most of these accidents can be prevented and avoided by the* proper safeguarding of machinery; and the hazards of industry may be greatly reduced by proper care on the part of the employers and managers to whose care the lives of the workers are intrusted. The proper light and illumination of the work places are of great importance to the health of the workers. It is to the interest of the employer that the workman should be able to see what he is doing. It is to the interest of the work itself that the worker should not strain his eyes in the performance of his functions. A large number of factories and work- shops are improperly lighted and illuminated, causing injury to the eyes and general health of the workers. The provision of sufficient air in workshops is of the utmost importance to the health of the worker. Labor in confined rooms is injurious to the health, does not furnish sufficient oxygen to the body, compels the worker to inspire deleterious substances, and pre- disposes him to various diseases, especially tuberculosis. During work more air is needed than during repose, and it is of the greatest importance that workshops should be well ventilated and the air therein be of a proper temperature, not overheated and frequently changed. 200 THE HYGIENE OF OCCUPATIONS While it is possible to provide adequate ventilation in homes and dwellings by natural methods of ventila- tion, such as windows, doors, transoms, and occasional special devices, it is of the utmost difficulty to provide adequate ventilation in factories and workshops by these methods. In all factories and workshops there should be provision made for artificial ventilation by mechanical means, which should allow the entrance of a large volume of air into the workshops without drafts, and every effort should be made to insure an equable temperature in the workshops. The general sanitary cleanliness of factories and workshops is important to the health of workers. There should be provision for an adequate number of wash rooms, dress rooms, lunch rooms, emergency and rest rooms, as well as insurance for the cleanliness of the walls, ceilings, floors, and windows; for the proper disposal of rubbish and garbage; the preven- tion of spitting on floors, and provision for toilet accommodations and their cleanliness. Working Conditions. — Besides the personal factors and the influence of the place of work there are many other conditions in industrial life which have a deleterious influence upon the health of the worker. Among the most important of these conditions are: 1. Too glaring light. 2. Too great relative humidity of the air in the shops. 3. Extremes in temperature. 4. Improper positions and attitudes during work, 5. Great differences in the air pressure. 6. Too prolonged work and exertion and consequent overfatigue. DUSTS 201 7. Insufficient pauses during work. 8. Too great tension and physical or mental strain durinof the work. 9. Last but not least the inadequate compensation cf the workers. The other injurious influences to which the industrial population is exposed are improper standards of living, ignorance of personal hygiene, the unsanitary housing of the working classes, improper feeding, etc. SPECIFIC OCCUPATIONAL DANGERS There are certain specific dangers found in many trades and industries. These dangers are mostly due to the materials which may be grouped as follows: 1. Infectious materials. 2. Dusts. 3. Poisons, gases, and fumes. Infectious Materials. — Certain materials, like gar- ments, underwear, rags, etc., may be infected with the germs of scarlet fever, typhoid, diphtheria, etc., and spread infection to the workers. Gardeners may be infected with tetanus; horsemen and coachmen with glanders; tanners, wool-workers, etc., with an- thrax; nurses, with the various communicable diseases of the persons of whom they are taking care; tunnel workers, with ankylostomiasis. Dusts. — ^There are many industries in which a great amount of dust is created during the work. The effects of the dust upon health vary with the amount of dust inhaled, the kind and character of the dust, the period of exposure, the individual health of the worker, and 202 THE HYGIENE OF OCCUPATIONS many other factors. All dusts cause some irritation to the mucous membrane of the eyes, nose, mouth, and throat. Metal or mineral dusts may also cause mechanical injury to the mucous membranes of the respiratory passages. Hoffmann classifies dusty trades according to the dust produced, as follows: Group I. — Exposing to Metallic Dust: Grinders, polishers, tool and instrument makers, jewellers, gold- beaters, brass workers, printers, compositors, engravers, pressmen. Group II. — Exposing to Mineral Dust: Stone, marble, and cement workers, glass cutters, diamond cutters, potters, plasterers, paperhangers, moulders, core makers, lithographers. Group III. — Exposing to Animal and Mixed Dust: Furriers, taxidermists, hatters, silk, wool, and worsted- workers, carpet, rug, rag, and shoddy-workers, hair mattress makers, upholsterers, etc. Group IV. — Exposing to Vegetable-fiber Dust: Cotton ginners; textile, flax, hemp, cordage, and paper manu- facturers; weavers, spinners, hosiery knitters, lace makers, jute and wood-workers. According to Hoffman, the mortality rate from consumption varies according to each group. Thus, the mortality rate in metallic trades is 37.4 per cent.; that from organic dust is 23.7 per cent.; from mineral dust, 28.6 per cent.; from vegetable dust, 27.4 per cent.; from animal and mixed dust, 32.2 per cent.; in all dusty trades, 28 per cent. Industrial Poisons. — ^Many poisons are either pror duced or found in industries and industrial processes. INDUSTRIAL POISONS 203 The list of principal poisons published by the Depart- ment of Commerce and Labor includes over fifty, among which lead, arsenic, mercury, zinc, phosphorus, and chromium undoubtedly cause the greatest injury. Lead. — ^There are innumerable trades in which lead is used in one form or another, and the workers often suffer from lead poisoning. Lead enters the system chiefly through the digestive tract, but also through the lungs and skin. The effects of lead poisoning are the following: constipation, abdominal cramps, or lead colic, anemia, blue line on the gums, pain in the joints, temporary blindness, "wrist drop," loss of motive power in hands and feet, progressive muscular paralysis, multiple neuritis, leading sometinjes to con- vulsions and insanity. The workers most frequently affected are those who work in the lead factories and smelting works, printers, type-founders, lithographers, potters, enamel makers, plumbers, painters, glass, gold, silver, and patent leather workers. The laws protecting workers from lead poisoning in this country are very inadequate. Women and children suffer more from lead poisoning than men, as their suscep- tibility to the poison is much greater. Arsenic. — ^This poison is extensively used in the arts and. trades. Arsenic affects the skin, the digestive tract, and the respiratory and nervous systems. The effects of arsenic are skin eruptions, catarrhal inflam- mations, colic, indigestion, nerve disturbances, pro- gressive muscular atrophy, etc. Mercury. — ^Mercury is used in many trades and may injuriously affect the workers. They come in contact with it in quicksilver, gold and silver mines, in the 204 THE IfYOIENE OF OCCUPATIONS manufacture of barometers, thermometers, electric meters, in the manufacture of drugs, in the felt and fur industries, in the manufacture of artificial flowers, in powder works, in photography, and in various chemical works. Mercury is introduced into the system by inhalation of the fumes, by ingestion of the salts, and by absorption through the skin. The effect of mercurial poisoning is manifested in stomatitis, gastric disturbances, a metallic taste in the mouth, ulceration of the gums, nerve paralysis, loss of memory, and other nervous disturbances. Phosphorics. — ^The danger of phosphorus poisoning is limited almost entirely to workers in match factories. Its effects are manifested in gastric disturbances and in caries of the teeth, and necroses of the bone of the jaw. Under the present federal law the manufacture of poisonous phosphorus matches is to be eliminated entirely. Other Poisons. — ^There are several other poisons which injuriouslj' affect the workers. Among these the most important are chromium, zinc, aniline, and others, which are employed principally in the chemical trades. Gases, Fumes, and Vapors. — ^There are also many industries in the processes of which dangerous gases, fumes, and vapors are produced. Some of the principal gases and substances from which injurious fumes arise, are: sulphuric acid, sulphuretted hydrogen, and other sulphur compounds; carbon monoxide, . carbon dioxide, carbon bisulphide, and other carbon com- pounds; nitric acid, hydrochloric acid, ammonia, chlorine gas, iodine, bromine, petroleum, benzine, nitrobenzbl, aniline dyes, and all coal-tar products; INDUSTRIAL BETTERMENT 205 chromium, potassium, alum, iron, lead, turpentine, cyanogen compounds, dynamite, etc. The dangers from gases and fumes depend on the toxicity of the substances, the irritating nature of the fumes, their corrosive action upon skin and mucotis membranes, the danger from burns, scalds, and ex- plosions, and finally upon the excessive temperatures of the places in which these gases are generated. The way in which these gases enter the system differs from that of dusts or poisons. While dust acts prin- cipally upon the respiratory system, gases and fumes have specific action upon the eyes, mucous membranes, and the blood. Some of the fumes which are the prod- ucts of various industries act as virulent poisons, and their action may prove fatal within a short time after exposure, as, for instance, after inhaling gases like carbon monoxide, .sulphuretted hydrogen, bromine, chlorine, cyanogen, etc. The effects of irritating gases and fumes upon the eyes, the skin, and mucous membranes are very marked in the numerous skin affections, erosions of the mucous membranes of the nose and mouth, and the various ulcerative and in- flammatory changes in the skin of hands, fingers, face, and arms. INDUSTRIAL BETTERMENT In order to prevent the injurious influences of pre- vailing industrial conditions and to promote the health of the workers many of the industrial evils which have been enumerated must be abolished, by means of proper legislation for the protection of 206 THE HYGIENE OF OCCUPATIONS workers, strict enforcement of the law, and the spread of education among both employers and workers. Many of the industrial factors which are inimical to the health of the employees are neither necessary nor unavoidable and can easily be prevented by proper care and thoughtfulness on the part of the employers or managers. Many other injurious influences can be avoided by special devices and protective care. In the following pages an attempt is made to give a brief summary of the vast subject of industrial betterment and workers' welfare. Age. — ^No child under sixteen is physically ripe for continuous muscular exercise, and no child under that age should be permitted to be at work in gainful occupation. The period of life between six and sixteen should be devoted to physical, mental, and moral train- ing, growth and development, and not to the economic exploitation of the child. Sex. — ^There should be legislative restriction (1) of the kind of work women may do, (2) of their hours of work, (3) of their work during certain periods. Women's work in many forms of labor, especially when there are abundant dusts, specific poisons, and extra hazardous machinery, should be either entirely prohibited or greatly restricted. The consensus of opinion of all investigators is that eight hours of daily work should be the limit for female labor and that night work for women should be entirely prohibited. It also goes without saying that women should not work during pregnancy or during lactation, and that special provision should be made for women during their monthly semipathological periods. THE WORKPLACE 207 Home Work. — Home work is at present greatly re- stricted in many States. The aim should be to abolish it entirely, as the home should not be converted into a workshop. Selection of Trade. — ^With a proper system of primary and industrial education and fundamental guidance, the selection of a proper trade in conformance with the physical condition of the worker would be greatly facilitated. A rigid preliminary physical examination by competent medical examiners would prevent the entrance of the physically unfit or of weaklings into a trade which requires robustness, great physical power, and endurance. Education. — ^The education of workers in matters of personal hygiene, in the protection of their own health and lives, and in the avoidance of the injurious influences of industry, would be a great gain and would prevent many industrial diseases and resultant evils. The Work Place. — ^The sanitation of the work place is of the utmost importance to the worker and should be under the supervision of State authorities, who should require a license for the establishment of fac- tories and workshops. The licenses should be con- ditioned upon the proper construction, size, plan, and arrangement of the building. The walls, floors, ceilings, and all other surfaces in factories should be smooth, without crevices, nooks, corners, mouldings, etc., and should be finished with some non-absorbent, light-colored material, easily washed off and cleansible. Special care should be given to fire protection and the avoidance of dangers from fires and panics. The 208 THE HYGIENE OF OCCUPATIONS height of the buildings in which factories are located should be limited, and the number of occupants on each floor should be limited also. The construction of all buildings where a large number of workers are congregated should be absolutely fireproof, with an installation of all modern fireproof devices, such as automatic fire sprinklers, extinguishers, etc. There should be ample means of exit, which should be enclosed in fireproof partitions, and there should be on every floor a zone of safety to which the workers may escape to remain there for a certain period during fire or panic. Frequent fire drills are also necessary in order to insure discipline among the workers and to prevent panics. The provision for proper light and illumination of factories should be in the hands of capable illuminating . engineers and the intensity of light for a given place should be properly calculated according to the various exigencies of each trade. Artificial illumination should be controlled so as to avoid the glare which is likely to injure the eyes of the workers or to cause undue eye- strain. Special provisions for insuring the purity of the air in shops should be taken by compulsory provision of artificial illumination and ventilation in all factories where a large number of persons are at work. The greatest care should be taken in providing ample washing facilities, a pure water supply, a sufiicient number of dressing rooms, and properly cleaned and well-flushed toilet accommodations. The cleaning of the work rooms should be the duty of specially appointed persons, and should be carried PREVENTION OF DUST 209 out by methods which prevent the raising of dust and insure cleanliness in the shops. There should also be some provision in especially large factories for rest rooms, emergency rooms, first aid and hospital service, and also for lunch rooms and some forms of periodic recreation. Prevention of Specific Occupational Dangers. — To prevent industrial infection from hair, hides, clothing, etc., all suspected material must be thoroughly dis- infected and fumigated, and the employees must be taught to take proper precautions in handling such products by explaining to them the modes of infection. Prevention of Dust. — ^The evil effects of dust in in- dustry may be prevented by the following measures: 1. Separation of the dusty processes from the less dust-producing processes and the isolation of these dusty processes in specially constructed rooms. 2. The instant and continuous removal of aJl dust created at the place of production, by special vacuum hoods and tubes covering every dust-pro- ducing process, all dust being exhausted by fans operated by one central motor. 3. Substitution of machinery for handwork in all processes where the workers are exposed to dust and where mechanical means which will cover the dusty process and prevent the dust from coming in contact with the workers, cannot be devised. 4. Substitution of the wet method for dry produc- tion, that is, all materials producing dust, should be well moistened during the process of manufacture. 5. By isolating the worker from the dusty process. This may be accomplished by separating the worker 14 210 THE HYGIENE OF OCCUPATIONS from the dust-producing process by a glass or other partition or screen, and by inducing each worker to wear properly adjusted respirators in order to prevent the entrance of the dust into the nostrils and mouth. Prevention of Poisons, Gases, and Fumes. — ^The pre- vention of the effects of industrial poisons, gases, and fumes does not differ in principle from the pre- vention of injury from dust. There are a number of poisons for which non-toxic substances may easily be substituted. This has been done already in a number of cases. Yellow phosphorus, now prohibited in manu- facture, has been replaced by red phosphorus; nitrate of silver has been substituted largely for mercury in the manufacture of mirrors; and in pottery produc- tion a leadless glaze is now being introduced. The removal of gases and fumes may easily be accomplished by means of proper ventilating devices. Prevention of Accidents. — The prevention of accidents due to machinery and other causes is a most important part of industrial hygiene. Motors, engines, and fly- wheels should be fenced in and provided with proper guards and rails. Wheels, shafts, drums, belts, gearings, etc., should be enclosed and protected by special de- vices. There should be in every establishment a rigid inspection by the foreman and by experts in the proper safeguarding of machinery. Factory Inspection. — Factory inspection is already a recognized State institution, and has done much toward the amelioration of the conditions of labor. In order to increase its benefits, part of the control of industries should be in the hands of qualified physicians. Medical factory inspection is a*demand INDUSTRIAL INSURANCE 211 of modern industrial hygiene no less than medical school inspection. Comprehensive medical factory inspection embraces the following features: State licensing of trades and industrial establishments; pre- liminary physical examination of applicants for em- ployment; periodic medical inspection and examina- tion of workers; exclusion of all who are physically unfit, or suffering from incipient disease; sanitary inspection of places, of trades, and all sanitation. Medical factory inspection is already established in. many European countries where its great value in relation to public health has already been recognized. Public control of environmental conditions, improve- ments in the housing of the working classes, spread of education, better systems of popular nutrition, and similar sanitary improvements are already in- cluded in the duties of social workers and form a part of public health progress. Industrial Insurance. — ^Finally, the promotion of public health demands the institution of new measures for the protection of the workers, as well as the general community, by means of compulsory industrial insur- ance. Insurance against accidents, against sickness, against death, against unemployment, and similar insurance is already in vogue in many countries, and this principle is rapidly spreading and promises to become one of the most important elements in industrial legislation and industrial welfare. CHAPTER VI THE HYGIENE OF MUNICIPALITIES GROWTH OF CITIES AND HEALTH Forty-two per cent, of the entire population in the United States works and lives in cities. The urban population has been steadily increasing and is still growing at the expense of rural communities. Four or five of the largest cities in the United States have as large a population as one of the European countries has. With the growth of cities and the concentration of population in large communities and congested areas, many problems have arisen. Not the least of these is the effect of large cities upon the health of the pop- ulation, and the increase of mortality and morbidity among their inhabitants. Ruskin's characterization of the city as a "great, foul, rattling, crawling, smok- ing, stinking, ghastly heap of fermenting brickwork oozing poison at every pore" is perhaps too strong to be applied to all cities, but it is graphic and illus- trative of certain aspects of large cities and of city life. Municipal hygiene deals with the problem of the prevention of disease caused by congestion and over- crowding, and with the promotion of the health of the GROWTH OF CITIES AND HEALTH 213 citizens of municipalities. According to the census, the average annual mortality per thousand in the United States in 1900 to 1909 was 17.1 in cities and 14.2 in rural communities. In some of the cities this mortality was much greater, especially so in the larger and more overcrowded cities. The rate of mortality from tuberculosis is also much higher in cities than in the country, and with the exception of typhoid fever this is also true of a great many other infectious diseases. The greater unhealthfulness of city life is due to the overcrowding and congestion of population; the lack of air and ventilation in the city houses; the diffi- culties of obtaining supplies of fresh water, meat, milk, and other necessities of life; the difficulty of a proper disposal of waste, garbage, and other city refuse; the presence of a great many offensive trades and public nuisances; the rapid spread of infectious diseases; and the many other conditions which exist in most cities. Municipal hygiene has made rapid strides within the last few decades and in most cities the inhabitants have at last realized that proper attention to hygienic needs will result in decreased death and disease rate and pay for itself in the greater efficiency and health- fulness of the population. A number of institutions in every city have been created for the purpose of promoting the health of the community and of preventing disease, premature death, and accidental injuries. The following is a resume of some of the hygienic activities in municipalities: 214 THE HYGIENE OF MUNICIPALITIES 1. Control of public supplies. (a) Provision for a public water supply and its purification. (6) Controlof the food supply; meat inspection; slaughter-house inspection; control of the milk supply, milk inspection; general food inspection. 2. Disposal of waste matters. (a) Collection and disposal of house refuse, garbage, and rubbish. (b) Collection and removal 'of street sweepings and snow. (c) Collection and removal of drainage and sewage. 3. Control of public utilities: highways, roads, streets, transportation, etc. 4. Control of offensive trades and public nuisances. 5. Promotion of health by the provision of parks, play- grounds, baths, etc. 6. Control and prevention of the spread of infectious disease. In many municipal activities the nurse has become an integral part. In some cities she is found in the street cleaning, in the housing, in the health, in the school, in the park, and in other departments, and her functions and usefulness are constantly being extended. Control of Public Supplies. — Public Water Supply. — The necessity for the provision of a large water supply in cities is obvious. From thirty to fifty gallons of water are needed for the average uses of each city inhabitant. A much larger supply is provided for in many cities. CONTROL OF PUBLIC SUPPLIES 215 The problem of a public water supply consists of the proper collection, storage, purification, and dis- tribution of water. The public water supply sources relied on by many cities are the natural or artificial water reservoirs, or collections of surface waters, and rivers, streams, lakes, and ponds, which are usually found at a great distance from the towns which they supply. The construction and maintenance of the water- sheds, reservoirs, etc., as well as the aqueducts which conduct the water into the cities, are within the province of the sanitary engineer. The function of the health authorities is to guard the water-sheds and to prevent the contamination of the ground near these and the pollution of the water by sewage, etc. To accomplish this the sewage of places near the sources of water supply must be disposed of properly, and precautions must be taken that the employees, and others in charge of water works, deposit their excreta in such a way as not to pollute the surface near the water-sheds. It is very rare, however, to find surface waters available for large cities which are entirely free from impurities or from organic pollution. It is necessary for the improvement of the health of the community to purify all surface waters. There are four principal methods of water purification for large cities: (1) slow sand filtration; (2) rapid mechan- ical filtration; (3) coagulation with precipitation and storage in large reservoirs; (4) disinfection by hypo- chlorites of lime and soda and by ozone and by ultra- violet rays. 216 THE HYGIENE OF MUNICIPALITIES Control of Food Supply. — As large quantities of food, meat and meat products, milk and milk products, vegetables and fruits, etc., are brought into the city daily, the problem of a public control of the food supply is of great hygienic importance. The control of the meat supply includes (1) ante- and postmortem inspection of the slaughtered animals; (2) sanitary inspection of the slaughter houses; (3) inspection of the places where meat-food articles are prepared and manufactured; (4) the sanitary inspection of the markets, butcher shops, etc., in which the meats and meat products are stored and sold. Owing to the danger of the contamination of the milk supply and to the frequent spread of disease by impure milk, the problem of the control of the city milk supply is very important. Some cities obtain their supply of milk from very great distances. Several large cities have recently adopted a system of controlling the sources of the milk supply by means of the sanitary inspection of dairy farms and creameries, of veterinary inspection of the cows, and a system of scouring the various places where milk is produced, stored, and shipped. The control of the city milk supply is accomplished by a proper inspection of the places where milk is stored, distributed, and sold, and by the introduction of a system of milk inspection and milk tests which have been inaugurated in almost every large city. In many cities provision is made also for the supply of pure milk to infants and children at a reason- able charge. The milk stations furnishing this have DISPOSAL OF WASTE MATTERS 217 become an established institution and ha\'e been a great factor in the reduction of the infant mortality rate. Disposal of Waste Matters. — The problem of the collection and disposal of the enormous quantities of city waste materials is a serious one. The waste materials consist mostly of fluid and semifluid refuse, sewage, ashes, garbage, rubbish, street sweepings, snow, etc. Thousands of tons of these are daily collected and disposed of. This is accomplished by various means according to the character of the waste material. Ashes, garbage, rubbish, street sweepings, and snow are collected in barrels and receptacles and carted away; sewage is collected in plumbing pipes and is disposed of through the city sewage system. The present methods of collection possess many faults. The ultimate disposal of the city waste materials is accomplished by dilution, utilization, and cremation. In many large cities the fluid sewage and refuse as well as the ashes, garbage, snow, etc., are emptied into the large water courses, such as lakes, seas, and oceans. This is a comparatively easy method of disposal, but it is not without many serious objections. As a great part of the refuse is of value, an attempt has been made in many cities to sort the waste materials, which are utilized for various purposes, in order to collect those of value. Perhaps the most hygienic method of disposing of most of the city waste mate- rials is by cremation in appropriate incinerators and crematories. The problem of ultimate sewage dis- posal has been referred to in Chapter II. 218 THE HYGIENE OF MUNICIPALITIES Control of Offensive Trades and Public Nuisances. — A number of trades which are carried on in cities may become oflFensive because of their odors, effluvia or gases, fumes and waste products. The trades which may become a pubHc nuisance are (1) the keeping of Hve animals; (2) the kiUing of animals; (3) the sale of animal matter; (4) the sale of animal products. The keeping of animals in cities may become a nuisance, and is carefully regulated by sanitary author- ities by means of veterinary supervision of the animals, prohibition of the keeping of certain animals within city districts, the restriction of stables, etc., in certain districts, and by means of the rules for the removal of manure and other refuse. The health authorities also carefully regulate the places where animals are killed and where animal products are manufactured, prepared, and sold. Other public nuisances, such as unnecessary noises, smoke from factories, gases and fumes, etc., are pre- vented by the city health authorities through their sanitary code and the police power of the city. Promotion of Health by the Provision of Parks, Play- grounds, Baths, etc. — The prevention of injurious influences is not the only function of municipal hygiene, which should also seek to promote the health of the citizens by the provision of parks, play- grounds, municipal baths, recreation piers, etc. Great density of population makes it necessary to provide for breathing spots in the form of public parks, and of grounds for the recreation and play of the growing population. THE SPREAD OF INFECTIOUS DISEASE 219 The provision for municipal baths in the form of shower-bath houses and ocean and sea-bathing facih- ties has contributed greatly to the promotion of the health of the city population, especially of that part which is unable to have these facilities at or near home. In most of these various provisions the trained nurse has a direct interest, not only because of their effects upon the general health, but also because she takes part actively in the work. At present a number of nurses are employed in the various city inspection forces, in the tenement and health departments, in the milk stations, in the parks, playgrounds, and in other similar institutions. Control and Prevention of the Spread of Infectious Disease. — ^The measures adopted in modern munici- palities to control the spread of infectious diseases may be summed up as follows: (1) Notification; (2) isolation; (3) quarantine; (4) inoculation; (5) disin- fection; and (6) education. Notification. — ^Before sanitary authorities are able to cope with infectious disease they must first know of its existence. Hence, the sanitary code of all municipalities makes stringent provision for the notifi- cation of the authorities, by physicians and others, of the occurrence of any infectious disease. The notifi- cation must be prompt and should apply to a large number of infectious diseases, although the laws as to the number of diseases to be reported on are not uni- form. The following diseases are reported in almost all municipalities: smallpox, scarlet fever, diphtheria, cholera, measles, croup, typhoid, typhus, epidemic meningitis, tuberculosis, erysipelas, septicemia, etc. 220 . THE HYGIENE OF MUNICIPALITIES Isolation. — In order to prevent the spread of the infectious disease, the victim of the disease must be isolated and prevented from coming in contact with healthy persons. This is especially needed in densely crowded districts of the city. The degree of isolation depends much upon the disease, the character of the dwelling in which the patient lives, and the intelligence of those who surround the patient. When- ever the disease is too virulent or the patient is placed in surroundings that make it impossible to isolate him properly, municipal authorities may compel the re- moval of the patient to a hospital. The duration and the manner of isolation depend upon the character of the disease and may last from a few days in a case of diphtheria to a few months in a case of scarlet fever. Quarantine. — ^This term designates the restrictive measures which prevent the introduction of diseased persons from one locality to another. The term is derived from the French word quarante, forty, the number of days vessels were detained in the first Venetian quarantine. Quarantine may be either national, State, or municipal, each community im- posing certain restrictions on the incoming people who arrive by railroad or by ship and who may be suffering from infectious diseases. Quarantine principally concerns International and Interstate Commerce, and is only rarely applied to cities. Inoculation and Serum Treatment. — In many muni- cipalities the Boards of Health have adopted pro- phylactic and curative methods of treating certain infectious diseases. The sanitary authorities supply diagnosticians, take cultures, make reports upon the THE SPREAD OF INFECTIOUS DISEASE 221 cultures, make curative injections of various sera, and also inoculate persons against certain diseases. In New York City this is at present done in cases of typhoid fever, etc. Disinfection. — Municipal authorities also disinfect and fumigate houses and infected objects. The dis- infection of rooms wherein infected persons are kept is made a routine practice in most of the cities. The methods of disinfection have already been referred to in the chapter on Housing Hygiene. Education. — Perhaps the most important function in the municipal prophylaxis of infectious diseases is accomplished by the educational measures undertaken in many cities, through the visiting nurses appointed for this purpose, and through the various bulletins and instructions which are issued from time to time by the authorities. Every case reported by a physician is visited by a competent nurse, who instructs the patient and his caretakers in the proper methods of cleaning, disinfection, and care of the patient and the infected objects. The diffusion of public education in regard to infectious diseases, and the effective work of trained visiting nurses, are the most important means of combating their spread. CHAPTER VII PERSONAL HYGIENE Personal hygiene is the science and the art of the preservation and promotion of individual health, and depends on two main factors: the prevention of con- stitutional diseases and the increase of the vital forces and resistance of the human body. Prevention of Constitutional Diseases. — ^A number of diseases are within control of the individual, who by proper care and forethought may prevent their occurrence. Among these diseases are a number of respiratory, digestive, circulatory, nervous, and other diseases, many of the contributing or predisposing causes of which are due either to excess or to direct violation of the principles of hygiene. Exposure to wind, rain, and external elements; exposure to dampness, drafts, and inclement weather may lead to bronchitis, pleurisy, pneumonia, and other respiratory diseases. By avoiding exposure and strong changes of temperature, by proper clothing and exercise of the body, by avoidance of drafts and dampness, and by protecting one's self against inclement weather many of the respiratory diseases may be avoided, if not entirely prevented. Moderation in food, slow mastication, selection of simple and digestible food products, moderation in INCREASE OF VITAL FORCE AND RESISTANCE 223 the use of intoxicating beverages, and similar pre- cautions, would greatly diminish the suffering from the digestive diseases to which so many succumb. Gas- tritis, intestinal troubles, and many diseases of the kidney, as well as the liver, are undoubtedly due to excess in diet and to indulgence in alcohol. The avoidance of too strenuous muscular activities, of strain and overuse of certain muscles and organs, prevention of the fatigue caused by hard labor and toil, the taking of proper rest at regular intervals, are all valuable prophylactic measures in the prevention of cardiac diseases, which cause so much suffering and so many deaths. Similar precautions, with the addition of avoiding too much strain in the pursuit of occupation, the taking of proper periods for recreation and rest, the avoiding of unnecessary stimulants and worry and anxiety, would greatly tend to the prevention of many nervous and mental diseases. If many of the constitutional diseases which count their victims by thousands and tens of thousands were analyzed, it would probably be found that more than one-half of these are preventable and can be avoided because they are due to the so-called "sins of civilization." Among these are gluttony, the use of alcohol, the use of other stimulating or sedative poisons, sexual overindulgence, and the hurry and scurry of modern life. Increase of Vital Force and Resistance. — ^The other most important factor in personal hygiene is the in- crease of the vitality and resistance of the body. Diseases, whether caused by environmental conditions 224 PERSONAL HYGIENE or by constitutional causes, can only affect the indi- vidual when his resistance is very low. The robust person in perfect health can withstand a great deal of exposure, of shock, and the results of overindulgence, while the weak and anemic will succumb to the slightest colds or digestive disturbances. The person with a strong vital resistance can withstand the effects of great strain, nervous tension, and bodily fatigue to which a person with less resistance would fall a victim. The germs of infections are ubiquitous, and are always with us. Many if not most persons carry the germs of tuberculosis, diphtheria, typhoid, and other infec- tious diseases. While some of them fall a prey to these diseases, others seem to carry the germs with impunity. The secret of the health of many persons is in their individual strength, in their vital force, and in their development of resistance. What are the secrets of individual health and of the increase of vital force and resistance? Scientists differ in their opinion and doctors disagree in their verdict. Many theories are advanced and many formulas of life are advocated. All agree that of the many pro- phylactic measures, none are of such importance as exercise and moderation. Moderation in the exercise of all bodily functions is absolutely necessary for the in- crease of vital resistance and the prevention of disease. Bathing and the care of the skin is important and tend to increase vitality. Warm and temperate baths for cleanliness and sanitary purposes, cool and cold baths, as well as daily sponging of the body with cold water, all tend to inure the body against colds, and to promote the cardiac and circulatory functions. PERSONAL HYGIENE OF THE CHILD 225 Proper breathing exercises at stated intervals and in the open atmosphere tend to increase the respiratory activities and to strengthen respiratory resistance. Muscular exercises with a view to using all the muscles of the body tend to strengthen the muscular system, to increase the vital activities of the body, to improve its circulation, and to make it more resistant to exposure and cold. These are the general and fundamental principles upon which individual hygiene is based. It is more important to comprehend them than to prescribe special rules and regulations for proper living, which can hardly be made so general as to apply to all con- ditions and persons, and in the application of which so many hygienists differ and disagree. The applica- tion, however, of these principles may differ somewhat according to the sex, age, and degree of health of various persons. Personal Hygiene of the Child. — ^This differs in its practical application according to age. There is neces- sarily a difference in the rules and regulations for the care and promotion of health of infants, of children under school age, of school children, and of adolescents. The general principles, however, are identical with those which . have been described as relating to all persons, whether children or adults. The rules of health are essentially those of proper feeding, clothing, exercise, bathing, and physical and mental training. Infants and young children demand more attention and closer supervision than do the older children. Milk and milk foods are almost the exclusive articles of food for infants under one year. There is at present 15 226 PERSONAL HYGIENE a tendency to regard the digestion of raw cows' milk as difficult in view of its immediate curdling within the stomach. The objections against pasteuri- zation and sterilization of milk for infants' foods are not considered serious. The modification of milk by changing the percentage of the proteid and fat con- stituents has become a regular practice in infant feeding. As to the clothing of infants, the opinion seems to prevail that woollen garments have the advantage over cotton and linen. The exposure of the legs or other parts of the body is to be avoided. Bathing in tepid water, 100° to 110° F., is best done before the last feeding in the evening. Regularity in the discharge of the bowels should be encouraged. Sponging with water, 70 to 90° F., is a good routine practice in the morning. As the child grows older, cereals, fruits, vegetables, and bread products may be added to the diet. The feedings should be at regular periods. Evening bath- ing in tepid water and morning sponging with cool water should be continued, and physical exercise and play should be encouraged. Young infants as well as older children should be kept in the fresh air as much and as long as possible. Outdoor play and exercise for older children should be encouraged. Sugar and confectionery seem to be well borne and digested by children. They should not be used in excess, however, or in the intervals between feedings, but should be given during each feeding. A slight rise of temperature in children is no indication of pathological conditions, as it may be PERSONAL HYGIENE OF THH AGED 227 caused by overfeeding, constipation, diarrhea, excite- ment, etc. The care of infants and children during sickness cannot be discussed here. The hygiene of the school child has been discussed in Chapter IV, but mention must be made here of the care of school children in their homes. The gain is slight if hygienic conditions surround the child in the school, but are neglected in the home. Instruc- tions should be given to mothers in the care, feeding, etc., of the school child while it is in the home, so as not to counteract the beneficial influences of school life. The most important rule for the care of the school child while in its home is the proper provision of sub- stantial and digestible breakfasts so that the child does not leave the house fasting or hungry. After the child is confined within the school for a number of hours it is the duty of its parents to keep it in the fresh air and to allow it to play and exercise outdoors during the part of the day when it is out of school. Too many children are given home tasks and too many children are unfortunately compelled to do some home work during the afternoons and evenings after school hours. During adolescence the nervous equilibrium is easily disturbed and much intelligent care is necessary to prevent nervous breakdown. Intelligent instruction in the elements of physiology and in sexual, hygiene is necessary for the promotion of the health of the child and for the prevention of various indiscretions and abuses. Personal Hygiene of the Aged. — ^The personal hygiene of the aged differs greatly from the hygiene of younger 228 PERSONAL HYGIENE persons. There is considerable difference in the exact age when a person seems or becomes old. Some are old at thirty, while others are young at seventy; nor does old age come on suddenly without previous due notice. Rather it creeps on gradually and slowly. A person is said to be as old as his heart and his arteries. The main indications, therefore, for the care of the aged is in the care of the circulatory system and the prevention of overstrain and fatigue. Indiscretions, overindulgence, exposure and irregu- lar life are more dangerous in the old than in the young, for the recuperative powers are much lessened in the aged. Much less sleep is needed by the aged, although more prolonged periods of rest are necessary. Too strenuous exercise must be avoided. There is need of much less food and there is greater danger from overfeeding. Bathing with cold water must be done with care, and perhaps avoided, unless the body is accustomed to the effects of cold water. The effects of certain shocks are dangerous. Warm woollen clothing should be worn in moderate as well as in cold weather. The best exercise for the aged is walking outdoors. Golfing is considered a good exercise for the aged who can afford it. There are very few hard and fast rules for the aged as for the young. Constitutional differences and environmental condi- tions invalidate universal and uniform laws of health. Personal Hygiene of the Sick. — ^The rules guiding the nurse in the care of the ill, the convalescent, and the diseased must necessarily differ according to the age and condition of the sick person, and especially accord- THE SICK BOOM 229 ing t6 the character, degree, and severity of the disease from which the person suffers. Here, again, common- sense and intelligence are perhaps more important than set ryles.and regulations. The feeding of sick persons must be done with care and according to the instructions of the physician, who alone is competent to judge of the necessary amounts of food required as well as of the kinds of food needed. As a rule, sick persons need more digestible and better prepared foods, at more fre- quent intervals, than do well persons. The nurse should learn the art of preparing certain foods and articles of diet which are appropriate for the sick. The bathing of sick persons is a procedure which should be done only according to the directions of a physician. Cold water must be used judiciously and with great care. Bedridden patients need special care tp prevent bed-sores. This can be accomplished by proper care of the bed and bedding, by smoothing out all wrinkles in the bedding, by appropriate support under the sacrum and heels, which are the places prin- cipally affected by bed-sores, and by massage of the body and special parts of the body as well as by alcohol rubs, inunctions, etc. The Sick Room. — Too much care cannot be given to the sick room. The room should be located in the part of the house which is the least noisy and which is sep- arated as far as possible from the other parts of the house. The room should be exposed to the sun, to the south side if possible, but the glare of the sunlight should be regulated and modified by shades. The room should be devoid of stuffy curtains, 230 PERSONAL HY&IENE carpets, rugs, and heavy and upholstered furniture, and should be simply furnished with as few articles of furniture as possible. Fresh air should be admitted into the room by open windows without disifts. In cold and inclement weather the placing of a board under the lower sash of " the window will insure the entrance of air in the opening between the upper and lower window sashes, without danger of drafts. Artificial illumination should be subdued and free from glare. All surfaces, wallsj ceilings, and floors should be .smooth and non-absorbent, and should be wiped daily with damp cloths. The use of carbolic acid, lysol, and other malodorous disinfectants which give the specific odor of the sick room should be avoided. Their use is unnecessary; they give a false sense of security without preventing the spread of infection. In infectious diseases the mode of the spread of infection from each disease should be known and proper precautions taken for its preven- tion. This cannot be done by promiscuous spraying or sprinkling with ill-smelling disinfectants. Dis- charges from tuberculous or typhoid patients should be placed in paper receptacles which may easily be burned and destroyed. Fresh air, good ventilation, good light, and absolute cleanliness in the sick room are better than deodorization or disinfection. INDEX Acetylene gas, 26 Air, 28 carbon dioxide in, 31 composition of, 28 diffusion of, 33 humidity of, 29 impurities of, 29 influences of, on health, 30 moisture in, 29 quantity needed, 32 value of chimneys for, 33 Anderson, Dr., on death rate in apartments, 24 Artificial light, 25 B Bacteriology, 19 Berkefeld filters, 53 Butter and buttermilk, 137, 138 Caebolig acid, disinfection by, 93 Carbon dioxide in air, 31 poison, 28, 29, 74 monoxide poison, 74, 83 Cesspool, 57 Cheese, 141 Cholera, milk and, 128 Cities, 212 growth of, 212 unhealthfulness of, 213 Coal gas, 26 Condensed milk, 137 Cream, 141 Cresols, disinfection by, 93 Desiccation, disinfection by, 90 Diphtheria, milk and, 127 Disinfection, 221 boiling, 91 carbolic acid, 93 chemical, 92' corrosive sublimate, 94 cresolS; 93 definition of, 89 desiccation, 90 dry heat, 91 formaldehyde, 95 gaseous, 94 Ume, 9^ of rooms, 96 physical, 90 sulphur dioxide, 95 steam, 92 sunU^ht, 90 Domestic animals, 79 danger of, 80 prevention of, 85 Dust and dirt, 76 cleaning of, directions for, 88 methods of, 86 dangers of, 78 germs adhering to, 78 organic matter in, 79 prevention of, within the house, 84 Prudden on removal of, 77 232 INDEX Dust and dirt, sources of, 77 street, 76 Dysentery, milk and, 128 Education, 221 Electricity, heating by, 39 Electric light, 25 Factory inspection, 210 Filters, 52 Berkefeld, 53 character of filtering media, 52 materials used in, 52 Fisher, Prof. I., report on National Vitality, 22 Foods, 98 adulteration of, 109 beverages, 113 canning of, 109 care, storage, and preserva- tion of, 106 cereals. 111 chemical composition of, 98 composition of, table of, 102, 103 condiments, 113 cost of, 105 definition of, 98 drying, 108 fruit, 112 preparation of, 103 raw, cooked, and prepared, 105 saccharine preparations, 112 salting, pickling, smoking of, 108 sources of, 98 storage in house, 107 supply, control of, 216 temperature of, 107 values of, estimates of, 101 relative, 98 vegetable, 110 vegetarian, 104 Garbage, 73 Gas, 26 acetylene, 26 coal, 27 -fixtures, 28 lieating by, 39 service system, 28 water, 27 Gases and poisons, 74 carbon dioxide, 28, 29 74, monoxide, 74, 83 sewer gas, 75 wall-paper, 75 H Habitations, hygiene of, 24 Heat, dry, disinfection by, 91 Heating, 37 central, 39 electricity, 39 essentials of, 37 gas, 39 grates, 38 hot water, 40 local, 38 means and methods of, 37 steam, 40 stoves, 38 temperature regulation of, 41 House drainage, 54 Human hfe, increase of length of, 21 resources, conservation of, 20 Hygiene, 17 definitions of, 17 personal, 18, 222 of the aged, 227 of the child, 225 of the sick, 228 increase of vital forces by, 223 prevention of constitu- tional diseases by, 222 public, 18 Ice, 53 dangers of, 53 INDEX 233 Ice-box, 54 Infectious diseases, control of, 219 trades, control of, 218 Insects, 80 disease and, 80 prevention of, 85 Kefir, 141 Kumiss, 141 Light and illumination, 25 amount of, 25 artificial, 25 character of, 25 electric, 25 intensity of, 25 location of, 25 natural, 25 sources of, 25 M Measles, milk and, 127 Meat, 113 adulteration of, 117 dangers to health in, 113 fish, 122 good characteristics of, 117 hygiene of meat foods, 113 infection by bacteria, 115 objections against chemical preparation of, 119 parasitic diseases due to, 114 postmortem changes in, 116 poultry and game, 121 preservation of, 118 ptoraain poisoning, 115 sanitary supervision of, 120 tapeworm, 114 trichina, 114 unfitness of, causes of, 116 Milk, 123 adulteration of, 141 by chemicals, 144 Milk, adulteration of, by foreign matter, 143 by skim milk, 143 by water, 142 bacteria in, 125 conditions favoring growth of, 147 retarding growth of, 147 diseased, 126 lactic acid, 146 blended, 136 buttermilk, 138 cholera and, 127 condensed, 137 cows', 130 abnormal, 134 appearance of, 132 color of, 132 colostrum, 133 composition of, 130 fat in, 130 ferments and gases in, 131 fore-milk and strippings, 134 mineral matter in, 131 reaction of, 132 specific gravity of, 132 sugar, 130 variations in, 133 deterioration of, 144 causes of, 145 diphtheria and, 126 dysentery and, 127 examination of, 154 by Health Department lactometer, 159 by lactoscope, 157 by pioscope, 157 by Quevenne lactometer, 159 by specific gravity, 158 chemical, 161 cream gauge, 157 precaution in, 155 fermentation of, lactic acid. 146 frozen, 155 importance of, 123 industry in, 123 impurities of, character of, 124 infant diseases and, 126 234 INDEX Milk, inspection of, 154 measles and, 126 pasteurization of, 151 chemical, 152 powders, 137 preservation of, 144 by cold, 149 objections to, 153 products, 135 scarlet fever and, 126 skim 136 standards, 139 definitions of, official, 140 sterilization of, 150 testing of, 154 tuberculosis and, 128 typhoid fever and, 127 Mortality, 22 reduction of, 22 Municipalities, 212 hygiene of, 212 hygienic activities in, 214 municipal hygiene, 212 N Nurse's role in prophylaxis, 23 O Occupation and health, 190 accidents in, 210 betterment, 205 of children, 196 diseases of, 193 dust, 201 factors influencing health in, 195 gases, fumes, atid vapors, 204 insurance of, 211 morbidity of, 192 mortahty rate of, 191 physiological conditions of, 190 poisons, 202 prevention of dangers, 209 of dust in, 209 of poisons, gases, and fumes in, 210 specific dangers of, 201 Occupation, tuberculosis and, 192 of women, 196 Offensive trades, control of, 214 Pasteurization of milk, 151 Pettenkoffer, Prof., 19 Plumbing, 58 house-drain, 60, 67 kinds of, 59 materials for, 58 pipes, 60 soil-pipe, 68 waste-pipe, 69 Poisoning, carbon dioxide, 28, 29, 74 monoxide, 74, 83 ptomain, 115 sewer-gas, 75 wall-paper, 75 Privy vaults, 56 proper construction of, 57 Prudden on removal of dust and dirt, 77 Ptomain poisoning, 115 Pubhc supplies, control of, 214 utilities, control of, 214 Quarantine, 220 Quevenne lactometer in exami- nation of milk, 159 Sanitation, 23 definition of, 23 Scarlet fever, milk and, 127 School, 162 building, 167 child, 163 care of, 172 feeding and nutrition of, 174 person of, 174 crowding of, in, 166 INDEX 235 School - child, detection and correction of physical defects of, 174 diseases of, 165, 175 education of, in hygiene, 175 eyes of, 164 growth and age of, 163 malnutrition of, 165 mental training of, 172 physical culture of, 173 purpose of keeping of, 172 record of growth of, etc., 173 spread of diseases among, 176 teeth of, 164 cleaning of, 170 supervision of, 171 furniture of, 171 height of, 168 influence of, 163 lighting, ventilation, and heating of, 169 mechanical ventilation in, 169 nurse, diagnosis of defective hearing by, 188 teeth by, 185 vision by, 186 of nasal breathing by, 186 of tuberculosis by, 184 instruction of, for treat- ment of pediculosis, 179 of ringworm, 181 of trachoma, 181 sanitation, 167 size of, 168 subdivision of, 168 water supply in, 170 Sewage, 54 disposal of, 54, 57 methods of, 55 method of water carriage, 57 air and gas, 61, 62 gas poisoning, 75 Siphonage traps, 64 Skim milk, 136 Steam, disinfection by, 92 heating by, 40 SunUght, disinfection by, 90 Tapeworm, 114 Temperature, regulation of, 41 Trades, offensive, control of, 214 Traps, 63 definition of, 63 kinds of, 63 loss of seal in, 63 siphonage, 64 back pressure, 55 non-siphoning, 66 Trichina, 114 Tuberculosis, milk and, 128 Typhoid fever, milk and, 128 Ventilation, 32 definition of, 32 essential points of, 35 natural, 32 mechanical, 34 Vent-pipes, 65, 70 Vital statistics, 19 importance of, 20 W Waste matters, 73 water and sewage, 74 Water, 41 aqueducts, 48 -borne diseases, 44 composition of, 42 contamination of, 47 diseases and, 42 distillation of, 50 filtration of, 51 gas, 27 good, 44 hard and soft, 44 health and, 41 hot, heating by, 40 236 INDEX Water, hot, supply of, 49 house supply of, 48 impurities of, 42 in food, 49 need of, 42 parasites in, 43 polluting of, 50 purification of, 49 chemical means of, 51 rain, 45 sedimentation of, 50 subsoil, 46 supply of, sources of, 45 surface, 46 wells, 48 Water closets, 71 modem, 71 apartments, 72 Whey, 141 Window area of room, 25 Workplace, 197 cleanliness of, 200 congestion, 198 hygiene of, 207 light and illumination, 199 proper construction of, 198 sanitation of, 197 sufficient air in, 199 working conditions in, 200