TRANSCRIBER'S NOTE

Obvious typographical errors and punctuation errors have been corrected after careful comparison with other occurrences within the text and consultation of external sources. Misspellings in the text, and inconsistent or archaic usage, have been retained.

The original book had many illustrations embedded in the text on both the left and the right. On handheld devices all such illustrations are displayed on the right, to avoid some sidenotes overlaying the image.

PRINCIPLES OF
PUBLIC HEALTH

A SIMPLE TEXT BOOK ON HYGIENE PRESENTING THE PRINCIPLES FUNDA­MENTAL TO THE CONSERVATION OF INDIVIDUAL AND COMMUNITY HEALTH

By THOS. D. TUTTLE, B.S., M.D.

SECRETARY AND EXECUTIVE OFFICER OF
THE STATE BOARD OF HEALTH OF MONTANA

YONKERS-ON-HUDSON, NEW YORK

WORLD BOOK COMPANY

1910

CONSERVATION OF HEALTH

"Our national health is physically our greatest asset. To prevent any possible deterioration of the American stock should be a national ambition."—Theodore Roosevelt.

The conservation of individual and national health is the keynote of these books

PRINCIPLES OF PUBLIC HEALTH

By Thos. D. Tuttle, M.D., Secretary and Executive Officer of the State Board of Health of Montana. Illustrated. Cloth. vii + 186 pages. List price 50 cents, mailing price 60 cents.

PRIMER OF HYGIENE

By John W. Ritchie, of the College of William and Mary in Virginia, and Joseph S. Caldwell, of the George Peabody College for Teachers, Nashville, Tennessee. Illustrated. Cloth. vi + 184 pages. List price 40 cents, mailing price 48 cents.

PRIMER OF SANITATION

By John W. Ritchie. Illustrated. Cloth. vi + 200 pages. List price 50 cents, mailing price 60 cents.

HUMAN PHYSIOLOGY

By John W. Ritchie. Illustrated in black and colors. Cloth. vi + 362 pages. List price 80 cents, mailing price 96 cents.

WORLD BOOK COMPANY

CASPAR W. HODGSON, Manager

YONKERS-ON-HUDSON, NEW YORK

Copyright, 1910, by World Book Company. All rights reserved

[INTRODUCTION]

The earliest history of remote ages describes methods employed in combating disease, and down through all the centuries the struggle against infection has been going on. The science of health as applied in recent years reveals wonderful progress in the avoidance of disease, and in the control of the violent epidemics by which in the past nations were almost exterminated. Modern methods of hygiene and sanitation as applied to public health have robbed smallpox and diphtheria of their death-dealing power; cholera and yellow fever have been forced to retreat before the victorious hosts of applied medical science; tuberculosis, the greatest foe of human life, is slowly but surely receding before the determined efforts of modern preventive medicine.

By nature man is endowed with resistive power sufficient to ward off most forms of disease, provided he keeps his health at a normal standard by right living. If, however, he allows his health to become impaired by reason of overwork, bad habits, wilful exposure to contagion or unhealthful surroundings, he readily falls a prey to disease.

The author of Principles of Public Health has here set forth the general rules of life by the observance of which every adult and every child not only can do much to preserve his own health but also can prove himself a prominent factor in raising the standard of public health. A campaign of education is demanded to arrest the enormous loss of life which is carrying so many to untimely graves, and the instruction given in this volume will be of inestimable value in teaching people how to avoid avoidable disease.

The author has not attempted to deal with all the diseases that may be classed as preventable; as the work is intended for use in the public schools, only such diseases are mentioned as it seems fitting to present to school children. To teach our children a proper respect for their own health and for the community welfare is to fit them for the best citizenship.

E. A. Pierce, M. D.

Portland, Oregon

[ACKNOWLEDGMENTS]

The author wishes to express his sincere appreciation of the valuable assistance rendered in the preparation of this work by Dr. S. T. Armstrong, of New York City; Dr. H. Wheeler Bond, Commissioner of Health, St. Louis, Missouri; Dr. H. M. Bracken, Secretary and Executive Officer of the State Board of Health of Minnesota; J. S. Caldwell, Professor of Biology, George Peabody College for Teachers, Nashville, Tennessee; R. J. Condon, Superintendent of Schools, Providence, Rhode Island; Mrs. Nona B. Eddy, of the Public Schools of Helena, Montana; Dr. F. M. McMurray, of Teachers College, Columbia University, New York City; Miss Jessie B. Montgomery, Supervising Critic in Training School, State Normal School, Terre Haute, Indiana; Dr. E. A. Pierce, Secretary and Executive Officer of the State Board of Health of Oregon.

[CONTENTS]

PART I
THE FIGHT FOR HEALTH

[CHAPTER I]
CONSTANT DANGER OF ILLNESS

Every boy and girl confidently expects to grow into a strong and healthy man or woman. How often we hear a child say, "When I am a man," or "When I am a woman;" but I have never heard a boy or a girl say, "If I live to be a man or woman." When you think of what you will do when you are grown into men or women, it never occurs to you that you may be weak and sickly and therefore not able to do the very things that you would most like to do. This suggests that sickness is not natural, else the thought that you may perhaps become sick would enter your mind. As a matter of fact, most sickness is not natural.

The fight for life

There is a constant struggle going on in the world. You see a fight about you every day among the animals. You see the spider catch the fly, the snake catch the frog, the bird catch the insect, and the big fish catch the minnow; and you have heard of wars where men kill one another.

The greatest enemies that men have to fight, however, are not other men, or wild animals, but foes that kill more men, women and children every year than were ever killed in the same length of time by war. These foes are small, very small, but you must not think that because things are small they are not dangerous. We call these foes disease germs.

Fig. 1. Looking at cells
through a microscope.

Fig. 2. Some skin cells as seen
through a microscope.

The nature of a germ

The germ is a very, very small body; it is the smallest living body that we know. Later we shall learn that our bodies are made up of cells, and that these cells are extremely small—so small that it takes a very powerful microscope to see one of them. The germ is still smaller than the cells in our bodies, and it is made of a single cell. There are a great many kinds of germs in the world. Fortunately, most of them are not harmful. Some germs cause disease, but there are other germs that not only are not harmful, but are actually helpful to men. Among the helpful germs are those that enrich the ground, and these should be protected; but all germs that cause disease should be destroyed as rapidly as possible. These germs are fighting all the time against our health. They are not armed with guns and cannon, neither do they build forts from which to fight; but they get inside our bodies and attack us there.

How to fight germs

There are three principal ways by which we fight disease germs: first, by keeping our bodies so well and strong that germs cannot live in them; second, by keeping germs out of our bodies; third, by preventing germs from accumulating in the world—that is, by killing as many of them as possible.

If it is possible to keep so well and strong that disease germs cannot live in our bodies, you will naturally infer that there are other causes of sickness besides disease germs. That is true, for there are a great many things beside germs that cause our bodies to get into such a condition that disease germs can enter and grow and make us ill. We sometimes call this a "run-down" condition. Before we begin, then, to study the germs that cause disease, we must learn how to keep our bodies strong and ready to fight these germs.

Questions. 1. What evidence have we that sickness is not natural? 2. Name some of the fights going on in the animal world. 3. What can you say of the amount of illness caused by germs? 4. Tell what you have learned about germs. 5. Name three ways of fighting germs.

Remember. 1. Most sickness comes from failure to observe Nature's laws. 2. We must keep up a constant fight against germs that cause sickness. 3. We fight germs by killing as many of them as we can, and by keeping our bodies so strong that if a disease germ enters it cannot grow.

[CHAPTER II]
THE NECESSITY OF CARING FOR THE BODY

Fig. 3. The organs of the body.

How the body is like an automobile

These bodies of ours are built somewhat like automobiles. An automobile is made up of a framework, wheels, body, gasoline tank, engine, and steering-gear. The human body has much the same form of construction. We have a frame, which is made of the bones of the body. We have arms and legs, which correspond to the wheels of the automobile. We have many little pockets in our bodies in which fat is stored, and these little pockets answer to the gasoline tank of the automobile. We have an engine which, like the automobile engine, is made up of many parts; and we have a head or brain, that plays the same part as the steering-gear of the automobile.

The automobile has a tank in which is carried the gasoline necessary to develop power for the machine. If the gasoline gives out, the engine will not run, and before the owner starts on a trip, he is always careful to see that the tank is well filled. In the same way, if we do not provide new fat for the pockets in our bodies in which the fat is stored, our supply will soon give out and our bodies will refuse to work, just as the engine of the automobile will refuse to work when the gasoline is used up.

What cells are like

The automobile is made of iron and wood and rubber, and each bit of iron and wood and rubber is made up of tiny particles. The body is made of bones and muscles, covered with skin, and all these are made up of very fine particles that we call cells. Every part of the body is made of these fine cells. The cells are so small that they can be seen only with a powerful microscope. If you look at your hand you cannot see a cell, because it takes a great many cells to make a spot large enough for you to see. In Figure 1 you see a boy looking through a microscope, and beside him you see a picture of what he sees. This picture does not look like the skin on your hand, neither does it look like the skin on the boy's hand; but it is nothing more nor less than a piece of skin taken from that boy's hand, and it looks just as a piece of skin from your own hand would look if you were to see it through a very strong microscope.

Why cells must not be killed

The whole body is made up of just such little cells as you see in Figure 4, and each cell is alive and has a certain work to perform. It is very important that we keep these cells from dying and that they perform the work for which they are intended, for if these cells die or fail to act, the body becomes sick or dies.

Fig. 4. A cell. (a) Cell body; (b) nucleus; (c) nucleolus.

You can scratch some of the paint from your automobile and the machine will work just as well as ever. Apparently no harm has been done, but an opening has been made through which moisture and germs can enter and cause the wood to rot and the iron to rust. You can remove certain parts of the automobile and still the machine will do its work; but you cannot take away too much of any one part without weakening the automobile, and if certain parts are missing (such as the sparker, the battery, or the steering-gear), the usefulness of the machine is destroyed. So it is with the body. You can scratch off some of the skin and not do any apparent harm, but you have made an opening through which germs may get into the body. You can remove certain parts of the body, such as the arm or leg, and still the body will do efficient service. But there are certain parts of the body that are necessary to life, just as certain parts of the automobile are necessary to the usefulness of the machine. You cannot remove the heart and live; you cannot remove the brain and live.

How cells are killed

You are probably thinking that it must be easy to kill such a little thing as a cell; and so it is. Cells can be killed by too much heat or too much cold. When you skin your hand, you kill many cells, and at the same time make an opening for germs to get in and cause sickness. You can kill cells also by starving them, for they must have not only enough food, but the right kind of food. If you feed your bodies on nothing but candy, pie, and cake, most of the cells will refuse to perform their work and many of them will die. These cells must have also an abundance of air, and the air must be pure and fresh. If you breathe the air that others have breathed or that contains poison of any kind, you will soon find that you are not feeling well. This simply means that so many of the cells are being starved for fresh air, that not enough strong ones are left to do the necessary work. You can kill these cells by overwork, for they must have a proper amount of rest. If you go to school all day long and then sit up until midnight every night, you must not expect the cells of your body to keep strong and well. You can kill these cells by the use of certain things that act as poisons to them, such as tobacco, beer, wine, or whisky.

Questions. 1. In what way is the body like an automobile? 2. What are cells like? 3. Why must cells not be killed? 4. Name five ways by which we kill cells.

Remember. 1. Each part of the body is important to the welfare of the whole body. 2. Each part of the body is made up of very small particles that we call cells; each cell in the body is alive and has a certain work to perform. 3. Cells are very easily weakened and killed. 4. There are five principal ways by which we kill the cells in our bodies: by too much heat or cold; by not giving them the proper kinds of foods; by not giving them enough fresh air; by giving them too much work to do; and by poisoning them.

[CHAPTER III]
HOW CLOTHING AFFECTS HEALTH

Fig. 5. Warm, dry clothing necessary for health.

Why the body should be equally covered

The body should always be kept at as nearly uniform a temperature as possible. In order to do this we wear clothing. Clothing keeps out the heat on a hot day, just as it keeps the heat in and the cold out on a cold day. The clothing should be equally heavy on all parts of the body. It is not right to wear a thick dress over your chest and leave your shoulders and arms bare, or nearly so. People who do this are killing a great many cells by letting part of their bodies become chilled while the rest is warm, probably too warm.

Why clothing should not be too heavy

The clothing should be just heavy enough to keep the body warm. If you wear such heavy clothing indoors that you are constantly perspiring, your underclothes become damp, and when you go out, even though you put on your overcoat, your body becomes chilled. If you begin to sneeze, that is Nature's way of telling you that you are killing many of your cells by too much cold.

People sometimes get warm from exercising, and then take off their coats. They should have removed their coats before they began to exercise. If you take off your coat after you are too warm, your body becomes chilled. Baseball pitchers know this, and if you watch a good pitcher, you will see that he always puts on his sweater as soon as he stops pitching, even though he is very warm. He knows that if he cools off too quickly, he will become stiff and sore and cannot pitch good ball.

When a draft is dangerous

Sometimes a person sits in a warm room until he begins to perspire freely. Then he opens a window and sits in the draft. Under ordinary conditions, the cool wind alone would chill the body, but now the rapid drying of the perspiration makes the body cool still more quickly. The sudden chill causes the person to take cold, which is simply another way of saying that he has killed many cells and caused others to fall sick, so that they cannot perform their work. We cannot get too much fresh air. Drafts do not hurt us if we are thoroughly wrapped up; but it is very dangerous to allow the wind to strike the body when it is not well protected, and especially when it is damp with perspiration.

Fig. 6. Properly prepared for wet weather.

Why damp clothing is dangerous

Damp clothing chills the body very rapidly and kills many cells. Indeed, if a single one of the germs that cause pneumonia were to enter your lungs while you were wearing damp clothing, it would grow so rapidly that you might have pneumonia in a very little while. That is why it is important to change your shoes and stockings as soon as you get them wet, and to take off immediately any clothing that becomes damp. It is hard for boys and girls to keep their feet dry in the winter and spring months, and rubbers are a nuisance; but if you expect to grow into the strong man or woman you picture yourself becoming, you must take care to wear your rubbers. Otherwise you may become weak and sickly, and never be able to do the things you hope to do.

The feet are not the only part of the body that needs to be kept dry. A wet coat is just as harmful as wet shoes and stockings; hence, you should always carry an umbrella or wear a raincoat when you go out into the rain. Umbrellas are unhandy for boys and girls to carry, but if you will remember that thousands of little cells in your body are being injured when you get wet and chilled, you will be willing to take your umbrella.

When to wear an overcoat

In cold weather the same amount of clothing should not be worn in the house and outdoors; for this reason, we have overcoats. If you wear your overcoat in the house, you will become overwarm and your underclothing will then become damp with perspiration; when you go outdoors into the cold air, this dampness will have just the same effect as would dampness that comes from outside.

Figs. 7 and 8. If you keep your overcoat on in the house, your underclothes become damp from perspiration, and when you go outdoors your body becomes chilled.

As soon as the weather gets cold, put on your overcoat every time you go outdoors, and take it off as soon as you come into the house. This is troublesome for boys and girls to do, because they want to run in and out of the house so often; but on the other hand, think of all the cells you will kill if you do not do this, and you will certainly consider it worth while to take off your coat and put it on again.

Questions. 1. How does keeping the body equally covered protect the cells? 2. Give reasons for not wearing too heavy clothing. 3. When is it safe to sit in a draft, and when dangerous? 4. What is the danger of keeping on wet shoes or other damp clothing? 5. When and why should overcoats be worn?

Remember. 1. Clothing should be just heavy enough to keep the body warm all the time. 2. Never take off your coat or sit in a draft when you are too warm. 3. Since wearing damp clothing causes a great deal of sickness, change your clothes as soon as they become wet or damp. 4. Do not forget to take your umbrella when it is raining and to wear your rubbers when the ground is wet. 5. In cold weather wear your overcoat when you are outdoors, but take it off when you come into the house.

[CHAPTER IV]
THE USES OF FOOD

We kill a great many of the cells in our bodies by starving them; either we do not give them enough food or we do not supply the right kind of food.

Why the body needs new cells

Not only must we feed the cells in our bodies, but we must be constantly making new ones, for in all our work or play, awake or asleep, we are constantly using up certain cells. These cells are used to make the body go, just as the engine uses coal to form the steam that gives it power to run. Boys and girls grow fast and, of course, if they expect to become well men and women, they must make a great many new cells all the time, in addition to those used in doing the work of the body. If we are to make new cells we must have the right kind of food with which to make them.

How the body keeps itself warm

We want to do something besides make new cells; we want to keep warm and well the cells we already have. No amount of clothing would keep you warm if you were not making heat inside your body all the time, any more than you could make a telephone post warm by putting your coat on it. Therefore it is necessary to have food that makes heat in the body, in addition to food that builds cells.

We eat a great many kinds of foods, and all that we eat is used either for building new cells or for producing heat in the body. Thus we can divide all our foods into two classes—building material and heat-producing material. The type of building material is lean meat, and the type of heat-producing material is fat meat and starches, such as potatoes and bread. Milk contains much building material as well as heat-producing material. That is why a baby grows and keeps warm while he takes nothing but milk.

The building foods

Lean meat is the best of all building foods. Eggs are largely a form of lean meat, and hence constitute a good article of food for building purposes. Certain vegetables contain a large per cent of building material; this is especially true of dried beans and peas. Wheat flour and corn meal (particularly when made of whole wheat and unbolted meal) contain much building material.

It is possible for one to live and grow when eating only vegetable matter. But the boy or girl who tries to become a strong man or woman by eating only vegetables will be disappointed; these are mostly heat-producing foods and will not make strong bodies. Experience has proved that the best results are obtained by eating what is called "a mixed diet," that is, a diet composed partly of lean meats and partly of fats and vegetables.

The heat-producing foods

Of the heat-producing foods, fat is the most powerful. Most of the fat that we eat is used immediately for producing in the body heat, and therefore power, but a part of it is stored up for future use. We see it in all healthy young persons. It is this stored-up fat that gives the body its rounded form. When any one has been sick he is thin, because, to produce heat and power while he was sick, he has had to use the fat stored up in his body. To have such a supply of fat is like having a bank account to draw on when out of work. We might call the deposits of fat in our bodies our health banks.

Fat meat is not the only form in which we eat fats; we eat them in a great many other ways. Certain vegetables, such as beans, contain an oil that forms fat. Ripe olives contain a great deal of fatty oil. Butter is a very important form of fat, and cream contains a large amount of it.

Cost of suitable foods

In selecting our foods we should think of two things: first, the value of the food as a heat-producer or as a building material; and second, the cost of the food. We may like butter much better than bacon, but we should remember that, pound for pound, bacon has a greater nourishing power than butter, and a pound of bacon will cost far less than a pound of butter.[1]

Vegetable foods produce heat by means of the starch which they contain. All vegetables contain starch. This starch is changed into a kind of sugar in the body, and when thus changed it is used to produce heat and power. All vegetable foods do not have the same heat-producing power. There is more heat-producing power in a pound of oatmeal than there is in ten pounds of cabbage. Ten cents' worth of dried beans will produce more heat in the body than will a dollar's worth of lettuce. Thirty cents' worth of corn meal will do more building in the body than will a piece of mutton worth a dollar and a half; but you would have to eat a large amount of corn meal in order to secure the building effect that would result from eating a small quantity of mutton. In most fruits the only nourishing quality is in the sugar they contain. This sugar produces heat in the body just as starch does.

The real value of advertised foods

You will see some foods advertised as possessing a wonderful nourishing power. Do not let such statements deceive you, for no food can have a greater nourishing power than the things from which it is made. If the particular food advertised is made from wheat flour, its nourishing power is just the same as that of an equal quantity of wheat flour. If it is made from corn meal, it can have no greater nourishing power than has the meal itself.

We have learned something about the materials necessary in food and why they are needed. We must now learn why foods that contain these materials sometimes do not give us as good results as we might hope for.

Questions. 1. What use does the body make of new cells? 2. How does the body keep itself warm? 3. Name two uses that the body makes of food. 4. What foods are especially useful for making cells? 5. What foods are chiefly used for making heat? 6. Select articles of food for two meals of equal nourishing value, one meal to be expensive and the other inexpensive. 7. How would you determine the real value of any food?

Remember. 1. Foods are used to make heat and power in the body and to make the body grow. 2. The foods that make the body grow are called building materials, and lean meat is the best kind of building material. 3. The foods that produce heat and power in the body are called heat-producing materials, and fats and starches are the best heat-producers. 4. All vegetables contain starch, some of them contain a fatty oil, and most of them contain some building material. 5. You can get as much building and heat-producing material from cheap foods as you can from expensive foods.

[CHAPTER V]
CARE OF FOOD—MEATS

Value of meat as a food

Meat is one of the most important articles of our diet. It furnishes essential materials for building cells, and it furnishes fat for making heat and power in the body.

Fig. 9. A double menace to health; the slaughterhouse is dirty, and the filth is drained into a stream.

Characteristics of good meat

Since meat is so important an article of food, we should be very careful to see that it is handled in a way to keep it always perfectly clean. We should make sure that it comes from animals absolutely free from any kind of disease, and that no germs have been allowed to develop poisons in it.

How meat may be kept clean

While people know that they ought to pay attention to these things, as a matter of fact they do not do it. They take very little interest in the way the meat that they are to eat is handled, and very few ever go to the slaughterhouse or into the back room of the butcher shop to see whether things are kept clean or not. Some people say, "Oh, we do not like to go there because it is such a horrid place." If these places were kept clean, as they should be, they would not be "horrid." And if the people who buy the meat would occasionally visit them, these places would be kept clean.

Fig. 10. Properly displayed foods, protected from handling and from dirt and flies.

If the slaughterhouse and the butcher shop where your meats are handled are not kept clean, the meat is sure to have germs growing in it, and these germs will cause poisons called ptomaines to form in the meat. There may not be enough of them to make you sick, but there will be enough to injure some of the cells of your body, and to deprive you of much of the nourishment that you would otherwise get from the meat.

All boys and girls should belong to a "Clean Meat League" and should try to persuade their parents not to buy meat from any butcher who does not keep his slaughterhouse and butcher shop clean.

Dangers from diseased meat

Sometimes butchers are anxious to make money fast and take little thought for the number of people they may make ill. They can buy sick cows very much cheaper than well ones. The meat from a sick cow looks just like the meat from a healthy cow, and the dishonest butcher sells both at the same price. The meat from the diseased cow is not suitable for food. It may cause you to have the same disease that the cow had, or it may only be changed to such an extent that it will not give you the nourishment that you should get from good meat. The butcher who sells you meat from a sick cow is of course dishonest.

Fig. 11. Improperly displayed foods, exposed to handling and to dirt and flies.

How to prevent the sale of diseased meats

Ask your father to visit the slaughterhouse where your meat is killed. The only thing you need to do is to persuade him to go and see whether the cattle are sick or not. If the cattle look sick, you will not have to ask him not to buy the meat. No person should ever eat meat that comes from a diseased animal, no matter what the nature of the sickness may be. People who will take the trouble to visit the slaughterhouses occasionally, to investigate these things for themselves, will not have such meat offered them.

Importance of giving animals clean food

Animals that are fed on filthy food are not fit for human consumption. Butchers often feed the offal (the insides) of animals to the hogs. This makes the hogs fatten quickly, but it also makes them diseased. When you go to the slaughterhouse with your father, ask him to go around to the back door, and if you see hogs eating this filth, do not buy any more meat from that butcher.

Questions. 1. What use does the body make of meat? 2. What conditions are essential for good meat? 3. How can meat be kept clean? 4. Why is meat from a diseased animal unfit for food? 5. How can you help in preventing the sale of meat from diseased animals? 6. Why should animals not be fed with offal?

Remember. 1. Meat that is not handled in a clean manner is sure to contain germs that cause a poison to form in the meat. 2. Never buy meat from a butcher who does not keep his slaughterhouse and butcher shop clean. 3. Meat from a diseased animal is not fit for food. 4. Meat from animals fed on filthy food should not be eaten. 5. Form a "Clean Meat League" and visit the slaughterhouse where your meat is killed.

[CHAPTER VI]
CARE OF FOOD—MILK

Value of milk as a food

Milk is another important article of food. The Department of Agriculture at Washington says that milk furnishes sixteen per cent of the nourishment of the people of the country. Milk is an excellent food when it is pure, but when it is not pure it is very dangerous.

Fig. 12. A clean dairy.

Milk as a carrier of germs

Milk has carried the germs of every disease of which the germ is known; it has also carried many diseases of which we do not know the germ. Disease germs grow rapidly in milk, and they do not make the milk look different or taste different from milk that is perfectly pure. If you could take two bottles of milk entirely free from disease germs and put typhoid fever germs in one, and should set both bottles in an ice box for twenty-four hours, you would not then be able to tell into which one you had put the germs. The milk in both bottles would look and taste just the same. The only difference between the milk in the two bottles would be that if you drank from one it would make you stronger and would furnish you with both building material and power-producing material, while if you drank from the other you would become very ill and would probably die.

How disease germs get into milk:

Since we cannot tell from the taste or the appearance of milk whether or not there are disease germs in it, we must take every precaution possible to keep them out. The first step is to learn where the disease germs come from and how they get into the milk.

Fig. 13. Polluted milk is sure to come from a dairy where cleanliness is not observed.

(1) By dirt on the cow

Every cow has more or less dirt on her sides and udder; some have a great deal. When the cow is milked, much of the dirt falls into the milk bucket. This dirt always contains a great many germs of different kinds, and many of them are germs that cause disease. Straining the milk will take out much of the dirt, but disease germs will go through the finest strainer that was ever made.

In Figure 13 we see a man milking a dirty cow. The owner has allowed his lot to become so dirty that the cow cannot find a clean place in which to lie down. If the man kept his lot clean, and if before milking the light dirt on the cow's sides and udder were wiped off with a damp cloth, no germs would fall into the milk.

(2) By dirt in the cow barn

Another source of dirt and disease germs in milk is the barn. The walls of a barn where cows are milked should always be kept clean and should be whitewashed frequently. If this is done, there will be comparatively little dirt on the walls to fall into the milk.

Fig. 14. Only clean milk will come from a dairy where proper precautions are taken.

Of course the walls and floors of a barn cannot be kept absolutely clean. There will always be some dirt, and the movements of the cows shifting their position and switching their tails, will stir up the dust; so it is important to remove the milk from the barn as soon as possible. Milk cans should never be kept in the barn. The milk should be taken directly from the barn to a cooling house and there strained.

All barns where cows are kept should have plenty of windows, that there may be an abundance of light and fresh air. Cows need fresh air just as much as people do, while a barn that is not supplied with plenty of light is very likely to be a dirty barn.

Keep dirt and disease germs out of the milk by keeping the barn clean and by taking the milk away from the barn as soon as possible.

Fig. 15. A dirty, insanitary milk-house.

Fig. 16. A clean, inexpensive milk-house.

(3) By dirt on the milkman

Another source of dirt and disease germs in milk is the milkman or milkmaid. No matter how careful we may be, our clothes hold more or less dust, and all dust contains germs, very often disease germs. When a person is milking a cow, the dust from his clothes is shaken off into the milk. The only way to avoid this is to wear, while milking, a special suit of clothes made of white cloth, which may be washed as soon as it shows the least particle of dirt.

The milker's hands, too, are often dirty. Perhaps he carefully washes his hands after milking, but not before. It is a common custom for milkers to moisten their hands with milk while milking, and to do this frequently. The result is that dirty milk from their hands is constantly dropping into the milk pail. This is a very bad habit, and doubly bad if the milkman has not washed his hands before milking.

Sometimes there are sick people at the dairy farm. Often some one nurses a sick person until milking time and then goes out and milks the cows. When this is done, the milker is almost sure to plant the germs of the disease in the milk. No milk should ever be used from any dairy where there is an infectious disease; and no one who has charge of a sick person, no matter what the nature of the sickness, should ever handle milk that is to be used by others.

Fig. 17. A model bottling establishment.

(4) By dirt in cans and bottles

The cans and bottles in which the milk is placed are frequently sources of dirt and germs. Milk cans and bottles are supposed to be thoroughly washed before milk is put into them, and they should be thoroughly scalded after they are washed. This is not always done, and sometimes the bottles are not washed at all.

Some dairymen will tell you that the bottles and cans are always washed and scalded just before the milk is put into them, and that this is never neglected by any dairyman. That is what a dairyman once told me. Then I asked him how he accounted for the fact that I had found a milk ticket in the bottle with the fresh milk. Of course he could not explain this, though I thought I could explain it for him. The old milk bottle was returned to the milkman with the ticket for the new milk inside it. The deliveryman left the fresh milk, but forgot to take the ticket out of the bottle; and the man who "washed" the bottles must have forgotten to take out the ticket too. Of course, the bottle was not washed at all, and if one bottle goes unwashed, it is reasonable to assume that others are neglected in the same way.

Milk bottles and cans should always be thoroughly washed before fresh milk is put into them. This washing cannot be done by little children; it is work for a man or woman, and careful work at that.

(5) By polluted water

I have just told you that milk vessels should be thoroughly washed. It is true, however, that disease germs may get into the milk through this very process of washing the vessels. Water sometimes contains disease germs, especially the germs that cause typhoid fever, cholera, and other diseases of the intestines. Such water is said to be polluted. When milk vessels are washed with polluted water, the germs are left in them and thus get into the milk. If the water used to wash the cans is thoroughly boiled, the germs will be killed; hence it is important to scald all milk vessels.

All water used about a dairy should be perfectly pure. If there is the least suspicion about the quality of the water, it should be examined by a chemist; and if it is not pure, the milk from such a dairy should not be used. In order to prevent the possibility of any infection, all water used to wash milk vessels should be thoroughly boiled even when the water is known to be pure, and the vessels should afterward be scalded, to kill any germs that may be left after washing.

(6) By flies falling into the milk

Flies very frequently get into the milk. Later we shall learn more about how flies carry germs, but at present it is enough to know that on every fly there are a great many germs, and whenever a fly gets into milk it plants those germs and they grow very rapidly. As soon as a cow is milked, the milk should be taken to a clean cooling house, with screens at all the windows and doors, and there strained into a vessel and cooled.

(7) By disease in the cow

The last way that we will mention by which germs get into milk is by disease in the cow herself. Cows suffer from many diseases, just as men do; and when a cow is sick, her milk is very likely to contain the germs of the disease that is making her sick. Especially is this true of tuberculosis, or consumption, as it is called. A great many children get consumption by drinking milk from consumptive cows. No milk should ever be used from a cow that is not healthy. All dairy cows should be examined at frequent intervals by a competent veterinarian to make sure that they are free from any disease.

Questions. 1. Milk forms what per cent of the food of the people of the United States? 2. Why is it important that milk should be kept clean? 3. Name some ways by which germs get into milk. 4. What is the danger from a dirty cow and barn? 5. How can this danger be prevented? 6. How does the milkman allow germs to get into the milk, and how can he avoid doing so? 7. How should milk cans and bottles be washed? 8. Why is it important that only pure water be used about the dairy? 9. How can flies be kept out of milk? 10. How should milch cows be tested to make sure that they are free from tuberculosis?

Remember. 1. Milk is a very important article of food; it is both a building and a heat-producing material. 2. When milk is not properly handled, it contains many disease germs. 3. Disease germs often get into milk from unwashed bottles and cans; from dirty barns; from dirty milkmen; from dirty water used to wash the cans and bottles; from flies falling into the milk; from diseased cows.

[CHAPTER VII]
DECOMPOSITION OF FOOD

Fig. 18. Partially decayed fruit is not fit for food.

Why partially decomposed foods should not be eaten

Vegetables and fruits that are partially decayed should not be eaten. Even if an orange is decayed only on one side, the products of decomposition—that is, the poisons produced by decay—have extended all through the orange. You cannot see them, but they are there. It is the same with a decaying apple, potato, or melon. It never pays to buy partially decayed or stale fruits or vegetables, for not only are they dangerous to health, but they are so reduced in nourishing qualities by decomposition that you get little value for the money you spend. It is always better economy to buy fresh fruits and vegetables, or even canned vegetables, when the latter are properly put up.

What causes decomposition

All decomposition (rotting) in fruits and vegetables is due to the action of germs. If you will look at a bunch of old grapes, you will notice that some of the grapes are rotten, while others have dried up. Now, if you examine them very carefully, you will find that all the decomposed grapes have breaks in the skin. The break may be very small, but it is there, and through this break the germs that cause decomposition have entered. You will find also that there is not the slightest break in the skin of any grape that has dried up. The germs could not enter, hence there has been no decomposition. It is the same with other fruits and vegetables: if the germs that cause decomposition cannot get inside, the fruit or vegetable will dry up, but will not rot.

Fig. 19. Fruits displayed for sale, but properly protected from flies, dust, and dirty hands.

Germs can go through a very small opening—so small that you may not be able to find it; but if there is decomposition, the hole is there.

The skin of the body acts in the same way as the skin of the grape and keeps out a great many germs that would make us sick were they able to get through the skin. They often get through the skin when we cut ourselves.

Meats decompose as well as fruits and vegetables, and the decomposition is due to the presence of germs in the meat. We cannot keep all germs out of meat, but we can keep out a great many of them by having everything clean about the meat, by keeping it covered as much of the time as possible, and by handling it only with clean hands.

Fig. 20. Fruits for sale, not properly protected from flies, dirt, and other sources of filth.

Why foods do not decompose in very cold places

When meat is kept so cold that it is almost frozen, the germs cannot grow, and decomposition is prevented. In this way meat can be kept perfectly free from decomposition for several weeks. After the meat is taken from the cold storage room, it should be cut as soon as possible into steaks, roasts, and other pieces for cooking; and when taken to your home, it should be kept in an ice box until the time to cook it. You cannot keep meat very long at home without decomposition starting, because small ice boxes are not cold enough to check entirely the growth of germs.

Unless the meat is to be eaten hot, it should be cooled after cooking and placed again in the ice box as soon as possible. Cooking kills the germs that are in the meat before it is cooked; but unless it is kept in a very cold place and protected from flies after it is cooked, germs will get into it again as soon as it is cold. Cooked meat will decompose just the same as uncooked meat.

What is formed in food by decomposition

When germs are allowed to grow in meat, as always happens when it is not kept in a very cold place, these germs cause the poisons that we call ptomaines. The people who eat such meat become sick, and in many cases do not recover. Cooking meat that contains ptomaines will kill the germs that caused the poison, but it will not destroy the poison that has already been formed.

Why some canned meats are poisonous

People not infrequently are poisoned by eating canned meat. Sometimes you will hear it said that the poison formed because the meat was in cans. This is not true; the cans had nothing to do with the forming of the poison. This was caused by germs that were allowed to grow in the meat before it was cooked. When the meat was cooked the germs were killed, but the poison was not destroyed. In other words, the poison developed before the meat was canned, and not after it was put into the cans.

Questions. 1. What is the objection to eating fruits when they are partially decayed? 2. Why do some foods shrivel while others decay? 3. Why does decomposition not go on in cold places? 4. What are ptomaines? 5. When are ptomaines formed in canned meats?

Remember. 1. Partially decomposed fruits or vegetables are not suitable for foods. 2. Meats in which germs have been allowed to grow should not be eaten. 3. Cooking meat kills the germs in it, but does not destroy the poisons that the germs have formed. 4. When canned meats are poisonous, it is because the poison was formed before the meat was canned; the poison is not caused by the can.

[CHAPTER VIII]
HARM DONE BY IMPROPER COOKING

Effects of improper cooking

Nearly all food should be cooked before it is eaten; but if the cooking is not properly done, much of the nourishing power of the food is destroyed, and in some instances the food is rendered actually injurious.

Why starchy foods should be thoroughly cooked

Starchy foods should be thoroughly cooked in order that the coverings which surround the little granules may be broken or made soft. If starchy foods are not thoroughly cooked, the little grains go into the stomach as hard as grains of sand; then most of them are not digested at all, but pass out of the system without furnishing any nourishment to the body. If starchy foods are fried in fats, as is the case with doughnuts, the granules of starch become coated with fat. As the fat is not digested until it comes to the intestines, the saliva never reaches the coverings of the starch, and more work is thrown on the other juices of the body. The result is that the little glands which make these other juices are overworked, or else the starch is not digested at all and therefore furnishes no nourishment to the body. When bread is sticky (we sometimes call it soggy) in the middle of the loaf, it is because the flour has not been thoroughly cooked and the little grains or granules of starch are still hard. You cannot feel these granules between your fingers, but they are hard just the same, and very little of such food is made use of in the body.

Remember that all starchy foods should be thoroughly cooked, and remember, too, that all vegetables are chiefly starchy in character.

How fats should be cooked

When fats are cooked over a very hot fire, an acid is developed that is injurious to the body. This does not mean that when the fire is hot enough to broil a steak well, it causes this acid to form; neither does it mean that heat sufficient to boil the grease for cooking doughnuts will cause it to form. Every cook knows that when she fries fat meat over a fire that is too hot, it has a bitter taste. This bitter taste is caused by an acid which will destroy a part of the usefulness of the food in the body and will cause many of the cells to stop doing their work properly.

How meats should be cooked

There is a great difference of opinion in regard to cooking foods, especially meats. Some people will tell you that meats should not be cooked at all; that man originally ate his meat raw and that this is the proper way. Others will tell you that all meat should be cooked until it does not show a particle of red, even until it is dry throughout. These are the two extremes; and it is never well to go to extremes in anything, especially in matters that concern the health.

Meat should always be cooked, because by being cooked it is made more easily digestible; but it should not be cooked, until all the juices, which contain much of the nourishing matter, are dried up and the meat made hard. Meat that is cooked until it is dry and hard is more difficult to digest than meat that is not cooked at all.

Questions. 1. What effect has improper cooking on foods? 2. Why should starches be thoroughly cooked? 3. What is the objection to starchy foods fried in grease? 4. What changes take place in fatty food when it is fried over a very hot fire? 5. Why should all meats be cooked? 6. What is the objection to cooking meat until the juices are dried out?

Remember. 1. Starchy foods should be thoroughly cooked so that the fine grains may be softened and the food thus made more easy to digest. 2. Fats should not be fried over a very hot fire because too much heat causes a poison to form in the fat. 3. Meats should be cooked, but never until they become dry, as the juices in the meat contain most of the nourishing material.

[CHAPTER IX]
HOW NEATNESS, CHEERFULNESS, AND GOOD MANNERS PROMOTE HEALTH

Why mealtime should be pleasant

The dining table should be the pleasantest and most inviting place in the house. If you are complaining and quarreling during the meal, you cannot enjoy the food; you cannot eat it properly; and your ill temper will so affect your body that you cannot properly digest what you eat. A dirty table, with flies swarming over the food, is not very tempting, and when seated at such a table, one does not eat the things that are best for him and sometimes does not eat anything at all.

Fig. 21. A clean, inviting dining-room.

How uninviting luncheons affect the appetite

The luncheons that boys and girls take to school with them are often prepared in so careless a way that they are extremely uninviting. The substantial school lunch can be made just as appetizing as the dainty refreshments at an afternoon tea or at a party. If the same care is devoted to the preparation of the one as of the other, boys and girls will eat their lunches with enjoyment and good appetites.

Why an attractive table calls for pleasing guests

If the table is made to look clean and inviting, do you not think that you, in your turn, should make yourself as neat and clean as possible before you come to it? Dirt on your hands and face not only does not look well, but contains a great many germs that may get into your food and thus find their way into your body and try to make you ill.

Fig. 22. Two lunches. Which is the more tempting?

How foods should be eaten

Besides being eaten in pleasant surroundings, all food should be eaten slowly. Let us suppose that we are all seated at a clean, inviting table and everyone is clean and happy. Before the children is the very kind of food that is best for them. It looks good and they know it is good, and they want to eat all they can of it. But they think of a game of jacks or of ball that they want to play as soon as dinner is over, so they simply "bolt" their food.

What are teeth made for? Why, to chew with, of course. But why are we given some teeth that are sharp like knives, and some that are flat like millstones? It seems probable that these different kinds of teeth are intended for special purposes, and so they are. If our teeth were intended only for cutting our food into bits small enough to swallow without causing pain, there would be no need for any except the sharp, knife-like teeth. But we have the big grinders, which were made to use, and it is very important that they be used in the right way.

Why food should be thoroughly chewed

We do not chew our food simply to make it fine enough to swallow, but for quite another reason as well. In our mouths there is a fluid called saliva. Think of something that you are very fond of eating, and the mere thought of it makes the saliva come into your mouth. This saliva has a very important duty to perform in connection with preparing the food for the little cells of the body. Each little grain of starch—and you will remember that all vegetable foods are composed largely of starch—has a capsule about it. This simply means that it is done up in a little package. The saliva helps to open this capsule by making it soft (just as water will soften the paper on a package of candy), so that the other digestive juices can reach the starch and turn it into the kind of sugar that is used in the body. If you do not chew your food very fine, the saliva will not reach the starch granules, the little packages of starch will be hard to open when they go into the stomach, and much of the starch will never be made use of in the body. The saliva has much the same action on the coverings of the little packages of meat, for all the meat that we eat is done up in similar packages.

A great Englishman, Mr. Gladstone, who lived to be eighty-three, made a practice of chewing every bite of food twenty times, and he thought this had a great deal to do with his being such a strong and well man and living to such an old age.

When desserts are not harmful

After you have eaten meats, bread, and vegetables, it will do no harm to eat a piece of pie or cake, or a dish of ice-cream or some other dessert. It is not easy, as a rule, to digest these things (that is, to get them into such shape that they can be used as food by the little cells in the body), but a moderate amount of them is very good for boys and girls, as well as for grown people. If you refuse to eat the meat and bread, but wait until the dessert is served and then fill your stomach with sweet things, you will be starving some of the little cells, and you will be reminded of this very soon. Sometimes you may be reminded of it by having a pain in your stomach, but more often by getting low grades in your lessons at school. Your teacher will know it, too, because you will be so restless and inattentive in your classes that she will have to give you a low grade in deportment as well.

Questions. 1. What kind of topics should be discussed at mealtime? 2. What is the objection to an untidy table? 3. What kind of luncheon do you like best? 4. What does a clean table call for? 5. What is the importance of eating slowly? 6. Why should we chew our food thoroughly? 7. When are desserts not harmful?

Remember. 1. The dining table should be the most inviting place in the house. 2. Unpleasant subjects should be avoided at mealtime. 3. A clean table calls for clean people. 4. Eat slowly and chew your food thoroughly, that the saliva may reach each grain of starch. 5. Desserts are not harmful if eaten at the end of a meal composed of good building and heat-producing materials.

[CHAPTER X]
DANGERS FROM POOR TEETH

We have learned that chewing is not merely a process of cutting our food into such lumps as we can swallow without hurting ourselves; but that the food must be ground up fine and thoroughly mixed with the saliva, that the saliva may reach every particle of starch. If we do not have good teeth, we cannot grind our food as fine as it ought to be ground, and, as a result, a great deal of the starch will not be reached by the saliva.

Nature starts every child with a full set of good, strong, clean teeth. These teeth, which we call first, or milk, teeth, are not very large, but they are perfect in every respect and last until the second, or permanent, teeth come in. That is, they will last so long if they are taken care of. If they are not taken care of, they will decay just as the later teeth will decay, and they must be cared for in the same way.

Why we have baby or milk teeth

Boys and girls sometimes wonder why they have a set of teeth that come out before they can have the teeth that must last them the rest of their lives. This is simply because there is not room enough in a child's mouth for the big, permanent teeth. We must have teeth while our jaws are growing, so we have first a set of little teeth. Then just as soon as our jaws get large enough for the big teeth, the little teeth come out and the big ones come in.

Teeth are about the hardest substance in the body. If we take care of our second teeth, they should last as long as we live. The only reason they do not last is because we do not take care of them. If a person would keep his teeth clean all the time, he would rarely be obliged to have a single permanent tooth pulled.

Why teeth break easily

Teeth are so hard that they are brittle, that is, they break easily. Glass is brittle, and you can chip off a piece of glass with a pin by sticking the pin into a crack in the glass. In just the same way you can chip off a piece of a tooth by sticking a pin between two teeth. That is what often happens when people pick their teeth with pins, or with any other hard substance. A metal toothpick is just as bad as a pin.

Fig. 23. Teeth were not intended for nutcrackers.

Another way by which little pieces are chipped off the teeth is by biting hard things. Sometimes we see boys and girls cracking nuts with their teeth; again we see them trying to bite wires in two. They put their teeth to many uses for which teeth were never made. They do not realize, while they are abusing their teeth in this way, that they are probably chipping the enamel, which is the hard, shiny covering of the tooth, and are destroying the one protection that their teeth have against decay.

Why teeth decay

When a little piece is chipped off a tooth, an opening is made through the enamel. Through this opening germs may lodge in the inner part of the tooth, which is soft. When this happens, a little black speck appears on the tooth, and after a while the tooth begins to ache. If you have a toothache, you go to a dentist, and he probably finds that germs have caused the tooth to decay until there is a hole extending into the very center of it.

Teeth grow very close together, but there is always a little space between them. Whenever you eat anything, particles of the food get into these spaces and if allowed to remain there, soon decompose. These decomposing particles of food between the teeth will gradually soften even the enamel, and in this way little openings are made for germs to get into the teeth.

How to care for the teeth

Never pick the teeth. You cannot make them clean by picking them. Every morning and night brush your teeth with a stiff toothbrush and a little tooth powder. Brush them both crosswise and up and down, to get out everything from between them. Do not think you have done your duty if you brush only your front teeth, the ones that show. Brush the back teeth just as thoroughly as you do the front teeth. Very few people will see your back teeth, but these decay just as fast as your front teeth, if they are not kept clean.

Fig. 24. A sanitary wash-basin with a separate bowl for washing the teeth.

How often one should go to the dentist

Twice each year you should have a dentist examine your teeth, to see if there are any little spots where decay has started. If you have kept your teeth perfectly clean all the time, and have not chipped off little pieces, there will be none of these decayed spots. But it is a safe plan to have the teeth looked over at least twice a year, for you may have broken a tooth without knowing it, and by the time a decayed spot is large enough to cause pain, or has made a hole that you can feel with your tongue, it has advanced much farther than it should have been permitted to do.