Physiology, hygiene and sanitation

Preface

It is the purpose of this volume to present such material on physiology, hygiene, and sanitation as may be of practical service to young people. For this reason function is emphasized rather than structure, and the laws of health receive more attention than the mechanical operation of bone, muscle, gland, and tissue.

In the earlier chapters of the book stress of teaching is laid on right habits of sitting, of standing, and of walking; on the relation of the school desk to spinal curvature; on laws of growth and their relation to correct habits of posture; on the development of muscular vigor; and on the renewal of the tissues of the body.

Attention is also called to the source of all muscular energy — the blood. Simple tests, easily applied, explain the cause of rapid and slow heartbeat and show how the power of the heart and of the lungs may be increased gradually. Reasons are given why the untrained heart should not be greatly taxed, and why extreme breathlessness is objectionable. The effect of alcohol on the heart and on the arteries is made plain, and the effect of tobacco on the action of the heart is illustrated by means of the sphygmograph.

vi PHYSIOLOGY, HYGIENE, AND SANITATION

Professor Chittenden's notable experiments with soldiers in New Haven and Dr. Cannon's experiments with cats in the Harvard Medical School add a touch of picturesque reality to the otherwise prosaic subject of digestion. Through these experiments we are introduced to the change of food from solid to liquid in the alimentary canal, to the absorption of chyle by the villi, to the enrichment of the blood, and to the work of the liver and the kidneys in purifying the blood.

The nervous system also is studied primarily from the point of view of function and of efficient service. The student learns how the body is controlled by laws of habit and by will power, how habits are formed, and how it comes to pass that a happy state of mind helps on the cause of good health.

The present volume is, in some respects, a readjustment of The Body and its Defenses. Certain subjects treated there have been pressed into smaller compass here ; while certain other subjects touched upon there have received more extended treatment here. To a large extent this new subject matter concerns itself with sanitation, hygiene, and the food requirements of the body. The following are a few of the new topics interspersed among the old : rules for right eating ; balanced menus ; food for bulk ; food waste ; why we cook our food ; pure-food laws, and food inspection ; canned foods; patent medicines; mistakes in eating;

PREFACE vii

auto-intoxication, how brought about, how avoided ; headache and auto-intoxication; the relation of alcohol to taxes, crime, and poverty ; treatment of the eyes ; hygiene of the ear.

A new feature of this book is its chapter on sanitation, where contrasts are drawn between country conditions and city surroundings ; between the solution of sanitary problems for congested cities and for scattered country communities.

Still another chapter shows how our common microbe diseases — measles, scarlet fever, malaria, smallpox, diphtheria, yellow fever, etc. — are passed about, and how we may escape them through vaccination, antitoxin, cleanliness, and general physical vigor secured through the observance of the laws of health.

In this volume, as in The Body and its Defenses, tuberculosis is studied — its cause, its prevention, and its cure ; also typhoid fever as related to pure water and clean milk ; also dangers from the public drinking cup and the public towel, from the fly, the mosquito, the hookworm, and the rat.

These and other related topics have been brought to the notice of the students of this volume with the hope of imparting such enthusiasm for personal health and such clear notions of how to secure it that healthful habits may result ; that the bodies of growing children may be strengthened as well as straightened ; that lives viii PHYSIOLOGY, HYGIENE, AND SANITATION

may thereby be lengthened ; and that through increased physical well-being the sum of human happiness may itself be increased.

For the convenience alike of teacher and of pupil, sideheadings serve as a ladder of connected topics throughout the book. A series of questions is also added to each chapter, and many illustrations reenforce the teachings of the text. Special mention should be made of indebtedness to the American Journal of Physiology for illustrations used by Dr. Cannon in his article on " The Movements of the Stomach studied by Means of the Rontgen Rays," and to Professor Chittenden for photographs of the soldiers with whom he carried on his food experiments.

Other valuable illustrations have been reproduced from The Human Mechanism by Theodore Hough and W. T. Sedgwick, from Alcohol and the Human Body by Sir Victor Horsley and Mary D. Sturge, and from Unser K'orper by F. A. Schmidt. To each of these and to many other important works this small volume is indebted not merely for illustrations but also for valuable facts which have been used in the preparation of its

subject matter.

F. G. J.

Contents

CHAPTER PAGE

I. Changeless Records i

Taking the Body's Record. When Cartilage turns to Bone. Making Our Own Records. How the Right Kind of Body Helps. Testing Yourself. The Correct Standing Position. The Correct Sitting Position. Lateral Curvature of the Spine. How to prevent Lateral Curvature.

Chapter I

Taking the Body's Record. Certain cities are able to keep changeless records of their criminals who have been captured. City officials measure each man carefully — his height in standing and in sitting; the distance from the outstretched finger tip of one hand to the outstretched finger tip of the other; the length and width of head, face, and right ear ; the length of left foot, of left middle finger, and of left forearm. Scars are noticed and recorded; also the color of hair and eyes, ^ - , i>

the shape of the nose, the number of teeth, etc. Each item is important as part of the final, full record

A Caliper Compass mkasukes the Length of his Head

In addition, a photograph is taken. And, strange though it may seem, a photograph is less important than measurements in identifying a man if he is ever arrested again and brought to the poHce station. The reason is that our bone measurements change Httle after we are twenty-two. Ever after that the size of face and head, the length of arms, of fingers, and of legs, remain practically unchanged.

This, then, is a sure and sensible way of keeping the record of a man.

When a criminal is under examination, no matter how violently he declares that he has never been arrested before, the officers measure him at once, then search

their written records. If they find any set of measurements which is a duplicate of those just taken, all the

The Middle Finger is Measured man's denials are in vain. Those officers know that never yet have two people been found who had precisely the same dimensions for all the bones which were measured.

It takes but ten minutes for the officers to get their record of a man — photograph and all. But it took the man himself twenty-two years to form the body which is now his physical record of himself; and the training began when he was very young.

When Cartilage turns to Bone. Notice any careful mother with a baby in her arms. See her firm hand against the back of the head as she holds the child up for a look at the world. She knows that for months there is more cartilage than bone

in the supports of a baby's body, and that while bones are in this condition they cannot be trusted to do independent work.

Certain Indians have known this for centuries. A famous tribe that admired flat-headed men secured

Chinook Baby in his Cradle

The weight on his forehead will help turn him into a flat-headed Indian these heads for their boys by a clever contrivance. They simply fastened a board by a hinge to the head of the cradle and allowed it to press down upon the forehead of the baby whenever he was strapped in place. As months passed, the small skull not only continued to grow but also set itself hard and firm in the desired shape. And, once firmly set, there was never any hope that the grown Indian could restore his head to the perfect shape which it had when he was born. Thus some of our bones and muscles are trained by other people before we are old enough to make decisions for ourselves. Yet, whoever is responsible for results, two laws of bone growth should never be forgotten :

1. Many bones can be compelled to take a bend in this direction or that while the child is growing.

2. Almost no bone can be forced to make a new bend after it is twenty years old.

But there is other training which is more complex, and for which we ourselves are responsible.

Making Our Own Records. On a certain day two boys entered the same shop and asked for work. The first boy was refused, the second was accepted. And the explanation lay with the bones and the muscles, which had made different records for the two bodies. The first boy walked with a shuffle and had a slouching body. Before he had spoken a word the business man who met him was unfavorably impressed and ready to reject him.

The second boy walked as if he respected his body thoroughly. His head was erect, his shoulders well squared, and the vigor of his body gave the impression that he was in the habit of doing things with energy. This boy was accepted as promptly as the first was refused.

How the Right Kind of Body Helps. Let two women enter a store or a schoolroom, a theater or a church. Which will be served most quickly, she who shuffles as she walks, has crooked shoulders and a head thrust forward, or the woman who steps forward gracefully, who walks as if her body were under her command, as if it were her true representative ? Surely the second woman is queen wherever she goes. Without question, at every stage of growth the body proclaims the story of what has happened to it and of all that it has done with itself since it began to live. It is also true that we have it more or less within our own power, while we are growing, to make the records which are to represent us the rest of our lives.

If a man by his own acts or his own carelessness must live miserably in a shanty when he might have lived gloriously in a palace, we are apt to blame him more than we pity him.

Testing Yourself. For the sake of making discoveries about yourself, stand before a mirror and study the outlines of your back, your chest, your shoulders, and your legs. Try to stand precisely as you do every day at home and at school, so that you may get a correct notion of the records your bones and muscles have made for you thus far in your life.

He stands Well

Notice his chest and his shoulders

The Same Hoy at Another Time

He lessens his lung capacity

Be keenly critical. Are you standing squarely on both feet? Are your knees bent or straight? Is your back erect enough to hold your head up where it belongs, or does your head droop forward so that your chin sticks out too far? Is one shoulder higher than the other? Is your chest rounded out like that of a soldier, or does it sag like a valley between your shoulders ? Rub your hand across your back to see whether or not a corner of a shoulder blade reaches out, like a young wing starting from the wrong place.

If you can give creditable answers to these questions, your future course is easy. Simply keep on growing as you have begun, and in the course of time you will have the shape you wish. If, on the other hand, you are dissatisfied with what you see, put each point right while still looking at yourself in the mirror.

The Correct Standing Position. Stand with both feet on the floor, each bearing its own share of weight, both knees unbent, both shoulders square and on a level with

each other. Draw in your chin until the back of your neck would touch a- stand-up collar. Inhale a breath so full and deep that your chest looks like that of a drum major in his regimentals. Now your back has its correct shape for standing.

The Correct Sitting Position. Make another test. Sit with feet squarely on the floor, back straight, head erect.

Back View

Notice his shoulders and his curved backbone and chest raised. Are you comfortable ? Can you draw a full, deep breath ? Test this thoroughly.

Now slip down in your seat, curve your neck forward, let your back be bent, let your chest fall in, and once more

6il

Right Position kor Readinc;

His lungs have ample space

Wronc. Position

He curves his back and crowds his lungs try to take a full, deep breath. Notice that you cannot do this now, because you have cramped your lungs.

Sit now with one elbow on the desk, or with one foot drawn up under you, or with some bend at the waist line that will give a twist to the spine near the hip. The objection to taking any one of these as the usual position is that gradually the relation of the bones to each other will be so altered as to distort the body. In no wise does it harm any of us to twist this way and that, to bend as far as we can in one direction or another. Indeed, all such exercise is good for the body, provided no position is taken often enough, and held long enough, to become habitual.

Lateral Curvature of the Spine. Dr. F. A. Schmidt, a scientific writer in Germany, says that Dr. W. Mayer examined the backs of three hundred and thirty-six girls and found that one hundred and eighty-nine of the number had what is called lateral curvature of the spine. He found that girls between seven and thirteen years of age had much more trouble than those who were under seven, and he concluded that the habits of sitting formed at the school desk explained the difference, because the older children had spent more hours, days, and years in the schoolroom than those who were younger.

Follow for yourself the work of muscle and bone, and understand what happens when a child gets into the habit of sitting at his desk with elbow up on one side, shoulder lifted, and body half screwed round. Notice that if you tip up one hip the spine curves sidewise, as a balance. If you raise one shoulder, it pulls the spine accordingly. Evidently each separate movement of the muscles of the back influences the cur\'es of the spine, and the same curv^es repeated day after day at the same desk mold the bones, and the cartilage lO PHYSIOLOGY, HYGIENE, AND SANITATION which Hes between them, in wrong positions until they are as truly pressed into a new shape as if the change were planned for.

The main objection to such curves is that if they are allowed to remain and to become habitual, they will

interfere with the successful working of the large organs of the body. Then, too, when a curve becomes permanent — although it may be small — the nerves themselves are often affected by it, and the body suffers at the point which is supplied by these nerves. A person enduring this pain may not know its cause, but his ignorance will not save him from suffering.

How to prevent Lateral Curvature. Let us form habits that will help us to prevent spinal curvature. Children may save themselves by being careful to balance the exercises which they allow the muscles of their backs to take. All that is needed is a little knowledge and a firm purpose. Whoever allows himself to be shaped by undesirable habits of muscle and bone will have cause for

Bad for the Back

If this position is taken every day for

long periods, the vertebrae will become

wedge-shaped

CHANGELESS RECORDS II

keen regret in later years. But he who, in his youth, controls his habits and shapes his body with care will never regret it. Instead, he will have a body that will be an honor to him for the rest of his life. Four rules will help: ,

1. Do not sit day after day in the same twisted position. Change frequently.

2. Do not carry a heavy weight of books on the same arm back and forth from school every day. Carry as few books as possible, and let each arm do its share of the work.

3. Do not carry a baby brother or sister on the same hip every day. Indeed, it is best to do little carrying on either hip. The weight, placed just there, will tend to give a wrong twist both to your back and to his.

4. If you must stand for hours at a stretch, learn to rest one leg by using the other. Don't let one side sag down habitually. Change sides.

1. How do cities get and keep records of criminals ? 2. Which is the more accurate record of a person — a photograph or measurements ? 3. After what age are bones set for life ? 4. \\'hy does a mother support the head of a young baby when holding it ? 5 . Give two laws of bone growth. 6. What effect does an erect, healthy body have on a boy's chance of success? 7. In what ways does the body tell facts about us?

8. Test your own body to see if you stand correctly. 9. What sitting positions are objectionable, and why? 10. What difference is there between sitting with a twist in the back once in a while and taking that position most of the time? 11. What must be guarded against ? 12. Do older or younger girls have more trouble from lateral curvature of the spine? 13. Why is this? 14. Mention various positions that bring curves to the spine. 15. What objection is there to these curves ? 16. Give four rules for preventing them.

Chapter II

The Strong, Bent Back. The coal heaver round the corner has a superb set of muscles over the working part of his back. They are so well developed that, as he stands bent over his work, it is evident that these muscles give him a back of tremendous strength. By their help he shovels coal for hours at a time, through the days and weeks of the year. Moreover, when he has finished his day's work he does not seem overtired. He even jokes at the expense of his own back, for although it is so well developed and so tireless, still the man himself frankly acknowledges that it is sadly bent, and that by no effort on his part can he stand straight or walk as would please him best. He says that this is the price he has had to pay for the kind of work he has chosen.

Bent by his Work

Multitudes of people have round shoulders developed in some such way as this. Notice their shape, know about their occupations, and draw your own conclusions.

A bicycle rider whom I know has a back quite as bent, not so much from the work it has done as from, the position it has beeit allowed to maintain. It is muscular, strong, and efficient, but it never looks well except when he is working his legs fast on his wheel.

Something must be wrong, and we wonder what it is. Here are these men, and multitudes of others, whose backs are well developed, but who are so bent as to look almost deformed. For years no one could entirely explain the cause of the combination — a strong but bent back.

Close observation and logical reasoning have answered the question, however, for we learn that muscles stay in tJie position in luhich they do their heaviest zuork.

Effect of Work on Stretched Muscle. A traveling man whom I know says that when, for a few weeks, he carries

Bent «y Bicycling his suit case persistently with his right hand, the right shoulder becomes an inch or an inch and a half lower than the other, while at the same time it becomes stronger. This shows that a muscle can be lengthened even while it is being strengthened.

Two oarsmen row with all their might. One does it with a straight back, the other with a curved back. Their work continues day after day, until one back is as strong and as muscular as the other. But see the results. One man walks as if he had spent his boyhood curved over a school desk without a thought about what was happening to his spine. The other man looks as if he might have spent those same years at West Point, with officers and fellow students who compelled him to stand straight whether he wished to or not. Yet the boyhood of the two men may have been alike. The difference just now depends upon their postures while they were rowing. Their muscles, when they walk, simply betray some facts about their recent histor}^

Bem uv Ace

To Balance Development. Fortunately, however, there is a happy outlook even for such people as are obliged to work with their backs bent, for there is another important fact about this law of contracting and stretching. I give it concisely :

Brief, vigorous exercise in the right position will undo much of the harin of long-continued exercise in tfu wrong position.

If a man who works in a bent posture all day will spend five minutes a day in taking vigorous exercise with his back straight, alternately tightening hard and then relaxing the muscles of his back and neck, he will find that within one month there will be an improvement. And the more faithfully the exercise is continued afterwards, the more good will it do. By this simple device a man may save himself from his rounded back and be able to hold his head where it should be.

It often happens that the muscles of the chest become thin and flabby for lack of exercise, even while the back has become very strong. But these muscles may be saved. Throw the shoulders well back and exercise the chest muscles hard in this position. Exercise them while they are thus stretched, and they will grow large and prominent in spite of what your occupation may be. If the exercise can be taken oftener than once a day, it will be so much the better.

The Law of Muscle Change. In this work of changing the shape and the power of a muscle, the greatest strain must be put on the last third or the last quarter of the contraction. Remember that each muscle is inclined to stay in the shape which it takes when it does its hardest work; in other words, the law is that doing a thing makes the part shape itself for that act. Evidently, then, to a large extent, we may develop our bodies according to our desire. Knowing this, a public lecturer — a doctor — told his audience that each man present could increase the size of his arms three quarters of an inch within one month and could increase his chest measure an inch and a half during the same length of time.

One Way of Developing the Muscles. To show what he meant, the lecturer asked his friend, a medical student, to illustrate the points one by one as he himself explained them. The student was well knit and well built, no unnecessary fat concealed the shape of his muscles, and he was ready to show the other men what they also might do in behalf of their own development.

Exercise for the Biceps i8

" Now," said the doctor, " show us the effect on the biceps of rotating the arm ; the forearm ; now rotate the leg — the big muscles ; show that tensor. Now again will you go through four or five exercises that bring into play in succession first one arm, then the other, and so on ? "

The student acted on the suggestions as fast as they were given. His smooth back and arms gave

no sign of separate muscles while he stood quietly waiting to be told what to do, but as soon as he followed directions and used arm, leg, back, or shoulders, there sprang into prominence one set of well-developed muscles after another.

Antagonistic Muscles. The student held no apparatus, but used arms and legs as if he were pulling against some invisible weight. He was, in fact, pulling against the force of his other muscles — antagonistic muscles, they are called. Try this for yourself, with your forearm or with your back. Try to bring out one muscle and see how many others are called into action. The doctor then explained that muscles can be developed in this way with no apparatus whatever. " Muscles," said he, "can pull in one direction only; the opposite pull has

Well-developed Muscles

Exercise without Apparatus to be done by antagonistic muscles." He made it plain that in arms, legs, and elsewhere, muscles are often

placed in pairs, called flexors and extensors, which balance each other with their power of pulling. He showed that these opposing muscles can be developed without apparatus by making flexor muscles bend the limb, and extensors straighten it out again. It is flexor and extensor muscles that help us close and open our hands; help us curl up our toes and stretch them out again vigorously.

Exercise without Apparatus. As he went on with his address, the doctor said that to make muscles develop, they should pull as hard as possible for a few seconds at a time, then let go completely, then pull again for a few seconds, and so keep up the alternation for five minutes in the morning, for five minutes at night, and for ten minutes a day between times. " To develop arm or chest," said he, " put in the extra ten minutes

He develops Arm Muscles whenever convenient." It appears, therefore, that in many cases the process of developing one muscle or set of muscles may be carried on without apparatus and without the gymnasium.

Examine your own muscles. Decide which are firm, which flabby. If they should be improved, talk the matter over with any good gymnasium director. He

will tell you what special daily exercise to take for special muscles. As for securing very big muscles, however, they are really of no advantage in the health line. Still the fact that up to a definite limit we have the power to increase the size of arm and chest and leg proves once again how truly each of us is master and architect of the body we are building. Studying Muscle Structure. But what about the substance out of which the body molds a muscle into shape and compels it to increase somewhat in size whenever it is forced to do unusual work? Get a piece of lean corned beef from the butcher; have it boiled thoroughly; place a board over it and press down upon it hard enough to squeeze out all the liquid ; remove the board, and with a needle of some sort pick apart the fibers as well as you can. Pick

Taking the Measurement

MUSCLES : WHAT THEY ARE AND WHAT THEY DO 2 I them away from each other into finer and finer threads until you think you have reached the smallest ones of all.

Now, with a good magnifying glass, examine one of these bits of beef muscle. You are able to pull them apart because the tough outside wrapping of each has been changed by boiling.

Bundles of Fibers.

However large or small a muscle may be, and wherever that muscle does its work, whether in creatures that walk, fly, or swim, every bundle of muscle is made up of fibers wrapped

together. Shapes are different; size varies — from those that draw an eyelid up and down, to those that kick a football to its goal ; the work of each is different ; their strength and power of endurance are different ; but each bundle is a combination of individual fibers. A few of these are wrapped together as a small bundle, small

Muscles of Different Shapes

Individual Muscle Fibers bundles are gathered into bundles that are larger, large bundles become larger yet, and thus from smaller to larger are the muscles built up.

Each is a bundle of other bundles ; each is adapted in size and shape to the special work which it must do; and every fiber in the bundles, large and small, is inclosed in what is called the sarcolemma. This sarcolemma, then, is simply an outer wrap that separates each fiber from its neighbors.

Connective Tissue. In addition, however, there is a close network of substance called connective tissue, which holds the individual fibers together. In this connective tissue

are the tiny blood vessels and the slender ner\'es which supply blood and stimulus to each smallest fiber. Fine threads of connective tissue also stretch away from each