Graded lessons in physiology and hygiene

II An X-ray Picture Of An Injured Right Hand

It shows: (1) Bones of the forefinger “ out of joint.”

(2) Little finger amputated.

(3) Three bones of the hand broken.

GRADED LESSONS

IN

PHYSIOLOGY AND HYGIENE

BY

author of “first book in physiology and hygiene,”

"PRACTICAL LESSONS IN PSYCHOLOGY,” AND EDITOR OF “THE CHILD-STUDY MONTHLY”

THOROUGHLY REVISED, AND WITH ADDED CHAPTERS ON SANITATION AND COMMUNICABLE DISEASES

BY

S. J. CRUMBINE, M.D.

SECRETARY OF THE KANSAS STATE BOARD OF HEALTH, FORMERLY DEAN OF THE SCHOOL OF MEDICINE OF THE UNIVERSITY OF KANSAS

Q,T

(ijit

COPYRIGH'T, 1900,

By WILLIAM O. KROHN

9-4876

Preface

The keynote of this book is health. There has been no attempt to prepare an extended treatise on anatomy and physiology. It has been the purpose of the author to present in simple language to the children in the intermediate grades a knowledge of the conditions which tend to preserve and strengthen the body.

While the facts of anatomy and physiology in this book have been made in a sense secondary to the main theme — hygiene — yet they embrace the results of the latest investiga¬ tions in these departments of research, and are ample for a clear understanding of the central subject. The lessons are designed throughout to come within the comprehension of young pupils, as well as to meet the wants of those in the more advanced classes, in emphasizing the common laws of health. This steady progression from the simple to the more difficult is made by easy, natural, well-graduated steps.

The author regards it not only the most logical arrange¬ ment, but also in harmony with the best pedagogy, to embrace the main discussion of the effects of alcohol and tobacco in separate chapters. Connected discussion is better than scat¬ tered fragments.

PREFACE.

That part of physiology and hygiene is actually taught that results in the daily living of correct habits of health on the part of the children to whom it is taught.

The work in the class room will be made much more interesting and valuable if the teacher will have the children actually carry out the teaching; for example, if, in homes where wells are used, the children he induced to make reports on the conditions of drainage at their homes, showing whether the well water is being polluted by surface drainage, or by drainage from the barnyard, the pig pen, or from the place where kitchen slops are thrown out (see page 48).

The children will also take great interest in actually ap¬ plying first aids (see page 243), and by actually practicing the resuscitation of persons from the effects of drowning (see pages 246-250).

Why should we not make practical application of this work in the same manner as wre practice the work in the sciences and on the football field ?

The children take a wonderful interest in such work, and thus the teaching is actually made a part of their daily living.

Table Of Contents

CHAPTER PAGE

I. Our Food . 9

II. Healthful and Unhealthful Foods . . 22

Chapter I. Our Food

Why We Eat. — Does it ever seem strange to you that these bodies of ours do not appear to wear out, though we are constantly using them ? We know that our clothes wear out, no matter how careful of them we may be. A wagon or piece of machinery tends to wear out with each movement it makes. You would not expect your pencil, pocket-knife, bicycle, or • skates to keep fresh after long and frequent use. Our bodies are constantly wearing out. Every movement of our bodies, however slight, causes some amount of wear. Why, then, do not our bodies waste away? Because they are be¬ ing continually repaired. Every little particle of worn-out matter is being replaced by a new one. The food we eat is being changed into the parts of the body that are wear¬ ing out.

You are growing very fast. But a few years ago you were much smaller than you now are. You expect that next year you will be even larger and stronger. What makes you grow ? Is it the air that you breathe? Ho, not that alone. Air is necessary to life; but you would soon starve if you had noth¬ ing hut air upon which to live. Water is necessary to life, yet none of ns could live on water alone. You have noticed the little tree in the orchard and the shrub in the garden, how rapidly they grow. If you should stand the shrub or tree in the middle of your schoolroom, on the clean, hard floor, and give it sunlight, air, and water, without any soil, would it grow? Ho; it would not even live. The roots, by means of which our little tree, when out of doors, was fastened to the soil, could not make their way into the hard floor.

If the tree is to live and grow, its roots must go down into the soil and find something just as necessary to its life, health, and growth, as air, sunshine, and water. The roots, even the smallest of them, work down into the earth and find food for the tree, and it is this food that makes plants and trees grow. The richer the soil — that is, the better the food — the faster they grow. In one garden we find the plants looking pale and sickly, growing scarcely at all, while in another garden the plants look fresh and thrifty and are growing rapidly. What causes the difference? You are quick to answer that in one garden the soil is richer, contain¬ ing more food for the plants, and that the gardener loosens the soil that the roots may have a chance to push their way farther and farther into the earth. The wise gardener also pulls up the weeds that would otherwise grow around the plants, so that these weeds may not use up the food in the soil that the plants need for their health and growth.

Why do you eat ? Because the food keeps your bodies in repair so that they will not wear out, and also because it makes you grow.

Have you ever thought how much one eats in a lifetime ? It is a nice problem in arithmetic to figure this out. Nearly every hoy and girl in your school eats at least two pounds of

OUR FOOD.

food in a day. In a year, then, each of you will eat two times 365 or 730 pounds of food. This is many times your own weight. By the time you have become sixty years old, how much will you have eaten ?

What to Eat. — Your bodies are repaired and made to grow by what you eat. If you eat poor food your bodies will be made of poor material, and will not grow as fast as they should, or do their work well. If you eat unhealthful food, your bodies will have to be repaired often; that is, you will have to call the doctor to give you some medicine to undo the harm caused by the improper food, whatever it may have been. You see how important it is that we know something about our foods. All of us should know what foods are good for us, and what will do us harm. What foods will promote health and growth, and what will cause disease and retard growth, is certainly very important knowledge.

Do you think the dark soil in the garden or flower-bed looks anything like the bright-eyed, laughing pansy ? Does the black loam resemble the rich green of the fern ? As we eat the ripe apple, juicy plum, luscious grape, or sweet pear, do we taste anything like the dark, gritty, sandy soil which made it possible for them to exist ? To all of these questions you answer, Ho. And yet the roots of the pansy, the fern, and the fruit tree all take some necessary food from the soil, which is then changed so that leaves are made to grow, flowers to bloom, and fruits to appear.

Is it not equally strange to think that the bread, potatoes, meat, and eggs you eat, as well as the milk and the water you drink, — in fact, every bit of good food of which you partake, — is taken up by the organs of the body and changed into bone, nerve, and muscle ? And yet, if we can only get the food into the blood, as the root gets the food from the earth into the sap of the plant, each part of the body will pick out just what it needs to make it strong. The bones will take up from the blood just those little particles they need for their growth and repair, and likewise the muscles and nerves will do the same. Your own body does not look like the food you eat any more than the plant looks like the soil upon which it feeds. Our food becomes changed in some way into all the different parts of the body — skin, hair, bone, muscle, brain, and nerve.

Since food thus becomes changed into the different parts and organs of which the body is composed, is it not very im¬ portant that we be careful to select the foods that are best suited to the repair and growth of our bodies ? But before we consider this further, let us follow the food we eat as it makes its journey through the body. The preparation of the food within the body so that it may be used in nourishing the body is digestion. The object of digestion is to separate the food from its hard and useless parts, and then to soften and dis¬ solve it so that it becomes liquid, and can flow with the blood to the various parts of the body requiring food.

How We Digest Food. — An important aid in the diges¬ tion of nearly all our foods is their proper cooking. Cooking changes the food so that it can be chewed easily. You would find it difficult to chew raw rice grains. Cooking softens the hard grains of rice, wheat, or oats, and it also makes most of the foods taste better. A raw potato does not taste very good, but what boy or girl does not enjoy eating nicely cooked

OUR FOOD.

potatoes at least once a day ? Again, cooking destroys many poisons in food. We will learn more about that in the chap¬ ter on “Disease Germs.”

Mouth Digestion. — After the food is properly cooked, the first step in digestion is to take it into the mouth, where the digestion is continued by chewing and grind¬ ing the food with the teeth, and pushing it about the mouth with the tongue. We move it from one side of the mouth to the other un¬ til it is in little, fine particles. While we are chewing our food well, it is mixed with a watery fluid, called saliva . There are

three glands on each side of the mouth that are busy making and secreting this saliva.

You will see their lo¬ cation in the picture. The saliva which the glands produce is carried into the mouth by means of little tubes called ducts. When we eat, taste, or even look at some foods we like, these glands make so much saliva that we sometimes say the mouth waters. You should remember to eat slowly, in order to give

Figure 1. — The Salivary Glands.

your teeth time to grind up the food, thus giving the food time to become well mixed with the saliva of the mouth. This helps very much in preparing the food for the further steps of digestion. After being thoroughly chewed, the food is swallowed.

Stomach Digestion. — In the back part of the mouth, at the throat, begins a long, narrow tube, which passes down to

the stomach. This tube, or food-pipe, is about nine inches long. It is called the esophagus. You all know where the pit of your stomach lies. This is the stomach’s center.

The stomach is simply an enlargement of the diges¬ tive tube. It is like a large bag with a coat of loosely woven muscles, and it has a queer little gate¬ keeper or valve (pylorus) at the lower end that will not open and permit the food to pass out until it is sufficiently digested and ready for the bowels or intestines. As soon as the food passes into the stomach, the muscular coat begins to contract, first length¬ wise and then crosswise. It thus keeps the food churning to and fro, and mixes it with a fluid or juice more powerful than the saliva of the mouth. This fluid in the stomach, so necessary to digestion, is called the gastric juice. It is formed

Figure 2. — The Stomach.

OUR FOOD.

in the many pocket-like glands in the lining of the inner wall of the stomach. The stomach churns away from two to four hours after every meal, according to the kind of food eaten, the way in which it has been cooked, and the health of the person eating it. After each meal the stomach should he allowed to rest a while before the next. This is why girls and boys should, as a rule, eat nothing between meals. If they do, the stomach becomes too tired to do its work well when meal time comes again, and they are not hungry. Irregular habits of eating, as well as improper, unwholesome food, cause disorders of the stomach, such as dyspepsia. Again, the gastric juice will not digest food in the proper length of time if the pieces are too large and not properly chewed or masticated. This is another reason for eating slowly. It should be remembered also that the juices so necessary to digestion are secreted more rapidly and do their work better if we are cheerful. If we come to the table cross, our food will not do us as much good and will not be so well digested as if we are cheerful and happy. Cheer is necessary to good digestion.

The juices of the stomach are mixed with the swallowed food, dissolving some of it, which is taken up by the blood and lymph vessels in the stomach walls and thus carried away ; but most of the pulpy mass, after being thoroughly mixed with the gastric juice, passes through the little gateway, or pylorus, to the intestines, to be mixed with still another juice.

Digestion in the Intestines. — At the lower end of the stom¬ ach the food canal becomes narrow again. This portion of the digestive canal below the stomach is called the intestines or bowels. The intestinal tube is about twenty-five feet long in the grown person. This long portion of the food canal is coiled np and closely packed away in the cavity of the abdomen, below the stomach, so as to take the smallest possible amount of room. The last few feet of the intestine is larger than the rest, and is called the colon. The portion directly attached to the stomach is longer, hut at the same time much smaller, and is called the small intestine. It is about twenty feet long

and one inch in diameter. The small intestine opens into the large intestine or colon, which is about two inches in diameter, and in the adult about five feet in length. The entire intestinal canal, then, consists of a tube of muscular tissue lined with a

mucous membrane. The walls of the intestines are from onesixteenth to one-eighth of an

inch in thickness. On their inner surface, imbedded in the mucous membrane, are innu¬ merable small tube-like glands that are very important. They pour out a liquid called the intestinal juice , which does its

part in the digestion of food. Along the lower side of the

stomach there is a large gland called the pancreas or sweet¬ bread. Each day this pours into the intestines about one quart of a liquid called the pancreatic juice. This juice is even more important than the saliva, gastric juice, or intestinal juice, for it does most of the work of digesting our food. It is so powerful that it breaks up the fats in our food, such as butter

Figure 3. — Showing the Three Coats of the Stomach. ( g ) Inner surface, mucous membrane, (mi) Circular layer of muscular fibers, (me) Outer layer of longitudinal muscular fibers, (p) Ridge of pyloric ring.

OUR FOOD.

and the fatty portions of meats, and changes them so that they will mix with water. The pancreatic juice also changes the starch in our foods, as the starch of potatoes, bread, and un¬ cooked fruits, into the sugar the body so much needs.

The liver, which is located in the upper part of the abdo¬ men and on the right side of the body, is a large chocolatecolored organ. It does an important work in the making of a fluid called bile. This fluid also is very necessary for the digestion of the food in the intestines.

Fresh human bile is a liquid of a brownish gold color. It is carried to

the intestines Figure 4. — The Liver — Its Under Surface.

through a lit¬ tle tube or duct, called the bile-duct. This enters the intes¬ tines just a few inches below the stomach. If the liver makes bile faster than it is needed by the intestines, it is stored up in a little pear-shaped sac, known as the gall-bladder. This hangs from the under side of the liver. The saying, “bitter as gall,” arises from the extremely bitter taste of the bile in the gall-bladder. Sometimes in cleaning a chicken or other fowl in preparation for cooking, by drawing out the liver, intestines, heart, and other organs, the gall-bladder becomes broken, and the bile it contains comes in contact with the meaty por¬ tions of the fowl to be eaten. These, because of the intense bitterness, are rendered entirly unfit for food.

While the bile is very important, it of itself does very lit¬ tle of the work of digestion ; but its presence makes the pancre¬ atic juice more powerful. Mixed with bile, the pancreatic juice does double the work of digestion that it could do alone. Bile contains some waste substances which are to be thrown off by the liver, but on its way out of the body it helps greatly in preparing the food. The bile and pancreatic juice enter the small intestine at nearly the same place. The liver is truly a wonderful organ. Besides making bile, it aids in various other ways in the digestion of food. It also helps to keep the blood pure by removing from it harmful substances that are formed within the body. It acts, too, as a wide-awake sentinel, in destroying many of the disease germs, or microbes, that find their way into the mouth and stomach along with our food. If in healthy condition, the liver will kill germs that might otherwise cause certain diseases, or seriously cripple the liver. If any of these little germs, or any other poisons, such as the poisons of poorly canned meats or vegetables, are swallowed with the food, they are also taken up with the food, and carried by means of the blood tubes into the liver. The liver works hard to keep these poisons from going any farther along the blood tubes to other portions of the body, and thus guards the rest of the body from the effects of the bad food. If the liver gets out of order it sends but little bile, instead of the quart a day it should send into the intestines.

OUR FOOD.

Poisons are then permitted to pass by unattacked, and the pancreatic juice cannot do the full work of digestion allotted to it. As a result of a disordered liver we have a rather common form of sickness known as biliousness.

Movements of the Intestines — We have seen how the food is chewed in the mouth, and how the stomach rocks the food to and fro from side to side and end to end. In a similar way the small intestine makes certain movements that mix the food with the bile, in¬ testinal, and pancreatic juices, and force it far¬ ther along the digestive tube or food canal. As the food goes farther and farther along the small intestine, it becomes

more and more liquid, until, at the end, only indigestible portions remain, such as unripe fruit, seeds, peelings, large pieces of food that were not chewed fine enough, and husks of grains, like the covering of the separate grains of corn, peas, beans, and the coarser forms of cracked wheat or oatmeal. These waste portions remain solid because the juices cannot act on them and digest them. At this stage of digestion in the small intestine, the food looks somewhat like milk with the undigested particles mentioned above floating in it. This food is still in reality outside of the body almost

Figure 5. — Cross section of Small Intestine, showing the three layers.

) <Sa/miyg/ano as much as if it were still untouched on your plate on the dinner-table. It must pass through the walls of the intestine,

enter the blood, and then be carried to the various parts of the body, before it really becomes food for the bones, nerves, and muscles.

Absorption of Food. — As the food is passed slowly along the small intestine, its liquid parts are absorbed into the lymph spaces; and by the time it reaches the large bowel, or colon, most of the water and all the digested food has been absorbed and carried away by the blood, and only the waste matter, such as seeds, hard portions of un¬ ripe fruits, peelings, husks, and the like, mentioned above, remain be¬ hind. This is driven on and out of the body. These waste portions, that naturally find their way into the large bowel, should be expelled at least once a day, in order to insure good health. If this is done regu¬ larly at a certain time, for example, at about the same hour each morning, the bowels form the habit of always acting at this time. If this waste matter is not given off, we have sickheadache and a feeling of heaviness, and may become ill ; for these waste substances are sure to poison the body if retained.

Figure 6. — Showing the Digestive Tube, or Food Canal.

OUR FOOD.

You see, then, that there are at least five important organs of digestion. The mouth, the stomach, the intestines, the pan¬ creas, and the liver. Food is softened and prepared for diges¬ tion by these five organs by first being properly cooked. Cooking is the first step in digestion. Will you also please remember that there are five digestive fluids : saliva, gastric juice, pancreatic juice, bile, and intestinal juice?

KEVIEW QUESTIONS.

1. Why do we eat?

2. Why should we eat several kinds of food?

3. What is digestion?

4. Why should our food be properly cooked ?

5. What important fluid in the mouth aids digestion?

6. Why should we eat slowly?

7. What is the stomach like?

8. How long does it churn the food?

9. What important juice in the stomach is necessary to digestion ?

10. Why should we eat regularly, and not between meals ?

11. What part of the work of digestion is done by the intestines ?

12. What help is given by the liver?

13. What juices combine to digest the food in the in¬ testines ?

14. How is the food carried through the body to its dif¬ ferent parts, after it is digested?

Chapter II. Healthful And Unhealthful Foods

We have learned that digestion is the process by means of which the food taken into the month is changed into liquid form, or a state of solution, suitable for being absorbed into the blood. This change may be rapid or slow, according to the nature of the foods the digestive juices are called upon to dissolve. We all know that it takes much longer to digest a piece of beefsteak than it does a cup of beef tea. We know that milk is more readily digested than roast pork or boiled cabbage. When a person is not very well, when we wish to save labor for the digestive organs and make digestion as easy as possible, the person is placed upon a “liquid diet.” How does this help to save work for the digestive organs and diges¬ tive juices, when they are not in good, healthy condition ?

You have observed that some animals seem to be eating all the time. The hen appears to be continually picking up seeds of weeds and grasses, grains of wheat or corn, and countless little bugs, as she goes about the yard. Other animals eat large quantities of food at one time, and then lie quiet and sleep for days. The other day in one of the parks I saw a very large snake — a boa constrictor — who eats only once in two or three months ; but when he eats it takes a very large meal to satisfy him — several chickens, a number of rabbits, and a small army of rats and mice. Other animals, such as the dog, ao not chew their fooa at all. They tear it apart so that the pieces can just be gotten into the mouth and swallowed, and that is all. The stomach and intestines of a dog have thicker and tougher walls, and the digestive juices have more power. That is the reason that dogs can digest even bones, which they frequently swallow. You have noticed that the cow will chew her food only a little at first. Notice how fast she eats the grass in the pasture and see how quickly she swallows it. Then while she is resting she brings the food back to her mouth again, and chews it finer. Deer also do the same. It is called “chewing their cud.” A little girl, about three years old, saw some deer in one of the city parks chewing their cud; she turned to me and said, “What do deer chew gum for ?” Cattle have four stomachs, one of which is called the paunch and is very large. In the full-grown ox it will hold two bushels. The fourth stomach is nearly like man’s in size and shape, and is really the true stomach, for it is the one in which most of the stomach digestion takes place. The other three are little more than storehouses and passage¬ ways for the food.

Even some of the small insects have a stomach and intes¬ tines which secrete digestive juices. In most worms the diges¬ tive tube passes straight through the body. Oysters and clams also possess a stomach and coiled-up intestines. The soft, dark-colored substance at the back part of an oyster or clam is the liver.

Kinds of Food. — Some animals can live on just one kind of food. The cattle on the range live and fatten on fresh or dried grass alone. The horse will do the same ; only he should have oats or corn in addition to grass or hay, if he has to work hard. A squirrel likes the kernels of nuts and some of the grains, but does not care for grass. A boy or girl eats more hinds of food than any other animal. Man requires a great variety of foods. He eats vegetables for one purpose, meats of some animals for another purpose, and could not live in a healthy condition if he did not have some food, such as salt, from the mineral kingdom.

Different Foods in Different Countries. — In traveling over the earth, we find the people of one country eat things as food that people of other lands could not bear to eat at all. There are people who eat bees and locusts ; others eat rats, mice, bats, and lizards. In some of the French restaurants roasted snails are regarded as a choice article of food, while to most people they are repulsive. A man who used to chop wood for heating the schoolhouse in which I first taught, used to find nests of black ants taking their long winter sleep in their curiously made houses in the chunks of wood. He would eat the ants with his bread at lunch with great relish. Yet this same man would never eat nice, ripe strawberries, for he said they made him ill. He was certainly a queer fellow, and I am sure his tastes differed from yours as well as my own.

Conditions That Modify the Demands for Foods. — The hab¬ its of life, as well as the character of the climate, make a great deal of difference in the kind and amount of food eaten. The active man who is working hard at some heavy, muscular labor out of doors, especially in winter, requires a larger amount of food, consisting of a great deal of meat, than does a person

HEALTHFUL AND UNHEALTHFUL FOODS.

whose work is not so hard. You have heard people say when they were very hungry, that they could “eat like a wood-chopper.” We all agree that the hard-working wood-chopper and miner require more food than would the tailor seated in his shop, or the clerk in a dry-goods store. The miner, the woodman, and the stage-driver are exposed to cold, rough weather, while the clerk, the tailor, and the newspaper editor are sheltered within doors during their work, which, in addi¬ tion, does not require so much physical energy as does the heavy work the others do out of doors. An Eskimo in the cold, frozen Forth can eat many pounds of meat a day, to which he often adds larger quantities of fat or blubber. The staple food of Arctic explorers consists chiefly of chopped meats and tallow pressed into cakes. They find it pleasant to the taste and a producer of bodily energy and warmth.