AUTHORIZED PHYSIOLOGY SERIES, No. 1. HEALTH FOR LITTLE FOLKS. OP THE UNIVERSITY G- OF LIBS, -H' . i- \ AUTHORIZED PHYSIOLOGY SERIES, No. /. (4uu^h Moru f J HEALTH FOR LITTLE FOLKS NEW YORK-:-CINCINN ATI- : CHICAGO AMERICAN BOOK COMPANY INDORSEMENT. The "Authorized Physiology Series" consists of: No. I. " Health for Little Folks." For Primary Grades. II. " Lessons in Hygiene," ^ A special edition of " How we Live," > For Intermediate Grades, by Johonnot and Bouton. III. "The Outlines of Anatomy, PhysiO For High Schools and ology, and Hygiene," by Roger S. / Advanced Classes in Tracy, M.D. ) Common Schools. In this series good judgment has been shown in the selection of facts that should be taught each grade, and in representing these facts in language which the pupils of the grades for which the books are designed can com- prehend. ' The treatment of the subjects of anatomy and physiology in the high- school book covers the usual ground ; in the books of the lower grades it does not unduly preponderate, but it is abundantly ample to enable the pupil to comprehend the topic which is the real object of the study, viz., the laws of health, and the nature of alcoholic drinks and other narcotics, and their effects upon the human system. The treatment of this part of the subject, in each book of the series, is full, clear, and in harmony with the latest teachings of science, and represents the spirit as well as the letter of the laws that require these truths taught all pupils in all schools. We are therefore happy to indorse and commend the same for use in schools. MARY H. HUNT, National and International Superintendent Department of Scientific Instruction of the Woman's Christian Temperance Union^ ALBERT H. PLUMB, D.D. \ DANIEL DORCHESTER, D.D. ( A ^ ^ HON. WILLIAM E. SHELDON. I REV. JOSEPH COOK. / COPYRIGHT, 1890, BY AMERICAN BOOK COMPANY. W. P. II (pp37 H77 EDUC UBRARY PREFACE. THIS little volume, as its title indicates, is de- signed as a first book in the study of such laws of practical hygiene as pupils of primary grades can comprehend, and as will lead to the formation of habits essential to a healthy, happy, and useful life. Formerly these topics, under the title of physiology, were studied chiefly by advanced pupils ; but recent widespread legislation has wisely changed this custom. Because right or wrong habits that may affect a lifetime are early formed, the child should as early learn which to choose and why.. Because only com- paratively few pupils ever reach the High School, the reason is obvious why the laws so generally specify that this study shall be pursued by "all pupils in all schools " under State or National control. Instruction in this branch, as in every other, should begin with the very simplest facts in each division of the subject, and progress by easy stages iii M75O288 IV HEALTH FOR LITTLE FOLKS. to those more complex. Great care has been taken to select for this book such topics, including the nature and effects of alcoholic drinks and other nar- cotics, as are adapted to the minds of children in primary classes, and to use only child language in presenting them. Truth is just as true when told in simple language as when put into technical terms that the child can not understand. The sentences which appear on these pages in heavy-faced type may be used as blackboard exer- cises for the pupils to copy in writing, or commit to memory. The subject matter of these is either a summary of the preceding text, or important facts, or hygienic rules, that should become a part of the pupil's knowledge. CONTENTS. CHAPTER p AGE I. WHY WE NEED TO EAT i II. KINDS OF FOOD 6 III. THE BODY NEEDS WATER, SALT, AND LIME . 18 IV. DRINKS THAT CONTAIN ALCOHOL ... 26 V. HOW FOOD IS CHANGED INTO BLOOD . . 39 VI. THE BLOOD ... . .. . 50 VII. How THE BLOOD is PURIFIED . . . . 63 VIII. THE FRAMEWORK OF THE BODY . . . 75 IX. THE MUSCLES . . . . Y . .80 X. BRAIN AND NERVES . , . . . 94 XL OUR FIVE SENSES . v . .* ,104 XII. THE SKIN in CHAPTER I. Why we need to Eat. LESSON I. WHY do people eat breakfast, dinner, and sup- per every day? If you are playing ball, and the dinner bell rings, you stop playing, put your ball in your pocket, and go to the table. Why? Because you are hungry, perhaps you say. But why should you be hungry ? Your ball is not. Do you say it is because you are alive ? Why should being alive make you want to eat ? 2 HEALTH FOR LITTLE FOLKS. Let us see if we can not find an answer to this hard question. There was once a little girl whose father used to stand her up against the gatepost every year when her birthday came around, and cut a notch in the post with his knife, just where the top of her head came. Every new notch was quite a distance above the last one, because every year she was a little taller than she was the year before. And every year this little girl needed a pair of shoes larger than her last ones, and larger mittens, and it took more cloth to make her dresses. It was harder, too, each year for her father to lift her, be- cause she was all the while growing heavier. What do you think it was that kept adding day by day to the size and weight of this little girl's body? "Food," some bright boy will say; and he is right. Good food builds up the body little by little each day until the boy or girl has grown to his or her full size. Now you know that children eat because they must have food to make their bodies grow. We need food to build up the body. But your father and mother come to the table, too, and they are not growing as children are. Why do they and other grown people eat? There must WHY WE NEED TO EAT. 3 be another reason for eating. Let us find that, too, if we can. Why does your coat or dress need to be mended after you have worn it awhile ? Because it wears out, you say. Yes, and so does your body. When you are thinking, or playing, or running, your body is wearing away. Even when you are asleep it is wearing away a little every time you breathe. Why, then, does not your body soon wear out like your coat or hat or dress ? Suppose every time a tiny little thread breaks in your coat or dress you take your needle and put a new thread in its place. That would make the gar- ment last a long time, would it not ? Careful mending, but of another kind, is going on all the time in our bodies. Your dress or coat is mended with a piece of cloth or thread ; the wear of your body is mended with your food. If we were to go without food a little while the body would begin to wear out because there would be no food to mend it. People have gone without food for forty days ; but the most of us would die before that time if we should eat nothing. Did you ever think that you might forget to eat sometimes if you were not put in mind of it? The hungry feeling which you have when you have HEALTH FOR LITTLE FOLKS. been without food for a few hours is to remind you that your body needs food and that you ought to Sheep and lambs in winter. eat. Now you know another rea- son why we eat. We need food to keep the body from wearing out. WHY WE NEED TO EAT. 5 We eat because our bodies are all the time wear- ing out and food is needed for mending them. But we need food for still another reason. Did you ever see a flock of sheep with their little lambs on a cold day in spring ? If you have, per- haps you noticed one or two very thin little i:vmbs standing all drawn up as though they were cold. These poor little lambs did not get enough to eat and they felt the cold more than the plump, well-fed lambs. People who do not have enough to eat feel the cold more than those who have plenty of good food, for food helps to warm the body. We need food to keep the body warm. Now you know three reasons why we eat. We eat because we must have food to make the body grow, to mend it, and to keep it warm. Questions. Why does a little girl need a larger dress every year than she did the year before ? Why must a boy's new boots be larger than his old ones ? What is it that makes children's bodies grow larger and heavier? Why must children eat? Why is the body something like a coat or dress? Why does the body not wear out like a coat or dress ? What is the body mended with ? Why does a hungry lamb feel the cold more than a well-fed lamb ? What tells us when the body needs food? Give three reasons why we need food. CHAPTER II. v Kinds of Food. LESSON II. Now that we know why we need to eat, let us step into the market and order a dinner. Here are meats of all kinds and vegetables and fruits. What a variety ! We may take our choice from them all. But first we must think what time of the year it is, and whether the weather is cold or very warm. Some kinds of food are better for warm weather and others for cold weather 6 KINDS OF FOOD. / If you were a little Eskimo boy or girl you would want a dinner of "whale blubber," which is almost clear fat. You would much rather have a tallow candle for dessert than the best fruit or candy. The reason is that the Eskimo boy lives in a cold country and likes the food that is best foj warming his body. Fatty foods are good for warming the body. Let us make believe we are going to market on a very cold morning. You, too, will then want to order food that is good for keeping the body warm ; but we need not order "whale blubber." We shall find other kinds of fatty food. We will order some butter to eat on our bread and to use in cooking. Good butter is a healthful fat ; but if it has a strong taste it is not good and we should not eat it. When we come to buy our meat we shall find some fat in that. There is some, too, in our milk. How would you like some nuts ? Here are hick- ory nuts, butternuts, Brazil nuts, hazel nuts, and chestnuts. They all contain more or less fat in the shape of oil. If well chewed they are health- ful, especially chestnuts when nicely roasted or boiled. 8 HEALTH FOR LITTLE FOLKS. Do not buy these nuts to eat between meals or after you have eaten all the dinner or supper you want Eat them as a part of your meal, or remem- ber not to eat so much other food when you are to have them. From butter, and meats, and nuts, we shall get all the fat we need. Here is some maple sugar. You are very fond of maple sirup on your cakes in winter, and you like other sweets. Sweet foods are good for warming the body. Many plants, fruits, and vegetables have a sweet taste because they contain sugar. The juice of the sugar-cane plant contains a great deal of sugar, which may be obtained in a dry form by boiling off the water. Most of the sugar we use upon the table and in cooking is obtained in this way from the sugar-cane plant. Maple sugar is obtained from the sap or juice of the maple tree. Sugar is also made from a kind of beet called the sugar beet. Most grains contain a little sugar; but it is so very little that you would scarcely notice it. Perhaps you have found that a few grains of KINDS OF FOOD. wheat taste sweet after you have chewed them for a while. This sweet taste comes not so much from the sugar in the grain as from the starch, which, Gathering the wheat. strangely enough, begins to change to sugar as you chew it. A crust of bread, too, tastes sweet when you have chewed it well, because the starch of the flour from which the bread was made changes to IO HEALTH FOR LITTLE FOLKS. sugar as it is chewed and moistened in your mouth. We need food containing starch, therefore, for the same reason that we need food containing sugar. Starchy foods help to warm the body. What kind of foods containing starch shall we order from the market ? Here are potatoes, which are little else than starch and water. You may order some potatoes ; but tell the cook not to fry them. Have them baked or boiled. Nearly all foods are less healthful when fried in fat than when cooked in other ways. Here is rice, which is another starchy food, and here is macaroni ; or you may order sago or tapioca to be made into pudding for dessert. Corn also contains starch and fat as well. Hence it is a good food to eat in the winter. We may buy canned corn, or corn meal which may be made into muffins and corn bread. Our bread, oatmeal, gems, muffins, cakes, and other articles of food made from flour, all come from the grains, such as wheat, rye, oats, barley, or corn. All of these grains contain starch. Starch forms a large part ot food made from grains. From all of this starch we get a great deal of KINDS OF FOOD. II sugar, because starch turns to sugar after we have eaten it. We get sugar, too, in other ways. Our fruits, such as apples, pears, oranges, and grapas, contain sugar which forms in them while they are ripening. But we are so fond of sweet thingst that we are not satisfied with the natural sugar Jpf the fruits and grains. We put extra sugar ip^jcmr fruits when we cook them or serve them 'e/n the table. We make our pies and puddings sweet with sugar, and some- times we add it to o"ur oatmeal or cooked wheat. We are generally^ in danger of eating too much sweet things rather than not enough. If we ea\t much candy we shall be likely to get more sweet than is good for us ; besides, we may get in the candy other things that will do us harm. Sometimes those who make candy put into it other things which are cheaper for them to use than sugar, but which make the candy unhealthful, and the col- oring matter is often poisonous. If you must have candy, it is better to make it at home out of good sugar than to eat what is sold in the stores. We must not eat so much sweet and fatty food that we do not care for other kinds of food. You remember that food is needed for mending 12 HEALTH FOR LITTLE FOLKS. and building up the body as well as for keeping it warm. We must keep a large place in our basket for foods that will mend the body. Fatty and starchy and sweet foods are good for warming the body. Questions. Why does the little Eskimo boy need much fatty food? What foods besides those that contain fat help to warm the body? How do we get sugar from grains? Name some healthful starchy foods. LESSON III. What can we buy for mending the body and making it grow large and strong ? Plenty of things. First, we will have some milk. The baby, you know, lives on milk for months, and grows larger and stronger every day. Milk contains every kind of food the body needs fat, sugar, and all ; but we are so made that we can get our food from other things as soon as we have teeth for biting and chewing. We must be very careful to use only good milk. Milk from an unhealthy cow may make us ill. Next to milk for giving us nearly everything the KINDS OF FOOD. 1 3 body needs for food is wheat. This is one of the grains that the farmer raises in his fields. The miller grinds the wheat into flour, and then it is ready to be made into bread. You have heard bread called the "staff of life." We need bread as much as the lame man needs his Thrashing the wheat. staff. Nearly every one eats bread three times a day and does not grow tired of it. We will order a loaf of bread for our dinner, but not white bread. Some parts of the wheat that we need for food are taken out of it when it is made into fine white flour. We will have Graham bread, or bread made from the whole wheat flour. 14 HEALTH FOR LITTLE FOLKS. We do not get the best bread from fine white flour. The farmer raises other grains besides wheat that make good food. Rye and oats are some of these. Good bread may be made from rye flour, also from corn meal mixed with wheat or rye flour; but neither of these kinds of bread is quite as good for constant use as bread made from wheat flour. Oatmeal makes excellent rolls or gems. Oatmeal cookies or crackers are good. Cooked oatmeal is one of the best dishes to have for your breakfast if you wish to grow large and strong. If you do not like oatmeal, or if it does not agree with you, you may eat instead some form of cooked wheat, as Graham mush, cracked wheat, or wheatena. What kind of meat shall we buy ? Here are beef, mutton, lamb, veal, pork, chickens, turkey, and game. We will take beef to-day. Beef is the best kind of meat for everyday use. Sometimes we may take mutton, which is nearly as good as beef. Fish, poultry, and game will give us a variety when we become tired of beef or mutton. We must be as careful about buying good meat KINDS OF FOOD. 15 as good milk. Meat that has been kept too long, or meat from a diseased animal, should never be eaten, as it may make us ill. Pork is not a safe meat to eat. It is often dis- eased. If it is ever used it should be very thor- oughly cooked. Then, if it is diseased, it will not be so likely to injure us as it will if eaten raw or partly cooked. Many people have died from eating raw pork that was diseased. If we do not care for meat we may eat eggs. Nearly everything we need for food is contained in the egg. We may cook eggs in a variety of ways. One good way is to break them into boiling water or milk. Another good way is to pour boiling water on the egg, and let it stand in the water, closely covered, for several minutes. In this way the egg can be cooked as hard as one likes it without be- coming tough, as when boiled. Eggs are not as healthful when fried in fat as they are when cooked in other ways. From peas and beans we get nearly the same kind of food as from meat, and they cost much less. In summer we can buy young peas in the pod ; but in winter we must buy them in cans or dried. Dried peas make excellent soup. l6 HEALTH FOR LITTLE FOLKS. Beans are good either boiled or baked. They also make good soup. Other wholesome vegetables are turnips, cabbage, tomatoes, celery, beets, and lettuce. If you were ordering your dinner in summer you would buy less meat and less sweet and fatty foods and more fruits than in winter. When the weather is very hot we all want to keep our bodies as cool as possible, and we need less heat-making foods. In summer we need less meat and fat and sweet food than in winter. Berries, apples, pears, peaches, grapes, and other delicious fruits ripen for us to eat in summer, because we need them most at that time of the year. Some fruit is good for us all the year around. We shall find in the market in winter oranges, grapes, apples, prunes, dried apples, dried peaches, several kinds of dried berries, and nearly every kind of fruit preserved in cans. We may take our choice of all these. If we buy canned fruit we should take that in glass or earthenware jars. Tin cans are liable to poison fruits or vegetables that are at all sour. KINDS OF FOOD. I/ In .hot weather we should eat plenty of good ripe fruit. Questions. Why is milk a good food? What kind of milk may make us ill ? What grain raised by the farmer gives us the best food ? What other grains besides wheat give us good food ? What is one of the best breakfast dishes for a growing boy or girl? What kind of meat is the best for steady use ? What other kinds of meat are good ? What kind is liable to be diseased? About what must we be careful when we buy meat? If we do not care for meat, what other kinds of food will take its place? How should our food in summer differ from our food in winter? Why should we not buy sour fruit in tin cans. CHAPTER III. The Body needs Water, Salt, and Lime. LESSON IV. DID you ever think how dreadful it would be if you could get no water to drink when you are thirsty? It would be worse than having no food to eat when you are hungry. People who have been lost at sea or fastened down in mines or wells, where they could get neither food nor drink, say they suffered more from thirst than from hunger. We can live longer without food than we can without water. Why is water so necessary to us ? One reason is because Diagra?n showing- pro- water makes up a large part of portion of -water to rest IT T r 1111 of th, tody. Skadti Ur b dleS - K y UI " Wh le b d y portion represents wafer. weighs sixty pounds, the Water 18 THE BODY NEEDS WATER, SALT, AND LIME. ig in it weighs forty-five pounds. About three quar- ters of our bodies by weight is water. No part of the body can do its work without water. When you chew your food the water of your mouth helps to prepare the food for being swal- lowed. When the food reaches your stomach it finds water there, as you will soon learn. A large part of the blood that drips from your finger when you have a cut is water. The water in the blood helps the blood to flow easily through all parts of the body. Your flesh, that feels so soft and tender, would be hard and dry like a piece of chalk if it were not for the water in it. Water is needed inside of the body to help keep it clean. You have learned that your body is all the time wearing away a little. The water in the blood which flows through every part of the body, as you will learn later, soaks up the worn-out matter and washes it away. The same water does not remain in your body all the time. When you run until you are very warm you can see the water coming out through your skin. You call it per-spi-ra-tion. Sometimes 20 HEALTH FOR LITTLE FOLKS. A city drinking fountain. on a cold morning you say you can "see your breath." What you see is the water passing out of your body in your breath like a little cloud of THE BODY NEEDS WATER, SALT, AND LIME. 21 steam. It is passing out just the same on a warm day, but you can not see it. The water that leaves the body every day must be made up by taking more. We do not have to drink all the water the body needs each day, for we get a great deal of it in our food. Perhaps you have seen the cook put a teacupful of rice in a kettle with a pint or more of water to boil for dinner. When it was brought to the table it filled a large dish, yet only a tea- cupful of rice was put into the kettle and nothing but water was added, with perhaps a pinch of salt. The rice swelled and soaked up the water, and when you ate the rice you were getting some of the water your body needed. Juicy fruits contain a great deal of water, and nearly all food contains some; but we do not get all the water the body needs from our food. When we run hard or become very warm we are almost sure to feel thirsty. This is because the water in our bodies has been rapidly leaving them in per-spi-ra-tion and more is needed to take its place. Thirst tells us when our bodies need water. We must be careful to drink only pure water. People are sometimes made ill by drinking water A country drinking fountain. THE BODY NEEDS WATER, SALT, AND LIME. 23 that contains impure or poisonous matter. One can not always know by the appearance of water whether it is pure or not. If you put a teaspoonful of salt in a glass of water and stir it awhile the salt melts away. It is in the water, but you can not see it. We say the water dissolves the salt. Water dissolves many things besides salt some that are poisonous. You can know when water has salt dissolved in it by tasting it, though you can not know by looking at it ; but you can not always know when water has poisonous matter dissolved in it either by seeing, smelling, or tasting it. How, then, can we know when water is good for us to use ? We must know where it comes from and whether it has been where it could soak up poi- sonous matter on its way to us. We should never drink from a well that is near a cemetery, barnyard, pig pen, or other foul place. We should never drink water from a stream that has flowed past any unhealthful place or received any foul drainage. Water that is not pure should be boiled and strained before being used. Questions. How much of our bodies is water? Why does the blood need water? How does water help to keep the body clean? 24 HEALTH FOR LITTLE FOLKS. Why does the body need a fresh supply of water every day ? From what do we get a great deal of water besides the water we drink? What does thirst tell us ? Why should we be careful to drink only pure water? When is water most likely to be pure? From what wells or streams should we never drink? LESSON V. Lime. Water dissolves lime, but lime is not a poison. Our bodies need lime, though we never eat it clear. We get it in our food and drink. The growing grain takes up lime out of the earth, and when we eat the bread and other food made from the grain we get the lime. The cow gets lime in the grass she eats and passes the lime on to us in her milk. Some water contains a great deal of lime^ and is called " hard " water. You can not make soap bubbles with hard water, for it will not foam. We need lime for our bones. In some parts of the country where there is much lime in the water the people grow to be very tall. It is thought that the lime they get in the water makes their bones grow large. Children who do not get enough lime in their food are likely to have small, weak bones. THE BODY NEEDS WATER, SALT, AND LIME. 25 Whole-wheat bread and good milk give us lime for our bones. Questions. From what do we get the lime our bodies need? What part of the body has a special need for lime? What shows that children need to eat food that has some lime in it ? Salt. Our bodies need salt. This, too, we get in our milk, vegetables, and grain ; but we want more salt than such food furnishes us. We there- fore put clear salt into many articles of food as they are being prepared for the table. Nearly all animals are fond of salt, especially those that live on grass, hay, and grain, or other vegetable food. The wildest sheep in the flock will crowd about the farmer when he goes out to give them salt. There are other salts beside the common salt we use on the table and in cooking. The chief use of some vegetables, such as lettuce, is the salts they contain. Questions. Why do we salt our food? What animals like salt ? From what do we get other salts beside the common white salt used on the table? CHAPTER IV. Drinks that contain Alcohol. LESSON VI. WHAT kind of fruit do you like best ? Most boys and girls like nearly all kinds. Good ripe fruit is a necessary part of our daily food. It is much better to spend our money for fruit than at a candy store. Men sometimes squeeze out the sweet juice of good fruits and make it into poisonous drinks. It is a great pity to have the fruit that is good for our use spoiled to make drinks that do us harm. It is well for us to learn how some of these drinks are made ; then we shall know why they are harmful. Wine. A harmful drink called 'wine is made from grapes. To make wine men crush grapes in a press and DRINKS THAT CONTAIN ALCOHOL. 2? squeeze their juice into a big tub or vat that is put under the press to receive it. You have often seen upon the skins of grapes a kind of dust that you could easily rub off. When grapes are being pressed the juice that flows from them washes off some of this dust and carries it into the vat. In this dust are some very tiny things called ferments. They are so small you can not see them unless you look at them through a glass called a magnifying glass or microscope. A micro- scope, as you may know, makes things look many times larger than they really are. If you should look at a ferment through a micro- scope you would see a very tiny speck without much shape or color. You might think it too small to do any harm ; but many ferments together can do a great amount of mischief. They quickly spoil good grape juice after it has been pressed out of the grape. How do you think they do this ? The juice of grapes is sweet, as you know, be- cause there is sugar in it. No one puts the sugar in the grape ; it forms in them while they are ripen- ing. Just how this is done we do not know. 28 HEALTH FOR LITTLE FOLKS. The ferments change this sugar of the grape juice, after it is pressed out, into a gas and a poison. They can not do this while the juice is inside of the unbroken grape, for they do not get inside the fruit while it remains whole. But when the juice is squeezed out of grapes and is left standing in the vat, the ferments that were on the stems and skins of the grapes begin to work upon the sugar of the juice. Other ferments, too, get into the vat from the air. Ferments are so small and light that they are easily carried about in the air. How can we know when ferments are turning the sugar of grape juice into a gas and a poison ? We can know by the little bubbles of gas we see rising up through the juice. This gas passes out into the air, but the poison remains in the wine and makes the wine poisonous. The name of this poison is alcohol. There is no alcohol in a sound ripe grape. No one should drink wine, for there is alcohol in it. Alcohol. All poisons do not at once kill those who take only a little at a time; but a man could easily take enough alcohol to kill him at once. The DRINKS THAT CONTAIN ALCOHOL. 2Q man who takes a little alcohol every day is seldom as strong a man, as wise a man, or as good a man as he would be without alcohol. The alcohol hurts his body and his mind. Alcohol may make a father cruel to his children and to his wife. It sometimes makes a man tell falsehoods and do other bad deeds. One of the most dangerous things about alcohol is that it can make those who take it want more alcohol. If you should begin to take wine, the alco- hol in it might make you want to drink more and more wine until you cared for nothing so much as for drinking wine. It is the nature of alcohol to make those who take it want more alcohol. Questions. What drink is made from the juice of grapes? How do men get the juice to make into wine? What gets into the juice as it is being pressed out? Why can you not see ferments without a magnifying glass? What do ferments do to the sugar of grape juice ? Why do they not do this while the juice is in the fruit? When do ferments begin to spoil grape juice? How can we know when ferments are beginning to work in grape juice? What becomes of the gas ? What becomes of the poison ? What is the name of this poison ? Why should no one ever drink wine ? What is alcohol ? What may alcohol do to a man who takes a little every day? What is one of the most dangerous things about alcohol? What harm might a little wine do to you if you should drink it? Why? 3O HEALTH FOR LITTLE FOLKS. LESSON VII. Cider. Men sometimes grind up apples and press out their juice to make a drink called cider. There are ferments on the skins of the apples just as there are on the skins of the grapes. When the apples are ground and their juice is pressed out, these ferments and others from the air get into the juice and quickly spoil it. They turn the sugar of the apple juice into gas and alcohol. You can see the bubbles of gas passing out of the apple juice in a very short time after it has been pressed out of the apples. These bubbles show you that the sugar is changing and alcohol is forming. We may eat our apples without fear of being poisoned by alcohol because the ferments can not turn the sugar of apple juice into alcohol while the juice is inside of the apple. They begin their work very soon after the juice is pressed out. Cider that is made in the morning will have alco- hol in it by night if the weather is at all warm. It begins to be a dangerous drink as soon as it begins to have alcohol in it. No one should think that because there is only a little alcohol in cider it is harmless, for a little DRINKS THAT CONTAIN ALCOHOL. 3! alcohol has the power to start a boy on the road to drunkenness. Every drunkard began his drinking habit by taking a little alcohol. He at first thought that a little would not hurt him ; but it made him want more, and when he took more he wanted still more. People used to think there was no harm in taking cider; but we know now that cider drinking has made many drunkards. As cider grows older, more and more alcohol keeps forming in it, for the ferments keep turning more of its sugar to alcohol. As this goes on, the cider is said to be growing hard. Hard cider often has as much as one cupful of alcohol to ten cups of cider. A man can easily get drunk on hard cider. Cider drunkards are usually very cross. Cider is not a safe drink because it contains alcohol. Cider is often made into vinegar. This is done by leaving it in a warm place until a new ferment enters it and changes the alcohol of the cider to a sharp acid. There is no alcohol in vinegar, be- cause these ferments change the alcohol to some- thing else. 32 HEALTH FOR LITTLE FOLKS. The ferments that turn alcohol to vinegar are not the same as those that turn sugar to alcohol. There are many kinds of ferments, and each kind has its own work to do ; but one thing is true of all kinds : ferments always change the nature of the substances they work upon. People have thought that cider must be good because the apples it is made from are good, or that wine must be good because the grapes it is made from are good. This is a mistake. The ferments change the nature of the grape juice and apple juice by turning their sugar to the poison alcohol. Questions. From what is cider made? What gets into the juice of the apple as it is being pressed out ? What do the ferments do to the apple juice? Why is the juice of the apple unharmed while it is in the whole apple ? How soon may you find alcohol in the pressed-out apple juice? When does cider begin to be a dangerous drink ? Why should no one think that cider is harmless when it has only a little alcohol in it? How does every drunkard begin his drinking habit? What does a little alcohol do to him? What do we know about cider drinking? Why does more alcohol keep forming in cider as it grows older? How much alcohol is often found in hard cider? Into what is cider often made? What causes the cider to change to vinegar? Why is there no alcohol in vinegar? What do fer- ments always do to the substances they work upon ? How do they change the nature of good grape juice and apple juice after these are pressed out from the fruit ? DRINKS THAT CONTAIN ALCOHOL. 33 LESSON VIII. Beer. Some drinks that have alcohol in them are made from grains, such as barley, rye, and corn. You remember that these grains contain starch, and that starch turns to sugar when you eat it. The starch in grains will also turn to sugar if the grain is kept warm and moist. This is what happens when the farmer sows grain in his fields. The earth where the grain lies is kept moist by the rain and warmed by the sunshine, and soon the grain begins to sprout. If you taste of sprouting grain you find it sweet. The starch in the grain has turned to sugar to feed the little sprouts before they have roots for drawing their food from the earth. When grain is to be used for making beer it is not put into the ground to sprout, but is piled in a heap where it is kept warm and moist. When the brewer sees the little sprouts coming out he knows that the starch of the grain is turning to sugar. Then he heats the grain to kill the sprouts and prevent their taking up the sugar. Next he grinds the grain, which is now called malt, and puts it in a big vat of water. The sugar 34 HEALTH FOR LITTLE FOLKS. of the malt soaks out into the water and makes the water sweet. In this way the brewer gets from dry grain a sweet liquid to make into a drink containing alcohol. The ferments that work in the sweet grain juice, to make beer, do not come from the grain, but from yeast which the brewer next puts into the vat. Some might get into it from the air if no yeast were put in, but the brewer prefers to use yeast. He also puts in hops, which give the beer a bitter taste. Soon after the yeast is put into the vat of grain juice, little bubbles of gas begin to rise through it and froth gathers on the top. The bubbles show that the sugar of the liquid is being changed to gas and alcohol. The alcohol does not pass off like the gas, but remains in the liquid, making it poisonous. This liquid is called beer. No one should ever drink beer, for it is poisoned with alcohol. The boy who begins to drink beer soon comes to be very different from the boy who never touches it, or from what he himself might be if he did not drink it. The alcohol in the beer dulls his mind. He can DRINKS THAT CONTAIN ALCOHOL. 35 not learn his lessons as well ; he can not even play as well, because he is not as strong as he would be without the beer. Beer drinking spoils a boy's chances of being a strong, wise, or good man. y <. i Homemade Beer and Wine. People sometimes steep roots and bark in water, a^id svjgjar and yeast, and let it stand until it has " worked," as they say. This- they call homemade) beer^and think it must be harmless because they put nothing bad into it. But we know th^re js alcohol in it, because the yeast that was putf-in turned the sugar to alcohol. It was the bubbles of gas escaping as the alcohol was forming that made it "work." We should not drink homemade beer, for it contains alcohol. The juice of elderberries, currants, or other fruit is often made into wine by housewives and called homemade wine. The juice of the fruit is squeezed out and put into bottles ; but the ferments get into it before it is bottled up and begin at once to change the sugar of the fruit juice to alcohol. All liquids that contain alcohol are poisonous drinks. 36 HEALTH FOR LITTLE FOLKS. Questions. From what are some kinds of alcoholic drinks made? What do grains contain? What becomes of the starch when you eat the grain? How is starch turned to sugar when the farmer sows it in his field? How does the brewer turn starch to sugar when he wishes to make beer? Why does he kill the sprouts? What does he call the grain after the sprouts are killed? How does he get the sugar out of the malt ? What kind of a liquid is the water in which the malt has been soaked? What does the brewer put in this sweet liquid to make it ferment ? What is yeast? What changes begin to take place in the sweet liquid after the yeast is put in? What becomes of the gas and what becomes of the alco- hol? What is the liquid called? Why should no one ever drink beer? What will be likely to happen to the boy who begins to drink beer? What shows that alcohol dulls his mind? How is homemade beer made? How does alcohol come to be in it? What kind of drinks are all liquids that contain alcohol? LESSON IX. DISTILLED LIQUORS. The alcohol in cider, beer, or wine is mixed with water. Those who learn to like alcohol by taking these drinks are likely to want drinks that contain more alcohol and less water. To make such drinks, men get rid of some of the water in liquors like cider, beer, and wine, by heating them. You have often seen steam coming out of the nose and around the lid of the teakettle when it is boiling on the stove. This steam is only water DRINKS THAT CONTAIN ALCOHOL. 37 changed by heat to another form. Another name for steam is vapor. When steam comes against a cold window pane it is changed back into water and trickles down the window in drops. The water that is changed into vapor by heating is changed back again into its liquid form by cold. Heat changes alcohol as well as water into vapor ; but it takes less heat to change alcohol into vapor than to change water into vapor. When wine or cider is heated to make stronger drinks the alcohol is changed to vapor before the water. It rises and thus becomes separated from the water. This vapor is made to pass through a long cold pipe, where it is cooled, and turned into a liquid which drips from the pipe. This liquid is very strong with alcohol. This process is called distillation, and the liquors made in this way are called distilled liquors. Brandy, whisky, rum, and gin are distilled liquors. They are usually more than half alcohol. Beer, wine, and cider do enough harm to those who drink them. Brandy, whisky, rum, and gin do still more because they contain more alcohol ; but the use of the weaker drinks leads to the use of 38 HEALTH FOR LITTLE FOLKS. the stronger. It is their nature to do so as it is the nature of all alcoholic drinks to lead to drunk- enness. Beer, wine, and cider are likely to make one want stronger drinks. The people of Japan have this saying, which is well worth remembering : "A man took a drink ; then the drink took a drink; then the drink took the man." Water will not make a man keep wanting to drink water. Milk will not make a man want to keep drinking milk ; but it is the nature of alcohol to make those who take any drink containing it want more alcohol. Questions. What is mixed with the alcohol in cider or wine ? Why do men often wish to get rid of some of the water in cider or wine? What is steam? What is another name for steam? How is steam changed back into water? When a mixture of alcohol and water is heated, why does the alcohol turn to vapor first? How can it be separated from the water? What are the liquors obtained by this process called? How much alcohol do they often contain? Name some of these strong liquors. What is it the nature of alco- holic liquors to do ? CHAPTER V. How Food is changed into Blood. LESSON X. DID you ever visit a paper mill ? If you ever did, perhaps you saw old dirty rags being ground up and made into clean white paper. In some mills paper is made from straw or wood. 39 4O HEALTH FOR LITTLE FOLKS. It is very wonderful that wood and straw and old rags can be changed into clean smooth paper. But a more wonderful change than this takes place in your body after every meal you eat. Bread, meat, potato, and other kinds of food are changed after you swallow them ; first into blood, and then into flesh, bone, skin, hair, and other parts of your body. The first part of this wonderful change begins in your mouth when you chew your food. The Teeth. You have in your mouth two rows of strong little cutters and grinders which you call your teeth. They are hard and white and of differ- ent shapes. The front teeth are shaped for biting off the food, the back teeth for chewing or grinding it. The work of chewing our food is very important. If it is not done well the food is likely to give us trouble afterward. It is very necessary, therefore, to have good teeth that can chew well. The teeth are made to last a long time, especially the second teeth, which begin to come out when we are about seven years old. Each tooth has a strong, hard covering to keep it from being injured or worn away. This covering may be cracked or broken by wrong treatment, and then the tooth soon begins to decay. HOW FOOD IS CHANGED INTO BLOOD. 4! No one wishes to have decayed teeth. They look bad and make the breath smell bad and they can not do their work well. To keep your teeth from decaying you should give them good care. Clean your teeth every day with a soft tooth- brush. Unclean teeth make a person very offensive to those about him ; they are also more likely to decay. Do not pick your teeth with a pin, but use a quill or wooden toothpick. A pin or anything hard may injure the hard covering of the teeth. Do not try to crack nuts with your teeth. If you do, you may crack your teeth instead of the nuts. Teeth were not made to be used for nut- crackers or scissors. Do not let anything very hot or very cold come against your teeth. Heat and cold may cause the hard covering of the teeth to crack. Chewing. When we chew our food the tongue pushes it between the teeth, the back teeth grind it, and the water of the mouth moistens it until it is ready to be swallowed. I have seen little boys and girls take a mouthful 42 HEALTH FOR LITTLE FOLKS. of bread or cake and then wash the food down with a drink of milk or water, scarcely chewing it at all. This is not right. The mouth has a fluid of its own called saliva that prepares the food for being swallowed better than any drink we can take. It is this saliva that turns starch into sugar. All starchy foods therefore need to be mixed well with saliva before they are swallowed so that the starch may be turned to sugar. It is said of one great man that he always taught his children to give as many bites as they had teeth to every mouthful of bread before swallowing it. This man has lived to be very old and is still strong and does a great deal of hard work. Here is a rule which may save 'you many doctor's visits if you follow it carefully: Chew your food well and do not drink while you are eating. Do not wash your food down with milk or water, but give it time to get well moistened in your mouth. When food is ready to be swallowed, the tongue rolls it to the back of the mouth and it drops down HOW FOOD IS CHANGED INTO BLOOD. 43 into a tube called the food pipe. This food pipe takes the food to the stomach. Questions. What wonderful change takes place in your body after every meal you eat? Where does the change in the food you eat first begin? Why is it necessary to have good teeth? Why should you clean your teeth every day ? Why should you not pick your teeth with a pin or other hard thing ? Why should you never crack nuts with your teeth? What may anything very hot or very cold do to the teeth if brought against them ? What takes place as we chew our food ? Why should we not wash down our bread or cake with drinks? Why does the saliva of the mouth need to be mixed with starchy foods? Where does food go when it is ready to be swallowed? LESSON XI. The Stomach. The stomach is a wonderful, soft, fleshy bag for preparing the ' food which we eat to be made into blood. It is shaped something like the body of a pigeon and lies crosswise in the body just at the waist. The boy who eats green apples is likely to have a pain that will tell him right where his stomach is to be found. When food reaches the stomach it meets there a watery fluid called the gas-trie juice. This juice mixes with the food and begins at once to dissolve it. The stomach churns the food slowly up and 44 HEALTH FOR LITTLE FOLKS. OESOPHAGUS EA TIC DUCT down and squeezes it around and around so as to mix it thoroughly with the gastric juice. If you could look inside your stomach as this slow churning process is going on, after you have eaten a meal, you would see the bits of bread and meat and potato grow- ing smaller until all the food in the stomach becomes soft and creamy something like thickened gravy, only lighter in color. When you swal- low your food in big hard lumps the stomach is not al- ways able to make those lumps fine. It will do its very best, for it is a faithful worker. It often tires itself out trying to do what you should have done with your sharp HOW FOOD IS CHANGED INTO BLOOD. 45 teeth. Some of the food becomes so well dissolved in the stomach that it passes directly into the blood without going farther. But how do you suppose it gets from the stomach into the blood? In a very curious way indeed. All over the inside of the stomach are many little blood vessels with walls thinner than the thinnest tissue paper. You know that if you put a piece of tissue paper into water it will soak up some of the water. The food that is ready to enter the blood from the stomach is so thoroughly dissolved that it can soak through the walls of the little blood vessels much as water soaks through tissue paper, and thus it gets into the blood. You could not tell it then from the rest of the blood. In fact, it is blood. Only a part of the food you eat is so well dis- solved in the stomach that it can enter the blood from there. The rest passes out of the stomach into the bowels. The bowels is a name given to a very long tube leading from the stomach to the lower end of the body. This tube is more than four times as long as your whole body, yet it is so snugly coiled up that it takes up only a small place in the lower part of the trunk of the body below the stomach. 46 HEALTH FOR LITTLE FOLKS. In the bowels where the food first enters from the stomach, more juices mix with the food and dis- solve it still more. Here are many more blood ves- sels, and as fast as the rest of the food is dissolved the blood vessels soak it up and take it into the blood. It is then ready to be carried to all parts of the body to feed and build up the body. Care of the Stomach. The stomach, like every other part of the body, is injured by making it do what it ought not to do. It is well to learn what your stomach can do and what it can not do so that you may give it only its proper work. Your stomach was not made to chew your food for you. Your teeth were made for that. If you try to make your stomach do the work your teeth should do, it will soon become too tired to do its own work well. Your stomach was not made to work all the time. After a meal it needs rest just as much as you do when you have been working or playing hard all day. For this reason you should not keep eating cake or nuts or candy or fruit between meals. The stomach was not made to digest more food than the body needs. Hunger tells you how much food you need. HOW FOOD IS CHANGED INTO BLOOD. 47 When you are no longer hungry, you have eaten enough. If you eat more than you should, you make your stomach do more work than it ought, and so you will be likely to tire your stomach with overwork. Everything you swallow has to go into your stomach. There is no other place for it to go ; and the stomach has to get rid of it. Remember this when you see something you would like to eat but know you have eaten enough already. The stomach can not do its work well unless it is kept sufficiently warm. If you cool it by drink- ing ice water or eating ice cream while at your meals, it has to stop working until it gets warm enough to go on. The stomach can digest some kinds of food more easily than it can others. It can not digest rich puddings, cakes, pies, and hot bread as easily as it can oatmeal porridge, wheat-meal mush, good whole- wheat bread a day or two old, or other wholesome food. Pork is not as easy to digest as beef or mutton. Very highly seasoned foods are not good for the stomach. Pepper, ginger, mustard, horse-radish, and strong spices are too hot and biting to be used very freely. You know how they make your mouth smart 48 HEALTH FOR LITTLE FOLKS. and burn if you take much of them. The stomach is lined with a very thin delicate skin as tender as the lining of the mouth, and hot things hurt it as surely as they hurt your mouth, only you do not feel it as much. You should never injure your stomach by drink- ing wine, cider, beer, rum, or any liquor that has alcohol in it. Alcohol is hot and biting, like mustard, pepper, and ginger ; but it is worse than these, for it can do harm in other ways that mustard and gin- ger can not do. It hurts the tender lining of the stomach, and when much of it is used it often makes sores on the inside of the stomach. Alcohol also injures the gastric juice and makes it unable to dissolve the food as it should. Alcohol also hardens the food in the stomach and makes it less easy for the gastric juice to dissolve. In these and other ways alcoholic drinks give people weak stomachs. No drink that has alcohol in it is good for the stomach. No one who wishes to have a healthy stomach should use tobacco. Tobacco contains a strong sub- stance that is dissolved by the saliva and thus gets into the stomach. This weakens the stomach and HOW FOOD IS CHANGED INTO BLOOD. 49 makes it less able to keep up the churning motion that mixes the food with the gastric juice. Many tobacco smokers and tobacco chewers are troubled with weak stomachs. Smoking or chewing tobacco injures the stomach. Questions. What is the stomach? What mixes with the food when it reaches the stomach? What does this juice do to the food? How does food look when the stomach has finished its work? Why should you never swallow your .food in big lumps? How does some of the food get into the blood from the stomach? Where does the remainder of the food go ? What is that part of the body called the bowels ? Where is this long tube packed away ? What mixes with the food in the bowels ? What do these juices do to the food? How does it get into the blood when it is dissolved? How may the stomach be injured ? Why should the stomach not be kept at work all the time ? How may you know when you have eaten enough? What harm may come from taking too much ice water or ice cream with your meals ? What kinds of food are hard for the stomach to digest? How do pepper, mustard, ginger, and other hot substances affect the stomach ? What does alcohol some- times do to the lining of the stomach ? What does alcohol some- times do to the gastric juice? What does it do to the food in the stomach? How does tobacco often harm the stomach? CHAPTER VI. The Blood. LESSON XII. DID you ever see a large river with boats sailing up and down on it? Here is a picture of one with a city on its banks. Some of the boats are carrying wheat, corn, vegetables, and other kinds of food to the people who live in the city where these things can not be raised. Thus the river brings food to the people by float- ing the boats that carry the food. The river also 50 THE BLOOD. 51 helps to keep the city clean. Pipes called drains run from all the houses to the river. Through these pipes unclean and waste matter flows from the houses into the river, and the river carries it away. The water of the river is very impure after it has received foul matter from all these drains, and it flows away to the ocean to be purified. Inside of our bodies is a wonderful stream that in some ways is like a river. It carries food to all parts of the body and washes away waste and worn- out matter from all parts. This wonderful stream is the blood. The Blood. You know how blood looks, for you have seen it coming out in red drops when you have scratched or cut yourself. You have learned, too, that blood is made from food. When you are well and eat the right kind of food, the blood carries to every part of the body just the kind of food every part needs. The bones get what they need for making more bone ; the stomach gets what it needs for making gastric juice. No part is left to starve. But if you eat cakes and candy when you should eat bread and butter, some parts of your body will have to go hungry. The blood will not have in it what all parts need. 52 HEALTH FOR LITTLE FOLKS. Blood made from good, wholesome food is better than that made from pie, cake, or candy. The blood needs good air, too, as well as food. If you spend most of your time shut up in the house the blood will become bad for want of pure air. To keep your blood pure you should run and play out of doors some time every day unless you are ill or the weather is too stormy. Grown people, too, need exercise in the open air as well as children. Take exercise in the open air to keep your blood pure. The blood often gets impure from the things we eat or drink. When people take such drinks as wine, beer, or cider, the alcohol in them quickly soaks through the little blood vessels of the stomach and gets into the blood. No part of the body needs alcohol. It does not feed any part, and it prevents many parts from get- ting the food they need. It is a poison when it goes into the stomach and when it is in the blood. Wher- ever it goes it does harm, as you will learn in later lessons. Do not poison your blood with beer, wine, cider, or tobacco. THE BLOOD. 53 Questions. Why is the blood in our bodies something like a great river ? What kind of food must you eat in order to have good blood that will feed all parts of the body ? What kinds of food will not make good blood for feeding all parts ? What besides good food does the blood need ? What kind of drinks makes bad blood ? What does alcohol do wherever it goes ? LESSON XIII. The Blood Vessels. How does the blood get to every part of the body ? Does it run around loose wherever it may happen to go ? No, in- deed. It stays all the time inside of little hollow tubes called blood vessels. When you cut yourself you cut open some of these tubes, and the blood runs out just as water runs out of a burst rubber hose. The blood vessels are of many sizes. Some are as large as your little ringer; some are smaller than the finest hair. But, however small they may be, they are still hollow tubes through which the blood can flow. Perhaps you wonder how the blood can carry food to all parts of the body if it is always shut up in the blood vessels. You remember how the food gets into the blood from the stomach by soaking 54 HEALTH FOR LITTLE FOLKS. through the thin walls of the small blood vessels. It gets out in the same way by soaking out through the thin walls of the small blood vessels all over the body. Every part of the body has its share of these small blood vessels with walls thinner than tissue paper. The kind of food needed by each part soaks out of the blood through these thin walls when it comes to the place where it is needed. The fa m ily pump . THE BLOOD. 55 The Heart. What do you think keeps the blood moving in the blood vessels? It does not always flow downhill like a river. The blood which was down in your feet two or three minutes ago may now be in your hands or head. This is another strange thing. How can the blood get from your feet up to your head when you are standing up ? It must flow uphill ; but blood can not flow uphill of itself any more than water can. Water is sometimes made to flow uphill by means of pumping machines. Men have invented some won- derful machines for pumping water from wells and rivers up into houses or into reservoirs on the tops of high hills. Fire engines force water through long pipes high up into burning buildings. The most wonderful of all pumping machines is the heart. You know where your heart is, for you have felt it going thud ! thud ! against your chest when you have been running. The heart is never still a minute. It is always pumping the blood through the blood vessels; but you do not always notice its action. When you run fast it has to beat harder and make the blood flow faster than when you are quiet, and then you feel it beating. HEALTH FOR LITTLE FOLKS. You can see from this picture how your heart looks. It is about as large as your fist and has four hollow places or rooms inside. These rooms are placed two above and two below, like the rooms in a two-story house. The blood flows from large blood vessels into the upper rooms of the heart until they are full, or nearly full. Then the walls of these rooms quick- ly squeeze together like the bulb of a syringe when you press it. This forces the blood out of the upper rooms into the lower rooms. It can not go back into the blood vessels again because little flaps called valves close like tight-fitting doors against the opening of the blood vessels and keep the blood from going back. When the lower rooms of the heart are full they too squeeze together and force the blood out into THE BLOOD. 57 the blood vessels that carry it away from the heart. About a tumblerful of blood is forced out of the heart at every beat. Arteries and Veins. The blood vessels that bring blood to the heart are called veins. Those that carry blood away from the heart are called ar- teries. The blood flowing to the heart in the veins moves slowly and evenly, like a man who is returning home tired by a long journey. The blood flowing away from the heart through the arteries flows more swiftly and with sudden spurts. At your wrist you can feel an artery swell out each time the blood spurts through it. You call it your pulse. The doctor knows by feeling your pulse how fast your heart is beating, for at every beat the arteries swell out with the fresh quantity of blood the heart forces into them. Each new quan- tity of blood thus forced into the blood vessels gives 58 HEALTH FOR LITTLE FOLKS. a sudden push to the blood in front of it, and so keeps the whole stream rushing through all the arteries. The large artery that receives blood from the heart for all parts of the body soon branches out inta smaller arteries. Some of these branches go to the head, some to the legs, some to the arms, and some to other parts. Each new branch sends out more and smaller branches until the smallest ones finally branch into the many hair-like blood vessels with very thin walls that run through every part of the body. From the smallest arteries the blood flows on through the hair-like blood vessels into the smallest veins. These join together and form larger ones until they all unite in two large veins that carry the blood back to the heart. Questions. What keeps the blood from flowing where it ought not to go ? Why does the blood flow out when you cut yourself? About how large are the largest blood vessels in your body ? What is the size of the smallest ones? How can the blood feed the body when it is shut up in blood vessels ? What keeps the blood moving in the blood vessels ? What is the heart always doing ? Why do you notice the beating of your heart more when you run than when you are quiet? How large is the heart? How is it divided? From what does the blood flow into the heart ? What forces it out of the heart? Into what does the blood go as it leaves the heart? What are the blood vessels that bring the blood to the heart THE BLOOD. 59 called ? What are those called that carry the blood away from the heart? How does the blood move through the veins ? How does it move through the arteries? Why does the doctor feel your pulse? Into what do the large arteries divide? Where do these branches go ? What kind of blood vessels are at the ends of the arteries? Into what does the blood flow as it passes out of these very small blood vessels? Where do the veins carry the blood? LESSON XIV. How the Heart and Blood Vessels may be in- jured. You can not begin to think how much work your heart does every day. The largest engines men have ever made can not lift as much, according to their size, as your busy little heart. The heart is never lazy. There is more danger that it will tire itself with overwork than that it will ever become lazy. Alcoholic drinks tire the heart by making it beat too fast. These drinks are also likely to make too much fat in the heart. The heart has to be very strong to squeeze the blood out with enough force to send it through all the blood vessels. A heart that has much fat in it is too weak to do this. 6O HEALTH FOR LITTLE FOLKS. Alcohol weakens the heart by making it over- work and by causing too much fat to form in it. Tobacco also makes the heart beat faster than it should. It weakens it and makes it unsteady. Among boys who smoke cigarettes many are found who have weak and unhealthy hearts, caused by this foolish and harmful habit. Blood vessels are elastic something like a rubber band. When you stretch a rubber band it springs back. The walls of the arteries stretch as the blood spurts through them and then spring back. If you stretch a rubber band over a large book and keep it there a long time, it will not always spring back when you take it off. It loses its power of springing back by being stretched too much. When a person is in good health his blood vessels will stretch just a little, but not too much. If a man takes a drink of wine or beer or other alcoholic drink, the alcohol weakens the blood vessels so that they stretch more than they should. The man's face grows red because all the little blood vessels just under the skin are stretched too much and are too full of blood. If the man keeps on drinking wine or beer every day, the little blood vessels may remain stretched all the time. Like the rubber band that is kept THE BLOOD. 6 1 stretched too long, they lose their power of spring- ing back. Alcohol sometimes causes the coats of the blood vessels to grow thin. They are then liable at any time to cause death by bursting. Drinks that have alcohol in them injure the blood vessels. Questions. How does the work done by your heart compare with the work done by a large engine ? How do drinks that have alcohol in them tire the heart? In what other way are they likely to injure the heart? Would too much fat in the heart make it weaker or stronger? What does tobacco often do to the heart? What shows tbis to be true? In what respect are the blood vessels like a rubber band? How does alcohol injure the bloodvessels? Why does a man's face grow red after he has taken an alcoholic drink ? What does alcohol sometimes do to the coats of the blood vessels ? CHAPTER VII. How the Blood is Purified. LESSON xv. DID you ever try to sit perfectly still ? You found that you could keep your hands still and your feet still and your head still for several minutes, per- haps, but there was one part of your body you could not keep still more than a few seconds at a time. Your chest would keep swelling out and then falling back in spite of all you could do. It would only keep still while you held your breath, and you could not hold your breath long. One can live several days without eating or drinking, but no one can live for more than five minutes without breathing. What happens when you breathe ? Watch and see. Your chest swells out and you feel the air going into your nostrils. Then your chest falls in again and you feel the air coming out. Where does the air go to when you breathe it in? 62 HOW THE BLOOD IS PURIFIED. 63 From your nose it passes down through the back part of your mouth into a small pipe in the front part of your throat. This pipe is called the wind- pipe. You can feel the windpipe in the front t of your throat. It is stiff and hard because there are in it hoops of gristle that keep it always open. From the windpipe the air goes to your lungs. The Lungs. What are the lungs and how do they look ? Suppose you had a cluster of grapes and by some means you could take out the inside of each grape and leave the skins whole on the stems; and sup- pose the stems were all hollow so you could blow into them as you can through a goose quill. By blowing into the end of the large stem of the bunch you could " blow up " the whole bunch of grape skins just as you blow up a bladder. If you should then press the whole bunch together the air 64 HEALTH FOR LITTLE FOLKS. would rush out of each grape as it does out of the blown-up bladder when you squeeze it. The lungs are made up of many little roundish sacs or cells fastened to hollow tubes much as grapes are fastened in a bunch by their stems. Each cell, which is called an air cell, has a very thin skin called its wall. In the walls of the air cells are many little blood vessels which have also very thin walls. You remember that we said the blood was much like a great river? Besides carrying food and drink to all parts of the body, it washes away waste and worn-out matter. When the water of a river becomes foul with the waste matter from people's houses it flows away to the ocean, where it mixes with the great salt waves and is tossed about by the winds until it is cleansed. There is no ocean where the blood can go to be cleansed. It must be purified in the body. The same blood that took up impure matters must soon go back to the same place again ; but it must not carry the impurities with it. These the blood must get rid of before it comes around again. The lungs is the place prepared for the special purpose of cleansing the blood. How the Blood gets to the Lungs. The heart, you remember, has four rooms in it two under and HOW THE BLOOD IS PURIFIED. 65 two upper ones. Blood enters the two upper rooms from the veins and passes out of the two lower rooms into the arteries. The blood that is sent out all over the body comes from only one of these lower rooms the one on the left side of the heart. From the lower room on the right side of the heart the blood goes directly to the lungs. The artery that carries the blood to the lungs like the other arteries divides into many small branches. From these branches come the many lit- tle blood vessels with very thin walls that lie in the wajls of the air cells. The air we breathe in rushes into all the little air cells to meet the blood. The blood rushes from the heart into the tiny blood vessels in the thin walls of the air cells to meet the air. There is nothing, then, between the blood and the air but the thinnest of thin walls. Through these the part of the air needed to purify the blood can easily pass into the blood ; and some of the impure matters in the blood can pass out into the air through the same thin walls. These impurities are carried out of the lungs by the air as we breathe it out. The blood that goes to the lungs from the heart is very dark because of the impurities in it. When 66 HEALTH FOR LITTLE FOLKS. this blood leaves the lungs it is bright red, because it has been purified. Where does the blood go when it leaves the lungs ? Back again to the heart, to be sent out over the body. The left lower and left upper room of the heart are always filled with bright-red blood that has just been cleansed in the lungs. The right upper and right lower rooms are always filled with dark blood that has come from the veins and is on its way to HOW THE BLOOD IS PURIFIED. / the lungs to be cleansed. It is this dark blood in the veins that makes the veins look blue. Now you know the whole long journey that the blood makes. First it comes out of the left lower room of the heart and rushes through the arteries that carry it to the very small blood vessels all over the body. It is then bright red. While on its way through the small blood vessels it gives out food and takes up waste matter. This causes it to lose its bright-red color and turn dark. .From the small blood vessels the dark blood flows sluggishly through the veins to the right upper room of the heart. The heart sends it out from the right lower room to the lungs to be purified. From the lungs it comes back to the left upper room of the heart, to be sent out of the left lower room again all over the body. Questions. Why is your chest always swelling out and in? What is the longest time one can live without breathing? What do you take in when you breathe? Where does this air go to? Of what are the lungs made up? What are these tiny cells called? What kind of walls have these air cells? What are in these walls? Why does the blood have to go to the lungs ? How does the blood go to the lungs? How does the air get there? What is between the blood and the air in the lungs? What passes through these thin walls into the blood? What passes out of the blood into the air in the lungs? What is the color of the blood as it goes to the 68 HEALTH FOR LITTLE FOLKS. lungs ? What is its color as it leaves the lungs ? Where does the blood go when it leaves the lungs? Where does it go from the heart? Describe the journey the blood makes from the time it leaves the right side of your heart until it gets back to the same place again. LESSON XVI. Pure Air. No one should breathe impure air ; and yet we make the air impure by breathing it. Every breath we throw out from our lungs spoils nearly half a barrel of air. If you remain shut up in a room with the doors and windows closed you soon have to breathe over again the air that you have spoiled with your breath. If a number of people are in the room at the same time, the air is made impure so much the quicker. We can not help making the air bad when we breathe ; but we can help breathing over again the air we have spoiled. All we have to do is to open the doors and windows of our houses. The bad air will go out of itself and good air will come in of it- self if we only give it a chance. Outdoor air is like the water in the ocean it is always in motion. Air in a shut-up room is like water in a tub, a marsh, or a still pond. When im- purities get in it they remain in it. HOW THE BLOOD IS PURIFIED. 69 Sometimes the air out of doors has only a little motion. You can just feel it blowing gently against your cheek, and you say a breeze is blowing. Some- times the air moves in strong gusts that flutter your clothes and snatch off your hat. You call that a^ wind. Both winds and breezes help to purify the air. Trees and plants, too, have something to do with keeping the air pure. Some of the poisons we breathe out are just what the trees and plants take in through their green leaves to make them grow. The wind that comes dashing past our open win- dows drives our impure air off over the meadows and woods, where this poisonous part is taken from it by the trees and plants. In this way outdoor air is kept pure for us to breathe. But we are often careless about having pure out- door air to breathe. We shut ourselves up in our houses with all the doors and windows closed and breathe bad air over and over again, making it worse with each breath. Our houses should be so built that the bad air can be always going out and the good air coming in ; but if we have to live in houses that are not so built we must find ways of keeping the air pure. In 7