5. Of what use is the sweat?

6. How should the nails be cared for?

7. Tell what care should be given the hair.

8. Why should you not use another person's hair brush?

9. Why should the skin be washed often?

10. Of what use is a cold bath?

11. Why should the hands be well washed before handling food?

12. Why does the drunkard have a red nose?



CHAPTER XIII

CLOTHING AND HOW TO USE IT

Kinds of Clothing.—People are beginning to learn that the wearing of the right kind of clothing has much to do with keeping them well. Many persons wear too heavy clothing in winter. Keeping the body too hot makes it weak.

Some kinds of clothing are much warmer than others. Some are expensive and others are cheap. Cheap clothes will often serve the same purpose as the more costly ones. If you look at your handkerchief or stockings, you will see that they are made of threads running crosswise to each other. All clothing is made from threads. Some of these are wool, some are linen, a few are silk, and many are cotton.

Woolen Clothing.—Woolen clothing, such as overcoats and fine cloth dresses and suits, is made from the wool cut from sheep. Enough wool can be sheared from two sheep in one year to make an entire suit of clothes. The raw wool is first twisted into threads and then woven by machines into cloth.



Linen.—Linen is used in making collars, cuffs, and handkerchiefs. It is made from fine threads taken from the flax plant. On a piece of ground as large as a schoolroom enough flax can be raised to make a half dozen collars. Garments to be worn in warm weather are sometimes made of linen.

Silk.—Silk is used in making neckties, gloves, ribbons, and dresses. Silk cloth is woven from the cocoons made by silkworms. A silkworm is about as big as your largest finger. It grows to this size from the egg in one month. In three or four days it spins a shell of silk thread completely surrounding itself. This shell is called a cocoon. Within this it changes to a moth.



When the cocoons are to be used for silk, the worm is killed by heat as soon as it has woven its home so that it may not change to a moth and eat off some of the silk in getting out. Many thousand worms are needed to get enough silk for a dress. The worms are raised largely in China, Japan, Italy, and France.

Cotton.—All calico, muslin, and most cheap clothing are made from cotton thread. This is made from the cotton fibers surrounding the seeds of the cotton plant (Fig. 52). The cotton used in this country is raised in the Southern states.

Cotton clothing is stronger and wears much longer than silk or wool, but it does not look so well and is not nearly so warm.

The Use of Wraps and Overcoats.—Outer wraps and overcoats should never be worn in a warm room or while working hard. They cause much sweat to form on the body, and as soon as one goes out of doors the sweat begins to pass off. This makes the body feel cold and in some cases leads to a long sickness.

When riding in cold weather, extra wraps should be worn. Scarfs and furs should not be worn about the throat except in extreme cold weather. Bundling up the neck and chin is likely to cause sore throat.

Danger from Wet Clothing.—Many children have caught severe colds leading to serious sickness by wearing wet or damp clothing. Wet clothing causes the heat to pass off from the body quickly, so that it is chilled before we know it. This may be shown by wrapping two bottles of warm water in cloths. Wet one cloth and let the other remain dry. In twenty minutes the bottle with the wet cloth will be cool, but the other one will still be warm. If your wet clothing cannot be changed at once, keep exercising or throw a heavy coat about you.

Untidy and Soiled Clothing.—All boys and girls should learn to keep their clothing as clean as possible. Do not wipe the hands on the clothing, or sit down in the dirt, or let food smear the front of the coat or dress.

The sweat is constantly bringing waste matter out of the body. This soils the clothing next to it. On this account clothing to be washed every week or oftener should be worn next to the skin. Very thin cotton underclothing should be worn in summer. Woolen clothes give more warmth for winter.



Shoes.—Badly fitting shoes cause sore feet and much pain. A shoe that is tight across the toes is sure to cause corns. A corn is a thickened part of the top skin which presses on the more tender part beneath. Soaking the feet in hot water and filing off the top of the corn or using a corn plaster will help it. Shoes should always be a half inch longer than the foot. Waterproof shoes or rubbers should be worn in wet weather. Rubbers should not be worn in the house.

Alcohol and Clothing.—Many persons think that a drink of whisky will make them warm when taken on a cold day. For this reason whisky is sometimes used when clothing is really needed. The use of whisky or any other alcoholic drink will not make the body warm. It may make one feel warm because it loosens the muscles in the blood tubes of the skin and so lets more blood come to the surface. In this way the body becomes colder because too much blood gets into the skin and is then chilled by the cold air. As alcohol deadens the feeling it may prevent one from feeling cold when the body is really very cold. Too little clothing and too much alcohol have been known to cause men to freeze to death.

Experience in using Alcohol to keep the Body Warm.—Doctor Hayes, who went as physician with Doctor Kane to explore in the Arctic regions, said that he would never again take alcoholic drink with him on such a trip. He declared alcohol was of no use in helping men to keep warm. He found from actual experience that those who use alcohol cannot endure cold so well as other people.

Doctor Carpenter, a well-known physician, tells of a crew of sixty-six men who tried to stay in Hudson Bay all winter. They used some alcoholic drink. Only two of the party lived through the winter. Later another party of twenty-two men passed the winter in the same place. They used no strong drink at any time and as a consequence all but two of them were reported well and strong in the following spring.



CHAPTER XIV

BREATHING

The Lungs.—The lungs are two light spongy bodies filling up the greater part of the chest. The heart lies between the lungs. The lungs are formed largely of thousands of thin-walled sacs and two sets of tubes. One set of tubes carries air into and out of the lungs, and the other set is filled with blood. These sacs and tubes are held in place by a loose meshwork of tissue.



Why we Breathe.—Breathing means taking air into the lungs and forcing it out. The air is made to go into the lungs in order that a part of it called oxygen may get into the blood. The blood then carries the oxygen to all parts of the body where it can help the organs do their work.



The air which comes out of the lungs is not the same as that which goes in. Some of the oxygen has been used up and in its place is a heavier gas named carbon dioxide, which has been given out by the body. This carbon dioxide is part of the waste formed in every part of the body from the used-up food and dying parts of the body. We breathe therefore to get oxygen into the body and to take out some of the waste matter.

All animals must breathe. If our breath is shut off only four or five minutes, death results. In the earthworm the oxygen goes right through the skin into the blood. Bugs and flies have several little openings along the sides of the body which lead into tubes branching throughout the body to carry air. A fish gets air through its gills lying under a bony flap on each side of the head.



How the Air passes into the Lungs.—The outer openings of the nose are called nostrils. From here two channels lead back through the nose to the throat. The cavity of the throat behind the nose and tongue is the pharynx. At the bottom of the pharynx is a tube made mostly of gristle. This tube is larger than your thumb and is named the larynx, or voice box. The bump on its front part forms the lump in the throat called the Adam's Apple.

From the voice box extends the windpipe called trachea, down to the lungs. The windpipe divides at its lower end between the lungs into two branches. One of these enters each lung.

The Air Tubes in the Lungs.—As the branch of the windpipe enters each lung it divides into smaller branches just like the limbs of a tree. These divide into still smaller tubes, which branch again and again until they are as small as a hair. These hairlike tubes have swollen ends called air sacs. The walls of the air sacs are much thinner than tissue paper.



How the Blood trades Waste for Oxygen in the Lungs.—The blood, which is constantly running from all parts of the body to the lungs, collects waste formed from the burnt food and dying parts of the organs. When the blood comes to the lungs, it is full of this waste, called carbon dioxide. The blood tubes divide into fine branches with very thin walls and form a rich network over the air sacs. This allows the carbon dioxide and water to pass out of the blood tubes into the air sacs, while the oxygen at the same time goes through into the blood. More than a pint of water is given off in the breath daily.

How we Breathe.—The bottom of the chest cavity is formed by an upward arching sheet of muscle called the diaphragm. This is fastened to the lower ribs. The ribs at rest slant downward and inward. When the ribs are pulled up or the arch of the diaphragm down, the cavity of the chest becomes larger. The air then runs into the lungs and swells them out. When the ribs are let drop or the arch of the diaphragm goes up, the air is pushed out of the lungs.

Without thinking, we work the muscles to draw up the ribs about eighteen times every minute, because all parts of the body are calling for oxygen. The harder we work the oftener we breathe because the muscles need more oxygen to make them go.

Why we should breathe through the Nose.—Most persons find it easy to breathe through the nose. In some, however, the passages in the nose are too small to carry the air without effort. On this account they let the mouth hang open and breathe through it.



The air should pass only through the nose because it is lined with hairs and tiny waving threads which catch the dust. In this way germs and dirt are prevented from getting into the throat and lungs, and in winter the cold air is warmed.

Why Some Children cannot breathe through the Nose.—When one has a cold, the lining of the nose becomes swollen and gives out a white substance called mucus. The swelling of the lining and the mucus fill up the passages. The nose should be kept clean by using a handkerchief and blowing out the mucus into it. Never put the finger into the nose. Disease germs often get on the fingers from things touched.

Children who have the habit of breathing through the mouth should be examined by a physician. He will, in most cases, find soft spongy growths called adenoids in the back part of the nose. They should always be removed as soon as possible. They may cause disease or deafness and may even injure the mind.



The Voice.—In the upper part of the voice box at the top of the windpipe is a fold of tissue stretched on either side. These two folds of tissue form the vocal cords. The air rushing past them causes sound. The different sounds are made by stretching the cords tight or loosely. By means of the tongue, teeth, and lips the sound is formed into words.

How to use the Voice.—A cold or much shouting makes the vocal cords swell and we become hoarse. Rest is the best cure. It is not polite to shout or whistle in the house and you should never use an angry tone of voice. When talking to a person, always speak distinctly but pleasantly and turn your face toward his and look directly into his eyes. Never use a harsh, loud tone of voice.

Why you should not spit on Floors or Sidewalks.—We used to think that any one well had no germs of sickness in his mouth, but we now know that many well persons have germs in their mouths which can cause long sickness when they get into other persons. If you are sick with diphtheria, scarlet fever, or sore throat, the germs of the disease are likely to remain in your mouth two or three months. Persons with tuberculosis throw out millions of these germs in their spit every day.

Spitting is not only an unclean habit but a deadly curse. Spit often contains the seeds of death. Women's skirts and the soles of our shoes carry it into the houses. It becomes dry, but the germs live and float about in the dust, then enter the mouth to make us sick. Carelessness with spit is said to cause more than a hundred deaths every day in our land.

Do not use an Open Spittoon.—It is much safer to have a smallpox patient in the house than an open spittoon in the summer. You can prevent the smallpox by vaccination, but you cannot keep the flies from carrying ten thousand germs of death from the spittoon to the food on the table. A million germs have been found on a single fly.



Spit should be dropped into a cup which should be kept covered when not being used. The spit should be destroyed by fire or some germ-killing fluid, such as lye or formalin.



Keeping Sickness away from the Throat and Lungs.—All sickness of the throat and lungs is caught from some one else. The germs are passed from one to another on the drinking cup, by sucking pencils, wetting the finger to turn the pages of a book, or putting the fingers in the nose or mouth.



Dust is the partner of disease. It contains germs. Avoid dust. Wipe up the rooms with a damp cloth; never use a feather duster. Avoid dry sweeping. Use a suction cleaner or have rugs which can be cleaned out of doors.

Give the lungs fresh air and deep breathing and the body good food and plenty of sleep to make it so strong that germs cannot overcome it when they enter.



Alcoholic Drink and the Lungs.—The most common disease of the lungs is tuberculosis. Nearly all bartenders who sell strong drink take some themselves. Lately it has been learned in Germany that tuberculosis causes one half of all the deaths among bartenders. Alcohol was once thought to be a good medicine for lung troubles, but it has been clearly proven that beer and whisky weaken the lungs and make them ready for the germs of disease. The body already weakened by the poison of the alcohol is then easily overcome by the disease.

Tobacco and the Lungs.—The occasional use of tobacco does not seem to hurt the lungs when fully grown. A study of many young persons has shown that the chest of smokers grows much more slowly than in those who do not use tobacco. As the lungs cannot grow any faster than the chest, they must grow slowly in boys using much tobacco.

Tobacco is a common cause of sore throat. Many smokers have been compelled to quit the habit because of throat troubles.

PRACTICAL QUESTIONS

1. Where are the lungs located?

2. What do the tubes in the lungs carry?

3. What part of the air do we use in the body?

4. Tell how the air gets into the lungs.

5. What passes from the blood into the air sacs?

6. Why should we breathe through the nose?

7. Why should you keep the fingers away from the nose?

8. What are the vocal cords?

9. Give two reasons why no one should spit on the floor.

10. Tell how alcohol harms the lungs.



CHAPTER XV

FRESH AIR AND HEALTH

How much Air we Breathe.—At every breath we take in about one pint of air. We breathe eighteen times each minute. Nine quarts of air therefore pass in and out of the lungs every minute. Air once breathed is not fit to breathe again. It contains waste and carbon dioxide which weaken the body.

If you breathe three full breaths into a wide-mouthed jar or bottle, it will contain so much of the carbon dioxide that a lighted candle or splinter will at once go out when thrust into the jar. A cat shut in a tight box two feet square and one foot high will die in less than a half hour.

Many years ago when the British and Hindoo soldiers were fighting each other, the Hindoos made prisoners of 146 of the British and locked them in a room about one half as large as a common schoolroom. There were only two small windows. During the night 123 of these men died because of the bad air.



How much Air should enter a Room.—The air laden with waste coming out of the lungs quickly mixes with the other air of the room. In this way all of the air in the room soon becomes impure. Forty children will give out nearly two barrels of air in one minute. In another minute this air has made all of the other air in the room unclean. It can still be breathed, but it makes children feel drowsy and lazy and may cause headache. They then do poor work.

To keep the air pure in a room, fresh air must be let in from the outside. If there are many in the room, the openings must be large or fans on a wheel must be used to force the air in. In the New York schools a little over a cubic yard of fresh air is forced into the room for each child every minute.

How to get Fresh Air into a Room.—When air is warmed it becomes lighter and rises. In many public buildings, fresh air heated by a furnace is forced into the rooms through pipes entering several feet above the floor. By a fan or heated flue the impure air is sucked out of the room through openings near the floor.



Changing the air in a room is called ventilation. To get plenty of fresh air in a room there must be one or more places for it to enter and one or more places for it to pass out. Where there is no furnace or fan, windows on one side of the room may be opened at the bottom to let in the air and the same windows opened at the top to let the impure air escape. Do not sit in a draft, but use a board or curtain to throw the air upward as it enters the window. A room should not be kept too warm. Sitting in a very warm room weakens the body and prepares it to take cold. The temperature of a living room should be between 65 and 70 degrees.

Fresh Air while you Sleep.—Thousands of people have weakened their bodies and brought on disease by sleeping in bad air. Many persons keep their windows so tightly closed during the night that the air smells bad in the morning. I knew a family who always slept with windows closed except in the very warmest weather. Three of the children died of tuberculosis, and a fourth one took the disease but was saved by keeping his windows wide open.

Bad air in the sleeping room makes one feel drowsy in the morning instead of refreshed by sleep. Your windows should always be open while you sleep. In cold weather a window should be open a foot at both the bottom and the top, or if there are two windows in the room, both may be opened at the bottom. In moderate weather the openings should be twice as large. A cap may be worn to keep the head warm, and the bed should be out of the draft.

Fresh Air gives Health.—Four hundred people die of tuberculosis in our country every day. A few years ago it was thought that no one could get well of this disease. Now three fourths of those in the first stages of the disease get well. The chief part of the cure is fresh air. Medicine is seldom used because no medicine will cure tuberculosis. Good food and rest are great helps.

Many of those with tuberculosis stay out of doors all day and at night sleep in tents or with all of the windows wide open, even in the coldest weather. Snow may blow in and the water in the room may turn to solid ice, but fresh air, the good angel of health, will give the body new strength and make it well and strong again.



Many years ago when the Indians lived in tents and often slept outdoors none of them had this dirty air disease of tuberculosis. Since they have formed the habit of living in houses nearly one half of some tribes have become sick with this catching disease.

Making the Lungs Strong.—It requires over three quarts of air to fill your lungs. When you breathe quietly, less than one pint of air passes in and out of your lungs. This shows that a large part of the lungs is not used. The air sacs at the top and in the bottom part of the lungs are seldom filled completely. It is in these places that disease begins.

Several minutes should be spent two or three times each day in exercising the lungs. Fill them completely with air many times. Learn to breathe deeply while you are walking in the fresh air. Hold the head up and the shoulders back so that every part of the lungs can be filled. Sit straight. Your life depends upon your lungs. Give them a chance to do their work and teach them to do it well.



Tobacco and Pure Air.—There is poison in the smoke of tobacco. This is shown by its effect on insects. Owners of greenhouses often buy the stems and other waste parts of tobacco. They pile it in a pan and after closing the doors and windows of the greenhouse tightly, set fire to it. The smoke rises and fills the whole house. In less than an hour it has killed many of the bugs and beetles which were destroying the plants.

A person not used to tobacco will sometimes be made sick by sitting only an hour in a room where persons are smoking. It is wrong for smokers to poison the air which others must breathe. For this reason a smoking room should be well ventilated.



CHAPTER XVI

THE BLOOD AND HOW IT FLOWS THROUGH THE BODY



The Blood keeps the Body Clean within and gives it Food.—Every tiny particle of the body, whether in the legs, arms, or head, must have food to keep it alive and help it do its work. It must also have oxygen, and it must be washed clean of its waste matter. All this is done by the streams of blood, which bathe every cell to bring it food and oxygen and to wash away its waste.

Parts of the Blood.—Blood consists of a clear, watery part called plasma and many little bodies named cells. The liquid found in a blister is the clear part of the blood. The cells which float in the watery part are so little and so close together that more than a million are in each drop of blood.

A few of the cells are white, but most of them are red, and it is their color that makes the blood look red. Your body contains about one gallon of blood. It is carried through the body in branching tubes called blood vessels (Fig. 70).



The Blood Vessels.—There are four kinds of blood vessels. They are the heart, the arteries, the capillaries, and the veins. The heart lies in the chest between the lungs. It squeezes the blood into the arteries. These carry the blood to all parts of the body. It then runs into the capillaries, which are tiny tubes connecting the arteries with the veins. The veins return the blood to the heart.

The blood flows so fast that it goes from the heart down to the toes and back again in a half minute.

The Heart or Pump of Life.—When the heart stops we die, because the blood can no longer flow to carry food and oxygen to the hungry tissues. The heart is a sac with thick walls of muscle. It is shaped like a strawberry and is about as large as your fist. Its cavity is divided into four parts. The two upper ones are called auricles and the lower ones are named ventricles. The blood enters the auricles and then pours through an opening into each ventricle, from which it passes out into the arteries.

The Arteries or Sending Tubes.—The blood is sent out from the heart through the arteries leading to all parts of the body. The chief artery is the aorta. It is larger than your thumb and extends from the heart down through the body in front of the backbone. It has more than twenty branches. All of these branch again and again like the limbs of a tree until they are finer than hairs.

A large tube, the lung artery, takes blood directly from the heart to the lungs. Here it branches into more than a thousand divisions, so that the blood can take in oxygen and give off to the lungs its waste.



The Capillaries or Feeding Tubes.—These are the tiny tubes, finer than hairs, which join the smallest end branches of the arteries with the beginnings of the little veins. They are so thickly scattered in the flesh that you cannot stick it with a pin without piercing one.

They are called feeding tubes because they have such very thin walls that the food in the blood and the oxygen brought from the lungs can pass through to feed the muscles and other organs. The dead parts of the body and also the ashes of the food used up, pass from the organs into the capillaries.

The Veins or Returning Tubes.—The veins, beginning in fine branches formed by the capillaries, return the blood to the heart. The branches unite into larger and larger vessels and finally flow into one main vein, the vena cava. This extends along in front of the backbone and opens into the heart.

Why the Blood flows in only one Direction.—The heart causes the flow of the blood. It does this by squeezing together its walls so as to make the blood go out into the arteries. When once in the arteries, the blood must go forward because there are little doors at the mouths of the arteries in the heart. These doors, called valves, open in only one direction, so that the blood cannot flow backward (Fig. 71). There are other valves between the upper and lower cavities of the heart, preventing the blood from being pushed back into the veins.



The movement of the walls of the heart in and out is called the heart beat. This can be plainly felt by placing the hand on the left side of the chest. The heart beats about seventy times each minute in grown persons, but much oftener in children. At each beat a wave of blood flows along the arteries. This is known as the pulse. It may be felt at the base of the thumb, where an artery runs just under the skin.

Why the Heart sometimes beats Faster.—When we run or do hard work, the heart may beat twice as fast as when we are lying down. This is because the muscles need more oxygen to help them act. Work makes them get hungry, and they send word by the nerves to the heart to hurry along the blood to bring more oxygen from the lungs.

When germs make the body sick, the heart often beats faster because it is affected by the poison made by the germs. The doctor then feels the pulse to tell how much the body is poisoned.

Use of Blood Cells.—The red cells act like boats. They load up with oxygen in the lungs and carry it to all parts of the body. Here they trade it off for carbon dioxide, a waste substance. This they carry back to the lungs to be cast out of the body.

There is one white blood cell to every four hundred red ones. The white cells are the body-guards. They change their shape and are able to crawl through the walls of the capillaries. Wherever the body is hurt, they collect in large numbers and eat the germs which are always trying to get into the body through sores. The white matter called pus in a sore is largely made of white blood cells which came there to fight the germs and were killed in the battle.

The germs of boils and fevers often get into the blood, but the white cells usually kill them before they have a chance to grow into large numbers and make the body sick.

How to stop Bleeding.—Most of the larger arteries are deep in the flesh and seldom get cut. There are many veins just under the skin. If the blood comes out in spurts, it is from an artery; but if it flows steadily, it is from a vein. If the blood does not run out in a stream, it will stop without any special care. As soon as the blood gets to the air it forms a jellylike mass called a clot. This helps stop the flow. All hurt places in the skin should be tied up in a clean cloth.



If a large artery is cut, a bandage twisted tight with a stick around the limb on the side of the wound next to the heart will stop the bleeding. If a vein is cut, the bandage should be placed on the side of the cut away from the heart.

Alcoholic Drinks weaken the Blood.—It has been noticed for some years that when a user of beer or whisky is attacked with fever, the disease is more severe than in one not using alcohol. The reason for this has lately been explained by a well-known scientist working in Paris. He put certain disease germs in rabbits, but they did not become sick. When he gave them a little alcohol and put the same amount of disease germs in them as before, they became sick and died. By careful study he learned that the white blood cells had in the first case killed the germs. In the second experiment the blood cells were made so weak and lazy by the alcohol that they did not put up such a strong fight against the germs.

Tobacco and the Blood.—Any one who chews or smokes tobacco regularly gets much of the poison into the blood. The vessels in the mouth and throat drink in some of the juice and also the poison from the smoke. How much this poison affects the blood cells is not known, but it is likely to do them some harm because it makes the growing cells of the body less active.

How Beer weakens the Heart.—Whisky was at one time thought to strengthen the heart, but doctors generally agree now that it weakens the heart. It may make the heart beat a little stronger for a few minutes, but after that the beating is weaker than usual.

Much use of beer is known to make fat collect around the heart and also cause some of the heart muscle itself to change into fat. In this way the heart becomes so weak that it can no longer do its work, and death results. The reports from Germany show that hundreds of persons die every year from weakened hearts made so by the use of much beer.

Alcohol hurts the Blood Vessels.—Careful examination of the blood vessels of drunkards after death shows that in many cases the alcohol has caused the walls of the vessels to become thick and sometimes hard. The thickening of the wall makes the channel of the tube smaller. The heart must then work much harder to get the blood through to feed the tissues.

Tobacco and the Heart.—Many boys who use tobacco regularly do not have a steady heart beat. This is specially true of those who smoke several cigarettes daily. A few years ago, when our country was at war with Spain, thousands of young men, wanted for soldiers, were examined to find out whether their bodies were strong enough to endure the hardships of war. Hundreds were refused admittance to the army because of weak bodies, and many of them were reported by the physicians as having hearts weakened by the use of tobacco.

The boys preparing for the army at the Military Academy at West Point and for sea fighting at the Naval Academy at Annapolis are not allowed to smoke cigarettes. Our country must have strong men for hard work. Tobacco never gives strength, but often causes weakness.



CHAPTER XVII

INSECTS AND HEALTH

Malaria or Chills and Fever.—Malaria is a disease in which the patient usually has a chill followed by a fever at the same time each day or every other day. Thousands of people suffer from this sickness in the warm parts of our country and hundreds of them die every year. In some regions people cannot live because this sickness attacks every one who comes there.

Many years ago a doctor found in the blood of malaria patients tiny animals. He thought that they might be the cause of the illness, but he could not find out how they got into the blood.

Finding out how Malaria Germs get into the Blood.—It had been noticed for many years that mosquitoes were always found wherever there was malaria. In the year 1900 two men decided to find out if they could live in a malaria region and not have the disease when the mosquitoes were kept from biting them.



They made their home a whole season in a cottage in the midst of many persons who were sick with malaria. They breathed the same air, ate the same kind of food, and drank the same kind of water as those who suffered from the disease, but they remained well. The only thing that they did different from those who got sick was to keep the mosquitoes out of their rooms at night by means of screens. This experiment and many other studies have shown that we catch malaria only by the bites of mosquitoes.



Only a Few Mosquitoes carry Malaria.—Malaria is not common in all regions where mosquitoes live, and it has been found that only one group of mosquitoes carries the germs. The two common groups are the straight-backed and the humped. To prove that the straight-backed ones did the harm several of them were allowed to suck blood from a man sick with malaria in Italy. They were then sent to London and let bite a healthy man. In a few days he became sick with malaria. Many experiments with the humped-back mosquitoes, found nearly everywhere in our country, show that they do not carry malaria germs.

Yellow Fever.—Until 1901 yellow fever was the scourge of many cities in the South. Thousands of persons lost their lives from it. Wherever the dread disease broke out in a city many persons would flee to the country because they thought that they could not breathe the air without getting the germs.

Some persons thought that mosquitoes might cause the disease, and in 1900 experiments were carried out in Cuba to learn whether mosquitoes really did carry yellow fever germs. Seven men made their home in a room well screened to keep out the mosquitoes. They used clothing which had been worn by others sick with the fever and even slept on pillows and blankets on which yellow fever victims had died. Many persons thought that these bedclothes were full of fever germs and that all the men would surely get the disease. Not one of them, however, got sick although they lived in the midst of these soiled materials for three weeks.



Seven other men were chosen for another experiment. A large room was prepared and made thoroughly clean. Only clean bedding and clean clothes were used. The men were given pure food and pure water, but into the room were let loose mosquitoes which had been sucking blood from a person sick with the fever. In a few days six of the seven men became sick with the fever and one of them died. From these experiments and other studies we now know that this dreadful fever is carried from the sick to the well only by the bites of mosquitoes.



How Mosquitoes Live.—Before we can get rid of any pests we must know where the eggs are hatched and the young pass their early life. The eggs of mosquitoes are laid on standing water. The water may be in an old tomato can, a rain barrel, a cistern, or a large pond. A day or two after the mother lays one or two hundred eggs, they hatch into dark, wriggling objects called wigglers. In from ten to twenty days later they change into flying mosquitoes. These habits of life show that the easiest time to kill them is when they are young.



Getting rid of Mosquitoes.—During warm weather mosquitoes cause the death of more than a thousand persons in the world every day besides making many others very sick. To get rid of mosquitoes is to prevent sickness and death. In one year yellow fever killed over five thousand people in New York and Philadelphia because the doctors did not know how to stop the disease from spreading.

When this fever broke out in New Orleans in 1905, less than five hundred persons died of it because the doctors had then learned that the disease is spread only by the yellow fever mosquito. They therefore began killing the mosquitoes. Kerosene was poured over all the ponds and stagnant pools of water which could not be drained. This kills the young mosquitoes because the oil gets into their breathing tube which they stick up to the surface of the water to get air. All rain barrels and tin cans were emptied and cisterns were tightly covered. Men, women, and children worked week days and Sundays killing mosquitoes because they knew that they were saving human life. The destroying fever was stopped.



Flies cause much Sickness.—Very few people are afraid of house flies because they do not bite. Although they are so small and seemingly harmless yet we know that they cause many more deaths every year than mad dogs, poisonous snakes, and all wild beasts.

Flies crawl around among slops, in spittoons, and in other unclean places. In this way they get thousands of germs of tuberculosis, typhoid fever, and cholera on their feet and then scatter them over our food as they crawl about on the table, in the grocery store, or among the milk cans. In our last war with Spain more than a thousand of our soldiers were made sick with fever carried to them by flies.

In Denver, Colorado, in 1908 fifty persons were made sick with the fever by flies which fed on the slops from a sick room and then crawled around in the milk cans from which those who became sick used milk.



How to fight the Flies.—House flies lay at one time about one hundred eggs in the dirt thrown out of horse stables, in garbage cans, or in any other unclean place. In a day or two the eggs hatch into little white worms which feed on the dirt. One or two weeks later the worms change to flies.

Flies may be kept out of houses by putting screens in the windows and doors or by darkening the rooms when they are not in use. The few which gain entrance may be caught in fly traps. All food in the store or the home should be kept covered. It is not safe to eat candy on which flies have wiped their feet or to drink the milk in which they have washed them.



The surest way to get rid of flies in any community is for all the people to work together and keep the entire neighborhood clean. No dead grass, weeds, or rags should be allowed to lie in the backyards or alleys. The cleanings from stables should be hauled away every week or stored in tightly covered boxes. Garbage cans must have close-fitting lids, so that there will be no place in which the young may hatch and grow.

Other Insects which carry Disease.—In certain parts of Africa, the sleeping sickness has made ruins of prosperous villages. Thousands of the natives are dying yearly from this disease. The germs are carried from one person to another by the bite of a fly.

Some fleas carry the germs of plague, which a few centuries ago swept across Asia and Europe destroying hundreds of lives daily. The plague is now common in India and was present in California in 1908 and 1910. The bedbug spreads several kinds of fevers in warm countries and may also be a carrier of leprosy and typhoid fever. These facts show that insects are dangerous and should be kept out of the home.

Any one troubled with these little pests in the house may learn how to get rid of them by writing to the Department of Agriculture, Washington, D.C.



CHAPTER XVIII

HOW THE BODY MOVES

The Need of a Framework.—The body needs a stiff framework made of bones for three purposes. One purpose is to give it shape, a second purpose is to help the body move, and a third one is to protect from injury some of the delicate organs, such as the heart and brain.

The bones are nowhere separate but are joined together with tough bands named ligaments. All the bones together form the skeleton.

All animals from fish to man have a skeleton. Many of the lower creatures, such as worms and flies, have no bony skeleton. Most of these move sluggishly or have a hardened outer covering, like beetles and wasps. The skeleton of animals such as the cat, rabbit, or cow, has about the same number of bones as man, and they are arranged in the same way.

Of what a Bone is Made.—Although the bones are so hard, they are not dead. They contain blood, have feeling, and are just as much alive as the softer parts of the body. It is the lime that makes them stiff. This can be eaten out by putting the bone in strong vinegar or other acid for a few days. A long bone will then become so limber that it can be tied into a knot.

The living part of a bone can be burned out by placing it on hot coals for a half hour. At the end of this time the bone will look just as before, but when it is touched, will crumble to pieces.

Forms of Bones.—The bones of the legs and arms are hollow. This form gives the greatest strength with the least weight. You can prove this by using two sheets of paper. Roll one sheet and fold the other one. Hang weights on both ends of each and use the finger for a support in the middle.

The cavity of these bones is filled with a soft white substance called marrow. This is largely fat. Each bone is surrounded by a tough membrane to which the muscles are attached.

Arrangement of the Bones.—The bones of the head form the skull. The other bones of the body not belonging to the limbs make up the trunk. There are over two hundred bones in the entire body. Eight of these form a case for the brain. Fourteen give shape to the face. A chain of twenty-six bones named vertebrae forms the backbone.



Twelve pairs of ribs encircle the chest. They are fastened behind to the backbone. The front parts of the ribs are made of pieces of gristle. The seven upper pairs are joined to the breastbone. The five lower pairs are named false ribs.

The collar bone is in front of the shoulder and behind it is the flat shoulder blade. There is one bone in the upper part of each arm and leg and two bones in the lower part of each limb. Twenty-eight small bones are found in the hand, while twenty-seven are present in the foot.

How the Bones may be Injured.—In the young some of the entire bones and parts of many others are soft like gristle. For this reason, the bones of the young seldom get broken, but they are easily bent and pressed out of their natural shape. On this account you should hold the body erect in sitting and walking. Bending over the table or desk day after day is not only likely to cause round shoulders, but is sure to squeeze up the lungs and other organs so they cannot do their best work.

Sitting at a table or desk, so that one shoulder is higher than the other or carrying books at the side, so that they rest on the hip may cause a curve sidewise in the backbone. Tight clothing about the waist presses the ribs out of shape and hurts the other organs within the body.



Caring for Broken Bones.—When a bone of the arm or leg is broken, the muscles tend to make the ends shove over each other. The broken ends are sometimes sharp, and if the limb is bent, these may tear through the flesh. This may be prevented by binding a board firmly on opposite sides of the limb across the broken part. This will hold the bones in place until the surgeon comes and will also allow the patient to be moved.

The surgeon will set the broken bones by bringing the ends together and holding them in place by sheets of wood or metal firmly held by a bandage. In a few days the membrane around the bone begins to grow new bone to join the broken parts.

How the Bones are joined together.—The two general classes of joints are the movable and immovable. Except the lower jaw, the bones of the skull are so tightly joined together that there is no motion between them. The bones of the wrist and back have but little movement. The freest motion is at the shoulder joint, where the round head of one bone fits into the shallow cup of another. This is called a ball and socket joint. Such a joint is found also at the hip. At the elbow and knee the bones move back and forth like a hinge and these are named hinge joints.

Working Parts of a Joint.—The ends of the bones are covered with a thin layer of gristle. The bones are held in place by several strong bands called ligaments (Fig. 82). These entirely surround the joint. On their inner sides is a delicate membrane which gives out a slippery fluid to make the joint work easily.

The ligaments are sometimes strained, stretched, or torn by a fall. The joint then swells because the watery part of the blood collects there. A sprained limb should be elevated to prevent swelling. Bathing it in very hot water is helpful.

The Muscles.—The muscles form the lean meat in any animal. They make up about one half the weight of the body. Each muscle is a bundle of thousands of little threads held together by other finer threads, while the whole is surrounded by a thin sheet. Little bundles formed of several of these threads called fibers may be seen in a piece of cooked beef picked to pieces. There are over five hundred muscles in the body.



Some of the muscles are more than a foot long and have the shape of a ribbon. Some are circular like those around the mouth, eyes, and stomach, while others are large in the middle and taper toward the ends.

How the Muscles are fastened to the Bones.—The two ends of a muscle are attached to different bones. In many cases the muscle is not joined directly to the bone, but is connected to a tough white cord called a tendon. The tendon is then fixed to the bone.

Several of the muscles in the forearm run into tendons in the wrist because if the muscle part were to extend along the wrist, this part of the arm would be large and clumsy instead of graceful and slender. Some of these tendons may be seen to move by bending the wrist and then working the fingers.

How the Muscles do their Work.—A tiny nerve thread runs from the spinal cord or brain to every muscle thread. Messages sent through the nerve threads to the muscles make them act. A muscle can act in only two ways (Fig. 84). It can become shorter or longer. When it gets shorter, we say it contracts. When it stretches out, it is said to relax.

A muscle cannot contract more than one fourth of its length. To pull the forearm up, the brain sends a message to the muscle fixed by one end at the shoulder and by the other end to a bone at the elbow. The muscle at once becomes shorter and thicker, as may be felt by placing the fingers on it. Although it shortens only two inches it is fastened to the bone so near the elbow that it draws the hand up two feet.

PRACTICAL QUESTIONS

1. Of what use are the bones?

2. What animals have bony skeletons?

3. What can you say of the form of bones?

4. How many bones in the body?

5. Name six bones.

6. What part of the arm has two bones side by side?

7. How many ribs have you?

8. Explain how a broken bone should be cared for.

9. Point out and name two kinds of joints.

10. What are ligaments?

11. Of what is a muscle made?

12. How many muscles in the body?

13. How many tendons can you feel in your wrist?



CHAPTER XIX

THE MUSCLES AND HEALTH

Making the Muscles Strong.—No persons use all of the five hundred muscles in the body every day. In slow walking only about twenty muscles are used, while in running more than four times that number are called into action. Muscles which are not used get lazy and weak.

Every time a muscle is made to act the blood vessels enlarge and bring to it more blood to supply food. The more food the muscle has the stronger it grows. The right arm is used more than the left in most persons. This makes it so much stronger that some boys can lift twenty-five pounds more with the right arm than they can with the left.

Using the Muscles keeps the Body Well.—All muscles must have more blood when they are used so that the heart is made to beat faster and stronger by exercise. In this way its valves and walls become able to do more work. Such a heart not only does its work better in a well person, but is able to keep pumping when the body is weakened by disease. Many persons die because the heart gets too weak to push the blood through the body.

In all the little spaces between the muscles and parts of other organs is some watery part of the blood containing much waste given off from the tissues. Moving the muscles presses on this watery waste in such a way as to move it along into the blood channels. It then can be cast out of the body by the lungs and other organs. One reason why we feel so good after exercise is because the poisonous waste has been taken away.

No one can remain well very long without taking exercise. Children as well as older persons should enjoy one or two hours of outdoor play every day.



How to exercise the Muscles.—Outdoor games give the best form of exercise. Tennis, baseball, cricket, rowing, and swimming are sports which bring nearly all the muscles into use. Every boy and girl should learn to swim. It is dangerous to go swimming alone or to swim in deep water. Cramp may seize the muscles at any time, so that the limbs cannot be moved. Hundreds of persons are drowned every year by venturing in deep water.

Taking care of the yard and garden and helping with other work about the home is one of the best ways of getting exercise and at the same time doing some good.

Special Kinds of Exercise.—A room with ropes, swings, and machines in it for exercise is called a gymnasium. Under the direction of a teacher the pupils can get quickly just the right kind of exercise to strengthen the weak parts of the body and keep every organ in health. The muscles oftenest neglected are those of the chest. Every one should keep his chest full and round by swinging the arms and practicing deep breathing every day.

Danger from too much Exercise.—Lately it has been learned that very violent exercise for more than a few minutes often injures the heart. The running of many races until you are all out of breath or much jumping of the rope is likely to strain the heart. It is always harmful to urge the body on until it is completely tired out.

Alcohol makes the Muscles Weak.—In the year 1903 two learned men in Switzerland spent much time to determine whether alcohol helped persons do more work. They tried more than two hundred experiments with men to whom they sometimes gave wine and sometimes food, and sometimes both were given together.

The results of these tests showed that when wine was given alone, the man's ability to do work was increased for a short time, but later he could not do so much work as when he had taken no wine. When the man took both food and wine, he could do only about nine tenths as much work as when he took food alone.

The most careful tests by other persons show that whisky will not help a man do more work, lift a heavier weight, or shoot straighter. In fact little or much whisky makes him less able to do any of these things.

Beer makes the Muscles Lazy.—Doctor Parkes of Netley secured two gangs of soldiers to do the same kind of work. He allowed the first gang to drink some beer, but the second gang were not allowed to have any. During the first hour the beer gang did the most work, but after that the temperance gang did far more work during the entire day. The next week beer was refused the first gang and given to the second. The beer helped the second gang do more work than the first one for nearly two hours, but after that they did much less than the first gang. This shows that men who wish to do their best work during the entire day should not use beer.

Tobacco and the Muscles.—Many experiments and studies have shown that the body cannot do its best work when even very small amounts of poison are taken day after day. The poison in tobacco is believed to weaken the muscles so much that no man on a football team in any of our large colleges or universities is allowed to smoke or chew during the season. Persons training for any contest where much strength is required do not use tobacco in any form.

Tobacco prevents Growth of the Muscles.—The moderate use of tobacco by men has but little effect on the muscles. It may cause them to tire a little more easily when doing very hard work. Tobacco poison does, however, show a marked effect on the muscles of the young.

Very careful measurements made at one of the large universities showed that the boys who did not smoke grew one tenth more in weight and one fourth more in height than those using tobacco regularly. This slow growth in tobacco users is partly due to the fact that tobacco makes the muscles in the walls of the blood vessels squeeze together so as to shut off some of the blood from the legs, arms, and other parts, so that they get too little food. Tobacco may also cause less food to be digested for the use of the body.



CHAPTER XX

HOW THE BODY IS GOVERNED

Making the Parts of the Body Work.—Each of the hundreds of organs in the body has a certain work to do and this must be done at the right time. In order that all may work together and each one do its part when needed, there is a chief manager called the brain and a helping manager named the spinal cord. Millions of tiny threads for sending messages connect the two managers with every part of the body. These threads form the nerves.

The Brain.—The brain is a soft bunch of matter filling the inside of the skull. The bones of the skull are a quarter of an inch thick and prevent any common knocks from hurting the brain. It is surrounded by three coverings which also help shield it from injury.

The surface of the brain is very uneven. There are a great many folds separated by grooves. Some of these are more than an inch deep.



Parts of the Brain.—The brain is divided into three chief parts. The upper and larger part is called the big brain or cerebrum. The lower part behind is the little brain or cerebellum. The part under the little brain and round like the thumb is the stem of the brain. It connects the larger parts of the brain with the spinal cord.

The big brain is partly separated into halves by a deep cut called a fissure. Each half is a hemisphere.

The outer layer of the brain is gray. It is made of millions of tiny lumps of matter which are the bodies of nerve cells. These are connected by threads much finer than hairs with other parts of the brain and spinal cord. Over these threads called nerve fibers one cell can talk to another somewhat as we talk over a telephone wire.



The Spinal Cord.—This is a bundle of nerve matter about as thick as your finger. It extends from the stem of the brain down the canal in the backbone. The outer layer of the spinal cord is white because it is made of the tiny threads, nerve fibers. The inner part is made of the bodies of nerve cells and therefore looks gray. The fibers are branching threads from the cells in the cord and brain.

The Message Carriers or Nerve Fibers.—In order that the managers may send messages, these fine threads, the nerve fibers, extend from them to all parts of the body. In many places from five to five hundred or more of these fibers are united in one white cord called a nerve.

Twelve pairs of nerves are joined to the under side of the brain and thirty-one pairs are connected with the spinal cord (Fig. 86). The nerves of the brain branch to all parts of the head and neck, and one pair goes down to the lungs, heart, and stomach. The nerves connected with the spinal cord branch to every part of the muscles, bones, and skin of the arms, trunk, and legs.

How the Nerves do their Work.—On a telephone wire we can send a message in either direction. A message can travel on a nerve in only one direction. For this reason there must be two kinds of nerves. One kind is called sending nerves because the brain and cord send orders over them to make the organs act. The other kind carries messages to the brain from the eyes, ears, skin, or other organs of sense, telling it how they feel. On this account these are named receiving nerves.

When we wish to catch a ball, the brain sends an order along the nerve threads down the spinal cord and out through the nerves of the arm to the fingers to get ready to seize a ball. The fingers are spread to grasp the ball, but they do not close until a message goes from the skin of the finger tips to the spinal cord, telling it that the ball is in the hand.

The Work of the Brain.—The brain is not only the chief manager of the body, but the home of the mind. The mind acts through the brain. The mind receives through the brain what the eye sees, the ear hears, the nose smells, and the fingers feel. All this knowledge is stored up in the mind and called memory. These facts and others learned later are worked over by the mind. This is called thought.

The mind rules and becomes good or bad according to whether it contains good thoughts or bad thoughts. It is wrong to read books and papers about robberies and murders or to tell or to listen to bad stories, because in this way evil thoughts get into the mind. The best way of keeping badness out of the mind is to fill it with goodness. It is said that Lincoln was so busy thinking how he could help others that there was no room in his mind for a bad thought. Doing some kindness every day helps much in the making of a good mind.

Habit.—The doing of anything over and over again until the body goes through the same motions without any or very little thought is called habit. The brain and nerves are so formed that when they get used to obeying the same order of the mind again and again, they will carry out these orders when the mind no longer gives them. Sometimes they will continue to obey the old orders even when new ones are given.

Many persons would like to break off the habit of drinking beer or whisky, of chewing tobacco, and using bad language, but they find it very hard to make the mind rule the body because they have let the nerves have their own way so long.

Speaking cheerfully to those we meet, giving a kind word to our friends, and looking pleasant are good habits which every one ought to form in youth. They not only make the mind better, but they help the body to keep well and will prepare the way for success in life later. Nobody wants a grumbling clerk or a sour-faced housekeeper.



Parts of the Body work without Orders from the Brain.—A snake with its brain crushed will still squirm and a chicken with its head cut off jumps about. These movements are caused by orders sent from the spinal cord. When the hand or foot is being hurt, the spinal cord orders the muscles to draw the limb away even before we feel the pain in the brain. Many of the movements of the body which are often repeated may be directed by the spinal cord, while the brain is left free to do other work. This is why the spinal cord is called the helping manager.

The action of the muscles in the walls of the blood vessels, the working of the stomach, the liver, pancreas, and other glands are not directed by the brain, but by the sympathetic nerves. These extend from a little cord on either side of the backbone to all parts of the body and make the organs, such as the heart and sweat glands, which we cannot make obey our will, do their work.

Injury to the Nerves.—The nerves are so important for the welfare of the body that all the chief ones are placed deep in the flesh, where they are not likely to be hurt. If the nerves leading to the arm were cut, it could not be moved, and we should have no feeling in it. The hurting of a part of the brain, the spinal cord, or the nerves may cause loss of feeling or motion in the leg, arm, or other part of the body. Such a part then seems asleep or dead and is said to have paralysis.

Pressing on a nerve prevents it from acting. Sitting so as to press on the nerve of the leg often makes the foot go to sleep. The bursting of a blood vessel in the brain may let a blood clot form and press on the nerves which govern the arm or the leg. This pressure may cause paralysis.

Resting the Brain.—When there is no food in the stomach, it has time to rest. When we sit down or lie down, the muscles get rest. The brain is always busy except when we are asleep. No one can live even a week without sleep. If a dog is kept awake five days, it will die.



Children need much more sleep than older persons. Men and women who work should have about eight hours of sleep daily to remain in good health. Children of twelve years should sleep nine hours each day; those of ten years, ten hours; those of seven years, eleven hours; and those of four years, twelve hours.

Getting the most out of Sleep.—You should go to bed every night at about the same hour. This will help you to fall asleep as soon as you are in bed. Do not sleep in the clothes which you have worn during the day, but hang them up to air, and put on a night robe.

Children should use a very low pillow, so that the body can lie straight in the bed. This gives the lungs and heart freedom to act. Do not lie on the back as this causes some of the organs to press on certain nerves and makes you dream. The windows should be opened wide because fresh air is the best aid to rest and health and keeps away tuberculosis.

PRACTICAL QUESTIONS

1. What makes the parts of the body work together?

2. Describe the surface of the brain.

3. Name the three parts of the brain.

4. Of what is the outer layer of the brain made?

5. Where is the spinal cord?

6. What are nerve fibers?

7. What work does the brain do?

8. What makes the mind good or bad?

9. What is habit?

10. How long should children sleep?

11. How can you get the most good out of sleep?



CHAPTER XXI

HOW NARCOTICS AND STIMULANTS AFFECT THE BRAIN AND NERVES

What Narcotics and Stimulants Are.—A narcotic is something which when taken into the body makes the organs do their work more slowly and tends to cause sleepiness. Alcoholic drinks, tobacco, opium, soothing sirups, and pain killers are narcotics.

A stimulant is a substance which makes the organs of the body do more and quicker work and does not later make the organs work more slowly. Coffee and tea are stimulants. Beer, wine, and whisky were once thought to be stimulants, but experiments have shown them to be narcotics. They urge the brain to faster work for a few minutes, but a half hour later they make it act slower than usual.

Alcohol hurts the Brain.—Within five minutes after a drink of beer or whisky has been swallowed, part of the alcohol has reached the blood. Within fifteen minutes much of the alcohol has gone from the stomach directly into the blood. In a minute after entering the blood vessels it reaches the brain.

If much strong drink is taken, the cells of the brain become so numbed that they cannot give the right orders to the muscles to move the limbs. The person then staggers about and is said to be drunk. Much whisky taken will make the nerve cells so numb that a man cannot move, and he will then lie down as if in a deep sleep.

A tablespoonful of whisky will make a child drunk and twice that amount may make him very sick. Much use of strong drink sometimes gives to the brain a terrible disease called delirium tremens. In this sickness the man thinks he sees horned animals, hissing snakes, and other creatures which annoy him.

Alcohol injures the Thinking Part of the Brain.—It was once thought that wine or whisky would make a man think better. Now we know that either of these drinks makes his thoughts slower and also causes him to make mistakes.

Two doctors in Europe made many tests with men to learn how alcohol affected their thinking. They found that when using wine the men could do about one tenth less work in adding numbers than when they took no strong drink. These doctors also tested the effect of alcohol on memory and discovered that the use of even small quantities of liquor caused their pupils to learn their lessons more slowly.

When persons have taken only a very little drink, they often say and do very foolish things. They sometimes tell secrets, for which they are very sorry when they get sober. Often they become angry at the least cause and strike or even shoot any person who seems to speak or work against them in any way.

Alcohol makes People Steal and Kill.—The alcohol in strong drink, when often used, appears to deaden that part of the brain which helps the mind know right from wrong. In one year the courts of Suffolk County in Massachusetts found 17,000 persons guilty of doing some wickedness and in over 12,000 of these cases alcohol was found to be the cause of doing the wrong for which they were arrested.

Some time ago there were collected the records of 30,000 prisoners, and among these over 12,000 had done their wicked acts while alcohol was numbing the brain. Lately another careful record of over 13,000 prisoners in twelve different states has been studied. In over 4000 of these men the use of strong drink was the first cause of their crimes.

Alcohol makes the Mind Sick.—Since the mind depends upon certain parts of the brain, whatever hurts the brain is quite sure to hurt the mind. When the mind cannot reason rightly, the person is said to be insane. A study of 2000 insane men in New York State showed that the use of alcoholic drink was the cause of the mind sickness in over 500 of them. Of 687 persons in Massachusetts who were so insane that they had to be cared for daily by others, more than 200 of them were brought to this sad condition by alcohol.

Brain of the Young easily overcome by Alcohol.—No one expects to become a drunkard or a criminal when he first begins to drink. The continued use of alcohol, however, soon numbs the brain and weakens the mind, so that the person's will power is lost. He is then not able to quit drinking even though he wants to stop. He has become a slave to alcohol.

The brain of a young person is injured much more quickly by alcohol than that of an older person and he is much more likely to become a slave than one who begins the use of drink late in life. Doctor Lambert, of New York, studied the cases of 259 slaves to alcohol. He learned that four began to drink before six years of age; thirteen between six and twelve years of age; sixty, between twelve and sixteen years; 102 between sixteen and twenty-one years; seventy-one, between twenty-one and thirty years; and only eight after thirty years of age. These facts teach that it is dangerous for the young to take strong drink at any time.

Laws against Alcohol.—The men who make laws for the good of the people are learning that alcohol is injuring the mind and body of many persons every year. For this reason laws have lately been passed forbidding the sale of strong drink in several entire states and in large parts of many other states.

Tobacco makes the Brain work Slower.—An examination of the age and habits of hundreds of the students entering a large university in New England showed that those who smoked required more than a year longer than those who did not use tobacco, to learn enough to enter the first classes in this school. Moreover, out of every hundred of those who took the highest rank in their work in the university, ninety-five did not use tobacco. It is likely that tobacco makes the mind work slower by preventing the full amount of blood from going to the brain. It does this by making the blood vessels smaller.

So far as known tobacco has but little effect upon the brains of older persons.

Superintendent Ogg of Indiana reports that the occasional users of cigarettes are a year, and the regular users two years, behind those who do not smoke. The conduct and honesty of the smokers were also found to be lower than among those who did not smoke.

Opium, Morphine, and Cocaine.—All of these harmful drugs are widely used in our country. They act on the brain in a strange way. All of them deaden pain. When a person first begins their use, only a small amount is required to produce the effect wanted on the body. Later the doses must be increased. After a few months' use the person becomes a slave to the habit of using them, and he cannot stop their use without the help of a doctor. It is therefore dangerous to use these drugs at any time.

Powders used for colds in the nose, also paregoric and laudanum, contain these harmful drugs.

Pain Killers and Soothing Sirups.—All pain killers contain opium or morphine or other harmful drugs. They are therefore dangerous to use. Pain is useful in telling us that some organ is out of order and needs care. Killing the pain does not help the sick organ, and it may let the organ get so sick as to cause death.

One use of the nerves is to tell us when any part of the body is hurt or sick. Pain is nature's warning, and to numb the nerves which tell us about it is as foolish as to kill a person because he brings us bad news. No medicine should ever be given children to make them sleep or stop their crying except by the advice of the physician.

Powders and Pills.—If you get sick, do not try to cure yourself with pills or powders bought at the store. Some of these medicines contain poisons which hurt the heart or other organs. A number of persons have been killed by taking such medicines. When you are sick, go to a good doctor who understands how the organs should work, and he will find which one is out of order and tell you exactly what medicine you need and what to eat in order to get well quickly.

Tea and Coffee.—These drinks usually wake up the brain and make it work better for a time. If too much of them is used, they may excite the brain in such a way as to make persons nervous. If taken for supper, they may prevent sleep. Children should not use either tea or coffee. Tea sometimes disturbs digestion, and coffee may injure both the stomach and the heart.

PRACTICAL QUESTIONS

1. What is a narcotic?

2. Name some narcotics.

3. What is a stimulant?

4. Name some stimulants.

5. How long before alcohol taken reaches the brain?

6. What effect does strong drink have on the brain?

7. Does alcohol help us think better?

8. What facts show that alcohol sends men to prison?

9. What shows that alcohol makes the mind sick?

10. Why is it dangerous for the young to take strong drink?

11. What shows that tobacco makes the brain work slower?

12. Why should you not use opium or morphine?

13. What do pain killers contain?



CHAPTER XXII

THE SENSES, OR DOORS OF KNOWLEDGE

The Organs of Sense.—In order that our body may keep out of the way of other persons and find food and drink and do its work, the brain must have some way of receiving news about what is near us, how it looks, and of what it is made. Special organs for receiving knowledge of people and things about us are scattered over the surface of the body. They are called sense organs. The chief ones are the two eyes, the two ears, the nose, and many organs of taste in the mouth, and the thousands of tiny organs of feeling in the skin.

The Eye.—The eye consists of a globe called the eyeball and parts which move this and protect it from injury. Each eyeball is attached at its back part to the large nerve of sight (Fig. 90). This carries messages to the brain, telling it what the eye sees.

The eyeball is held in a socket in the front of the skull. A layer of fat lines the socket and keeps the eye from being injured by jars. The eyebrows at the lower edge of the forehead prevent the sweat from running into the eyeball.



The eyelids can close over the front of the eyeball to shut out dirt or anything else likely to hurt it. The lids have learned to do their work so well that we do not need to think to close them when anything flies toward the eye, for they are shut before we can think.

A salty fluid called tears flows from the tear gland at the upper and outer side of the eyeball. The tears keep the front of the eyeball clean.

Parts of the Eyeball.—The outside of the eyeball is a tough white coat except in front, where it is as clear as glass. Within the outer coat is a very thin black lining to keep the light from scattering. In front the lining is not against the outer coat, but hangs loose and has in it a round hole called the pupil to let the light pass through. The part around the hole is the iris. It may be blue, black, or brown, and can squeeze up so as to make the pupil very small when the light is strong.



The end of the nerve of sight forms a tender pink covering over most of the inner surface of the eyeball. The cavity within the eyeball is filled with three clear substances. The lens, shaped like a flat door knob, is fixed just behind the pupil. In front of the lens is a watery fluid and behind it is a clear jellylike mass. The use of the lens and also the other substances is to bend the rays of light together so that they will meet at one place.

How the Eyeball is Moved.—Six muscles fixed to the bones of the socket holding the eye have their other ends fastened to the tough coat of the eyeball. One muscle turns the ball upward, another turns it downward, one turns it inward and another turns it outward. If an inner or an outer muscle is too strong, a person may have cross eyes.

Keeping the Eye Strong.—Nearly all young children have perfect eyes. After a year or two in school the eyes of some children become weak. Many children get weak eyes after they are ten or twelve years old. This is because they have not taken care of the eyes.

The eyes are often hurt by reading a book with fine print, reading in a dim light, or by leaning over the book so that the eyes look downward instead of straight forward. As the eyes are very weak after measles and most other diseases, they should not be used much until a week or more after recovery.

In reading the book should be held a little over a foot in front of the chest and you should sit nearly straight and let the light fall on the page from one side. Never read while lying down because it strains the eyes. Stop reading as soon as the eyes smart.

Helping the Eyes to See.—Very few old people can see to read without the help of glasses, because the lens of the eye hardens in old age. To see things near by, the shape of the lens must be changed. In some children, the shape of the eyes has become so changed by straining them to read fine print or see things in a dim light that the eyes hurt after being used for any kind of work, and the head may often ache and make the whole body feel bad. Such eyes need help. You should have them examined by an eye doctor who can fit you with glasses which will help you see clearly without headache.

Keeping the Eyes Well.—Bits of dirt often get beneath the eyelids and cause much pain. By taking hold of the eyelashes the lid may be pulled out from the eye and any dirt removed with the corner of a clean handkerchief passed gently along the lid.

The eyes sometimes become sore because they are rubbed with soiled fingers on which are germs. These germs get inside the lids and grow, and in this way poison the eyes. Unless care is used sore eyes are likely to spread from one child to another in the school. The sick child rubs its eyes and then handles a book or pencil on which the germs are smeared by the fingers which touched the eyes. The next child picks up the same book later, gets the germs on the fingers, and then rubs the eyes. For this reason you should never rub the eyes. If you have sore eyes, be careful that no one else catches the sickness from you.

The Ear.—The ear is made of three parts called the outer ear, the middle ear or eardrum, and the inner ear. The outer ear is made of a plate of skin and gristle and a slightly bent tube about one inch long. At the inner end of this tube is a thin membrane or drumhead. Beyond the drumhead is the cavity of the middle ear about as large as a pea. A chain of three tiny bones stretches from the outer drumhead across this cavity to a tiny inner drumhead. Beyond the inner drumhead is the inner ear.



The middle ear is kept full of air by means of a tube leading from it to the throat. A cold or other sickness may cause this tube to fill up and make you deaf. The inner ear consists of a sac and four bent tubes filled with a watery fluid. They are also surrounded by watery fluid contained in channels in a bone of the skull. The end of the nerve of hearing is on one of the tubes.

How we Hear.—Throwing a stone in the water makes waves which move farther and farther outward. In the same way a noise causes waves in the air. These waves pass into the ear tube, strike the outer drumhead, and make it move. This moves the chain of bones in the middle ear so that they cause motion in the inner drumhead. This in moving back and forth makes waves in the fluid of the inner ear which strike on the ends of the nerve of hearing and cause messages to be carried to the brain.

Care of the Ears.—The ears should not be struck or pulled, as the eardrum is easily broken. Do not put pencils, pins, or anything else in your ears. Wax naturally forms in the ear tube to keep out bugs and flies. The outer part of the tube may be kept clean by wiping it with a moist cloth over the little finger. If you often have earache or a running ear, you should have it examined by a physician. Neglecting a sick ear may cause deafness.

Some persons are deaf in one ear and do not know it. Test each ear by covering the other one with a heavy cloth and note how far off you can hear the ticks of a watch.

The Nose.—The nose has a skin-like lining, but it is always kept moist by little glands which give out a watery fluid. The endings of the nerve of smell are in the lining in the upper part of the nose. Two nerves lead from the nose to the brain.

When we catch cold, much blood rushes to the lining of the nose and it becomes swollen. It then gives out a thick white mucus. This covers the nerve endings, so that we cannot smell.

Smell is of great use in telling us whether our food is good, by helping us to enjoy food with a pleasant odor, and by warning us against bad air.

The Sense of Taste.—The nerves by which we taste end in the soft covering of the tongue and some other parts of the mouth. A food cannot be tasted while it is dry. For this reason much slippery fluid flows into the mouth from glands under the ears and tongue. This fluid, called saliva, softens the solid food when it is well chewed, so we can taste it.

The Senses of the Skin.—There are endings of nerves in the skin all over the body. They are of three or four different kinds. Some of them tell us about heat, others tell us about cold. Some tell us about the shape, the smoothness, or hardness of objects, while others tell us when the skin gets hurt.

Most of the nerve endings are in the deeper part of the skin, so that they are covered by the epidermis and cannot be hurt by the rough things handled.

Alcohol and the Senses.—The senses are but little affected by a small amount of alcoholic drink. The sense of taste, after being accustomed to the sharpness of strong drink, may be less easily pleased with the taste of common food and drink.

The use of large amounts of alcohol blunts all the senses. In a drunken man the senses of the skin are so numbed that he does not know when anything touches him, and he may be badly burned before he feels the pain.

Heavy drinking makes the hearing less keen, enlarges the blood vessels of the eyes, and makes them appear red and bloodshot.

Tobacco and the Senses.—The use of tobacco does not injure the senses of the skin and usually has no effect on hearing. Both chewing and smoking, if much practiced, make the sense of taste less delicate, so that one cannot enjoy his food to the fullest extent.

Much smoking of tobacco may hurt the nerve of sight and in a few cases it has made men blind. Many boys have weakened their eyes by the use of cigarettes.

PRACTICAL QUESTIONS

1. Name the chief sense organs.

2. Of what use are the eyelids and tears?

3. Name four parts of the eyeball.

4. What is the iris?

5. Of what use is the lens?

6. What moves the eyeball?

7. When do children get weak eyes?

8. How are the eyes often hurt?

9. How may poor eyes be helped?

10. What makes the eyes sore?

11. How do germs get into the eyes?

12. Name the three parts of the ear.

13. What does the inner ear contain?

14. What may result from neglecting a sick ear?

15. Of what use is smell?

16. Why should food be well chewed?

17. In what part of the skin are most of the nerve endings?

18. What effect does tobacco have on the sense of taste?



CHAPTER XXIII

KEEPING AWAY SICKNESS

Too Much Sickness.—Many diseases are caused by our own carelessness and our bad habits of living. We have about one doctor for every one hundred families. There are enough people sick every day to make a city as large as New York or to equal the number of people living in the thirteen states of Idaho, Nevada, Wyoming, Arizona, New Mexico, Utah, Delaware, Montana, Vermont, New Hampshire, North Dakota and South Dakota, and Oklahoma.

A careful study of disease and its cause shows that at least one half of all the sickness in our land can be avoided by right living.

The Cause of Sickness.—Some people are so foolish as to make themselves sick. They weaken the body by using much beer or wine, by breathing bad air, by lack of exercise, or by fast eating. When the body becomes weak, it is likely to get sick at any time.



It is not always our own fault when we are sick. It may be caused by the carelessness of others who have let germs escape from their bodies so that they are able to reach us. One half of the sickness in our land is catching sickness. That is, it is sickness which passes from one person to another and is caused by tiny germs or microbes. A catching sickness is called a contagious disease. Some of the common catching diseases are sore throat, colds, diphtheria, pneumonia, typhoid fever, measles, grippe, and whooping cough.

How we get a Catching Sickness.—We get a catching sickness by taking into our bodies the germs from some other person. The germs of the sick do not pass off in the breath, but in the spit or anything else which comes from their bodies. This is why the spit and all slops from the sick room should be burned, buried, or destroyed in some way.



We should think it very wicked if a showman should turn his lions and tigers loose in a crowd of women and children. Somebody would surely be killed and others hurt. It is just as wrong to turn loose the germs of the sick by throwing the spit and the slops where they will get into a stream or where the flies may find them and by soiling their feet leave death in their trail wherever they crawl.

How the Germs of Sickness catch Us.—The germs of sickness have no feet to walk and no wings to fly, yet they easily travel from the sick to the well. They are not killed by being frozen, or drowned by floating in water, or destroyed by drying. For this reason they can travel with the ice, water, milk, and dust.

In Buffalo, New York, fifty-seven children caught the scarlet fever in one week by using milk cared for by a boy who was getting well from the scarlet fever.

The germs of sickness are so small that a million can hang to the hands or clothing and not be seen. For this reason they are often left clinging to the fingers, desks, books, and pencils, and travel in large numbers on the feet of flies. The surest way the germs have of getting from one person to another is by the common drinking cup.



The Common Drinking Cup is an Exchange Station for Germs.—The most careful examinations have shown that there are thousands of children as well as grown persons who have very light attacks of scarlet fever, tuberculosis, or other diseases and go to school or about their work scattering the germs of sickness in their spit. A child seldom drinks from a cup without leaving on it thousands of germs. Some of these may be germs which will cause sickness. On one drinking cup used in a school, the germs were found to be as thick as the leaves on a maple tree in June.

In an Ohio school one warm day, a boy with beginning measles drank from the cup which was afterward used on the same day by the teacher and all the other pupils. In less than two weeks every pupil and the teacher were suffering from measles. Put nothing into your mouth which has been in another's mouth.



The Golden Rule.—If you have a catching sickness, such as measles, chicken pox, or whooping cough, stay away from others. Since the germs of some diseases, like scarlet fever and diphtheria, remain in the spit sometimes several months after you feel well, don't scatter your spit. Hold a handkerchief before your face when you sneeze or cough. Wash your hands before handling food.

Some Animals carry Sickness.—Mosquitoes carry malaria and yellow fever and some other diseases. Flies carry typhoid fever, grippe, diphtheria, and tuberculosis. Bedbugs and fleas carry the plague and leprosy. Rats carry the plague. Cats sometimes carry diphtheria. Many cows have tuberculosis and the germs of this disease are then sometimes found in their milk. Some children have caught tuberculosis from drinking such milk.



Keeping away Smallpox.—Smallpox was once the most terrible of all diseases. It is so catching that two or three were often sick with it at one time in the same family. Sometimes nearly one half the people of a whole town would have the disease in one year. Over a hundred years ago nearly every grown up person had little pits scattered over his face as a result of having had smallpox.

You can always keep away smallpox by being vaccinated. The doctor can vaccinate you by putting on the freshly scraped skin of your arm some weak smallpox germs from a clean healthy calf which has been vaccinated. Your arm will in a few days get sore and you will not feel well for about one week, but you will be made safe from smallpox for several years.

Fifty nurses were vaccinated in Philadelphia and cared for many sick with the smallpox, staying with them day after day, but not one of the nurses took the disease. Every one should be vaccinated when a year old and again at the age of ten or twelve years.

Colds.—Some colds are catching, but we generally take cold because we have weak bodies or have been careless. If you want to be free from colds, remember these six rules:—

Don't sit still in wet clothes or with wet feet.

Don't sit in a cold draft or in a cold room.

Don't sit on the damp ground or on the ice when you are resting from skating.

Don't cool off quickly after exercising.

Sleep in a room with the windows wide open.

Take a cold bath every morning and draw fresh air to the bottom of the lungs many times every day.

Tuberculosis or Consumption.—This disease is so common and deadly that twenty persons die from it in our country every hour. It is caused by tiny germs (Fig. 63) which lodge in the lungs, glands, bones, or other parts of the body, where they give off poison and hurt the tissues. We take these germs into the body with dust or food, and also by putting to the lips a drinking cup or other things used by a consumptive. Generally the germs will not grow in a strong body, even when they have lodged there.

Preventing Consumption.—Living in poorly lighted houses without much fresh air, working in dusty rooms, using much strong drink and tobacco, eating poor food, losing sleep, neglecting a cough, and taking little or no outdoor exercise weaken the body so that the consumption germs can grow in it. Deep breathing, sitting and walking erect, living in rooms with sunshine, sleeping with the windows open eight or nine hours every night, and eating good food will prevent one from taking consumption and will often cure the disease. Persons with this sickness give out the germs in their spit, which should be caught in a cup and burned.