Fig. 50 —At the left is a bunch of flax gathered from the field, and on the right is a spool of thread made from the flax and ready to be woven into linen.
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.
Fig. 52 —These fibers from the lint about the seed of cotton are woven into cotton cloth.
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.
Fig. 53 —Showing how to prevent the shoe from pressing on corns caused by wearing tight shoes or socks roughly darned.
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.
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.
Fig. 54 —The ribs and front wall of the chest cut away to show the lungs. A piece of one lung is cut off to show the heart. A and E, parts of the breastbone; F, diaphragm.
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.
Fig. 55 —Photograph of a salamander, showing the gills on either side of the head, which are used in breathing.
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.
Fig. 56 —The windpipe and lungs viewed from in front. On the right, the tissue is removed to show the air tubes.
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.
Fig. 57 —A bunch of air cells at the end of an air tube in the lungs, showing the blood vessels which receive the oxygen and give out the carbon dioxide.
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.
Fig. 58 —Face cut through the middle to show how the adenoids stop the air from passing through the nose. Arrows show the course which the air should take.
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.
Fig. 60 —Photograph of a house fly on a piece of bread. This fly had been feeding on spit and a study of its legs and body showed more germs present than there are hairs on a person's head.
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.
Fig. 61 —An exact drawing of the germs in a spot as large as a period, on the edge of a drinking cup.
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.
Fig. 62 —A dish of beef broth jelly left open two minutes in a room being swept. Each spot is a city of thousands of germs which grew from one germ dropping on the jelly. By counting the spots you can tell how many germs fell from the dust on this dish three inches in diameter.
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.
Fig. 63 —Photograph of consumption germs, the tiny rods which often grow and cause tuberculosis in bodies weakened by beer or whisky. Much enlarged.
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.
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.
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.
Fig. 64 —The direction of the flame of the candle shows how the fresh air enters and the bad air leaves a room.
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.
Fig. 66 —This man is curing himself of tuberculosis by sleeping at night, and sitting by day, on this porch.
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.
Fig. 67 —Unhealthful position which squeezes the lungs so that they cannot work freely.
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.
Fig. 68 —The cells in the blood. The two white ones were drawn while crawling. Much enlarged.
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).
Fig. 69 —Photograph of the heart from in front with the lungs pinned aside. One fourth natural size.
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.
Fig. 70 —Arteries, the tubes carrying the blood from the heart through the body. Only the chief vessels are shown on one side.
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.
Fig. 71 —The heart with the front part cut away to show the four chambers and valves. The arrows show the direction in which the blood flows.
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.
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.