Fig. 73 —Position of the common humpback mosquito at rest with body full of blood sucked by thrusting the bill into the flesh.
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.
Fig. 75 —The yellow fever mosquito biting the finger. Note how the lower lip is bent.
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.
Fig. 76 —A bunch of mosquito eggs floating on the surface of the water. Enlarged about fifteen times.
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.
Fig. 77 —Photograph of wigglers, the stage in which the mosquito lives a week or two in water.
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.
Fig. 79 —Photograph of the worm stage or larva of the fly at the left and three of the sleeping stage or pupæ at the right. Twice the natural size.
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.
Fig. 80 —Photograph of a half handful of manure which had been thrown out of a horse stable. Note more than one hundred houseflies in the sleeping stage.
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.
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 vertebræ 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.
Fig. 82 —How the bones are held together. A piece has been cut out of the tough ligament to show the cup of the hip bone into which the head of the thigh bone fits.
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.
Fig. 83 —Fifty of the muscles just under the skin. Note the white cords, the tendons in the regions of the hands and feet.
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.
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?
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.
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.
Fig. 86 —The under side of the brain and the spinal cord with the chief nerves of one side of the body viewed from in front.
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.
Fig. 89 —Sleeping in the position shown in the lower figure prevents free breathing and tends to cause round shoulders. The upper figure shows correct position.
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.
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?
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.
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?
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.