The Child's Day Part 4

You have never seen the whole of your ear. The part on the outside of the head, of course, you can easily see and feel. Sometimes you notice a deaf person put his hand behind his ear and press it forward so as to catch the sound waves better. These waves roll in at the little hole you can see, and travel along a short pa.s.sage till they come to a round _drum_, a piece of very thin skin stretched tight like a drumhead.

Have you ever beaten a drum with a stick? You felt the drumhead quiver under the blow, did you not? Well, when the sound waves beat against the drum in the ear, it quivers and starts little waves inside the ear. Each little wave in turn beats against a little bone called the _hammer_; the hammer beats against another called the _anvil_, and this against a third called the _stirrup_; and the quiver of the stirrup is pa.s.sed on to a little window, opening into a little room with a spiral key-board; and from this, the wave travels along a nerve to the brain. As the waves reach the brain, the brain hears. In this way we hear all sorts of sounds, from the tick of a watch to the whistle of a train.

[Ill.u.s.tration: THE WAY BY WHICH SOUND WAVES REACH THE BRAIN

A section through the right ear.]

There is a sensible old saying, "Never put anything smaller than your elbow into the inner part of your ear." Now, of course, you can't put your elbow into such a tiny hole! So the old saying means, never put anything in. The eardrum is very thin and can easily be broken. Even a slap on the ear, or a loud sound too close to it, might crack and spoil the drum and make one deaf.

The outside ear needs careful washing; there are so many little creases that gather dirt and dust. The deep crease behind the ear, too, will become sore if it is not kept clean.

Besides cleaning your ears, you must train them to listen. Some boys and girls hear just a word or two of what is said, and then guess at the rest and think they are listening, or else ask to have it repeated. We should try to hear exactly what is said; and if we listen carefully, it will soon be much easier to understand at once.

Of course, if you really cannot hear, the doctor can tell you what is the matter, and usually can help you very much. Sometimes people become deaf simply because the throat is swollen. Indeed, most deafness comes from colds and catarrhs and other inflammations of the nose and throat. These spread to the ear through a little tube that runs up to the drum cavity from the back of the throat. Sometimes, when you are blowing your nose, you may feel your ear go "pop"; and that means that you have blown air up into the ear through this little tube. Be sure to see a doctor if you don't hear well; and be sure, too, to tell your teacher, so that she may know why it is you do not hear what she says, and ask her to give you a seat near her, so that you can hear.

Then, too, you should learn to notice outdoor sounds--the songs of the birds, the noises that the animals make, the wind in the trees, and the patter of the rain. The old Nors.e.m.e.n have a story that their G.o.d Heimdall had such keen ears that he could hear the gra.s.s growing in the meadow and the wool growing on the backs of the sheep! Your ears can never be so keen as that; but there are many, many happy outdoor sounds that you should listen for. They will help to make you happy, too.

Careful listening may sometime save your life. You can hear the car or the train coming, and you can learn to tell from which direction a sound comes. You can learn to tell one sound from another in the midst of many sounds. In more ways than you can think of now, this habit of listening will protect you from danger.

The Germans have a proverb, "Hear much and say little." What does it mean?

[Ill.u.s.tration: "DO YOU HEAR IT? CAN YOU SEE IT?"]

III. SEEING AND READING

You can learn a great deal through your ears, but think how much more you can learn through your eyes. Just count over all the things that you have had to get your eyes to tell you to-day, and then shut your eyes for a minute and think what it would mean never to be able to see. Don't you think you ought to take very good care of your eyes?

You are going to keep them very busy all your life, and they deserve the very best care you can give them.

[Ill.u.s.tration: THE LIGHT ON THE PAGE, NOT IN THE EYES]

Just as soon as lessons begin, you get out your books; and a good share of the day in school you have a book before you, reading it or studying it or copying from it. It makes a great difference to your eyes how you hold the book and how the light falls. In reading, you should always hold your book so that the light falls upon the page from behind you, or from over one of your shoulders. In this way, the brightest light that comes into your eyes is not from the window, but from the page of your book.

If the light comes from a window in front of you, or if you sit in the evening with your face toward the lamp when you read, the light coming straight from the lamp or the window, as well as the light coming up from the pages of the book, pours into your eyes; and this dazzles and confuses your eyes, so that you can't see plainly and comfortably and are very likely after a while to find that your head aches. At home, of course, you can seat yourself with your back to the light when you read; and usually at school your seats are so arranged that the light falls from behind you or from one side. If not, by turning a little in your seat, you can get the light from over your shoulder.

Notice how the light falls upon the blackboard. When the light comes from the windows behind you, or from one side, you can see what is written there quite plainly. But if the blackboard happens to be between two windows, and especially if this is the lightest side of the room, you will find that the light dazzles you so that you cannot see the writing clearly.

You must have noticed, too, that if, after you have been reading from the blackboard you look down again suddenly to the page of your book, for an instant you will not see the letters plainly. Then, almost before you have time to notice it, you feel a little change take place inside your eyes, and the print upon the page of your book becomes quite plain. This is because your eye has to change the shape of one of the parts inside it, called the _lens_, before you can see clearly the things that are near you. This change, which is called _accommodation_, is made by a little muscle of the eye; and if you keep your eyes working at close work, like reading or writing or fancy-work, too long at a time, or if your eyes need gla.s.ses to make them see clearly, and you haven't them on, this little muscle becomes tired. Then the print of your book, or your writing, or the st.i.tches you have taken begin to blur before your eyes. Your eyes begin to feel tired, and your head begins to ache. This is what we call _eye strain_.

Sometimes this eye strain upsets your appet.i.te or your digestion and makes you sleepless and worried. The trouble may be caused by your own carelessness: you may have been reading too long, or in a poor light, or with the light shining right in your face instead of coming over your shoulder. But sometimes it is caused by the fact that your eyes are not just the right shape; and then the only way to relieve it is to have proper gla.s.ses, or spectacles, fitted, which will make up for this too flat or too round shape, or too large or too small size, of your eyes.

If you cannot see clearly what is written on the blackboard when the light falls upon it from behind you, or above; or if, in a good light, you cannot read the words in your book quite easily, without straining at all, when you hold the book either at arm's length or a foot from your face; or if your head aches or your eyes begin to feel tired or uncomfortable, or the letters begin to blur, after you have read steadily--say, for half an hour,--it is a pretty sure sign that there is some trouble with your eyes. Then you had better have them examined at once by your family doctor or by the school doctor. In many schools now there are doctors to test the children's eyes, and ears, too, so that each child may have a chance to see and hear everything that the other children can see and hear.

Not very many years ago people thought that gla.s.ses were only for old people, but now we know that many children's eyes need gla.s.ses, too. I knew a little girl whose sight was so poor that when she was standing and looked down at the gra.s.s, she couldn't see the green blades. She thought that the gra.s.s looked like a green blur to everyone, just as it did to her; and so she never said anything about it. She was twelve or thirteen years old before she found out that she couldn't see clearly. Of course, trying hard to see things gave her a headache and made her tired and cross. So some one took her to a doctor, and he saw at once what was the matter and fitted her with gla.s.ses. Soon she was quite well and strong; and how glad she was to see the leaves and a hundred other things she had not seen before!

[Ill.u.s.tration: THE EYEBALL IN ITS SOCKET

The muscle from M to M, which helps to turn the eyeball, has been cut away to show the optic nerve.]

Here we have a picture of the _eyeball_, as we call it. The little bands fastened to it are the bands of muscle; and as soon as I say _muscle_ you know what they are for--to move the eyeball about, up and down and from side to side. There are muscles outside the eye as well as inside. Coming out from the back of the eyeball is a pearly white cord quite different from the muscle bands. This is what we call a _nerve_. This nerve in your eye carries to your _brain_, or thinking machine, picture-messages of whatever you look at.

The nerve in your eye gets messages of light much as the nerve deep in your ear gets its messages of sound--from tiny waves in the air. The light waves are smaller and faster even than the sound waves, and the eye nerve is the only nerve that can get pictures of them. You know that, for wireless messages, the receiving machines are not all alike and cannot all take the same messages, if the messages are sent with different sorts of electric waves; and neither can our receiving machines. Some get messages of sight, and some of sound, and some of touch, or taste, or smell.

Now shut your eyes as quickly as you can. How long did it take you? A minute? No, not a quarter of a second. It is about the quickest thing you can think of--"the twinkling of an eye." You shut your eyes "quick as a wink" whenever anything seems likely to fly or splash into them, and this is what the eyelids are for. If anything gets into the eye before the lids can shut, the eye "waters," and _tears_ pour out of it. These are made by a gland-sponge up under the upper lid, so as to wash any dust or sand or other harmful speck out of the eye before it can hurt the sensitive eyeball.

Now look at some one's eyeball. It is like the picture, isn't it?--bright white around the edge and then a ring of color, brown or blue or gray; and inside the color-ring, or _iris_, a little round black hole that we call the _pupil_. Watch the little hole change as you turn the face toward the window. It becomes ever so much smaller.

Now turn the face away from the window, back again into the shadow.

How did the pupil change this time?

[Ill.u.s.tration: EYES PROTECT THEMSELVES AGAINST THE LIGHT]

The iris, or color-ring, acts like a curtain, like the ring-shutter of a camera, and closes up the hole, or pupil, when the light is too bright and would dazzle or burn the inside of the eye; but when the light is dim, the iris opens again, so as to let in light enough with which to see. Look at the little window in your kitten's eyes. It is not the same shape as yours; but when you carry her to the light, you see how the iris closes in and leaves just a little black slit or line.

You remember the blind children? Isn't it wonderful how they can play games and study, too, even though they are blind! They have to make their senses of touch and hearing tell them many things that you learn through your sense of sight. Many of these children _need not have been blind_, if the nurse who first took care of them when they were born had known enough to wash their eyes properly, not with soap and water, of course, but with just one or two drops of a kind of medicine--an _antiseptic_, as we call it--that makes the eye perfectly clean.

But you children who have good eyes that can see, do you really see things when you look at them? You can train your eyes just as you can train your ears. You can teach them to read quickly down a page, and to find things in pictures, and, better still, to see things out of doors, in the garden and the woods and on the seash.o.r.e. We hear a great deal about "sharp eyes," but most of us see very little of all we might see. Our eyes are on the lookout, too, to protect us from dangers that may come; with our skin and nose and ears, they are constantly on the watch; so the better we see the safer we are.

Even if your eyes are perfect now, you will need to take good care of them to keep them strong. Don't let any story, no matter how interesting it is, tempt you to read in a dim light or a light that is too strong. And if you can't see the blackboard easily, or can't read big print, like the school calendar, across the room, tell your mother or your teacher, so that she can ask the doctor to find out what the matter is.

IV. A DRINK OF WATER

It is astonishing what thirsty work studying is! Scarcely is the second recitation over before your throat begins to feel dry, and up goes your hand--"May I get a drink?"

If anyone even says the word "water," it makes you thirsty. It is so good that just the thought of it makes you want some. I should like you to notice how much water you drink every day. Perhaps a gla.s.s in the morning when you get up, and one at night before you go to bed, and three or four in between.

Why do we need so much water? Well, how much do you weigh? Perhaps you will find it hard to believe, but more than half of that weight is water; and because we are always giving off water from the skin and from the body, we need plenty more to take its place.

No living thing can grow without water. Take a bean, for instance, and put it in an empty gla.s.s on the window sill; and even if the sun shines full upon it, nothing will happen, except that after a few days it will shrivel and dry up. But fill the gla.s.s with water, and in a few hours the bean will begin to swell; and in a few days it will burst, and a little shoot will grow out of one end of it and a tiny root at the other. The water and the warmth together have made it sprout and grow.

[Ill.u.s.tration: A DRINKING-CUP EASILY MADE]

Children at school and people on trains should have their own private cups, for serious diseases may be caught from the mouths of other people. You can get a metal pocket folding cup for ten or fifteen cents, or paper ones for a few cents a dozen. If you don't have your own cup, I hope you will get one and carry it. Here is a pattern for a paper cup that you can easily make for yourselves. Try it and see.

When you have once learned how, you can make it very quickly and have a fresh cup every time you want one; but of course you should be sure first that the paper itself is clean.

If you drink milk, this takes the place of some of the water and gives you food as well. It is both drink and food; and a very good food for children it is, too. You know, babies can live on it because it has everything in it to make them grow.

Do you know why it is that people are so careful nowadays about having milk and drinking-water very clean? It is because they have found that the tiny plants, called germs, that make people sick are often carried about in these drinks. A disease called _typhoid fever_ is carried in this way.

Fifty years ago, cities and towns used to be very careless about where they got their water supply, and would often take it out of streams into which other cities emptied their sewage. Now, however, they are much more particular; and the health officers, or Boards of Health, are insisting that public water supply, such as is brought into our houses in pipes, shall be taken either from some spring or deep-flowing well, or from a stream or lake up in the hills, into which no drainage from houses or farmyards, and no dirty water from factories, empties.

[Ill.u.s.tration: A PIPE FOR THE CITY WATER SUPPLY

This pipe is laid for many miles to bring water from the distant hills.]

We are still, however, far from being as careful as we should be about this; and I am sorry to say that America has had more deaths from typhoid fever than any other civilized country. Germany, which, of all countries in the world, is the most particular about keeping its water supply pure, has the fewest deaths from this cause, in proportion to its population--scarcely one fifth as many as we have.

Therefore, by taking proper care, it would be quite possible to prevent at least two thirds of our nearly 400,000 cases of typhoid fever and 35,000 deaths from typhoid, every year.