Read CHAPTER III - NERVES of Child's Health Primer For Primary Classes, free online book, by Jane Andrews, on

How do the muscles know when to move?

You have all seen the telegraph wires, by which messages are sent from one town to another, all over the country.

You are too young to understand how this is done, but you each have something inside of you, by which you are sending messages almost every minute while you are awake.

We will try to learn a little about its wonderful way of working.

In your head is your brain. It is the part of you which thinks.

As you would be very badly off if you could not think, the brain is your most precious part, and you have a strong box made of bone to keep it in.

We will call the brain the central telegraph office. Little white cords, called nerves, connect the brain with the rest of the body.

A large cord called the spinal cord, lies safely in a bony case made by the spine, and many nerves branch off from this.

If you put your finger on a hot stove, in an instant a message goes on the nerve telegraph to the brain. It tells that wise thinking part that your finger will burn, if it stays on the stove.

In another instant, the brain sends back a message to the muscles that move that finger, saying: “Contract quickly, bend the joint, and take that poor finger away so that it will not be burned.”

You can hardly believe that there was time for all this sending of messages; for as soon as you felt the hot stove, you pulled your finger away. But you really could not have pulled it away, unless the brain had sent word to the muscles to do it.

Now, you know what we mean when we say, “As quick as thought.” Surely nothing could be quicker.

You see that the brain has a great deal of work to do, for it has to send so many orders.

There are some muscles which are moving quietly and steadily all the time, though we take no notice of the motion.

You do not have to think about breathing, and yet the muscles work all the time, moving your chest.

If we had to think about it every time we breathed, we should have no time to think of any thing else.

There is one part of the brain that takes care of such work for us. It sends the messages about breathing, and keeps the breathing muscles and many other muscles faithfully at work. It does all this without our needing to know or think about it at all.

Do you begin to see that your body is a busy work-shop, where many kinds of work are being done all day and all night?

Although we lie still and sleep in the night, the breathing must go on, and so must the work of those other organs that never stop until we die.


The little white nerve-threads lie smoothly side by side, making small white cords. Each kind of message goes on its own thread, so that the messages need never get mixed or confused.

These nerves are very delicate little messengers. They do all the feeling for the whole body, and by means of them we have many pains and many pleasures.

If there was no nerve in your tooth it could not ache. But if there were no nerves in your mouth and tongue, you could not taste your food.

If there were no nerves in your hands, you might cut them and feel no pain. But you could not feel your mother’s soft, warm hand, as she laid it on yours.

One of your first duties is the care of yourselves.

Children may say: “My father and mother take care of me.” But even while you are young, there are some ways in which no one can take care of you but yourselves. The older you grow, the more this care will belong to you, and to no one else.

Think of the work all the parts of the body do for us, and how they help us to be well and happy. Certainly the least we can do is to take care of them and keep them in good order.


As one part of the brain has to take care of all the rest of the body, and keep every organ at work, of course it can never go to sleep itself. If it did, the heart would stop pumping, the lungs would leave off breathing, all other work would stop, and the body would be dead.

But there is another part of the brain which does the thinking, and this part needs rest.

When you are asleep, you are not thinking, but you are breathing and other work of the body is going on.

If the thinking part of the brain does not have good quiet sleep, it will soon wear out. A worn-out brain is not easy to repair.

If well cared for, your brain will do the best of work for you for seventy or eighty years without complaining.

The nerves are easily tired out, and they need much rest. They get tired if we do one thing too long at a time; they are rested by a change of work.


Think of the wonderful work the brain is all the time doing for you!

You ought to give it the best of food to keep it in good working order. Any drink that contains alcohol is not a food to make one strong; but is a poison to hurt, and at last to kill.

It injures the brain and nerves so that they can not work well, and send their messages properly. That is why the drunkard does not know what he is about.

Newspapers often tell us about people setting houses on fire; about men who forgot to turn the switch, and so wrecked a railroad train; about men who lay down on the railroad track and were run over by the cars.

Often these stories end with: “The person had been drinking.” When the nerves are put to sleep by alcohol, people become careless and do not do their work faithfully; sometimes, they can not even tell the difference between a railroad track and a place of safety. The brain receives no message, or the wrong one, and the person does not know what he is doing.

You may say that all men who drink liquor do not do such terrible things.

That is true. A little alcohol is not so bad as a great deal. But even a little makes the head ache, and hurts the brain and nerves.

A body kept pure and strong is of great service to its owner. There are people who are not drunkards, but who often drink a little liquor. By this means, they slowly poison their bodies.

When sickness comes upon them, they are less able to bear it, and less likely to get well again, than those who have never injured their bodies with alcohol.

When a sick or wounded man is brought into the hospital, one of the first questions asked him by the doctor is: “Do you drink?”

If he answers “Yes!” the next questions are, “What do you drink?” and “How much?”

The answers he gives to these questions, show the doctor what chance the man has of getting well.

A man who never drinks liquor will get well, where a drinking man would surely die.


Why does any one wish to use tobacco?

Because many men say that it helps them, and makes them feel better.

Shall I tell you how it makes them feel better?

If a man is cold, the tobacco deadens his nerves so that he does not feel the cold and does not take pains to make himself warmer.

If a man is tired, or in trouble, tobacco will not really rest him or help him out of his trouble.

It only puts his nerves to sleep and helps him think that he is not tired, and that he does not need to overcome his troubles.

It puts his nerves to sleep very much as alcohol does, and helps him to be contented with what ought not to content him.

A boy who smokes or chews tobacco, is not so good a scholar as if he did not use the poison. He can not remember his lessons so well.

Usually, too, he is not so polite, nor so good a boy as he otherwise would be.


1. How do the muscles know when to move?

2. What part of you is it that thinks?

3. What are the nerves?

4. Where is the spinal cord?

5. What message goes to the brain when you put your finger on a hot stove?

6. What message comes back from the brain to the finger?

7. What is meant by “As quick as thought”?

8. Name some of the muscles which work without needing our thought.

9. What keeps them at work?

10. Why do not the nerve messages get mixed and confused?

11. Why could you not feel, if you had no nerves?

12. State some ways in which the nerves give us pain.

13. State some ways in which they give us pleasure.

14. What part of us has the most work to do?

15. How must we keep the brain strong and well?

16. What does alcohol do to the nerves and brain?

17. Why does not a drunken man know what he is about?

18. What causes most of the accidents we read of?

19. Why could not the man who had been drinking tell the difference between a railroad track and a place of safety?

20. How does the frequent drinking of a little liquor affect the body?

21. How does sickness affect people who often drink these liquors?

22. When a man is taken to the hospital, what questions does the doctor ask?

23. What depends upon his answers?

24. Why do many men use tobacco?

25. How does it make them feel better?

26. Does it really help a person who uses it?

27. Does tobacco help a boy to be a good scholar?

28. How does it affect his manners?