The Child's Book of Nature / Three parts in one

by Worthington Hooker

Nerves like telegraphic wires.

These nerves act like the wires of a telegraph. The brain is the mind’s office, as we may call it; here the mind is, and it sends out messages by the nerves as messages are sent from a telegraphic office by its wires. This is done by electricity in the telegraphic office, but how the mind does it we do not know. When you move your arm, something goes from the brain along the nerves to the muscles, and makes them act, but what that something is we do not know.

If the wires that go out from a telegraphic office are broken off in any way, the man in the office may send out messages, but they will not go to the place he wishes. He may work his machine, and send the electricity along the wire, but it will stop where the break is. Just so, if the nerves that go to the muscles of your arm were cut, the muscles could not receive any message from the mind. You might think very hard about raising the arm, but the message that your mind sends to the muscles is stopped where the nerves are cut, just as the electricity stops where the break is in the wire.

The two sets of nerves.

The brain.

While the mind sends out messages by one set of nerves, it receives messages by another set; it receives them from the senses. Just see how this is. If you put your finger upon any thing, how does the mind in your brain know how it feels? How does it know whether it is hard or soft, rough or smooth? The mind does not go from the head down into the finger to find out this; it knows it by the nervous cords that stretch from the brain to the finger. When you touch any thing, something goes, as quick as a flash, from the finger along these nerves to the brain where the mind lives, and lets it know what kind of a thing it is that your finger has touched. So, when you smell any thing, it is the nerves which connect your nose with the brain that tell the mind what kind of a smell it is. And when you taste any thing, it is the nerves of the mouth that tell the mind in the brain whether it is bitter, or sweet, or sour, etc. So, too, when you see any thing, it is the nerve which connects the eye with the brain that tells the mind what it is that you see.

The nerves of the face and head.

The brain, in which the mind lives and with which it thinks, is the softest part of the body. You can see what sort of a thing your own brain is by looking at the brain of some animal at the meat-market. You can see it very well in the calf’s head when it is prepared for cooking by being sawed in two. I have compared the nerves to the wires that stretch out from the telegraphic office; but there are only a few wires, while the nerves that branch out from the brain, all over your body, can not be counted. Here is a figure showing how the nerves branch out over the face and head; there are a great many of them, and so there are in all other parts of the body.

The nerves, by dividing, spread out, so that there are little nerves every where. If you prick yourself with a pin any where, there is a little nerve there that connects that spot with the brain, and that tells the mind about it. Now all the nerves in all parts of the body have their beginnings in the brain. In this soft organ are bundled together, as we may say, all the ends of the nerves, so that the mind can use them. There the mind is at its post, just like the man in the telegraph office; and from that great bundle of the ends of nerves it is constantly learning what is going on at the other ends of them in all parts of the body.