The body the soul’s house, with a great deal of machinery in it.
I have told you some things in the previous chapters about how the body is built and kept in repair. I have told you that the blood is the building material from which all the parts of the body are made. The use of food, you have seen, is to make the blood, and the chief use of the breathing is to keep the blood in good order. The heart, with its arteries and veins, keeps the blood moving all about the body, so that it may be used in building and repairing. But what is the body built and kept in repair for? It is a house for the mind or soul. The soul—the thinking part of you—so long as it remains in this world, dwells in the body.
The body is something more than a house for the soul. The head, where the soul dwells, is but a small part of the body. But it uses all parts of it. When the hand is moved, the soul uses the hand; when you walk, it uses the legs and the feet; when you see, it uses the eyes; it uses the ears as its instruments to hear with, and the nose is its smelling instrument; and so of other parts.
You can think, then, of the body as having in it many different kinds of machinery that the mind or soul uses. And the object of eating, and drinking, and breathing, and having the blood circulate, is to make all this machinery for the mind to use.
How the mind uses its machinery.
Let us see, now, how it is that the mind uses the machinery of the body. Raise your hand. What makes it go up? It is what we call the muscles. They pull upon it and raise it. But what makes them do it? They do it because you think to have them do it. It is your thinking mind, then, that makes them raise the arm.
But the mind is not there among the muscles; it is in your head. Now how does the mind get at the muscles to make them work? It does not go out of the brain to them, just as a man goes out of his house among his workmen to tell them what to do. The mind stays in the brain all the time; but there are white cords, called nerves, that go from the brain to all parts of the body, and the mind sends messages by these to the muscles, and they do what the mind tells them to do.
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 yourarm 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 comparedthe 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.
The mind very busy in attending to all its nerves.
A great business the mind has to do in attending to all these ends of nerves in the brain; and how strange it is that it does not get confused, when so many messages are coming to it over its wires from every quarter! It always knows where a message comes from. It never mistakes a message from a finger for one from a toe, nor even a message from one finger for one from another.
And so, too, in sending out messages to the muscles, there is no confusion. When you want to move a finger, your mind sends messages by the nerves to the muscles that do it. The message always goes to the right muscles. It does not go sometimes to the muscles of another finger by mistake, but you always move the finger which you wish to move. And so of all other parts. Messages go from your busy mind in the brain to any part that you move. You can see how wonderful this is, if you watch any one that is dancing or playing on an instrument, and think how the messages are all the time going by the nerves so quickly from the brain to the different parts of the body. I shall tell you more about this in another chapter.
Messages go from the brain by some nerves, and come to it by others.
The man in the telegraph office receives messages by the samewires by which he sends them out. It is not so, as I have told you before, with the mind’s wires, the nerves; the mind receives messages from the senses by one set of nerves, and sends messages to the muscles by another set. If you burn your finger, you pull it away from the fire. Now in this case the mind gets a message from the finger by the nerves, and so knows of the hurt. The message goes from the finger along some nerves to their ends in that bundle of them in the brain; and the mind, being there on the watch, receives it. Now what does the mind do? Does it leave the finger to burn? No; it sends a message at once along some other nerves to the muscles that can pull the finger out of harm’s way.
Questions.—What are some of the things that I have told you in the chapters before this? What is the body built and kept in repair for? In what part of the body does the soul live? Tell how it uses different parts of the body. When your arm is raised, how is it done? In what way does the mind make the muscles act? What are the nerves? How are they like telegraph wires? What is it that goes along the wires? Do we know what it is that goes along the nerves? Give the comparison between cut nerves and broken wires. From what does the mind receive messages? Tell about touching, smelling, tasting, and seeing. What is said about the brain? What is said about the number of nerves? What is said about the mind’s attending to all its nerves? What is said about its making no mistakes in its messages? Give what is said about the burning of a finger.
Questions.—What are some of the things that I have told you in the chapters before this? What is the body built and kept in repair for? In what part of the body does the soul live? Tell how it uses different parts of the body. When your arm is raised, how is it done? In what way does the mind make the muscles act? What are the nerves? How are they like telegraph wires? What is it that goes along the wires? Do we know what it is that goes along the nerves? Give the comparison between cut nerves and broken wires. From what does the mind receive messages? Tell about touching, smelling, tasting, and seeing. What is said about the brain? What is said about the number of nerves? What is said about the mind’s attending to all its nerves? What is said about its making no mistakes in its messages? Give what is said about the burning of a finger.