CHAPTER IX.
BRAIN AND NERVES.
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.