Man is the only animal that has a hand. The monkey has something like a hand; but, if you watch him as he takes things, you will see that it is a very awkward and bungling thing compared with your hand.
The hand a set of machinery.
The hand is often said to be a wonderfulinstrument. I would rather say that it is a wonderfulset of machinery. An instrument or tool is commonly fitted to do only one thing, as a chisel, a spade, a saw, etc. But how many and how different things can be done with the hand!
It does both coarse and fine work.
Let us look at some things that the hand can do. See the blacksmith wielding the heavy hammer; how strongly his hand grasps the handle! See how it is done. The fingers and thumb are bent by those large muscles that are up in the arm. Now these same fingers, that grasp the hammer so strongly, and do this heavy work, can be trained to do work of the lightest and finest kind. They can take hold of the pen and write. They can move the tool of the engraver, making those fine lines that you sometimes see.
In the machines that man makes there is no such changing from coarse, heavy work to that which is fine and delicate. A machine that does heavy work does that only, and one that does fine work does that only. No man ever made a machine that would pulla large rope one moment, and the next pull a fine thread, and do the one just as well as the other. But that wonderful machine, the hand, can do this. It can grasp the rope firmly, and yet can take between its thumb and finger a thread so fine that you can hardly see it.
Variety of things done by the hand.
But the difference in the work of the hand is not merely in coarseness and fineness. It can do a great many different kinds of coarse work and a great many different kinds of fine work. The hand works very differently with different things. See how differently it manages a rope, a hammer, a spade, a hoe, a knife and fork, etc. It takes hold of them in different ways to work them. And then, as to fine work, how differently it manages a pen, an engraver’s tool, a thread, a needle, etc.
If you watch people as they do different things, you can get some idea of the variety of the work that the hand can perform. See how differently the fingers are continually placed as one is playing on an instrument. You can see very well what a variety of shapes the hand can be put into if you observe a deaf and dumb person talking with his fingers. On the following page is a representation of the different ways in which the letters are made.
Variety of shapes which the hand takes in the deaf and dumb alphabet.
The most common things that it does wonderful.
A buttoning machine.
The most common things that we do with our hands are really wonderful. Watch one as he is buttoning up his coat: how easily his fingers do it; and yet it is a wonderful performance. Suppose a man should try to make a machine, shaped like the hand, that would do the same thing, do you think that he would succeed? It would be very strange if he did. Suppose, however, that, after working a long time, he did really succeed, and that you saw hismachine, with its fingers and thumb, put a button through a button-hole in the same way that you do it with your fingers. Do you think that it could manage buttons of all sizes, large, middle-sized, and small? No; it could only button those that are of one size. The different sized buttons would require different machines; and, besides, a machine that could button up could not unbutton. But your hand is a machine that, besides buttoning and unbuttoning buttons of various sizes, is doing continually a great variety of things that machines can not do. No machine can take up a pen and write, or even move a stick about as your hand can. When some ingenious man makes a machine that can do any one thing like what the hand does, it excites our wonder, and we say, How curious! how wonderful! how much like a hand it works!
The hand an instrument of feeling.
But the hand is not merely a machine that performs a great many motions; it is also an instrument with which the mind feels things. And what a delicate instrument it is for this purpose! How small are the things that you sometimes feel with the point of the finger! As you pass it over a smooth surface, the slightest roughness is felt. A great deal of knowledge, as I told you in Chapter XIV., gets into your mind through the tips of your fingers. Messages are going from them continually by the nerves to the mind in the brain. The blind, I have told you, read with their fingers. They pass them over raised letters, and the nerves of the fingers tell the mind what the letters are, just as the nerves of your eyes are now telling your mind what the letters are in this book.
The hand guided by the touch.
Now, while the hand is performing its different motions as a machine, it is generally very much guided by this sense of touch. If your hand had no feeling in it, it would make awkward business even in such a simple operation as buttoning; and it could not do it at all if you did not look on all the time that it was doing it. Your eye-nerves would have to take the place of your finger-nerves, as in the reading of the blind the finger-nerves take the place of the eye-nerves. As it is, you need not look at your fingers while they are buttoning, for they are guided by the feeling that is in them.
There was once a woman who lost the use of one arm, and at the same time lost all her feeling in the other. She had a baby to take care of. She could hold it with the arm that had no feeling, because she could work the muscles in that arm, but she could not do it without looking at it all the time. If she looked away, the arm would stop holding the baby and let it fall, for it could not feel that it was there. In her case the eye-nerves had to keep watch in place of the arm-nerves that could not feel.
How it differs from machines made by man.
You see that the hand is different from the machines that man makes in two things—in the variety of things that it can do, and in the connection which it has with the mind by the nerves. While the mind, by the nerves, makes it do things, it knows by other nerves all the time whether it is doing them right.
See, now, what are the parts of this wonderful set of machinery. There are in the hand and arm thirty bones. There are about fifty muscles, and all these are connected with the brain by nerves. It is by them that the mind makes the muscles perform all thevarious motions of the hand and fingers, and then there are other nerves that tell the mind what is felt in any part of this machinery.
How to get an idea of the variety of things which the hand can do.
I have mentioned in this chapter a few of the things that are done by the hand, but there is no end to the things that can be done by this set of machinery. You can get some idea of this in two ways—by moving your hands and fingers about in all sorts of ways, and by thinking of as many as you can of the different things that people, in work or in play, do with their hands. And observe in how many more ways the hand is useful than the foot is. The foot has but a few things to do compared with the multitude of things done by the hand.
Questions.—What animal has something like a hand? How does it compare with your hand? Why would you call the hand a set of machinery rather than an instrument? What is said about the fingers doing heavy and light work? Tell about the rope and the thread. What is said about the different kinds of both coarse and fine work that the hand can do? What is said about playing on an instrument? What is said of the alphabet of the deaf and dumb? What is said about the common things done continually by the hand? What is said of the hand as an instrument for feeling? If your hand had no feeling, what would happen? Tell about the woman who lost the power of motion in one arm and feeling in the other. In what two things is the hand different from the machines made by man? What are the parts of the machinery of the hand? In what two ways can you get an idea of the variety of things that this machinery can do?
Questions.—What animal has something like a hand? How does it compare with your hand? Why would you call the hand a set of machinery rather than an instrument? What is said about the fingers doing heavy and light work? Tell about the rope and the thread. What is said about the different kinds of both coarse and fine work that the hand can do? What is said about playing on an instrument? What is said of the alphabet of the deaf and dumb? What is said about the common things done continually by the hand? What is said of the hand as an instrument for feeling? If your hand had no feeling, what would happen? Tell about the woman who lost the power of motion in one arm and feeling in the other. In what two things is the hand different from the machines made by man? What are the parts of the machinery of the hand? In what two ways can you get an idea of the variety of things that this machinery can do?