So far in this book, we have been learning about the body. We know something about the wonderful life-jelly of which all living things are made—how it is itself the soft parts of plants and animals, and how it builds for itself the hard shell and bones and wood, which are its supports and its tools. We know, also, something about how each particular animal or plant or human being starts as a minute fleck of this life-jelly, grows to be, first a seed or an egg, and then a full grown animal, a man, or a tree. We know, too, something of the living bricks which build the bodies of living creatures; and something of the difference between young creatures and old ones. More than this, I trust, we have learned that all this curious information is not to be looked at merely as something interesting or amusing; but that like all the teachings of science, it is something that will help us to live wisely. For as we come to know, we ought also to learn to do; and while we are finding out something about living things, we ought also to be finding out something about living.

We have, I say, thus far been learning about our bodies. Now we shall turn to a still more important part of us, and try to learn something about our minds. Our bodies, we found, are very much indeed like the bodies of animals and even of plants. Perhaps we shall find that our minds also are like those of other living things. Perhaps we shall find them to be something very different indeed.

Most of us, I suppose, have seen at least one little baby. I don’t mean a small baby merely, one that sits up in its carriage with a pillow behind its back, and smiles up at you when you look in under the hood. I mean a real little baby, a week or two old, that can’t turn its head over on the pillow or put its hands anywhere in particular, and instead of being nice and pink, is as red as a little beet—for the little baby’s skin is so very thin that it uses it to breath thru, to help out its poor little lungs, just as the frogs and other water creatures which have lungs breath thru the skin also. You know the size of baby I mean; if you haven’t had any younger brothers and sisters, there must at least have been something like it in the next house.

Now there are several very strange facts about such little babies, of which by no means the least strange is this: If you take such a very weak and tiny creature, just able to move its arms and legs, and put a finger or a small stick across the palm of its hand, the little one will grip so hard that you will have no small difficulty in getting its fingers loose again. In fact, some babies will actually allow themselves to be lifted in this way; and will hang by their hands a minute or more before they will flop down again into a helpless heap.

So here is one thing that the wee baby can do better than he can when he gets to be older and a good deal stronger, and better sometimes than he will ever be able to do it again. It is something, too, that he did the first time he tried, didn’t have to learn, didn’t have to practice, didn’t have to do anything but just be born knowing how. Pity we can’t all get our geography lessons and our piano practice done this easy way!

There are not a few other things which we all did exactly right the first time, without ever being shown how, or practicing, or seeing anyone else. For instance, when we were very young indeed, and very small, about as young and small, in fact, as people ever get, somebody gave us our first drink of water. We were not a day old then; and we didn’t even know enough to look at the same point with both eyes at once, but let them straggle off, one eye looking at one thing and the other at another, so that both got generally mixed up and couldn’t make out much of anything. But we knew all about drinking. We shut our little mouths tight round the stopper of our bottle, and sucked away like little steam pumps. The water went down the front of our throats, crossed over to the back, and went into our thirsty tummies. Meanwhile, our breath went in at our noses, down into the back of our throats, crossed over to the front, and went down our wind-pipes. But tho wind and water had to go crosswise of the same passage, we never made a mistake, and opened or shut the wrong lid for the wrong fluid, so as to let the air into our stomachs or the water into our lungs. Which really, when you consider how young we were, and how this was the first drink we ever took, was decidedly clever of us.

An act of this sort, which we are born knowing how to do and do right the first time without ever practising or being taught, is called an instinct. Mighty handy, too, they are, these instincts. Think what would happen to a baby that didn’t have the sucking instinct, and couldn’t take a spoonful of water nor a drop of milk till somebody had explained about drinking and showed him how to swallow without letting it run down the wrong way. I don’t believe there would be much chance of that baby’s ever growing up. To be sure, the other instinct that makes the little baby grip so hard on one’s finger, really, isn’t any particular use to him in these days. Long, long ago, nevertheless, when our ancestors were wild men and only half human, the little baby had to cling to its mother when she ran thru the forest with the wild beasts chasing her. Then if the little baby couldn’t hang on tight, it was pretty likely to get eaten up. But the babies that clung to their mothers, while their mothers were climbing a tree with both hands, and so couldn’t hold on to them, these babies lived to grow up, and the memory of that far away time still lingers in each little baby’s grip.

Some things are so important that one really has to know them. Did you ever think why girls like to play with dolls and boys do not? Why, on the other hand, boys can throw stones and girls cannot? Girls like to play with dolls, because when they grow up to be women and have real babies of their own, these babies have got to be dressed and fed and washed and tended and taken care of when they are sick. All this is very hard work indeed, about as hard and trying work as anybody ever has to do; so that if your own particular mama did not have a natural and instinctive love in her heart for all babies, she would not have jumped up at night every time you cried, no matter how cold and sleepy she was. If taking care of little babies were just plain work, to be done no better than other sorts of work are done, it would be pretty unpleasant for the babies. So women are made to love babies so much that even when they are little girls they like to play at taking care of doll babies, in default of real ones. But boys and men, they don’t count; so they do not have this taking-care-of-babies-and-dolls instinct.

But the boys and men can throw things, because before the invention of guns (which really was not very long ago) and before men lived in cities and planted crops, about the only way to get anything to eat was to get out and throw something at an animal and kill it. Then, too, when there was a war (and this often used to be most of the time) the fighting had to be done with spears and swords, which had to be thrown, or else used to strike and thrust with, which is pretty much the same thing as throwing. So it happened that for ages upon ages before our ancestors became civilized, while the women stayed at home and took care of the children, the men went out and threw things. And that is why today, girls like to play with dolls, but boys like to hunt and fish; and why boys can throw stones, and girls can’t.

Boys, then, are born with the throwing instinct. Throwing is as easy for them to learn as walking. But girls haven’t it. For them learning to throw is as hard as learning to walk on the hands. So we see how both with walking and throwing, the inborn instinct makes learning easy, tho it does not altogether take the place of practice.