Now, my reader, we have come to the last chapter of this book, which is going to be the hardest chapter of all, and I think, the most important. For though it is going to be about something that nobody quite understands, and something that the more one thinks about, the more he doesn’t understand it, nevertheless it is something that you will have to think about many times in your lives hereafter, and you might as well make a beginning. Besides, though you won’t understand all that I am going to say—largely I am afraid, because I don’t understand it myself—still I trust that you will remember some of it; and by and by when you are sorely puzzled over these matters, perhaps it will help you out.

If you will think back over what I have already told you in this book about animals and plants, and recall also what you have yourselves seen, and what you have learned about your own bodies and the way they work, I think you will agree with me, that of all the strange and wonderful things in this most strange and wonderful world, a living thing is the strangest and the most wonderful.

Think, for example, how a little egg, no bigger, it may be, than the head of a pin, with no help from outside, except perhaps a little fresh air and a little warmth, just goes ahead and makes itself over into a grown animal. Consider, too, how well it does the job—every scale and feather and tooth and bone and gland and muscle and claw and nail and blood vessel and nerve and hair, all just in the right place, and just of the right size. When one builds a house, the owner consults the architect, and the architect advises with the contractor, and the contractor puts some of the work on the sub-contractor, and the contractor and the sub-contractors direct the workmen; and among them, in a year or so, they manage to get the house together. But in the world of living things, one little fleck of living protoplasm goes ahead all by itself, and builds a whole living animal, sometimes in a few days. Yet there are more different parts to be made and fitted together in one of your little fingers, than in any common dwelling house, even tho you count the laths behind the plastering and the shingles on the roof—yes, and the nails that hold them on. As for your brains, they are, each one of them, for complexity, like all the parts of all the houses in a fair-sized city, with all the furniture, and all the tableware, and all the pots and pans in all the kitchens thrown in for good measure. If you think that a watch or a battleship is a complicated affair, think what goes on in the brain of a tiny ant.

Think, too, how resourceful an egg is. It tries its best to grow into a proper animal; but if somebody interferes, to prevent that, then the egg goes pluckily ahead and makes the best it can of a bad matter. If it gets jarred apart so that it cannot make one animal, why then it makes two, or four, or eight. When it can make neither one animal nor two proper and separate twins, it doesn’t give up, but makes some sort of double monster, that at least manages to keep alive. For my own part, I feel a sincere respect for eggs. I wish more of us had their pertinacity.

After the egg has made itself into a grown animal, consider how well fitted out that animal is. It has, usually, eyes, nose, mouth, ears, sense of touch, of heat and cold, of taste, and the rest. It has born in it the instincts to find its proper food, to find or build its shelter, to take care of its young, to escape its enemies, and in general to like the things which it is best for it to do. Yet if it doesn’t happen to have these sense organs and instincts and the rest, still it always has something nearly as good, and manages somehow to get its living in the world.

Yet I sometimes think that the most extraordinary thing about living things, both animals and plants, is the enormous number of different kinds of them. There are some twenty different sorts of cats, of various sizes from lions down; and twice as many different sorts of dogs, wolves, foxes and other dog-like creatures. There are thirty-two different kinds of willow trees in North America, thirty-six different kinds of pine trees, Sixty-three different oaks. As for insects, about three hundred thousand different sorts have already been given names; and there are at least ten times as many more that are still nameless. Do you know how many different races of men there are that you can tell apart by their looks?—Chinamen, Negroes, White men, Tartars, Eskimo, Indians, Malays, Arabs, and I don’t know how many more, all alike in being human, and yet all different.

Why there should be such a lot of different animals and plants and men is something that nobody fully understands. We do know, however, and know very certainly, that there haven’t always been all these various sorts in the world. If we could go back a sufficient number of thousand years, we should come to a time when, instead of twenty sorts of cat, there were only ten. Back of that, was a still more ancient time when there were only five. A long time before even that early day, there was only Patriofelis, “the father of cats,” and even he, as you know, was also a good deal like a seal.

So too there must once have been a “father of dogs” whose descendants have changed, some into proper dogs, and some into wolves, and some into foxes, and some into jackals, coyotes, dingos, fennecs, and the rest of the forty-odd sorts of wild dogs—to say nothing of all the various tame dogs, collies and terriers and mastiffs and bull dogs and setters, that you can count up for yourselves.

Once too, there was only one kind of man. He probably lived somewhere in southern Asia, and spread out from there, till he possessed the whole earth. Some of him went south-east into the Pacific Islands, and changed into Malays and Australians. Some of him went south-west into Africa and became Negroes. Some became Persians, Egyptians, Hindus, and Arabs. Those that kept on further and entered Europe turned various shades of white and became us. For very few white men are really white—only certain Swedes and Norwegians and Danes. The rest of us, who call ourselves white, are merely not quite so black as our very-many-times-great-grandfathers and our somewhat distant cousins, the Negroes.

Most of these early men, however, started north-east; and because they couldn’t very well cross the great mountains and deserts in central Asia, they ran round the eastern end, and then came back on the other side. On their way, they turned to Chinamen and Japanese. Those that got way up to the north under the Arctic circle became Eskimos. Some of them crossed over by way of Siberia and Alaska (for these countries have not always been as cold as they are now) and turned into American Indians.

Then, after these people had got north of the great Asian mountains, others of them turned west, and came clear across into Europe. In fact, they came near to overrunning Europe during the last days of the Roman Empire so that the famous Charlemagne had to fight them in the eighth century, as you will learn when you study history in school, or still better when you read stories of knights and paladins of the early Middle Ages. So part of us white men came to Europe, and then to America, directly from southern Asia. And part of us came round by way of China and Tartary and Russia; tho now we are all mixt up together so that no one can tell which from t’other. Yet even now, whenever you get up in the gallery and look down on the people’s heads, you can see that some white men have long, egg-shaped heads and narrow faces, and some have round bullet-shaped heads and broad faces. The long sort of head came straight up from India, by way of Asia Minor; and the round sort came round the end of the mountains and across central Asia. That’s the reason why, tho we are all white men, we can’t wear one another’s hats.

That’s about the way it is with all kinds of animals and plants. Each one starts somewhere, and spreads out in all directions as far as it can, gradually changing as it goes, until from being one sort of pine or oak, there come to be dozens, and instead of one kind of cat or dog there are a score. On the whole, too, the latest kinds of animals and plants are better than the earlier ones and there are a great many more of them. This is what we call Evolution—but why it all happens or what it is all for, Is just precisely “one of those things that no fellah can find out.”

Still one can’t help thinking that if we men can make as many things as we do out of iron—knives and saws and locomotives and bridges and sky-scrapers and battle-ships and all sorts of wonderful machinery, and make them better and better all the while, some wiser being than ourselves might make other and still more wonderful machines out of the life-jelly which we call protoplasm, and keep making them better and better and more and more kinds of them as the ages have gone on.