Natural Wonders

by Edwin Tenney Brewster

All except the first hole on each side, the one nearest the mouth. That never closes again, but remains open and becomes the hole into the ear. There is a hole in from the outside, as you know, the one you used to put beans and pencils in, only you oughtn’t. And there is another hole from the inside, beginning high up in the throat just where you can’t see it, and running in till it almost joins the other hole. Between the two is just a thin skin, which is the “drum” of the ear, and if you get a hole in it you may never be able to hear again. Because this drum never grew. It is the place that remained after one tunnel came in from outside, and another from inside, and the two didn’t quite meet.

So it comes about that all of us land creatures with backbones, who breathe with lungs, start making gill slits which we can’t possibly use. Then, because we have them on hand, we use the one farthest in front for the hole of the ear, and close the rest up again. And we take all that trouble—though it doesn’t trouble us much at the time—just because various other backboned creatures, which live in the water and don’t have lungs, had to make gill slits to breathe with.

There are a lot of things of this sort—parts and organs and members which one creature, while it is in the egg, makes and doesn’t use, just because some other creature, when it grew up, had to have them. You know what a short tail a hen or a turkey or a pigeon has—just a stub of a tail, only just big enough to stick its tail feathers in. But a little hen or turkey or pigeon, while it is still in the egg, has a tail like other animals, long enough to wag.

There is a kind of salamander, which is unlike most salamanders, efts, newts, and the like—these are all pretty much the same thing, and you find them almost anywhere in the brooks and the ponds and the damp woods. All of these that you are ever likely to see breathe with gills like a fish, and can live in the water. Only instead of having their gills covered over with a bony plate like the fish, these creatures often have them outside, like a sort of lace collar that hangs down at the side of their necks. Tom, the chimney sweep, in Charles Kingsley’s famous tale, after he turned into a water baby, had just such tufted gills so that he could swim under water like any newt or eft, and if you haven’t read “The Water Babies,” it’s certainly high time you did.

What I started to say is that this particular kind of salamander lives on the land. So he doesn’t need gills and doesn’t have them. But the little salamander, while he is still in the egg, has gills like any salamander, though for all the use he can ever put them to, he might just as well have been furnished with a pair of skates; for by the time he hatches out of the egg, the gills have been taken to pieces by his white corpuscles and the stuff used to make some other part of the body.

All the same, if you break open the egg, take the little creature out, and put him in the water while he still has gills, he will swim away, and live under water as well as any water creature. But if you wait till he hatches out of himself and has lost his gills, then if you put him in the water, he will drown just as you would. So the little salamander, that is going to spend his life on dry land, still has gills while he is in the egg and has no use for them, all just because other salamanders that live some of the time in the water need gills to breathe with.

Then there are the snakes, which have lungs and breathe air like any land animal. Only a snake is so very slender that there isn’t room in him for two lungs side by side. So he has only one proper lung, very long and thin, that runs from his neck pretty well down to his tail. Nevertheless, the snakes still keep the other lung, small and quite useless, tucked away beside the front end of the one they do use. Other reptiles have two lungs, so the snakes have to have two lungs also, though they can’t possibly use them both, and the other which they don’t use, merely takes up room.

We human beings are just as bad as the rest. Every little while, somebody comes down with appendicitis and has to be taken to the hospital to have his “vermiform appendix” taken out. The appendix isn’t the slightest use to anybody, we are better off without it, but in cows and dogs and rabbits and kangaroos, and various other animals, especially those that eat grass and leaves, it is a good deal of use for helping to digest food. So we have to have it, to be like the rest—and then pay the doctor to cut it off.

We don’t move our ears as horses and dogs and rabbits do. But still the muscles are there; and people say that anybody who wanted to take the trouble could learn to wag his ears like a baboon. Anyhow, the muscles are there, though we don’t use them and other creatures do.

We are said to have no fewer than one hundred and eighty such useless things about us—all sorts of little things that are no use to us at all and no use to half the animals that have them. But they are useful to the other half, and we all have to be in the fashion. Among these is a strange sort of single eye, set in the middle of the head, so that we really have three eyes instead of two. Our third eye is no bigger than a pea, and it lies tucked away between the two sides of the brain, well inside the skull, where it cannot possibly see anything. All the four-footed creatures have it. But in none of them is it the slightest use, except in certain lizards, especially in one in New Zealand, where it is a real eye placed in the middle of the forehead between the other two. Several American lizards also have this extra eye, though it isn’t good for much seeing, among them the “horned toad” of California, which of course isn’t a toad at all. So, just because a few lizards want three eyes to see with, the rest of the four-footed animals and we human beings have to have an extra eye that we don’t want, tucked away in pitch darkness inside our heads.