All animals feel. So, too, do all plants. At least, all animals and plants sometimes move when they are touched. So they must feel. Whether they know that they feel or not, is another matter. Most likely, all plants and all the lowest animals, feel as we feel in our sleep, when we get tired of one position and turn over, or feel cold and pull up the bed clothes, without knowing at all what we are about. Somebody has said that the mind “sleeps in plants, dreams in animals, and wakes in man,” and that is really just about the state of affairs.

All animals except the very lowest also taste and smell. At least they choose their food, as they couldn’t very well do if they did not smell or taste it. Tho when you come to think of it, for an animal living in the water, taste and smell are all the same thing. The food is in the water, the creature’s mouth is full of water, and its nose (if it happens to have one, as most water creatures do not) is full of water also. So it doesn’t make much difference whether you say that the creature tastes the water or smells it.

Most animals have eyes and can see. Not a few also, which have not eyes, can still tell light from darkness. The earthworm, for example, has no eyes at all, yet it always avoids bright light, and keeps in its burrow when the sun is out. Neither has it ears, yet when it is part way out of its hole, it will at once pull back again when certain notes are sounded near it on a piano.

We might almost say that every bit of the life-jelly of which all living things are made has itself all the five senses. All of it seems to feel, and all in some faint way to see and hear, taste and smell, move and remember. Besides this, the life-jelly makes itself all sorts of eyes and ears, all sorts of mouths and noses, all sorts of muscles and brains, in order that it may see and hear, smell and taste, feel and move and remember better than it could do without them.

But all this time that we have been thinking about ants, and star-fish, and earthworms, we have been neglecting the creatures which we really care most about, and certainly know best, the cats and dogs and horses and rabbits and various pets of all sorts which we know by name, and which in return we believe are fond of us. These animals, the four-footed creatures with fur, and the birds, are of all living things most like ourselves. They are most like us in body, they are like us also in mind; and they have the same senses that we have—five, seven, ten, a dozen or more, according as we choose to count them.

They have, I say, the same senses that we have; but they use them differently. Nothing, I think, is more striking about dogs, for example, than the small use they make of their eyes. Often, indeed, they seem half blind; they fail to recognize their own masters ten yards away; get separated from them, and run round frantically, smelling of everything in range; while all the while, the master can see the dog perfectly well, and pick him out at a glance from a dozen others. One would think that the dog would simply look round, see his master, and join him.

I don’t think that they really are half blind. They probably can see nearly as well as we. They simply don’t use their eyes, and depend instead on their noses. Sight is the most important sense for us, as it seems to be for the birds. But the beasts seem to depend most on smell.

The tales we read about the scent of dogs, and especially of bloodhounds, are often almost beyond belief. The bloodhounds, I understand, are so-called, not because they are especially fierce, in fact they seem to be on the whole a rather gentle sort of dog, as dogs go, but because they are supposed to smell one’s blood, and to be able to follow the smell almost anywhere. I suppose they really do smell the perspiration; but they do it thru the sole of a heavy boot, when one has simply walked along over the ground; and they follow that inconceivably faint odor, hours after, and pick it out from all other smells, even those of other people cutting across the track.

Yet I sometimes think we make out the dog’s sense of smell to be more wonderful than it is. The same dog that tracks footprints so marvelously will nose round in all sorts of dirt as if he had no sense of smell at all, and eat things that we would not have in the house.

We also can do a little smelling. Anybody can smell the vapor of bromin in the air when there is one part in two hundred thousand. Hydrogen sulphid, which is the gas that makes the smell of rotten eggs, will scent up 1,700,000 times its bulk of air. The least little grain of musk will scent a room; as little as the fifty thousand millionth of an ounce can be smelled by a good nose. Tea and wine tasters (who of course are really tea and wine smellers) can pick out the place where grapes or leaves grew, and the season of the year. Wine tasters can tell one year’s vintage from another, and distinguish between the top and the bottom of a single bottle.

No dog, probably, can smell anything like such small quantities of these substances, or detect such minute differences. We smell musk and wine and tea; he smells footprints. One can’t say that either has a better nose than the other. Really, a good deal of the difference between us and the animals is that we depend on sight and hearing, because we can use these two senses to handle words. We can see words, and we can hear words; we cannot taste or smell them. So we get to relying on eyes and ears. But the animals, which don’t use words anyway, they think more about smells.

There is still another way in which we are apt, I think, to overestimate the senses of animals. We know, for example, that a horse will find his way home on a dark night, when everything is pitch black, and the driver cannot see his hand before his face. We say that the horse must have wonderful sight to make out his way under such conditions.

The real fact is, however, that the horse goes straight home thru darkness and storm, not because his eyesight is good, but because it is poor. He is at home in the night, because he does not see especially well by day. Those of you who have read The Last Days of Pompeii (as everybody should, for it is a famous old story) will remember that when, during the eruption of Vesuvius, the city was darkened under the shower of ashes, so that the inhabitants wandered about in the streets completely lost and quite unable to find their way out, the blind girl was able to lead her friends straight to safety. She had always lived in the dark, and could find her way as well one time as another.

So it is with horses and other animals. They seem to see in the dark, when they really hear and smell. A horse especially depends for finding his way, on his muscular sense. While his driver is noticing houses and trees and sign-boards, the horse is noticing so long a pull up one hill, so much holding back down another, so much level stretch between. The man is lost when he cannot see his houses and sign-boards; but the horse’s hills and levels are still there.

You remember the rats that, when the passage in their maze was shortened, kept running full tilt against the end wall; and then when the passage was lengthened, kept turning too soon and butting into the side wall. The rats were depending on their muscular sense. They remembered their way as so long a straight run, then a turn. They could run as fast by night as by day, because they didn’t do much seeing either time.

We also depend on our muscular sense far more than we commonly realize. Doubtless we all know how to button our coats. But how do we know? We certainly do not know how it tastes, smells or sounds. I don’t think we often remember how it looks. What we do remember is the feeling of the buttons and the movements we make. But if we try buttoning with the other hand, or put on a coat that buttons on the other side, we feel as awkward as can be. We can see as well as before; the touch has not changed; there never was any taste, hearing, or smell. The difference is in the movements. The muscular sense is learning something new.

How hard it is to bat on the other side, to use any tool the other way round, or make any change which is strange to the muscular sense. That shows how much we all rely on it. If we play the piano, and remember pieces without the notes, it is by this muscular sense that we do it. Our fingers seem to know the tune; and in a sense, they really do. Surely, if a musician can find his way back and forth over the keyboard thru a long piece of music, by means of his muscular sense, it is not so remarkable that a horse should find its way home over the road, or a rat scamper thru its holes, guided by the same means. They don’t really see in the dark, they simply turn on another sense. We have it also; but mostly we trust to our eyes, instead.

There is another sense, too, on which animals are more given to depending than we are, and that is the sense of equilibrium and direction, which, as I have explained, has its seat in a part of the inner ear. You know the game where you are blindfolded, turn around three times, and then try to blow out a candle. If your direction-sense is at fault, as it generally is, you turn too far or not far enough, blow where the candle isn’t, and make everybody laugh. Men who have to find their way about over a wild country, explorers and the like, sometimes have this direction sense trained to a wonderful degree. They simply cannot get lost anywhere. The rest of us, who depend on street numbers and the sign-boards on the lamp posts, don’t have much use for this sense, and so never really learn to use it. Many animals depend on it a good deal. They find their way home in truly marvelous ways; and we say it is “instinct.” It really isn’t instinct, but just plain sight, hearing, smell, and direction sense. Men who have practiced their direction sense can find their way quite as well.

So in general, the animals haven’t different senses from ours, nor on the whole better ones. But they use them differently; and cultivate some senses which we let go to waste. For the most part, the animals depend on smell far more than we. Smell is apt to be their principal sense, as sight is ours. Because they don’t use their eyes as much as we do, they notice and remember more of what they learn thru their sense of direction and their muscular sense. But a man who tries hard can usually beat any animal at his own game.

The fact is, I suppose, that we, men and beasts and birds alike, have all the senses there are, all that any sort of creature could have anyway. Then each, according to his nature and habits, uses one more than the rest, to think and remember with.