CHAPTER XIV.

THE SMELL, THE TASTE, AND THE TOUCH.

I have told you that most of what the mind knows about the world around it comes to it by the sight and the hearing. But it learns a great deal by the other senses, and these I will tell you about in this chapter.

[Sidenote: How we smell things.]

Did you ever think how it is that you smell any thing? You put a rose up to your nose, and the fragrance is pleasant to you. Now what is this fragrance? Is it something that goes up into your nose? You can not see any thing come from the rose. But in reality very fine particles come from it. They are finer than the finest powder. They float every where about in the air, and, as you breathe, they go with the air into your nostrils. Every perfume that you smell is made of such particles.

But how do you think the mind knows any thing about these particles when they come into the nose? It is in this way. In the lining of the nose are the fine ends of the nerve of smell. These ends of the branches of this nerve are so small that you can not see them. Now the fine particles that I have told you about touch these ends of the nerve, and the nerve tells the mind about them; and this is smelling.

The nose is a more extensive organ than most people think it is. There are divisions in it. These fold on each other in such a way that there is a great deal of surface in the nose, and the ends of the nerve of smell are all on this surface.

[Sidenote: The smell of some animals.]

Some animals have a very sharp smell. In them the divisions in the nose are very great in extent, and so the nerve spreads over a large surface. The dog, you know, is able to track his master by scenting his footsteps. The cat, too, has a very quick smell for rats and mice.

Some persons have a sharp smell for some things. I have heard of a blind gentleman who could always tell when there was a cat any where near him by his sense of smell. Once he was very sure that there was one near by, though no one could see her; he insisted upon it that he was right, and after a while pussy was found in a closet of the room. There was also a blind and deaf person who could distinguish between different people that he knew by the sense of smell.

[Sidenote: The enjoyment afforded by the sense of smell.]

The sense of smell affords us great enjoyment. The Creator has, for the purpose of gratifying us, scattered sweet-smelling flowers all over the earth. These are all perfume factories, as I told you in Part First, made by him to give us pleasure. He could have made the flowers and fruits in such a way that they would have no smell; but, in his desire to please us and make us happy, he has given to them a great variety of pleasant odors. There are, it is true, some unpleasant smells in the world, but these are not any thing like as common as the pleasant ones; and many of them are manifestly very useful in warning us of danger. For example, the unpleasant odor caused by filth and decay tells, people where these causes of disease are, so that they may get rid of them. And plants that are poisonous generally have a disagreeable odor, which leads us to avoid them.

[Sidenote: How we taste and how we feel.]

The sense of taste is another source of gratification to us. The nerve of this sense has its fine ends mostly in the tongue. What we take into the mouth touches these ends of the nerve, and the nerve tells the mind about it; and this is tasting.

Besides the pleasure which we have from the taste, the great use of this sense is to guide us in the choice of food. Animals choose the kinds of food that are proper for them, and they do it by their taste. They very seldom make a mistake in this. The sense of taste, like that of smell, sometimes warns us of danger. If out food tastes bad, we know that there is something wrong about it and do not eat it, and so, perhaps, avoid being made sick.

The sense of touch gives a great deal of knowledge to the mind. This sense has a large number of nerves in all parts of the body, and they are making reports continually to the mind. Especially busy in this way are the nerves of the tips of the fingers. It is by the fine ends of these nerves that the mind finds out how different things feel. It finds out whether they are soft or hard, smooth or rough, etc.

These nerves in the tips of the fingers are of great service to the mind in guiding it in using the muscles. In playing with the fingers on an instrument, the feeling in the ends of them is a guide to the mind in working them. So it is with any thing that we do with them. You could not do some of the simplest things if there was no feeling in your fingers. You could not even button and unbutton your coat. I shall have more to say about this when I tell you particularly about the hand.

[Sidenote: The nerves of touch in the skin.]

The nerves of touch are not placed on the surface of the skin. We have really two skins, an outer and an inner one. The nerves are in the inner skin, and are covered by the outer skin. This outer skin is very thin except on the sole of the foot and the palm of the hand; from its thinness it is called the scarf-skin. It is this which is raised when a blister is drawn; and perhaps you know that it does not hurt to prick this when we want to let the water out; but if the needle touches the inner skin, where the nerves are, you feel it very quickly.

Now, when you touch any thing, the nerves in the inner skin feel it through this scarf-skin. This is so thin and soft that the nerves can feel through it; and, at the same time, it is a good protection to them. If it were not for this, the nerves would be affected too much by the rubbing of things against them. They could not even bear the air. If you had no scarf-skin you would be in great distress all the time. You know how much pain you suffer if you rub off the skin, as it is called, any where. It is the scarf-skin only that is rubbed off, and this exposes to the air the fine ends of the nerves in the inner skin.

The ends of the nerves of touch are in rows on the tips of the fingers. It is these rows that make the curved lines that you can see so plainly.

[Sidenote: How some animals feel.]

[Sidenote: Whiskers of the cat.]

There are no animals that have such perfect instruments of touch as our fingers are. Animals that have hoofs, as the horse and the cow, can not feel much with their fore feet. They have their sense of touch mostly in their lips and tongues. The elephant has this sense chiefly in the finger-shaped thing at the end of his trunk. There is not much feeling in the paws of dogs, cats, etc. The whiskers of the cat are feelers. There are nerves at the root of each of those long hairs, so that when any thing touches the whiskers the cat’s mind knows it at once.

[Sidenote: Feelers of insects.]

Insects have feelers extending out from their heads. Sometimes they are very long, as you see in this insect, called the ichneumon fly. We see insects, as they are going about, touch things with these feelers as we do with our hands. Bees can work in the dark, in their hives, guided by their feelers; indeed, the bee will not work at all if his feelers are cut off: he does not seem to know what to do with himself. Insects sometimes appear to tell each other things by their feelers. In every hive of bees there is a queen. If she dies, those that know about it go around very quickly, telling the other bees by striking their feelers with their own; and those that are told tell others, and thus the sad event is soon known all over the hive.

_Questions._--By which senses does the mind get most of its knowledge? What is fragrance? How does the mind know any thing about it? What is said of the extent of the organ of smell? What is said of the smell of some animals? Of the acute smell of some persons? What is said of the enjoyment afforded by the sense of smell? How are offensive odors sometimes useful? What is said of the sense of taste? What are its uses? Where is the sense of touch? Where is it especially active? What do the nerves of touch in the fingers tell the mind? In what way do they help us in using the muscles? Tell about the two skins of our bodies. Why is the outer skin needed? What makes the curved lines on the tips of the fingers? What is said of touch in animals that have hoofs? What are the whiskers of the cat for? What is said of the feelers of insects? What is told about the bees?