Like a good many other interesting things, protoplasm cannot usually be seen by the naked eye; it is in such small quantities that it takes a microscope to find it. And when you have found it, so far as its looks are concerned, it would hardly seem to pay for the trouble, for to the eye it is nothing but a colorless, jelly-like substance. It looks more like the white of an egg than anything else. But remember it is not safe to judge protoplasm or people by looks alone. Napoleon was small, and he was not handsome; yet if you had seen him, you would have seen the greatest man living in the world at that time. So when you look at protoplasm you see something very much more wonderful than it seems. In fact, the great Napoleon himself owed his physical life to protoplasm, as did also Shakespeare and Plato, and every person who has ever lived, for protoplasm is the only living matter in the world. You cannot understand that all in a minute, but you begin to see that protoplasm is _rather_ important, and as well worth knowing about as the latest fashion in bicycles or sleeve patterns. Sometimes a bit of protoplasm lives all by itself. It is just a little speck of colorless, jelly-like substance. Yet it can do a number of things. One little creature, which is only a bit of protoplasm, has a name much larger than itself. We call it “Amœba.” [Illustration: [Cells]] Rather a pretty name, on the whole, and very uncommon. I doubt if you know a single person by that name. It is a name, too, that everybody ought to know. Well, as I told you before, and shall probably tell you a great many more times, for I do not want you to forget it, the amœba is only a bit of protoplasm. Yet it can go about. You watch it some fine day under your microscope and see it travel. It runs out a little, thin bit of its body, so [Illustration: [Cells]] and then the rest of the body sort of pulls itself up to that. In this way, by putting out little finger-like projections and drawing the rest of the body up to them, it can move quite a distance if you give it time enough. You can imagine so changeable a creature as the amœba can scarcely be found twice of the same shape, and how its friends recognize it is more than I can tell. Suppose you were in the habit of changing your shape whenever you moved, being long and thin one minute, short and thick another, having fourteen arms one day and none the next? How _could_ you expect people to know you when they met you? But perhaps the amœba has an unsocial nature and does not care whether it is recognized or not. Because it changes its shape so often the amœba has received its pretty name. For “amœba,” you must know, comes from a Greek word meaning “change.”