CELLS.

[Illustration: [Cells]]

[Illustration: [Cells]]

Cells are a matter of importance.

To be sure there are cells and cells, and some are much more important

than others.

For instance, there are prison cells, more’s the pity, and anther cells

and honeycomb cells and ovary cells and many more like them. All these

are small, hollow spaces with walls around them.

But there is another kind of cell, more important than all these others

put together, and they are not hollow and do not always have a wall.

Perhaps you are not very much interested in cells, but you had better be

in these we are going to talk about, for they have a great deal to do

with football games and dancing and going to parties and picnics. In

fact, without them there could be no football and no dancing and no

parties nor picnics.

All these things depend upon cells. So we may as well begin at once to

find out what they are.

These cells that we are going to talk about are alive. They are made of

protoplasm. You do not know what protoplasm is? I can tell you it is

time you did then, for if it had not been for protoplasm you would not

be in the land of the living. The protoplasm made you; so if you are not

interested in it, _I_ think you ought to have been a cabbage or a squash

or a liriodendron or some other thoughtless vegetable not expected to be

interested in protoplasm.

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.”

It is sometimes called “Proteus” for the same reason. Of course you know

all about Proteus, the sea god who lived at the bottom of the ocean and

paid homage to the great god Neptune, who was ruler of the seas. Proteus

took care of the sea calves, and he had a queer way of changing his

shape whenever he chose. He used to go to sleep on the rocks while the

calves were sunning themselves, and because he was very wise and could

help people who were in trouble, they used to go there and catch him.

But he was not as friendly as he was wise, and would never tell anything

unless forced to; and when he found himself a prisoner, he would at once

change his form, and so try to escape by frightening his captors. He had

a pleasant habit of all at once changing into an enormous serpent and

opening a mouth full of frightful teeth; then, if _that_ did not

frighten badly enough, he would all at once turn into a bull or a raging

fire or a fierce torrent. He has been known to change into a dozen

dreadful things in as many minutes, so no wonder his name has come to

mean “something that changes.” And no wonder the amœba is called

“proteus,” not that it indulges in any such outrageous transformations

as the sea god, for it never does anything worse than change the shape

of its own little jelly-like body.

Although it can move along, I do not think it would amount to much in a

race, as it only moves a few inches in the course of a day; still that

is a good deal, considering its size.

A great deal depends upon size in this world.

You could go as far in ten seconds as a snail could in as many hours.

The distance would not count for much as far as you are concerned, but

it would be a good day’s work for the snail. So when an amœba travels a

few inches, that counts for as much in its life as a long day’s walk of

a good many miles would in yours, or as a few hundreds of miles on a

railway train.

The amœba can do more than travel. If you touch one it will shrink

together, showing that this little bit of protoplasm has a sort of

_feeling_ power.

When it is hungry it eats. For an amœba can get as hungry as anybody.

Hunger does not depend upon size. You can get as hungry as an elephant,

although you cannot eat as much. You would starve to death, too, as soon

as an elephant, perhaps sooner. An amœba no doubt gets as hungry as you

do, and it certainly would starve to death if it did not have something

to eat.

How can it eat without a mouth? Just as easily as it can travel without

feet. You do not know protoplasm if you think it cannot eat when it is

hungry. Very likely the reason it travels about is because it wants to

find something good to eat. It does not care for roast turkey and

cranberry sauce, nor for apple pie and plum pudding.

_That_ is not what it is looking for. It is looking for some tiny speck

of food smaller than itself.

It lives in the water, of course. It would dry up if it were out in the

air. You should think it would _melt_ in the water? Well, it does not,

any more than a jellyfish melts. When it comes to some little speck of

dead plant or animal, or, for all I know, to some living speck small

enough, it proceeds to eat it.

[Illustration: [Cells]]

It glides over it in the way you know about, and wraps the food speck up

in its body. Then it draws out all the good part of the food into its

own substance and goes on, leaving behind the waste particles.

Do you not think that is a good deal for an amœba to be able to do? But

it can do more than this; it can divide itself in two and make two amœbæ

out of one.

The little amœba is called a “cell.” After awhile you will see why. The

whole amœba is just one cell.

As to whether it is a plant or an animal you will have to ask the amœba,

for I cannot tell you. Some think it is a plant and some say it is an

animal.