This section is from the "The New Student's Reference Work Volume 5: How And Why Stories" by Elinor Atkinson.
All worms are of a higher order than the spiny-bodied animals such as the sea-urchin and the starfish. This is not exactly because some of them do such bright things as to build houses and hang front gates. It is because they are better made ; and so, on the whole, are better fitted for their work in the world.
To be "better made," in the animal and vegetable world, means to have more parts, and each part fitted to do some special thing. The amoeba has no feet, no stomach—no anything, you might almost say. If it needs a foot it makes it. When it wants to eat, it wraps itself around its food and one side is as good as the other for this "made to order" stomach. When we get up to the sea cucumber we find a little animal that has lungs and nerves and a stomach. To be sure the sea cucumber throws away its stomach when it gets excited, and then grows a new one.
Now, when we come to the worms, we find still better machines for living. Take the worms you call "fish" worms. Their real name is earthworms, because they help to make the kind of earth in which plants grow best. You would be surprised to know in how many ways the earthworm is like you.
For one thing, he has a stomach ; not a stomach like the amoeba, made and unmade all the time ; nor like the sea cucumber to be thrown away whenever he gets peevish—but a real stomach that he keeps all the time, and uses for nothing else. His body, as you see, is a tube. Inside the tube is another tube. This inside tube is his stomach.
And he has blood, too. After the worm's food is digested it becomes blood, as our food does. He has the beginnings of hearts, also. I say hearts, because worms have several hearts. The earthworm, for instance, has five. They are simple little hearts that answer his purpose very well, but they wouldn't do for you at all. You must have one heart with several parts, instead of five simple hearts. Whenever Nature wants anything better done, you notice, she turns it over to one part that will give the whole of its mind to it.
The earthworm has one vein and one artery. Both are tubes like those that carry blood to and from your heart. One runs along his back, above his tube-like stomach. The other runs under his stomach. The five little hearts connect these two blood vessels, like the rounds of a ladder, as you see from the picture. After the worm's food is digested into blood, it oozes out into the rest of his body. The different parts of the worm are bathed in it, and so are made to grow. Most of the earthworm's blood is used in this way; so only a part of it is passed back through the hearts. These hearts do not have so much to do as your heart does, and that is why they are so simple. In the next higher group of animals—those with a shell, like the crawfish—we will find the heart is not so simple.
You notice the earthworm is made up of sections or rings of muscles, just as your backbone is made up of rings of bone. So he not only hints at the heart and blood vessels of animals higher than himself, but he seems to say:
"See how useful it is to be made up of rings. See how I can bend and turn and twist and get in and out, everywhere. The animals below me cannot do this. After awhile there will come an animal with a backbone, made up of rings. He will crawl on the ground, and be called a serpent. Then will come other animals with stiffer backbones and feet. They will not have a great many hooklike feet as I have. They will have only four good, jointed feet. In the water, also, there will be animals with backbones. Instead of feet they will have paddles or fins. Into the air will come animals with backbones, two feet and two fins, called wings. With these wings they will swim the air.
"Last of all will come the most wonderful animal of all. At first, when he is a baby, he will creep about on his little stomach, just as I do. Then he will go about on four legs for a while—will creep on his hands and feet. Then, when his backbone grows stronger, and he has learned to stand alone, as the fern learned to do long ago, he will begin to walk with two of his legs, and the other two legs, now called arms, will be set free to use in other ways.
"On these arms will be hands, and on these hands five fingers, like the five rays of the starfish and the five petals of a flower. With these five fingers he will grasp, first of all, his food, as the star fish does with his five rays. Then with these hands and fingers he will make boats to go about in the water like fish. At first he will make only play boats, then, as he grows older, big boats, with fins, called paddles. After awhile he will make other boats with paddles or wings for swimming in the air. These the will call flying machines.
An earth-worm showing the sections or rings of muscle.
So, although he cannot swim as well as the fish, nor fly at all, as the bird does, he can make swimming machines and flying machines and so turn into a fish or a bird whenever he likes ; just as if he were part of a fairy tale.
"What a wonderful big brother we worms will have then!" says the little worm.
"But," adds the little worm, "let him not be too proud and forget us—his humble relations; and how nature made us all before she made him, and so learned how to give him that wonderful heart and brain. If she had not first made our crude little stomachs, where would she have learned to make his good one? And until she had made our little hook-feet she couldn't make hands and feet for him. Our nerves helped teach him how to feel. Our dim eyes that just enable us to tell light from darkness, taught him how to see. Our five simple little hearts helped show how one larger heart could be made for him, to feed his brain and body, and to teach him to love all his little brothers of the water, the earth and the air.
" Let him remember these things, and love all living things and be kind."