The History of a Mouthful of Bread / And its effect on the organization of men and animals

by Jean Macé

That which makes this idea of life most difficult to comprehend is, that one cannot prove it by a direct experiment, since there is not one of our organs which could exist separately from the others. Although independent in their special action, yet these multiplied lives are nevertheless in a state of absolute and mutual dependence, from the imperative need they have of each other to make them act, each having for its share only one particular function, the effect of which extends to all the others. This is called the division of labor; and if you still do not understand me clearly, I will explain it in another way. The heart sends to all the organs—does it not?—the blood, without which they could not live: separated from the heart, the lungs would die immediately. It is to the lungs the blood goes to find the air, without which it could not maintain life. Separated from the lungs, the heart would die immediately. There is nothing belonging to us which can avoid the inexorable requirements of blood and air; consequently, there is nothing which can live an isolated life.

I will borrow a simile from human society which you will understand at once. In civilised countries, where division of labor is established, the tailor makes clothes, the mason makes houses, and the baker makes bread. If you could throw them each alone by himself into a wood, the mason would not be able to dress himself, the baker would sleep in the open air, and the tailor would not know how to make bread. Or rather, as not one of them can carry on his trade without the co-operation of a multitude of hands, they could none of them do anything at all. Each completely independent in his work, yet each dependent upon the others, both for living, and even for being able to work, our workmen can only act when they remain bound in close union with the vast society of which they form a part; and our organs—those other laborers whom you have seen working for so long—our organs are just in the same predicament. But in the primitive societies, among savage tribes, where each man can make his clothes, his house, his bread (when he has any), and everything else for himself, you might take such an individual if you liked, and separate him from the rest of the tribe, and he would go on living as before. And so with the rings of the worm, that primitive society of organs. Each of them is a universal workman, who knows how to make everything. Separate him from his fellows, it will not disturb him at all, and he will go on living as if nothing was thematter.

I still remember some profound reflections I indulged in one day some years ago whilst leaning on my spade and looking at a worm that I had just cut in two, and whose two halves were walking off one on each side.

"There was only one creature here just now," I said to myself, "and now there are two! Have I had power, then, to create one with a stroke of the spade?"

I had not then got hold of the key which I now give you, and to which no possible objection can be raised. If there are two beings after the stroke of the spade it is because there were two before. Nay, there were even many more, if we may trust to the "Manual of Zoology" by Milne Edwards, a very good book, excellent for an old scholar like myself, and which I have found very useful in my country-home, as it has enabled me to relate to you one after another the mysterious wonders of life.

He says that, "if one cuts an earthworm across into two, three, ten, or even twenty morsels, each of these morsels will go on living in the same way as the whole, and will form a new individual."

Twenty! that seems to me a great many, because, as far as I can trust to my brief observations as a gardener, it is necessary that some of the rings should remain united together and afford each other mutual support, in order to succeed in repairing the bleeding breaches; but I would much rather believe it than try the operation. My mind is easy when I am defending the plants that I have sown in my garden from the gluttonous worm who would rob them of their food; but it would not be so if I were cutting them up on my table to learn something about them.

Besides, there is no need of an operation to convince oneself of the particular life of each ring. There is one worm, well known by name at least, though happily not to be met with every day, and that is the tape-worm, who establishes himself in the intestine of man, and lives on the chyme, as the other worm does on garden-mould. They call him the Solitary worm in France; and if ever one might suppose a creature appropriately named, it would surely be him; for certainly there is not much society to be looked for in the dwelling he chooses for himself! But it happens that this pretended solitary worm, with his unlimited chain of rings, is only a long row of perfectly distinct beings, so distinct indeed that, from time to time, some of the rings let themselves go, fall off like ripe fruit, and go away to live elsewhere, ready to become the nucleus of a new set, if a happy accident carries them into another intestine, the only place favorable to their development.

At last, then, here is a corner of the curtain raised; here we see the associated organs which constitute an animal, living for once a life positively and in all respects their own. We are now satisfied about this; and when at another time we find them bound together in the chains of a union too ingenious to be severed with impunity—which we shall discover by seeing their action stop at the moment of separation—we shall know the cause.

Do not think, my dear child, that a wretched earthworm can prove nothing as regards other creatures. The worm is the starting-point of all the organisations which come after him. Of what is he composed? Of a tubewhich is itself composed of rings. Well, it is upon this very tube that the whole animal machine has been founded: and these rings, as they expand and modify themselves in a thousand different ways, give birth to all those varieties of being which drive classifiers to despair, because they will not understand that there ought only to be one animal, since there is only one Creator of animals. Now, this animal is a digestive tube served by organs; it is a worm, i.e., which goes on constantly embellishing itself. I said to you long ago, and at a time when you scarcely knew anything, "Have you ever observed a worm or a leech in motion? You see a successive swelling up of the whole surface of its body as the creature gradually pushes forward, as if there was something in its inside rolling along from the tail to the head. Such is precisely the appearance which the oesophagus would present to you as the food passes down it, if you had the opportunity of seeing it in action; and this has been called the vermicular movement, in consequence of its resemblance to the movement of a worm."