THE biologists tell us that the human embryo repeats, very rapidly during the early months of its development and more slowly during the later months, all the forms of life which preceded man upon this earth.
The round speck which is the germ becomes a hollow sphere, a sort of sac with a double wall, which is known as the gastrula and whose orifice of invagination, when it closes, receives the name of the blastopore. This is protozoic life, the as yet gelatinous beginning of animal life, and is followed, after transformations that would take too long to enumerate, by polypoid life.
Next, on either side of the head, appear the branchial arches, corresponding with the gills of the fish. At the end of the first month, the limbs are still no more than mere buds; on the other hand, the embryo is provided with a tail, which, folded against the body, nearly touches the forehead. It now has the appearance of a tadpole and lives a life which is wholly aquatic, bathed in the amniotic fluid which represents for it the water in which the embryos of fish and frogs move about freely.
It now becomes a matter of forming a resolution and knowing what to do with it. The embryo is almost in the situation occupied by life at the origin of the species; and nature, as though to humiliate man or to humiliate herself by remembering her mistakes and hesitations, returns to her gropings, her asymmetrics, her repentances, her unsuccessful experiments. Tentative forms, such as the dorsal cord, are reabsorbed; the primitive kidneys disappear, to make room for the final kidneys, which are enormous, filling the greater portion of the peritoneal cavity. Enormous too is the liver, which invades almost the whole of the visceral cavity; enormous the head, almost as large as the rest of the body; and in this enormous head the primitive ocular vesicles are formed, themselves enormous, as is the umbilical vesicle. This is the incoherent and monstrous period corresponding with the period of madness and gigantism when nature, as yet inexperienced, was blindly sketching uncertain creatures, formidable, unbalanced and anomalous, birds, crocodiles, elephants and fish in one, as though she had not as yet decided what to do, not yet completed her classifications, disentangled her laws, or acquired the sense of proportion, of balance, or of conditions essential to the maintenance of the life which she was creating.
This, roughly speaking, is the recapitulation which occurs before our eyes, but of which, no doubt, many incidents escape us or do not sufficiently attract our attention, for it is possible that they reproduce types with which we are not acquainted and which have not even left geological traces, seeing that the number of species which have disappeared is infinitely greater than that of the species which we know.
Dr. Hélan Jaworski may therefore very justly assert that the embryonic period corresponds with the geological period. And, even as, in the great terrestrial evolution, we observe the gradual disappearance of the armour-plated fishes, the monstrous reptiles and the gigantic mammals, so, in the minor embryonic evolution, we see the primitive kidney, the dorsal cord and the umbilical vesicle dissolve, while the liver diminishes and the disproportion between the head and the rest of the body is lessened. In a word, nature is learning wisdom, recognizing her errors, profiting by her experience, doing her best to repair her blunders and acquiring a sense of equilibrium, economy and form.
Dr. Jaworski finds other analogies between the geological period corresponding with man’s appearance upon earth and the birth of the child, analogies which are ingenious, but rather more hazardous. Birth is in fact preceded by a miniature deluge, caused by the tearing of the foetal envelopes, which allow the amniotic fluid to escape. Then the child, at the moment of entering into life, suddenly experiences a sort of glacial period; it passes, in fact, from an environment with a temperature of over 98° to the outer air, which is barely 60° or 65°. The sense of cold is so terrible that it wrests a first cry of suffering from the new-born child.
What is the meaning of this strange recapitulation?
Dr. Jaworski thinks that, if the brief process of embryonic evolution which prepares the way for the birth of man repeats the great process of terrestrial evolution, this latter, on its side, might well be but a vast embryonic period that is preparing for a birth which we cannot as yet imagine. I do not know whether he will succeed in maintaining this stupendous theory. If he does, he will really have made us, as he promises to do, “take a step towards the essence of things.” Meanwhile, thanks to his preparatory studies, he will always have made us take another and a very useful step towards a truth which this time is incontestable, which, though less unexpected, has never been elucidated with so much patience and which is no less big with consequences.
Dr. Jaworski, then, undertakes to demonstrate that the human body unites in itself, in a plainly recognizable form, all the living creatures which now exist upon earth and which have existed since the origin of life. In other words, each creature sums up in itself all those which have preceded it; and man, the last-comer, contains within himself the whole biological tree, so much so that, if we could distribute his body, if we could segregate each of his organs and keep it alive in isolation, we should be able to reconstitute all existing forms, to repeople the earth with all the species which it has borne, from the primitive protoplasm to the synthesis, the final achievement, which is man.
We might perhaps go farther than Dr. Jaworski and declare, with the occultists of the east, that we likewise contain within us, in the germ or in a rough-hewn state, all the creatures and all the forms that will come after us. But here we should be leaving the domain of science proper to lose ourselves in a speculation which by its very nature is incapable of verification.
So it is not merely in a figurative sense, such as that foreshadowed by the current idiom, where it speaks of the vascular tree, the branches of nerves, or the ovarian cluster; it is not merely by analogy, but in a literal and strictly scientific sense that our heart, fundamentally, is nothing but a medusa and our kidneys sponges, that our intestines represent the polyps and our skeleton the polypites, that our reproductive organs are worms or molluscs, that the vertebral column and the spinal marrow take the place of the Echinodermata, while the Brachiopoda and the Ctenophora would be derived from our eye and the reptiles found in our digestive apparatus, the birds in our respiratory organs and so on.
I repeat, there is no question here of metaphors or of more or less approximate, elastic and plausible correspondences but of rigorously and meticulously established proofs.
I cannot, of course, set before you the details of Dr. Jaworski’s exegesis. It would not permit of the slightest solution of continuity and, in the three volumes published so far, it leads us to conclusions which are very difficult to contest. People used to assert, without attaching too much faith to what they said or scrutinizing it too closely, that man is a microcosm. It seems to be clearly proved to-day that this is not merely literally defensible, but scientifically accurate. We are a prehistoric colony, immense and innumerous, a living agglomeration of all that lives, has lived and probably will live upon earth. We are not only the sons or brothers of the worms, the reptiles, the fish, the frogs, the birds, the mammals and no matter what monsters have defiled or affrighted the surface of the globe: we bear them within us; our organs are no other than themselves; we nourish all their types; they are only awaiting an opportunity to escape from us, to reappear, to reconstitute themselves, to develop and to plunge us once again into terror. In this respect, quite as much as in respect of the secret thoughts, the vices and the phantoms with which we are filled, we might repeat the words which Emerson’s old man used to speak to his children, when they were frightened by a strange face in the dark passage:
“Children, you will never see anything worse than yourselves!”
If all the species were to disappear and only man remained, none would be lost and all might be reborn of his body, as though they were coming out of Noah’s ark, from the almost invisible protozoa down to the formidable antediluvian colossi which could lick the roofs of our houses.
It is therefore fairly probable that all these species take part in our existence, in, our instincts, in all our feelings, in all our thoughts; and here once more we are led back to the great religions of India, which foresaw all the truths that we are gradually discovering and which already, thousands of years ago, were telling us that man is everything and that he must recognize his essence in every living creature.