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THE biologists tell us that the human embryo1 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 speck2 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 transformations3 that would take too long to enumerate4, 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[202] first month, the limbs are still no more than mere5 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 tadpole6 and lives a life which is wholly aquatic7, bathed in the amniotic fluid which represents for it the water in which the embryos8 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 humiliate9 man or to humiliate herself by remembering her mistakes and hesitations10, returns to her gropings, her asymmetrics, her repentances, her unsuccessful experiments. Tentative forms, such as the dorsal11 cord, are reabsorbed; the primitive12 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[203] 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 monstrous13 period corresponding with the period of madness and gigantism when nature, as yet inexperienced, was blindly sketching14 uncertain creatures, formidable, unbalanced and anomalous15, birds, crocodiles, elephants and fish in one, as though she had not as yet decided16 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.
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This, roughly speaking, is the recapitulation which occurs before our eyes, but of which, no doubt, many incidents escape us or do not sufficiently17 attract our attention, for it is possible that they reproduce types[204] with which we are not acquainted and which have not even left geological traces, seeing that the number of species which have disappeared is infinitely18 greater than that of the species which we know.
Dr. Hélan Jaworski may therefore very justly assert that the embryonic19 period corresponds with the geological period. And, even as, in the great terrestrial evolution, we observe the gradual disappearance20 of the armour-plated fishes, the monstrous reptiles21 and the gigantic mammals, so, in the minor22 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 lessened23. 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 equilibrium24, economy and form.
Dr. Jaworski finds other analogies between the geological period corresponding with man’s appearance upon earth and the[205] birth of the child, analogies which are ingenious, but rather more hazardous25. Birth is in fact preceded by a miniature deluge26, 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 wrests27 a first cry of suffering from the new-born child.
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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[206] maintaining this stupendous theory. If he............