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Page:Popular Science Monthly Volume 34.djvu/192

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THE POPULAR SCIENCE MONTHLY.

parison to an upward-growing tree, the central axis of which, put out lateral branches, would be more just, the central stalk of it continuing to rise like the Lombardy poplar, and giving at its apex man.

Gentlemen, we have reached the end of our year's task. I have explained at length the genealogy taught by M. Haeckel, and have examined step by step the systems that have been proposed to take its place. We have inquired whether the point of departure of the vertebrates has been from a soft-bodied worm, or from a crustacean possessing an exterior skeleton. We have concluded that our genealogy has passed by the ganoid fishes, to land in what paleontologists call the labyrinthodonts, and what I have sometimes designated as medium vertebrates. Thence the current has carried us, not in the direction of the mammals, which, however, had already appeared in the Triassic age, but into the full dominion of the reptiles, where we speculated concerning the dinosauric origin of the monotremata or of some similar group. There we met the aplacental marsupials, which we designated as confirmed pro-mammals, and showed that, with some reserves—of the cetaceans, for example—all the recent placental mammals, and consequently ourselves, have issued from them. Here the problem became complicated. To this point, except for the origin itself of the mammals, our origin appeared clear. The lemurs were already a cause of embarrassment. The uncertainties increase respecting the immediate descent of man, although we have at last freed ourselves from prejudices respecting it, and can discuss it coolly. Several opinions, each advanced by illustrious authorities, confront us; I have expounded them impartially, occasionally myself raising objections, as well as favorable arguments. I have not done, and now you may say that I have some secret preference—that you are convinced of it.

There are for me only two doctrines to be considered—one which derives man from the primary stock of the mammals in a direct line and without the intervention of orders, not from a mathematical point, but from that confused mass succeeding the marsupials, in which the differentiations are indecisive and tend toward the ungulates or toward man; and the other one, which accepts the branch or the order of the primates with all its consequences—the lemurs or prosimians at the base, then the monkeys or simians, and man all alone at the summit.

Does one of these ennoble us more than the other? Certainly. The one that regards us as the dominant and central branch of the mammalian tree, the continuation of the prototype in the direct line, and which posits us as the crown of an evolution, the point of departure of which is at the monera, is well calculated to