Page:Popular Science Monthly Volume 34.djvu/193

Rh flatter our pride. But is it true, and would not our choice of it be a subjective one?

All that I have told you this year and last shows that I incline toward the other solution, and the conclusion that we are descended from the monkey. One consideration to me takes the lead of all the others. The type of the cerebral convolutions in all the primates where it is well characterized in its ascendant evolution is that of man; it varies from the cebian to the pithecoid, from that to the anthropoid, and from the last to man only in degree. The development to the extreme of the simian type of the circumvolutions, and the abrupt increase in the volume of the brain in passing from the anthropoid to man, on which I have insisted, are, apart from the histological examination, the two fundamental anatomical characteristics of man.

That the foot of the monkey has a more or less opposable thumb; that it is more or less adapted to their arboreal life; that it should appear strange to us that the human line, after having experienced a partial transformation of its foot, should have resumed the original foot of its ancestors—these are details. The cranial and facial characteristics, which are the result in man of the considerable volume of his brain, the atrophy of the nasal fosses, and of their numerous posterior cavities, which has brought about the disappearance of the muzzle, the compensatory perfection of the touch and the vision, which, with the modifications necessitated by the equilibrium of the skull, have contributed to a bipedal attitude and an entire new series of differential characteristics—are details also. That which dominates all is the cerebral type, already human, but in a rudimentary condition, in the apes, as it is the same type amplified and perfected in man.

All the organs—foot, hand, teeth, thorax, pelvis, and digestive tube—have been evolved in the mammals, have been transformed capriciously, have taken different courses, and have been specialized in different directions, sometimes to the same result. One only has remained stationary, or has varied but little—the brain—except in man. With him, or one of his ancestors among the primates, it took a start, it grew, developed, making everything bend to its needs, subordinating everything to its own life