to have been about parallel to the quantitative progress from the anthropoid precursor to civilized man. But it is not possible to introduce here this very complex question with the necessary developments.
It would not be absurd to try upon the gibbon an experiment conformable to our hypotheses. Without going so far as to wish to reproduce the formation of a new Pithecanthropus, we might attempt to picture what would happen to the attitude in placing the gibbon under conditions favorable to the transformation of its habits of locomotion.
As an intermediate form between man and monkeys, it is difficult to image anything more satisfactory than the skull of Trinil. If this skull, as is probable, is not exceptional for its race, we can count upon finding other specimens approaching still more nearly, either to man or to the monkey. But what the race of Trinil has not yet furnished, have not the lowest human races furnished in abundance? Do there not exist human crania, inferior compared with the average of their race, which show to us all the transitions theoretically desirable between man and the Pithecanthropus? All the inferior human crania which it would be possible to show as approaching the form of Trinil by certain characters would make up very well for the absence of the better specimens of the race Pithecanthropus. But it will be difficult to find, among normal human skulls, specimens as pithecoid as that of Trinil. We see frequently in a race such and such individual characters recalling an ancestral type, for it is easier to descend than to ascend in matters of evolution; but the pathologic arrests of development supervening during the embryonic stage only are capable of giving rise to a whole ensemble of characters recalling a remote phase of phylogenic evolution. Microcephalous idiots only, even among the lowest human races, present such an ensemble of characters which come to realize a morphologic type inferior to that of Pithecanthropus itself.
The distance existing between the Pithecanthropus and normal man must be considered as a necessary result from the point of view of evolution. It is the superior portion of the intermediate race which can have survived and formed an inferior human race. This latter must then present characters superior to the average of its ancestors, even independently of the progress that this human race can have realized since the Pliocene epoch. The existence of human crania presenting at once the ensemble of the cranial characters of Pithecanthropus has not yet been demonstrated, unless we take into account the microcephaly more or less accentuated, that is to say, a veritable anomaly by arrest of development. But we cannot represent a race by an abnormal skull, and it will be noted in the present instance that the resemblance existing
