RECENT DISCOVERIES RELATING TO THE ORIGIN AND ANTIQUITY OF MAN.
Let us therefore conclude with consideration of the ancestry of man according to the modified concept of "dawn men," not "ape-men." In the first place, over an incredibly long period of time the Dawn Men have been tool-makers, of high adaptability and wonderful technique. We have then a biped, a being with a hand capable of grasping and controlling tools, a tool-maker with as fine a sense of touch as that of any of the present-day etchers, engravers and artists. In my opinion, the pro-man psychology, leaving out the evidence of anatomy and morphology, is certainly that of a Dawn Man and not of an "ape-man." I agree with my colleagues that man passed through an arboreal stage, but I believe that this stage did not progress so far as to carry man into a stage approaching that of the anthropoid apes. Dollo has stated the law of the irreversibility of evolution. The brachiating hand of the ape was used as a hook-apes do not grasp a branch with the fingers and thumb but hook the whole hand over the branch, as trapeze workers do to-day-and the thumb was therefore a grave danger. If man had gone through a prolonged period of brachiating in the branches of trees he would have lost his thumb. I agree to putting our arboreal ancestors back to Eocene time, but I predict that even in Upper Oligocene time we shall find pro-men, and if we find Oligocene pro-man-in Mongolia, for example-that he will have pro-human limbs, not proanthropoid ape limbs.
Osborn
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