A. Up to a certain point, the evidence is strikingly favourable to the hypothesis of human evolution. By this is meant the gradual development of the modern type of skeleton found in association with a large and active brain, capable of manifesting its activity in a great variety of ways. Most of the oldest human skeletons just described, differ from this type. Although a difference cannot be demonstrated in respect of cranial capacity, yet those older skeletons are usually distinguished by the heavier jaw and by stout curved limb-bones of such length as to indicate an almost dwarf stature. Still these indications, even though marking a more primitive status, point undeniably to human beings. Passing beyond these, a few fragments remain to suggest a still earlier stage in evolution. And with these at least we find ourselves definitely on the neutral ground between the territories of man and ape, though even here on the human side of that zone.
In the same way, and again up to a certain point, the characters of human implements confirm the inferences drawn from the skeleton. For the older implements are re-gressively more and more crude, and an increasing amount of skill is needed to distinguish artefact from natural object.
Again, the associated animals seem to become less familiar, and the percentage of extinct species increases the further we peer into the stages of the past.
One of the most remarkable researches ever published upon these subjects is due to a group of scientists associated with Professor Berry of Melbourne University. In this place, only the most important of their memoirs (1910) can be called in evidence. In those particular publications, the initial objective was an attempt to measure the degree of resemblance between different types of skull. That endeavour may be roughly illustrated by reference to Fig. 26, in which tracings of various skull-outlines are adjusted to a conventional base-line. Should a vertical line be drawn from the mid-point of the base-line so as to cut the several contours, the vertical distances between the successive curves could be measured. The distance separating Pithecanthropus (P.E. of the figure) from that of the corresponding curve for the Spy skull No. 1 (Spy 1 of the figure) is clearly less than the distance between the curves for the second Spy skull (Spy 2) and the Papuan native.
Fig. 26. Outline tracings of skulls reduced in size to a common dimension, viz. the line Gl—Op, representing a base-line of the brain-case. Pe, Pithecanthropus. Papua, a New Guinea native. Hl, Sm, At are from skulls of monkeys. (After Dubois.)
But Mr Cross used a much more delicate method, and arrived at results embodied in the figure (27) reproduced from his memoir. A most graphic demonstration of those results is provided in this chart. Yet it must be added, that the Galley Hill skull, although shewn in an intermediate position, should almost certainly be nearer the upper limit. This criticism is based upon the conviction that many of the measurements upon which the results are dependent, assign to the Galley Hill skull a lowlier status than it originally possessed before it became distorted (posthumously). Again the Pithecanthropus is apparently nearer to the Anthropoid Apes than to Mankind of to-day. Let it be noticed however that this is not necessarily in contradiction with the opinion expressed above (p. 128 line 2). For Mr Cross' diagram is based upon cranial measurements, whereas the characters of the thigh-bone of Pithecanthropus tend to raise it in the general scale of appreciation. On the whole then, the evolutionary hypothesis seems to receive support from three independent sources of evidence.
