It required no knowledge of that art for Man, as soon as he became "erectus," to fling stones at other animals whom he wished to kill or to frighten. The significance of the erect position of Man was ably shown by Dr. Munro, in his address at Nottingham in 1893. Its mechanical and physical advantages, the differentiation of the limbs into hands and feet, and the relation between the more perfect condition of those organs and the development of the brain, were pointed out. The difference between the semi-erect attitude of the anthropoids and the perfectly upright position of Man represents a wide gap. The chief movement in the act of progression in Man is performed by an enormously developed group of muscles known as the calf of the leg. In the upper limbs the hand has become the most complete and perfect mechanical organ ever produced. From the first moment that Man recognized the advantage of using a club or a stone in attacking his prey or defending himself, the direct incentives to a higher brain-development came into existence. What a memorable event in the history of humanity (continues Dr. Munro, whose argument I have briefly summarized) was the manufacture of the first sharp stone implement!
How long it took Man to make the discovery and acquire the art, who can say? Even now, the human mind works slowly. May it not have worked even more slowly in that time of Man's infancy? It seems not unreasonable to conclude that this great discovery may have come upon him by degrees, and that the first step in it—the ascertaining that a stone with a sharp edge was more effective than a smooth one, and that such a sharp edge might be produced by smartly knocking one stone against another—would give rise to a rude and simple implement, to which a single knock had given all the effect desired. We may therefore expect that, if any remains of Man's work at this stage are found at all, they would be in such a form as to be scarcely distinguishable from stones which had suffered a natural fracture.
When, therefore, the lamented Sir Joseph Prestwich asserted that there are to be found, on the chalk plateau of Kent, a number of flint implements of rude primitive form, in which the trimming is often very slight, made on the edges of rude natural flints, besides others which, though not the result of chance, show no special design, he stated that which is not in itself
