For the creation of Man was by no means the creation of a perfect being. The most essential feature of Man is his improvableness, and since his first appearance on the earth the changes that have gone on in him have been enormous, though they have continued to run along in the lines of development that were then marked out. The changes have been so great that in many respects the interval between the highest and the lowest men far surpasses quantitatively the interval between the lowest men and the highest apes. If we take into account the creasing of the cerebral surface, the difference between the brain of a Shakespeare and that of an Australian savage would doubtless be fifty times greater than the difference between the Australian's brain and that of an orangoutang. In mathematical capacity the Australian, who cannot tell the number of fingers on his two hands, is much nearer to a lion or wolf than to Sir Rowan Hamilton, who invented the method of quaternions. In moral development this same Australian, whose language contains no words for justice and benevolence, is less remote from dogs and baboons than from a Howard or a Garrison. In progressiveness, too, the difference between the lowest and the highest races of men is no less conspicuous. The Australian is more teachable than the ape, but his limit is nevertheless very quickly reached.