To memory, then, is due the advance of the savage beyond the lower animal; to tradition, the child of memory, the advance of modern man beyond ancient man; to tradition stored in books the advance of civilised men beyond the savage. To written symbols are due also man’s vast powers for future advance. The brute, the mammoth, the mastodon, the whale, the elephant, and the tiger, became ever more and more helpless in the presence of a knowledge and an ingenuity that gathered with the rolling years, and, though accumulated for ages, were yet relatively new things in this enormously old world. Low animals, in proportion as they lack memory, move in a narrow, instinctive groove. Their mental traits are all inherited, and therefore each individual follows exactly in the footsteps of its predecessor. Since they cannot learn, they cannot adapt themselves to circumstances. Removed from the ancestral environment they perish. Cast in a rigid, inexpansive mould, every individual resembles every other of the same species, as much mentally as physically. [Sidenote: Man can Revert to Savagery] It is different with man. He is preeminently the educable, the reflective, the adaptive animal. Since the experiences of no two men are quite similar, they differ in knowledge, ideas, and aspirations, and, therefore, none are very closely alike mentally. The child does not follow exactly in the footsteps of the parent. So great is human adaptability that, though the mind of the savage differs immensely in all except instinct and power of learning from that of the civilised man, yet, were the child of the latter trained from birth by the former, he could not be other than a savage. On the other hand, utter savages--for example, the Maories of New Zealand--have passed in a single generation from barbarism to civilisation. The average individual amongst us may be trained to fill the rôle of a beggar or a king, a scientist or a monk, a thief or a legislator. He is able to dwell in the Tropics or in the Arctic, in the town or in the wild. Memory, knowledge, intelligence, adaptability, are all links in a single chain of efficiency. [Sidenote: Dawn of Human Life]