Now Wallace shews very clearly that in the savage there are organs whose development is out of all proportion with their _present utility_, and even faculties and physical characters which are either useless or injurious, at least to the individual. “But,” says he, “if it can be proved that these modifications, though dangerous or useless at the time of their first appearance, have become much more useful, and are now indispensable to the complete development of the intellectual and moral nature of man, we ought to believe in the existence of an intelligent action, foreseeing and providing for the future, just as we should do, when we see a breeder set to work to produce a definite improvement in any direction in any cultivated plant or domestic animal.” The relative development of the body and the brain, the organ of intelligence, is one of the points upon which our author insists most strongly. The height of the orang, he says, is almost equal to that of man; the gorilla is much taller and bigger. Nevertheless, if we represent by ten the average volume of the brain in the anthropoid apes, this same volume will be represented by twenty-six in savages, and by thirty-two in civilised men. The English naturalist also makes the remark, that among savages, the Esquimaux, for instance, we find individuals the capacity of whose skull almost reaches the maximum which is given for the most highly developed nations. Finally, Wallace, relying upon the experiments and calculations of Galton, admits distinctly that though the brain of savages is to that of civilised man in the proportion of five to six, the intellectual manifestations are, at the most, that of one to one thousand. The material development is, then, out of all proportion to the function. A brain, a little more voluminous than that of the gorilla, would, in the eyes of the eminent traveller, be perfectly sufficient for the inhabitants of the Andaman Islands, of Australia, Tasmania, and Tierra del Fuego. Wallace explains the development of the ideas of justice and benevolence by the advantages which would result from them to the tribe and to each individual. But faculties essentially _individual_, and without _immediate_ utility to others, are not subject, according to him, to selection. “How,” says he, “could the struggle for existence, the victory of the most fitted and natural selection give any aid to the development of mental faculties,” such as ideal conceptions of space and time, of eternity and infinity, the artistic feeling, abstract ideas of number and form, without which arithmetic and geometry are impossible?