These more exact inquiries are, however, but slowly accumulating, for man is a long-lived animal, and our impatience is great. We must wait often for many generations, before small, though no doubt important, changes are revealed by our methods of research. For this reason much attention has been given to the race histories of the lower animals, for in their case we may in a few years have many generations under observation, and we can follow out their histories in a comparatively short period of time. We are justified in making use of the facts so obtained and of utilising them cautiously for the interpretation of human race history, for we constantly and in every day life assume points of similarity between man and the lower animals. The blow or the spear thrust which injures us we know will also injure them, and we infer that the contortions which follow their application are symptoms of the pain that we, too, should feel. We know,--and scientific inquiry has vastly extended our knowledge,--that animals have all of them many points of structural similarity, and that their life and race histories are in many ways strikingly like our own. The chief muscles and nerves in man may be recognised in the dog; the main lines of development are in both cases the same, and the action of food and poison produces results in which there are few points of difference. Of course, when we infer from the facts observable in the study of animal life that similar facts will be observable in human life as well, we have to exercise due caution. It is here that the acumen of a scientific mind is exercised to the fullest degree; we are liable to error, and our results are perhaps tentative, and must be viewed as such, but no one can doubt the suggestiveness and consequent utility of these studies. Just as our knowledge of comparative anatomy and physiology has been essential to a proper understanding of human anatomy and physiology, so the few facts we at present possess concerning human racial development receive significance when examined by the side of a similar but far more extended array of facts drawn from a study of animal racial development. If, then, it be true that we have before us a small but increasing mass of evidence regarding the laws of racial change, is not this evidence worthy of our closest study? Is it not at least as worthy as the study of the politics of the hour which absorbs so much of our best energies; for what are the petty combinations of parties, or even those temporary associations of individuals, which aim at a common or national policy, by the side of the health and the capacity of that race of which we are but passing representatives, a race whose future we can make or mar by the course we now pursue? _Evolution._