In dealing with war it is not enough to discuss the place of warfare in Nature or its effects on primitive peoples. Even if we decide that the general tendency of civilisation is unfavourable to war we have scarcely settled matters. It is necessary to push the question further home. Primitive warfare among savages, when it fails to kill, may be a stimulating and invigorating exercise, simply a more dangerous form of dancing. But civilised warfare is a different kind of thing, to a very limited extent depending on, or encouraging, the prowess of the individual fighting men, and to be judged by other standards. _What precisely is the measurable effect of war, if any, on the civilised human breed?_ If we want to know what to do about war in the future, that is the question we have to answer. "Wars are not paid for in war-time," said Benjamin Franklin, "the bill comes later." Franklin, who was a pioneer in many so fields, seems to have been a pioneer in eugenics also by arguing that a standing army diminishes the size and breed of the human species. He had, however, no definite facts wherewith to demonstrate conclusively that proposition. Even to-day, it cannot be said that there is complete agreement among biologists as to the effect of war on the race. Thus we find a distinguished American zoologist, Chancellor Starr Jordan, constantly proclaiming that the effect of war in reversing selection is a great overshadowing truth of history; warlike nations, he declares, become effeminate, while peaceful nations generate a fiercely militant spirit.[1] Another distinguished American scientist, Professor Ripley, in his great work, _The Races of Europe_, likewise concludes that "standing armies tend to overload succeeding generations with inferior types of men." A cautious English biologist, Professor J. Arthur Thomson, is equally decided in this opinion, and in his recent Galton Lecture[2] sets forth the view that the influence of war on the race, both directly and indirectly, is injurious; he admits that there may be beneficial as well as deteriorative influences, but the former merely affect the moral atmosphere, not the hereditary germ plasm; biologically, war means wastage and a reversal of rational selection, since it prunes off a disproportionally large number of those whom the race can least afford to lose. On the other hand, another biologist, Dr. Chalmers Mitchell, equally opposed to war, cannot feel certain that the total effect of even a great modern war is to deteriorate the stock, while in Germany, as we know, it is the generally current opinion, scientific and unscientific, equally among philosophers, militarists, and journalists, that not only is war "a biological necessity," but that it is peace, and not war, which effeminates and degenerates a nation. In Germany, indeed, this doctrine is so generally accepted that it is not regarded as a scientific thesis to be proved, but as a religious dogma to be preached.