In this chapter I shall invite attention to what the biologists have discovered concerning racial change, and the conditions under which the change occurs. Before the simultaneous publication in 1858 by Darwin and Wallace of their “Law of Natural Selection,” biologists believed in the Lamarckian view of heredity, a notable follower of Lamarck being our own Herbert Spencer. Lamarck briefly sums up his views in the following passage: “All that nature has caused individuals to acquire or lose through the circumstances to which their race has found itself for a time exposed, and consequently, through the predominant exercise of certain organs, or through a failure to exercise certain parts, it preserves through heredity to the new individuals that are produced by them, provided the changes acquired are common to the two sexes, or to those that have produced these new individuals.” Now this view is the one that is popularly held to this day, and it is the very view which the new school of biologists have set themselves to combat. Lamarck would have accounted for the long neck of the giraffe by supposing that in remote ages its ancestors were short-necked like other animals, but that it exercised this neck in browsing off high trees, that the necks elongated in consequence of this stretching, and that this elongation was transmitted by heredity, although even by imperceptibly slight degrees, from one generation to another, until the part gradually grew to the present length. Lamarck would cordially have agreed with the modern educationalist in the belief that the children of a man who gives himself to learning will have better head-pieces than if the father had been a soldier or professional cricketer. In this Lamarckian view of heredity we have two ideas; first, that fresh characters may be acquired during an individual’s lifetime, due to the action of his surroundings or environment; and secondly, that these fresh characters are transmitted to the offspring and may produce in time marked racial change. The first idea is undoubtedly and admittedly true. The build of a soldier, a clerk, a ploughman, and an athlete is distinctive; the horn that grows upon a mechanic’s hand, and the development of the muscles of a blacksmith’s arm, are commonplace facts. It is the second idea, the supposed transmission of these acquired characters, which is now so seriously called in question. _Darwin’s Law of Selection._