chief actors in the final triumphal stage of the theory, Darwin, Spencer, and Huxley. His analysis is marked by a conspicuous desire for fairness all round: he has honestly endeavored to assign to each of these three great thinkers his own true share—no more, no less—in the genesis of the modern evolutionary concept. Yet, though the book contains, strictly speaking, little on this head that was not already implicitly within the reach of special students of the evolution of evolutionism, it will probably prove a great surprise to that large section of the reading public which habitually confines the idea of evolution to organic development alone, and which still believes that Darwin "invented" the theory of descent with modification. To all such people—and they include the mass of the averagely well-read—Mr. Clodd's revelation will come with all the charm of a sudden surprise. He has been enabled through the kindness of Mr. Herbert Spencer to give fuller and more authoritative details of the fundamental facts than have yet been published; and he shows more fully perhaps than any one else has hitherto done the central importance of Mr. Spencer's position in the evolutionary advance.
May I begin with a passage which I quoted from one of Mr. Spencer's own early works no less than eleven years since, in my little monograph on Charles Darwin? It occurs in an essay on The Development Hypothesis, in that long-defunct paper, the Leader. (The Italics are in the original.)
"Even could the supporters of the development hypothesis merely show that the origination of species by the process of modification is conceivable, they would be in a better position than their opponents. But they can do much more than this. They can show that the process of modification has effected, and is effecting, great changes in all organisms, subject to modifying influences. . . . They can show that any existing species—animal or vegetable—when placed under conditions different from its previous ones, immediately begins to undergo certain changes of structure fitting it for the new conditions. They can show that in successive generations these changes continue, until ultimately the new conditions become the natural ones. They can show that in cultivated plants, in domesticated animals, and in the several races of men, these changes have uniformly taken place. They can show that the degrees of difference, so produced, are often, as in dogs, greater than those on which distinctions of species are in other cases founded. They can show that it is a matter of dispute whether some of those modified forms are varieties or modified species. They can show too that the changes daily taking place in ourselves—the facility that attends long practice, and the loss of aptitude that begins when practice ceases—the development of every faculty, bodily, moral, or intellectual,
