even those who do not forget that the theory of the transmutation of species has been a familiar and influential doctrine, established upon fairly conclusive arguments ever since the beginning of the nineteenth century, are likely to forget the fact that the doctrine, in its proper modern form, takes its origin, as a respectably fathered and militant hypothesis, in France in the middle of the eighteenth century. The histories of the theory of evolution mention, indeed, a number of names in the eighteenth and in many earlier centuries, with which vague and more or less eccentric foreshadowings of the now accepted doctrine are connected. But the books on the subject which we have in English are unfortunately either inadequate or inaccurate or both; and they rather disguise than reveal the real character and significance of the evolutionist movement in the eighteenth century. Many of them—Mr. Clodd's book, for example, and Huxley's essay, and Professor Packard's 'Lamarck,' as well as the French works of Perrier and of Quatrefages on the precursors of Darwin—ignore some of the most important and most influential eighteenth century evolutionists; Professor Osborn's survey ('From the Greeks to Darwin,' 1894) is more comprehensive but regrettably inaccurate. There is therefore some occasion for a fresh attempt to clear up some points in the earlier history of the central conception of modern biology.
It is unfortunate that the eighteenth century manifestations of evolutionism should have so generally been grouped, by those who have written of them, in one class with the ancient adumbrations of Darwinism, as if all alike were merely interesting historic accidents. The ancient foreshadowings of the doctrine were, indeed, little more than happy but fortuitous guesses of ingenious minds. But the mid-eighteenth century outcropping of the theory was a natural, one may almost say an inevitable, consequence of the progress which had up to that time been made in natural science. And the theory found expression, not in the sporadic utterances of an obscure philosopher here and there, but in the best-known writings of three of the most celebrated leaders of the opinion of their time; so that, however little it may have gained acceptance, the theory must have been pretty widely known among their contemporaries. It is, of course, a fact sufficiently familiar that Buffon in 1749 propounded the conception of the transformation of species as a possible hypothesis; that he pointed out the homological evidence in favor of such an hypothesis, and tended in some passages to accept it; but that, in his most important passage on
- In this paper the word 'evolution' is used in its common contemporary sense, as meaning the descent of species from earlier species. The reader will, however, remember that in the eighteenth century the same term was employed to designate the process of the generation of individual organisms as conceived by the preformationist,—i. e., the process of the literal 'development' or unfolding of the ready-made and preexisting parts of the embryo. Most 'evolutionists' in this eighteenth century sense were not evolutionists in the more modern sense in which the word is here used.