560 THE POPULAR SCIENCE MONTHLY 



that any other species ever departs from its specific type, but that in 

 these larger creatures even the " accessory touches " have been com- 

 paratively little altered. 



Thus, in a long series of passages, from 1753 on, we find Buffon 

 reiterating with explicitness and emphasis the same teaching, which 

 has, for him, its principal bases in two of his most cherished concep- 

 tions : namely, in his conviction that the sterility of hybrids shows that 

 species are real " entities of nature " ; and in his embryological theory 

 of " organic molecules " and of the " internal mold " which " casts 

 into its own shape those substances upon which it feeds " and " can 

 operate in the individual only in accordance with the form of each 

 species." One of the first of modern naturalists to make the idea of 

 organic evolution familiar to his contemporaries and to discuss it 

 seriously, Buffon repeatedly rejected that theory, at all periods of his 

 career; and he did so, not from timidity merely nor from an affectation 

 of deference to scriptural authority, but upon reasoned grounds which 

 he plainly stated and had every appearance of presenting as conclusive. 

 Yet it is also undeniable, as will presently be seen, that he did not 

 maintain this negative position without occasional waverings and 

 doubts and at least one clear, though possibly inadvertent, self-contra- 

 diction. 



3. In spite of his habitual emphasis upon the constancy of true spe- 

 cies, Buffon insisted more than any of his predecessors, and more, per- 

 haps, than any of his contemporaries, except Maupertuis and Diderot, 

 upon the variability of organisms and the potency of the forces making 

 for their modification. 



Though nature appears always the same, she passes nevertheless through a 

 constant movement of successive variations, of sensible alterations; she lends 

 herself to new combinations, to mutations of matter and form, so that to-day 

 she is quite different from what she was at the beginning or even at later 

 periods. 28 



The passage is from one of Buffon's later writings; but its close 

 counterpart is to be found as early as 1756 : 



If we consider each species in the different climates which it inhabits, we 

 shall find perceptible varieties as regards size and form; they all derive an 

 impress to a greater or less extent from the climate in which they live. These 

 changes are made slowly and imperceptibly. Nature 's great workman is Time. 

 He marches ever with an even pace, and does nothing by leaps and bounds, but 

 by degrees, gradations and successions he does all things; and the changes which 

 he works — at first imperceptible — become little by little perceptible, and show 

 themselves eventually in results about which there can be no mistake. 29 



For the most part these changes were clearly represented by Buffon 

 as taking place only within the limits of species ; they amounted merely 

 to the formation of new " races " or varieties. Since his criterion of 



™Supp., V., 1778, p. 3. 



29 Vol. VI., pp. 59-60. I have borrowed Butler's excellent rendering of 

 this passage. 



