BUFFON AND THE PROBLEM OF SPECIES 565 



kind to breed with horses. " One was therefore wrong formerly in main- 

 taining that mules are absolutely infertile." Other experiments in the 

 crossing of goats and sheep, dogs and wolves, canaries and goldfinches, 

 are recited; they all go to show that sterility is merely a question of 

 degree. 



All hybrids (mulets), says prejudice, are vitiated animals which can not 

 produce offspring. No animal, say reason and experience, is absolutely infertile, 

 even though its parents were of separate species. On the contrary, all are capable 

 of reproduction, and the only difference is a difference of more or less." 



That hybrids are relatively infertile, and probably incapable of 

 breeding with one another, Buffon still maintains ; " their infecundity, 

 without being absolute, may still be regarded as a positive fact." 

 Something, therefore, is still left of his test of unity of species. But 

 now that it seemed to be reduced to a mere difference in degree, it was 

 no longer the sharp-cut, decisive, impressive thing that it had at first 

 appeared. And, feeling that his criterion of species had a good deal 

 weakened, Buffon was led — not, indeed, even now to an altogether 

 unequivocal affirmation of the descent of real species from one another 

 — but to a confused, half-agnostic utterance, in which he seems to take 

 at least the possibility of such descent for granted : 



In general, the kinship of species is one of those profound mysteries of 

 nature which man will be able to fathom only by means of long and repeated 

 and difficult experiments. How, save by a thousand attempts at the cross-breeding 

 of animals of different species, can we ever determine their degree of kinship? 

 Is the ass nearer to the horse than to the zebra f Is the dog nearer to the wolf 

 than to the fox or the jackal? At what distance from man shall we place the 

 great apes, which resemble him so perfectly in bodily conformation? Were all 

 the species of animals formerly what they are to-day? Has their number not 

 increased, or rather, diminished (sic) ? . . . What relations can we establish 

 between this kinship of species and that better known kinship of races within 

 the same species? Do not races in general arise, like mixed species, from an 

 incapacity in the individuals from which the race originated for mating with the 

 pure species? There is perhaps to be found in the dog species some race so rare 

 that it is more difficult to breed than is the mixed species produced by the ass 

 and the mare. How many other questions there are to ask upon this matter 

 alone — and how few of them there are that we can answer! How many more 

 facts we shall need to know before we can pronounce — or even conjecture — upon 

 these points! How many experiments must be undertaken in order to discover 

 these facts, to spy them out, or even to anticipate them by well-grounded 

 conjectures!" 



This passage certainly indicates a strong inclination towards an 



acceptance of a thorough-going doctrine of descent; yet in Butler's 



lengthy compilation of the evidences of Buffon's evolutionism it is not 



cited at all ! The volume containing it, says Butler, offers " little 



which throws additional light upon Buffon's opinion concerning the 



mutability of species " ! 38 In truth, it offers one of the best of the 



" Supp., III., p. 20; the italics are Buffon's. 



* Supp., III., 1776, pp. 32-33. 



ffi " Evolution Old and New," p. 165. 



