IOO EVOLUTION, OLD AND NEW. 



the immutability of species, and indicates only the 

 doctrine of the permanence of essential features and the 

 variability of details (toutes les touches accessoires) ; 

 he repeats this eleven years later in his * ^poques de la 

 Nature'" (published 1778).* 



But I think I can show that the passages which M. 

 Geoffrey brings forward, to prove that Buffon was in the 

 first instance a supporter of invariability, do not bear 

 him out in the deduction he has endeavoured to draw 

 from them. 



" What author," he asks, " has ever pronounced more 

 decidedly than Buffon in favour of the invariability of 

 species ? Where can we find a more decided expression 

 of opinion than the following ? 



" ' The different species of animals are separated from 

 one another by a space which Nature cannot overstep.' " 



On turning, however, to Buffon himself, I find the 

 passage to stand as follows : 



" Although the different species of animals are sepa- 

 rated from one another by a space which Nature cannot 

 overstep yet some of them approach so nearly to one 

 another in so many respects that there is only room enough 

 left for the getting in of a line of separation between 

 them"] and on the following page he distinctly en- 

 courages the idea of the mutability of species in the 

 following passage : 



" In place of regarding the ass as a degenerate horse, 

 there would be more reason in calling the horse a more 

 perfect kind of ass (un aue perfectionne), and the 



* 'Hist. Nat. Gen.,' torn. ii. p. 391, 1859. 

 t Tom. v. p. 59, 1755. 



