DA R WIN A ND DESCENT. 2 1 1 



' Wlio was to see that " my theory " did not include 

 descent with modification ? The " my " here has been 

 allowed to stand. 



Again : — 



" The fact that instincts . . . are liable to make' 

 mistakes ; — that no instinct has been produced for the 

 exclusive good of other animals, but that each animal 

 takes advantage of the instincts of others ; — that the 

 canon of natural history, ' Natura non facit saltwm' is 

 applicable to instincts as well as to corporeal structure, 

 and is plainly explicable on the foregoing views, but 

 is otherwise inexplicable, — all tend to corrohorate the 

 theory of ^ natural selection" (p. 243). 



We feel that it is the theory of evolution, or descent 

 with modification, that is here corroborated, and that it 

 is this which Mr. Darwin is mainly trying to establish ; 

 the sentence should have ended " all tend to corro- 

 borate the theory of descent with modification ; " the 

 substitution of " natural selection " for descent tends 

 to make»us think that these, conceptions are identical. 

 That they are so regarded, or at any rate that it is the 

 theory of descent in full which Mr. Darwin has in his 

 mind, appears from the immediately succeeding para» 

 graph, which begins "This theory," and continues six 

 lines lower, " For instance, we can understand, on the 

 principle of inheritance, how it is that," &c. 



Again : — 



" In the first place, it should always be borne in 

 mind what sort of intermediate forms must, on my 

 theory, formerly have existed" (p. 280). 



" My theory " became " the theory " in 1 869. No 



