DARWIN AND DESCENT. 221 



Again : — 



" The succession of the same types of structure 

 within the same areas during the later geological 

 periods ceases to be mysterious, and is simply explained 

 by inheritance" (p. 345). 



I suppose inheritance was not when Mr. Darwin 

 wrote considered mysterious. The last few words have 

 been altered to " and is intelligible on the principle of 

 inheritance." It seems as though Mr. Darwin did not 

 like saying that inheritance was not mysterious, but 

 had no objection to implying that it was intelligible. 



The next paragraph begins — "If, then, the geo- 

 logical record be as imperfect as I believe it to be, 

 . . . the main objections to the theory of natural 

 selection are greatly diminished or disappear. On the 

 other hand, all the chief laws of palaeontology plainly 

 proclaim, as it seems to me, that species have been pro- 

 duced by ordinary generation." 



Here again the claim to the theory of descent with 

 modification is unmistakable ; it cannot, moreover, 

 but occur to us that if species " have been produced 

 by ordinary generation," then ordinary generation has 

 as good a claim to be the main means of originating 

 species as natural selection has. It is hardly neces- 

 sary to point out that ordinary generation involves 

 descent with modification, for all known offspring 

 difier from their parents, so far, at any rate, as that 

 practised judges can generally tell them apart. 



Again : — 



" We see in these facts some deep organic bond, 

 prevailing throughout space and time, over the same 



