l87i.] 'DESCENT OF MAN.' 315 



you ; I have got so sick of the whole subject that I felt in 

 utter doubt about the value of any part. I intended, when 

 speaking of females not having been specially modified for 

 protection, to include the prevention of characters acquired 

 by the S being transmitted to ? ; but I now see it would 

 have been better to have said " specially acted on," or some 

 such term. Possibly my intention may be clearer in Vol. II. 

 Let me say that my conclusions are chiefly founded on the 

 consideration of all animals taken in a body, bearing in mind 

 how common the rules of sexual differences appear to be in 

 all classes. The first copy of the chapter on Lepidoptera 

 agreed pretty closely with you. I then worked on, came back 

 to Lepidoptera, and thought myself compelled to alter it — 

 finished Sexual Selection and for the last time went over 

 Lepidoptera, and again I felt forced to alter it. I hope to 

 God there will be nothing disagreeable to you in Vol. II., and 

 that I have spoken fairly of your views ; I am fearful on this 

 head, because I have just read (but not with sufficient care) 

 Mivart's book,* and I feel absolutely certain that he meant to 

 be fair (but he was stimulated by theological fervour) ; yet I 

 do not think he has been quite fair. . . . The part which, I 

 think, will have most influence is where he gives the whole 

 series of cases like that of the whalebone, in which we can- 

 not explain the gradational steps ; but such cases have no 

 weight on my mind — if a few fish were extinct, who on earth 

 would have ventured even to conjecture that lungs had 

 originated in a swim-bladder } In such a case as the Thy- 

 lacine, I think he was .bound to say that the resemblance of 

 the jaw to that of the dog is superficial ; the number and 

 correspondence and development of teeth being widely dif- 

 ferent. I think again when speaking of the necessity of 

 altering a number of characters together, he ought to have 

 thought of man having power by selection to modify simul- 

 taneously or almost simultaneously many points, as in making 

 a greyhound or racehorse — as enlarged upon in my ' Domes- 



* ' The Genesis of Species,' by St. G. Mivart, 1871. 



