18661872] SEXUAL SELECTION 95 



fully consider them ; and, even if I had time, I do not Letter 459 

 suppose that I should have anything to say worth printing 

 in a scientific journal. It would obviously be absurd in me 

 to allow a mere note of thanks from me to be printed. 

 Whenever I have to bring out a corrected edition of my 

 book I will well consider your remarks (which I hope that you 

 will send to Nature], but the difficulty will be that my friends 

 tell me that I have already introduced too many facts, and 

 that I ought to prune rather than to introduce more. 



To E. S. Morse. 1 Letter 460 



Down, Dec. 3rd, 1871. 



I am much obliged to you for having sent me your two 

 interesting papers, and for the kind writing on the cover. 

 I am very glad to have my error corrected about the pro- 

 tective colouring of shells. 2 It is no excuse for my broad 

 statement, but I had in my mind the species which are 

 brightly or beautifully coloured, and I can as yet hardly 

 think that the colouring in such cases is protective. 



To Aug. Weismann. Letter 461 



Down, Feb. 29th, 1872. 



I am rejoiced to hear that your eyesight is somewhat better; 

 but I fear that work with the microscope is still out of your 

 power. I have often thought with sincere sympathy how 

 much you must have suffered from your grand line of em- 

 bryological research having been stopped. It was very good 

 of you to use your eyes in writing to me. I have just re- 

 ceived your essay ; 3 but as I am now staying in London for 

 the sake of rest, and as German is at all times very difficult 

 to me, I shall not be able to read your essay for some little 

 time. I am, however, very curious to learn what you have to 

 say on isolation and on periods of variation. I thought much 



1 Prof. E. S. Morse, of Salem, Mass. 



2 " On Adaptive Coloration of the Mollusca," Boston Soc. Nat. Hist. 

 Proc., Vol. XIV., April 5th, 1871. Mr. Morse quotes from the Descent of 

 Man, I., p 316, a passage to the effect that the colours of the mollusca 

 do not in general appear to be protective. Mr. Morse goes on to give 

 instances of protective coloration. 



3 Ueber der Einfluss der Isolirung auf die Artbildung : Leipzig, 1872. 



