18641869] STERILITY OF HYBRIDS 287 



To T. H. Huxley. Letter 208 



Down, Jan. 3oth [1868]. 



Most sincere thanks for your kind congratulations. I 

 never received a note from you in my life without pleasure ; 

 but whether this will be so after you have read pangenesis, 1 

 I am very doubtful. Oh Lord, what a blowing up I may 

 receive ! I write now partly to say that you must not think 

 of looking at my book till the summer, when I hope you will 

 read pangenesis, for I care for your opinion on such a subject 

 more than for that of any other man in Europe. You are so 

 terribly sharp-sighted and so confoundedly honest ! But to the 

 day of my death I will always maintain that you have been 

 too sharp-sighted on hybridism ; and the chapter on the 

 subject in my book I should like you to read : not that, as I 

 fear, it will produce any good effect, and be hanged to you. 



I rejoice that your children are all pretty well. Give 

 Mrs. Huxley the enclosed, 2 and ask her to look out when one 

 of her children is struggling and just going to burst out crying. 

 A dear young lady near here plagued a very young child for 

 my sake, till it cried, and saw the eyebrows for a second or 

 two beautifully oblique, just before the torrent of tears began. 



The sympathy of all our friends about George's success (it 

 is the young Herald) 3 has been a wonderful pleasure to us. 

 George has riot slaved himself, which makes his success the 

 more satisfactory. Farewell, my dear Huxley, and do not kill 

 yourself with work. 



The following group of letters deals with the problem of the causes of 

 the sterility of hybrids. Mr. Darwin's final view is given in the Origin, 

 sixth edition (p. 384, edit. 1900). He acknowledges that it would be 

 advantageous to two incipient species, if by physiological isolation due 

 to mutual sterility, they could be kept from blending : but he continues, 

 " After mature reflection it seems to me that this could not have been 

 effected through Natural Selection." And finally he concludes (p. 386) : 



" But it would be superfluous to discuss this question in detail ; for 

 with plants we have conclusive evidence that the sterility of crossed 

 species must be due to some principle quite independent of Natural 

 Selection. Both Gartner and Kolreuter have proved that in genera 



1 In Vol. II. of An imals and Plants, 1868. 



2 Queries on Expression. 



1 His son George was Second Wrangler in 1868 ; as a boy he was an 

 enthusiast in heraldry. 



