Alfred Russel Wallace 



in fertility and sterility occur, and I think yon will also 

 admit that if I demonstrate that a considerable amount of 

 sterility would be advantageous to a variety, that is suffi- 

 cient proof that the slightest variation in that direction 

 would be useful also, and would go on accumulating. 



Sir C. Lyell spoke to me as if he greatly admired pan- 

 genesis. I am very glad H. Spencer at once acknowledges 

 that his view was something quite distinct from yours. 

 Although, as you know, I am a great admirer of his, I 

 feel how completely his view failed to go to the root of 

 the matter, as yours does. His explained nothing, though 

 he was evidently struggling hard to find an explanation. 

 Yours, as far as I can see, explains everything in growth 

 and reproduction, though of course the mystery of life and 

 consciousness remains as great as ever. 



Parts of the chapter on Pangenesis I found hard read- 

 ing, and have not quite mastered yet, and there are also 

 throughout the discussions in Vol. II. many bits of hard 

 reading on minute points which we, who have not worked 

 experimentally at cultivation and crossing as you have done, 

 can hardly see the importance of, or their bearing on the 

 general question. 



If I am asked, I may perhaps write an article on the 

 book for some periodical, and if so shall do what I can to 

 make pangenesis appreciated. 



I suppose Mrs. Darwin thinks you must have a holiday, 

 after the enormous labour of bringing out such a book as 

 that. I am sorry I am not now staying in town. I shall, 

 however, be up for two days on Thursday, and shall hope 

 to see you at the Linnean, where Mr. Trimen has a paper 

 on some of his wonderful South African mimetic butterflies. 



I hope this will reach you before you leave. — Believe 

 me yours very faithfully, Alfred R. Wallace. 



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