360 EVOLUTION [Chap. V 



Letter 270 been at Abingcr Hall for a month for rest, which I much 

 required, and 1 saw there the cut-leaved vine which seems 

 splendid for graft hybridism. 



Letter 271 To Francis Galton. 



Down, Nov. 7th, 1875. 

 I have read your essay : with much curiosity and interest, 

 but you probably have no idea how excessively difficult it is 

 to understand. I cannot fully grasp, only here and there 

 conjecture, what are the points on which we differ. I dare- 

 say this is chiefly due to muddy-headedness on my part, but 

 I do not think wholly so. Your many terms, not denned, 

 " developed germs," " fertile," and " sterile germs " (the word 

 " germ " itself from association misleading to me) " stirp," 

 "sept," "residue," etc., etc., quite confounded me. If I ask 

 myself how you derive, and where you place the innumer- 

 able gemmules contained within the spermatozoa formed by 

 a male animal during its whole life, I cannot answer myself. 

 Unless you can make several parts clearer I believe (though 

 I hope I am altogether wrong) that only a few will endeavour 

 or succeed in fathoming your meaning. I have marked a 

 few passages with numbers, and here make a few remarks 

 and express my opinion, as you desire it, not that I suppose 

 it will be of any use to you. 



(1) If this implies that many parts are not modified by 

 use and disuse during the life of the individual, I differ 

 widely from you, as every year I come to attribute more and 

 more to such agency. 2 



(2) This seems rather bold, as sexuality has not been 

 detected in some of the lowest forms, though I daresay it 

 may hereafter be. 3 



1 " A Theory of Heredity" {Journal of the Anthropological Institute, 

 1875). In this paper Mr. Galton admits that the hypothesis of organic 

 units ''must lie at the foundation of the science of heredity," and proceeds 

 to show in what respect his conception differs from the hypothesis of 

 pangenesis. The copy of Mr. Galton's paper, which Darwin numbered 

 in correspondence with the criticisms in his letter, is not available, and 

 we are therefore only able to guess at some of the points referred to. 



! This seems to refer to p. 329 of Mr. Galton's paper. The passage 

 must have been hastily read, and has been quite misunderstood. Mr. 

 Galton has never expressed the view attributed to him. 



3 Mr. Galton, op. tit., pp. 332-3 : "There are not of a necessity two 



