icp EVOLUTION [Chap. Ill 



Letter 129 should esteem it a great favour if you will allow me to call 

 on you and have half an hour's conversation with you. 



As far as I am personally concerned, I am sure I ought to 

 be grateful to you, for since my accident nothing has given 

 me so much pleasure as the perusal of your book. Such 

 studies are now a great resource to me. 



Letter 130 To C. Lyell. 



2, 1 k'sketh Terrace, Torquay (Aug. 2nd, 1861]. 

 I declare that you read the reviews on the Origin more 

 carefully than I do. I agree with all your remarks. The 

 point of correlation struck me as well put, and on varieties 

 growing together ; but I have already begun to put things in 

 train for information on this latter head, on which Bronn 

 also enlarges. With respect to sexuality, I have often 

 speculated on it, and have always concluded that we arc too 

 ignorant to speculate : no physiologist can conjecture why the 

 two elements go to form a new being, and, more than that, 

 why nature strives at uniting the two elements from two 

 individuals. What I am now working at in my orchids is 

 an admirable illustration of the law. I should certainly 

 conclude that all sexuality had descended from one prototype. 

 Do you not underrate the degree of lowncss of organisation 

 in which sexuality occurs — viz., in Hydra, and still lower in 

 some of the one-celled free conferva; which "conjugate," 

 which good judges (Thwaitcs) believe is the simplest form of 

 true sexual generation? 1 But the whole case is a mystery. 



There is another point on which I have occasionally 

 wished to say a few words. I believe you think with Asa 

 Gray that I have not allowed enough for the stream of 

 variation having been guided by a higher power. I have 

 had lately a good deal of correspondence on this head. 

 Herschel, in his Physical Geography? has a sentence with 



1 See Letter 97. 



3 Physical Geography of the Globe, by Sir John F. W. Herschel, Edin- 

 burgh, 1861. On p. 12 Herschel writes of the revelations of Geology 

 pointing to successive submersions and reconstructions of the continents 

 and fresh races of animals and plants. He refers to a " great law of 

 change" which has not operated either by a gradually progressing variation 

 of species, nor by a sudden and total abolition of one race. . . . The 

 following footnote on page 12 of the Physical Geography was added in 



