1876.] AND SELF-FERTILISATION.' 465 



orders, I think it will be very important, for then we shall 

 positively know why the structure of every flower permits, or 

 favours, or necessitates an occasional cross with a distinct 

 individual. But all this is rather cooking my hare before I 

 have caught it. But somehow it is a great pleasure to me to 

 tell you what I am about. Believe me, my dear Gray, 



Ever yours most truly, and w^ith cordial thanks, 



Ch. Darwin. 



C. Darwin to G. Bent ham. 



April 22, 1868. 



.... I am experimenting on a very large scale on the 

 difference in power of growth between plants raised from 

 self-fertilised and crossed seeds ; and it is no exaggeration to 

 say that the difference in growth and vigour is sometimes 

 truly wonderful. Lyell, Huxley and Hooker have seen 

 some of my plants, and been astonished ; and I should much 

 like to show them to you. I always supposed until lately 

 that no evil effects would be visible until after several genera- 

 tions of self-fertilisation ; but now I see that one generation 

 sometimes suffices; and the existence of dimorphic plants 

 and all the wonderful contrivances of orchids are quite in- 

 telligible to me. 



With cordial thanks for your letter, which has pleased me 

 greatly. 



Yours very sincerely, 



Charles Darwin. 



[An extract from a letter to Dr. Gray (March 11, 1873) 

 mentions the progress of the work : — 



'' I worked last summer hard at Drosera, but could not 

 finish till I got fresh plants, and consequently took up the 

 effects of crossing and self-fertilising plants, and am got so 

 interested that Drosera must go to the dogs till I finish with 

 this, and get it published ; but then I will resume my beloved 

 Drosera, and I heartily apologise for having sent the precious 

 little things even for a moment to the dogs." 



