362 GEOEGE JOHN EOMANES 1893 



to find so much variability of the conspicuously in- 

 definite kind in nature as in cultivation. For, by 

 hypothesis, natural selection is present in the one 

 case (to destroy useless variations) while absent in 

 the other. But I allow this does not apply to the 

 examples you give me. Only remember the point in 

 publishing your paper. 



Hotel Costebelle, Hyeres : February 10, 1894. 



Dear Mr. Henslow, I am much indebted to you 

 for all your most interesting letters, and also for 

 prospect of receiving your books. Although for- 

 bidden to write letters myself, or to think about 

 anything as yet, I must send a few lines, pending 

 arrival of the books and papers, giving my general 

 impression of your views as set out in your corre- 

 spondence. 



Briefly, it seems to me that your argument is per- 

 fectly clear up to a certain point, but then suddenly 

 becomes a petitio principii. In other words, so far as 

 your view is critical of natural selection considered 

 as a hypothetical cause of adaptive evolution, I can 

 well believe you have adduced a formidable array of 

 facts. But I fail to follow, when you pass on to the 

 constructive part of your case or your suggested 

 substitute for natural selection in self-adaptation. 

 For self-adaptation, I understand, consists in results 

 of immediate response to stimuli supplied by environ- 

 ment. But, if so, surely the statement that all the 

 adaptive machinery of plant-organisation is due to 

 self-adaptation is a mere begging of the question 

 against natural selection unless it can be shoivji how 



