208 GEOEGB JOHN EOMANES I88I- 



logical change is not in itself injurious, I do not see 

 why physiologically isolated forms should be less fit 

 than those from which they have been separated, 

 though I can very well see why this should be the 

 case with such geograpJiically isolated forms as you 

 mention, for there the schooling is different. Lastly, 

 physiological selection, if not in itself injurious, does 

 not require that its children should be ' protected 

 against the struggle for existence.' On the contrary, 

 as I say in my paper, it is calculated to give this 

 struggle a better chance than ever to develope adap- 

 tive character in the sexually isolated forms, because 

 the swamping effects of intercrossing are diminished. 

 But I really did not intend to afflict you with 

 another jaw of this kind. I am, however, very glad 

 that we now understand each other better than we 

 did. At all events on my side I think I now know 

 exactly the points which I have to make good if 

 Nature is so constituted as to admit of my theory. 

 One thing only I have forgotten to say, viz. that 

 nothing can be argued against the theory from the 

 fact of hybridisation occurring in cases where, 

 according to the theory, it ought not to occur. This 

 argument only becomes valid where it is found that 

 the resulting hybrids are fertile. In relation to the 

 theory, a sterile hybrid is all the same as a failure to 

 cross. 



Yours very sincerely, 



G. J. KOMANES. 



P.S. — I forgot to ask you if there would be any 

 facilities in spring at Kew for repeating Adam's graft 



