238 GEOKGE JOHN EOMANES issi- 



If you are acquainted with my new theory of 

 ' Physiological Selection ' (published in ' Journ. Lin. 

 Soc.' 1886) you will understand why I regard your 

 facts as furnishing first-rate material for testing 

 that theory. If you cannot get access to my paper, I 

 will send you a copy on my return to London in 

 December. 



My object in now writing over and above that of 

 thanking you for your paper is to ask whether you 

 yourself, or any other American naturalist whom you 

 may know, would not feel it well worth while to try 

 some experiments on the hybridisation of the peculiar 

 species. Although I agree with you in thinking it 

 probable that many of these species may be ' rem- 

 nants,' I also think it abundantly possible that some 

 of them may be merely evolved forms. A botanist 

 on the spot might be able to determine, by intelligent 

 comparison, which of the peculiar species are most 

 probably of the last-mentioned character. These he 

 might choose for his experiments on hybridisation. 

 And I should expect him to find marked evidence of 

 mutual sterility between closely allied unique species 

 growing on the same island, with possibly unimpaired 

 fertility between allied species growing on different 

 islands. If this anticipation should be realised by 

 experiment, the fact would go far to prove my 

 theory. 



Even if you do not happen to know of any botanist 

 who would care to undertake this experimental re- 

 search, you might possibly know of some one who 

 would gather and transmit seeds for me to grow in 

 hothouses here. 



