456 GEOGRAPHICAL DISTRIBUTION [Chap. VI 



Letter 347 your Memoir, 1 and heartily do I thank you for it. I have 

 not read it, and shall not be able very soon, for I am 

 much overworked, and my stomach has got nearly as bad 

 as ever. 



With respect to the discussion on climate, I beg you to 

 believe that I never put myself for a moment in competition 

 with Dana ; but when one has thought on a subject, one 

 cannot avoid forming some opinion. What I wrote to 

 Hooker I forget, after reading only a few sheets of your 

 Memoir, which I saw would be full of interest to me. 

 Hooker asked me to write to you, but, as I told him, I 

 would not presume to express an opinion to you without 

 careful deliberation. What he wrote I know not : I had 

 previously several years ago seen (by whom I forget) some 

 speculation on warmer period in the U. States subsequent 

 to Glacial period ; and I had consulted Lyell, who seemed 

 much to doubt, and Lyell's judgment is really admirably 

 cautious. The arguments advanced in your paper and in 

 your letter seem to me hardly sufficient ; not that I should be 

 at all sorry to admit this subsequent and intercalated warmer 

 period — the more changes the merrier, I think. On the other 

 hand, I do not believe that introduction of the Old World 

 forms into New World subsequent to the Glacial period will 

 do for the modified or representative forms in the two Worlds. 

 There has been too much change in comparison with the 

 little change of isolated alpine forms ; but you will see this 

 in my book. 2 I may just make a few remarks why at first 

 sight I do not attach much weight to the argument in your 

 letter about the warmer climate. Firstly, about the level of 

 the land having been lower subsequently to Glacial period, as 

 evidenced by the whole, etc., I doubt whether meteorological 



opinion on important points, nevertheless regarded him as the naturalist 

 who had most thoroughly gauged the Origin of Species, and as a tower 

 of strength to himself and his cause" (Proc. R. Soc, Vol. XLVI., p. xv, 

 1890 : Letters of Asa Gray, edited by Jane Loring Gray, 2 vols., 

 Boston, U.S., 1893). 



' " Diagnostic Characters of New Species of Phaenogamous Plants 

 collected in Japan by Charles Wright . . . with Observations upon the 

 Relations of the Japanese Flora to that of North America and of other 

 parts of the Northern Temperate Zone " {Mem. American Acad. Arts 

 and Sci., Vol VI., p. 377, 1857). 



2 Origin of Species (1859), Chap. XI., pp. 365 et seq. 



