June 16.
I have deferred answering your letter until having had a talk with Mr. Galton about rudimentary organs. He thinks with me that if the normal size of a useful organ is maintained in a species, when natural selection is removed, the average size will tend to become progressively reduced by inter-crossing, and this down to whatever extent economy of growth remains operative in placing a premium on variations below the average at any given stage in the history of reduction.
I think I thoroughly well know your views about natural selection. In writing the manuscript note, so far as I remember, I had in view the possibility which Huxley somewhere advocates, that nature may sometimes make a considerable leap by selecting from single variations. But it was not because of this point that I sent you the note; it was with reference to the possibility of natural selection acting on organic types as distinguished from individuals—a possibility which you once told me did not seem at all clear, although Wallace maintained it in conversation.
I do not myself think that Allen[11] made out his points, although I do think that he has made an effort in the right direction. It seems to me that his fundamental principle has probably much truth in it, viz. that æsthetic pleasure in its last analysis is an effect of normal or not excessive stimulation.
Very sincerely and most respectfully yours,
Geo. J. Romanes.
From C. Darwin, Esq.
Down, Beckenham, Kent: August 9.