WCP6806

[1]

May 21/[18]89

Dear Mr Gulick,

You must have been wondering why your answer to Mr Wallace has never appeared in Nature. Therefore I write to explain.

A month or two ago (in reply to my continued enquiries) the Editor told me that he had such an unusual press of matter on hand — 300 columns in type — that he was keeping back all controversial matters for the time. Seeing that so long an interval had already elapsed since W's letter, and also that his book was then announced as "forthcoming", I told the Editor I thought he had better wait till the appearance of that book, in order to [2] give you the opportunity of dealing with W. in a single letter or discussion if W. should respond. I hope you will think that this was the best course for me to take under the circumstances.

I have now read W's book. It appears to me that he fully concedes the central or essential principle of "segregate fecundity" — i.e., that mutual sterility between incipient species is not merely a by-product of specific differentiation, but a condition to the occurrence of such differentiation in common areas, and, therefore, a true "factor" of organic evolution.

He gives you but scant justice, and abandons all his previous objections to "physiological solution", save [3] the one about chances against suitable views of "physiological complements". Here, no doubt, his criticism is valid, and arises from my not having properly stated that the "negative segregation" requires to be supplemented by some form of "positive segregation" — as you point out in your own paper. The only kind of "positive segregation" ^expressly recognized by W. is the psychological. If you answer him you ought to point out that you have shown many other kinds — and, also, that repeat your proof that natural selection cannot act as he supposes. His book as a whole, however, strikes me as very able. [4]

Your shells have been seen both by Cambridge & Edinburgh professors, but funds seem scanty at present. Edinburgh, however, will, I think, very likely eventually purchase.

Yours very truly, | G. J. Romanes [signature]