LETTER 272. TO T.H. HUXLEY. Down, November 12th .
Many thanks for your "Biology," which I have read. (272/1. "A Course of Practical Instruction in Elementary Biology," by T.H. Huxley and H.N. Martin, 1875. For an account of the book see "Life and Letters of T.H. Huxley," Volume I., page 380.) It was a real stroke of genius to think of such a plan. Lord, how I wish I had gone through such a course!
LETTER 273. TO FRANCIS GALTON. December 18th .
George has been explaining our differences. I have admitted in the new edition (273/1. In the second edition (1875) of the "Variation of Animals and Plants," Volume II., page 350, reference is made to Mr. Galton's transfusion experiments, "Proc. R. Soc." XIX., page 393; also to Mr. Galton's letter to "Nature," April 27th, 1871, page 502. This is a curious mistake; the letter in "Nature," April 27th, 1871, is by Darwin himself, and refers chiefly to the question whether gemmules may be supposed to be in the blood. Mr. Galton's letter is in "Nature," May 4th, 1871, Volume IV., page 5. See Letter 235.) (before seeing your essay) that perhaps the gemmules are largely multiplied in the reproductive organs; but this does not make me doubt that each unit of the whole system also sends forth its gemmules. You will no doubt have thought of the following objection to your views, and I should like to hear what your answer is. If two plants are crossed, it often, or rather generally, happens that every part of stem, leaf, even to the hairs, and flowers of the hybrid are intermediate in character; and this hybrid will produce by buds millions on millions of other buds all exactly reproducing the intermediate character. I cannot doubt that every unit of the hybrid is hybridised and sends forth hybridised gemmules. Here we have nothing to do with the reproductive organs. There can hardly be a doubt from what we know that the same thing would occur with all those animals which are capable of budding, and some of these (as the compound Ascidians) are sufficiently complex and highly organised.
LETTER 274. TO LAWSON TAIT. March 25th, 1876.
(274/1. The reference is to the theory put forward in the first edition of "Variation of Animals and Plants," II., page 15, that the asserted tendency to regeneration after the amputation of supernumerary digits in man is a return to the recuperative powers characteristic of a "lowly organised progenitor provided with more than five digits." Darwin's recantation is at Volume I., page 459 of the second edition.)
Since reading your first article (274/2. Lawson Tait wrote two notices on "The Variation of Animals and Plants under Domestication" in the "Spectator" of March 4th, 1876, page 312, and March 25th, page 406.), Dr. Rudinger has written to me and sent me an essay, in which he gives the results of the MOST EXTENSIVE inquiries from all eminent surgeons in Germany, and all are unanimous about non-growth of extra digits after amputation. They explain some apparent cases, as Paget did to me. By the way, I struck out of my second edition a quotation from Sir J. Simpson about re-growth in the womb, as Paget demurred, and as I could not say how a rudiment of a limb due to any cause could be distinguished from an imperfect re-growth. Two or three days ago I had another letter from Germany from a good naturalist, Dr. Kollmann (274/3. Dr. Kollmann was Secretary of the Anthropologische Gesellschaft of Munich, in which Society took place the discussion referred to in "Variation of Animals and Plants," I., 459, as originating Darwin's doubts on the whole question. The fresh evidence adduced by Kollmann as to the normal occurrence of a rudimentary sixth digit in Batrachians is Borus' paper, "Die sechste Zehe der Anuren" in "Morpholog. Jahrbuch," Bd. I., page 435. On this subject see Letter 178.), saying he was sorry that I had given up atavism and extra digits, and telling me of new and good evidence of rudiments of a rudimentary sixth digit in Batrachians (which I had myself seen, but given up owing to Gegenbaur's views); but, with re-growth failing me, I could not uphold my old notion.
(275/1. Mr. Romanes' reply to this letter is printed in his "Life and Letters," page 93, where by an oversight it is dated 1880-81.)