Unless you can make several parts clearer I believe (though I hope I am altogether wrong) that only a few will endeavour or succeed in fathoming your meaning. I have marked a few passages with numbers, and here make a few remarks and express my opinion, as you desire it, not that I suppose it will be of any use to you.
1. If this implies that many parts are not modified by use and disuse during the life of the individual, I differ widely from you, as every year I come to attribute more and more to such agency. (271/2. This seems to refer to page 329 of Mr. Galton's paper. The passage must have been hastily read, and has been quite misunderstood. Mr. Galton has never expressed the view attributed to him.)
2. This seems rather bold, as sexuality has not been detected in some of the lowest forms, though I daresay it may hereafter be. (271/3. Mr. Galton, op. cit., pages 332-3: "There are not of a necessity two sexes, because swarms of creatures of the simplest organisations mainly multiply by some process of self-division.")
3. If gemmules (to use my own term) were often deficient in buds, I cannot but think that bud-variations would be commoner than they are in a state of nature; nor does it seem that bud-variations often exhibit deficiencies which might be accounted for by the absence of the proper gemmules. I take a very different view of the meaning or cause of sexuality. (271/4. Mr. Galton's idea is that in a bud or other asexually produced part, the germs (i.e. gemmules) may not be completely representative of the whole organism, and if reproduction is continued asexually "at each successive stage there is always a chance of some one or more of the various species of germs... dying out" (page 333). Mr. Galton supposes, in sexual reproduction, where two parents contribute germs to the embryo the chance of deficiency of any of the necessary germs is greatly diminished. Darwin's "very different view of the meaning or cause of sexuality" is no doubt that given in "Cross and Self Fertilisation"--i.e., that sexuality is equivalent to changed conditions, that the parents are not representative of different sexes, but of different conditions of life.)
4. I have ordered "Fraser's Magazine" (271/5. "The History of Twins," by F. Galton, "Fraser's Magazine," November, 1875, republished with additions in the "Journal of the Anthropological Institute," 1875. Mr. Galton explains the striking dissimilarity of twins which is sometimes met with by supposing that the offspring in this case divide the available gemmules between them in such a way that each is the complement of the other. Thus, to put the case in an exaggerated way, similar twins would each have half the gemmules A, B, C,...Z., etc, whereas, in the case of dissimilar twins, one would have all the gemmules A, B, C, D,...M, and the other would have N...Z.), and am curious to learn how twins from a single ovum are distinguished from twins from two ova. Nothing seems to me more curious than the similarity and dissimilarity of twins.
5. Awfully difficult to understand.
6. I have given almost the same notion.
7. I hope that all this will be altered. I have received new and additional cases, so that I have now not a shadow of doubt.
8. Such cases can hardly be spoken of as very rare, as you would say if you had received half the number of cases I have.
(271/6. We are unable to determine to what paragraphs 5, 6, 7, 8 refer.)
I am very sorry to differ so much from you, but I have thought that you would desire my open opinion. Frank is away, otherwise he should have copied my scrawl.
I have got a good stock of pods of sweet peas, but the autumn has been frightfully bad; perhaps we may still get a few more to ripen.
LETTER 272. TO T.H. HUXLEY. Down, November 12th [1875].
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.