To T. H. Huxley   27 May [1865]1

Down. | Bromley. | Kent. S.E.

May 27th.—

My dear Huxley

I have taken a long time to thank you for the Catalogue, the introduction to which I read with much interest.2 The cause has been that I have had a very bad month; but I know begin to hope that through the aid of an acquaintance of yours (Dr Chapman) my health will receive some considerable improvement from the application of ice to the spine.3

I write now to ask a favour of you, a very great favour from one so hard worked as you are. It is to read 30 pages of M.S, excellently copied out, & give me not lengthened criticism, but your opinion whether I may venture to publish it.4 You may keep the M.S. for a month or two. I wd not ask this favour, but I really know no one else whose judgment on the subject wd be final with me.

The case stands thus; in my next book5 I shall publish long chapters on bud—& seminal—variation, on inheritance, reversion, effects of use & disuse &c. I have also for many years speculated on the different forms of reproduction.6 Hence it has come to be a passion with me to try to connect all such facts by some sort of hypothesis. The M.S which I wish to send you gives such a hypothesis; it is a very rash & crude hypothesis yet it has been a considerable relief to my mind, & I can hang on it a good many groups of facts.7 I well know that a mere hypothesis, & this is nothing more, is of little value; but it is very useful to me as serving as a kind of summary for certain chapters. Now I earnestly wish for your verdict given briefly as “Burn it”—or, which is the most favorable verdict that I can hope for, “It does rudely connect together certain facts & I do not think it will immediately pass out of my mind”   If you can say this much & you do not think it absolutely ridiculous I shall publish it in my concluding Chapter.8 Now will you grant me this favour? You must refuse if you are too much over worked—

I must say for myself that I am a hero to expose my hypothesis to the fiery ordeal of your criticism

Believe me my dear Huxley | yours most sincerely | Ch. Darwin

LS(A)

1
The year is established by the reference to T. H. Huxley and Etheridge 1865 (see n. 2, below).
2
Huxley sent CD a copy of T. H. Huxley and Etheridge 1865, A catalogue of the collection of fossils in the Museum of Practical Geology, with an explanatory introduction, at the beginning of May (see letter from T. H. Huxley, 1 May 1865). CD had read the proof-sheets of the preface in 1857 (see Correspondence vol. 6, letter to T. H. Huxley, 16 December [1857], and letter to J. D. Hooker, 25 December [1857]).
3
According to Emma Darwin’s diary (DAR 242), John Chapman visited CD on 20 May 1865. See also letter to John Chapman, 16 May [1865], and Appendix IV. Chapman was proprietor and editor of the Westminster Review, to which Huxley had been a regular contributor (Wellesley index; see also A. Desmond 1994–7, 1: 185).
4
The copy that CD sent to Huxley has not been found; however, the manuscript from which the copy was made is in DAR 51: C36–74. For a transcript of the original manuscript, which was titled ‘Hypothesis of Pangenesis’, see Olby 1963. This first statement of pangenesis differed in several respects from the version that was later published in chapter 27 of Variation; see Olby 1985, pp. 84–6.
5
CD refers to Variation, which was published in 1868.
6
CD’s notebooks and manuscripts indicate that he developed his ideas about heredity and reproduction over a thirty-year period (see Kohn 1980, Hodge 1985, and Olby 1985). For an earlier indication that CD was attempting to develop a hypothesis connecting information on reproduction, see Correspondence vol. 6, letter to T. H. Huxley, [before 12 November 1857]. For a discussion of nineteenth-century debates on heredity and their bearing on the theory of transmutation by natural selection, see Gayon 1998.
7
The hypothesis of pangenesis that CD outlined to Huxley suggested that each individual cell throws off minute particles (gemmules) that circulate in the bodily fluids and are capable of generating new cells, or remaining dormant until required. The gemmules are drawn together by mutual attraction and into the right places in the right order to, for instance, reconstruct (in organisms that have that capability) a tail or other limb where one has been torn off. Cells throw off gemmules at all stages of development and all gemmules circulate until required: thus embryo gemmules thrown off by embryo cells come together, when conditions are right, to form what CD called the germ (the female element) or the male element; the germ, if fertilised (or even if not, in the case of parthenogenesis), grows into a new embryo (see Olby 1963). Gemmules could also remain dormant for several generations before being sparked into activity. Thus CD thought pangenesis could explain both sexual and asexual reproduction, as well as reversion and the regrowth of body parts. For a discussion of the development of the hypothesis of pangenesis during the 1860s and the part played by CD’s contemporaries, including Herbert Spencer, Charles Victor Naudin, and Richard Owen, in shaping it, see Geison 1969.
8
The manuscript discussed here was expanded and revised before being published in the penultimate chapter of Variation, ‘Provisional hypothesis of pangenesis’ (Variation 2: 357–404).

Manuscript Alterations and Comments

0.2 May 27th.—-] in CD’s hand
3.5 a very] ‘a’ interl in CD’s hand
3.6 crude hypothesis] ‘hypothesis’ interl in CD’s hand

Please cite as “DCP-LETT-4837,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-4837