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Darwin Correspondence Project

To J. D. Hooker   11 May [1859]

Down Bromley Kent

May 11

My dear Hooker

Thank you for telling me about obscurity of style. But on my life no nigger with lash over him could have worked harder at clearness than I have. But the very difficulty to me, by itself leads to probability that I fail. Yet one lady who has read all my M.S. has found only 2 or 3 obscure sentence.1 But Mrs. Hooker having so found it, makes me tremble.—2 I will do my best in proofs. You are a good man to take trouble to write about it—

With respect to our mutual muddle, I never for a moment thought we could not make our ideas clear to each other by talk or if either of us had time to write in extenso.

I imagine from some expressions (but if you asked me what, I could not answer) that you look at variability as some necessary contingency with organisms, & further that there is some necessary tendency in the variability to go on diverging in character or degree.3 If you do, I do not agree. “Reversion” again, (a form of inheritance) I look at as no way directly connected with variation, though of course inheritance is of fundamental importance to us, for if a variation be not inherited, it is of no signification to us.— It was on such points as these I fancied that we perhaps started differently.—

I fear that my Book will not deserve at all the pleasant things you say about it & good Lord how I do long to have done with it:—

Since the above was written I have received & been much interested by A. Gray. I am delighted at his note about my & Wallace’s paper:4 He will go round, for it is futile to give up very many species, & stop at an arbitrary line at others. It is what my grandfather called Unitarianism, “a feather-bed to catch a falling Christian”.—5

The geology at p. 447 seems to be inextricable confusion.6

Some time ago A. Gray wrote to me for my notions on recent migration during late periods, & I gave him the passage before Glacial period by the almost continuous circumpolar land.— I presume he alludes to this, not correctly, by putting me before E. Forbes Hooker & De Candolle.—7

But he has changed my doctrine, apparently after consulting Dana.—8 I knew there was some slight evidence from range of the shell Gnathodon in U. States of warmer climate since Glacial epoch; but I do not believe there is any such evidence for Europe.— I once consulted Lyell on this point & he seemed to know little & be very doubtful about this warmer period since Glacial. I doubt whether Megatherium & Co. have really been found together with the northern Elephant; nor do I at all admit that Megatherium, Mylodon & Co are by themselves proof of warmer climate. The argument from the woolly Elephant & woolly Rhinoceros I look at as false.9

If my letter did start these speculations, I am sorry I ever wrote it, for in my opinion they botch the subject.—

Yours affect | C. Darwin

I return the Paper by this Post


Georgina Tollet had agreed to read CD’s manuscript. See letter to John Murray, 5 April [1859].
Frances Harriet Hooker had probably read the part of CD’s manuscript on geographical distribution that had been sent to Hooker for his comments (see letter to J. D. Hooker, 11 March [1859]).
See letters to J. D. Hooker, 3 May [1859] and 6 May [1859].
CD refers to proof-sheets of A. Gray 1858–9, on the flora of Japan, which had possibly been forwarded to him by Hooker. There is an annotated copy of the work in the Darwin Pamphlet Collection–CUL, but this did not arrive until later (see letter to Asa Gray, 24 December [1859]). In the paper, Gray referred to Darwin and Wallace 1858 as ‘the only noteworthy attempt at a scientific solution of the problem of the geographic association of related species, aiming to bring the variety as well as the geographic distribution of related species within the domain of cause and effect’ (A. Gray 1858–9, p. 443).
CD often repeated this saying of Erasmus Darwin.
In the concluding pages of A. Gray 1858–9, Gray attempted to explain the botanical relationship between the Japanese flora and that of the eastern United States by putting forward the argument for migration rather than the hypothesis of the multiple creation of species. The discussion to which CD refers describes the post-tertiary glacial period (A. Gray 1858–9, p. 447).
By ‘not correctly’ CD means that Gray had given him priority for the migration theory over Edward Forbes, Hooker, and Alphonse de Candolle (A. Gray 1858–9, pp. 445–6). In his letter to Asa Gray,11 August [1858], CD had informed Gray that he had had the idea of migrations during a world-wide cold period earlier than Forbes, but had not published it.
Gray adopted James Dwight Dana’s idea of a post-glacial warm period, the so-called ‘fluvial’ period, and asserted that ‘the fluvial epoch would again commingle the temperate floras of the two continents at Behring’s Straits’ (A. Gray 1858–9, p. 448).
Gray had argued that the discovery of large quadrupeds such as Megatherium in both North America and Europe indicated ‘that the climate [of the fluvial epoch] was as much milder than the present on this as on the other side of the ocean.’ (A. Gray 1858–9, p. 448).


Gray, Asa. 1858–9. Diagnostic characters of new species of phænogamous plants, collected in Japan by Charles Wright, botanist of the US North Pacific Exploring Expedition … With observations upon the relations of the Japanese flora to that of North America, and of other parts of the northern temperate zone. [Read 14 December 1858 and 11 January 1859.] Memoirs of the American Academy of Arts and Sciences n.s. 6: 377–452.


JDH finds style of CD’s MS obscure.

CD wary of JDH’s starting point on variability: it is not inherent, it does not lead necessarily to divergence, and it must be distinguished from inheritance.

Asa Gray has misread CD’s views on pre-glacial migrations and botched the subject.

Letter details

Letter no.
Charles Robert Darwin
Joseph Dalton Hooker
Sent from
Source of text
DAR 115: 15
Physical description
ALS 8pp

Please cite as

Darwin Correspondence Project, “Letter no. 2461,” accessed on 22 April 2024,

Also published in The Correspondence of Charles Darwin, vol. 7