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Darwin Correspondence Project

From Francis Galton   8 November 1875

42. Rutland Gate

Nov 8/75

My dear Darwin

Alas! alas!— and I had taken such pains to express myself clearly, and I see what I mean, so clearly!—1

I was most obliged for the Brown-Séquard reference in the Lancet, & will certainly alter the paragraph. His non-publication of the paper even in abstract read by him at the Brit. Assocn. in 1870, had given me additional fear that there was something wrong.2

All the other points you refer to in your letter, I will do what I can, about:— viz:– make clearer, answer, or amend; but it is too late to make more than small alterations in the proof.

Thank you for reference & offer to send Panum, but I have a description of his results, so far as I want them, in C. Dareste (Ann: Sc: Naturelles 1862 sur les œufs à double germe p.34.3

In my ‘Fraser’ article, there is a most unlucky & absurd collocation of words, which I heartily hope no critic will seize upon, for which I simply ca’nt account except in the supposition of badly scratching out in the MS & variously altering some passage   It is about “double yolked eggs” & “single germs”. I ought never to have passed it in proof; but there it is.4

That twins born in one chorion:— never mind whether 2 ammions or not,— is Kleinwächter’s dictum which he fortifies by numerous modern German authorities.5 Kiwisch6 being the only one who, it appears, still talks of fusion of membranes. I also noted the remark in the Catalogue of the Museum Coll: Surgeons “Teratology” that twins in one chorion are probably (I think that was the word) derived from 2 germinal spots on one ovum.7

If you care to see Kleinwächter, I could send it you.

Very sincerely Yrs | Francis Galton

CD annotations

Top of letter: ‘To be returned’ pencil


CD had criticised the obscure terminology in a proof copy of Galton’s ‘Theory of heredity’ (Galton 1875b; see letter to Francis Galton, 7 November [1875]).
Charles Édouard Brown-Séquard had communicated a paper ‘On apparent transmission of abnormal conditions due to accidental causes’ at the meeting of the British Association for the Advancement of Science at Liverpool in 1870, but it was not published (see Report of the 40th Meeting of the British Association for the Advancement of Science (1870), Transactions of the sections, p. 134). CD had referred Galton to a recent summary of Brown-Séquard’s research on the inheritance of acquired conditions (Brown-Séquard 1875; see letter from Francis Galton, 3 November 1875 and n. 3, and letter to Francis Galton, 4 November [1875] and n. 5). Galton discussed Brown-Séquard’s experiments in Galton 1875b, pp. 344–5.
CD’s reference to Panum has not been found. Peter Ludwig Panum’s work on the formation of double monstrosities in birds (Panum 1860) is mentioned in Camille Dareste’s ‘Mémoire sur l’histoire physiologique des oeufs a double germe’ (Dareste 1862, p. 34).
Galton’s article on twins published in Fraser’s Magazine contains the expression ‘double-yoked eggs’, but not ‘single germs’ (Galton 1875a, p. 567).
Ludwig Kleinwächter’s work on twins (Kleinwächter 1871) is cited in Galton 1875a, p. 567. The chorion and amnion are, respectively, the outer and inner membranes around an embryo.
Franz Kiwisch.
Galton referred to twins produced by ‘double-yolked eggs that are due to two germinal spots in a single ovum’ in Galton 1875a, p. 567. The formation of double embryos is discussed in the Descriptive catalogue of the teratological series in the Museum of the Royal College of Surgeons of England (London: R. Hardwicke, 1872, pp. xiv–xix).


Brown-Séquard, Charles Édouard. 1875. On the hereditary transmission of the effects of certain injuries to the nervous system. Lancet, 2 January 1875, pp. 6–7.

Kleinwächter, Ludwig. 1871. Die Lehre von den Zwillingen. Prague: Haerpfer.

Panum, Peter Ludwig. 1860. Untersuchungen über die Entstehung der Missbildungen zunächst in den Eiern der Vögel. Berlin: George Reimer.


Responds to suggestions and criticisms CD made to "theory of heredity" [see 10245].

Letter details

Letter no.
Francis Galton
Charles Robert Darwin
Sent from
London, Rutland Gate, 42
Source of text
DAR 105: A88–9
Physical description
ALS 4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 10250,” accessed on 7 June 2023,

Also published in The Correspondence of Charles Darwin, vol. 23