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Darwin Correspondence Project

To Fritz Müller   28 August 1870

Down. | Beckenham | Kent. S.E.

Aug 28—70

My dear Sir

I have to thank you very sincerely for two letters: one of April 25th—containing a very curious account of the structure & morphology of Bonatea.—1 I feel that it is quite a sin that your letters shd. not all be published; but in truth I have no spare strength to undertake any extra work, which though slight would follow from seeing your letters in English through the press—not but that you write almost as clearly as any Englishman. This same letter also contained some seeds for Mr Farrer which he was very glad to receive.2

Your second letter of July 3d was chiefly devoted to mimickry in Lepidoptera: many of your remarks seem to me so good, that I have forwarded your letter to Mr. Bates; but he is out of London, having his summer holiday, & I have not yet heard from him.3 Your remark about imitators & imitated being of such different sizes, & the lower surface of wings not being altered in colour strike me as the most curious points. I shd. not be at all surprised if your suggestion about sexual selection were to prove true; but it seems rather too speculative to be introduced in my book more especially as my book is already far too speculative.4 The very same difficulty about brightly coloured caterpillars had occurred to me, & you will see in my Book, what I believe is the true explanation from Wallace.5 The same view probably applies in part to gaudy Butterflies.— My M.S. is sent to Printers, & I suppose will be published in about 3 months: of course I will send you a copy.6 By the way I settled with Murray recently with respect to your Book, & had to pay him only 21£"2s"3d which I consider a very small price for the dissemination of your views: he has 547 copies as yet unsold.7 This most terrible war will stop all science in France & Germany, for a long time: I have heard from nobody in Germany, & know not whether your Brother, Häckel, Gegenbaur Victor Carus or my other friends are serving in the army.8 Dohrn has joined a cavalry regiment.9 I have not yet met a soul in England, who does not rejoice in the splendid triumph of Germany over France: it is a most just retribution against that vain-glorious, war-loving nation. As the Posts are all in confusion, I will not send this letter through France.— The Editor has sent me duplicate copies of the Revue des Cours Scientifiques, which contain several articels about my views; so I send you copies, for the chance of your liking to see them.—10

My dear Sir | Ever Yours very sincerely | Ch. Darwin


The letters referred to have not been found. CD had discussed the structure of Bonatea speciosa in Orchids, pp. 87, 302–5, 330. In Orchids 2d ed., p. 76, CD added a reference to Roland Trimen’s description of Bonatea (Trimen 1864), but did not mention Müller’s account.
The seeds were probably of Passiflora; Müller had sent seeds of Passiflora for Thomas Henry Farrer with his letter of 16 February 1870.
Henry Walter Bates had developed a theory about mimicry in butterflies that proposed that a palatable species would benefit from imitating one that was unpalatable (Bates 1861). Müller became interested in mimicry after reading Wallace 1869c, and began observing resemblances in endemic butterflies (see letter from Fritz Müller, 29 March 1870 and n. 3).
Müller also discussed butterflies in two letters to his brother, Hermann Müller, written on 5 May 1870 and 14 June 1870 (Möller ed. 1915–21, 2: 175–9). Müller suggested two points in favour of mimicry being the result of sexual selection. Firstly, he argued, the imitated species tended to be very brightly coloured, so the coloration was more attractive than protective. Secondly, only the upper surface tended to be imitated, so that the imitator was still protected from predators while not flying, since most butterflies rested with their wings closed (see Möller ed. 1915–21, 2: 179). CD refers to Descent.
In Descent 1: 416–17, CD gave Alfred Russel Wallace’s explanation that bright colours served as a warning to predators that a caterpillar was unpalatable.
Descent was published on 24 February 1871 (see Correspondence vol. 19, Appendix II). Müller’s name appears on CD’s presentation list for Descent (DAR 210:11. 32; Correspondence vol. 19, Appendix IV).
CD refers to the English translation of F. Müller 1864, Facts and arguments for Darwin (Dallas trans. 1869). According to John Murray’s ledger book (John Murray Archive, National Library of Scotland), 1000 copies were printed. Murray received a ten per cent commission for sales and warehousing. After one year, a loss of £21 2s. 3d. was recorded, but over the next ten years small profits were recorded each year.
France had declared war on Prussia on 19 July 1870 (Wawro 2003, p. 65). Prussia had the support of the North German Confederation and the southern states of Baden, Württemberg, and Bavaria. CD refers to Hermann Müller, Ernst Haeckel, Carl Gegenbaur, and Julius Victor Carus. See letter from J. V. Carus, 2 October 1870.
For more on Anton Dohrn’s service in the Prussian army during the Franco-Prussian war, see Heuss 1991, pp. 104–9.
Emile Alglave was the editor of the weekly Revue des Cours Scientifiques; CD’s copies of some issues of the journal are in the Darwin Pamphlet Collection–CUL. In July and August 1870, a number of issues focused on the debate over CD’s candidacy in the zoological section of the Académie des Sciences (see letter from Armand de Quatrefages, 18 July 1870). A paper by Paul Broca on transformism was also published in the journal (Broca 1870a; see letter from Paul Broca, 4 August 1870 and n. 2).


Bates, Henry Walter. 1861. Contributions to an insect fauna of the Amazon valley. Lepidoptera: Heliconidæ. [Read 21 November 1861.] Transactions of the Linnean Society of London 23 (1860–2): 495–566.

Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

Descent: The descent of man, and selection in relation to sex. By Charles Darwin. 2 vols. London: John Murray. 1871.

Heuss, Theodor. 1991. Anton Dohrn: a life for science. Translated from the German by Liselotte Dieckmann. Berlin and New York: Springer Verlag.

Orchids 2d ed.: The various contrivances by which orchids are fertilised by insects. By Charles Darwin. 2d edition, revised. London: John Murray. 1877.

Orchids: On the various contrivances by which British and foreign orchids are fertilised by insects, and on the good effects of intercrossing. By Charles Darwin. London: John Murray. 1862.

Trimen, Roland. 1864. On the structure of Bonatea speciosa, Linn. sp., with reference to its fertilisation. [Read 1 December 1864.] Journal of the Linnean Society (Botany) 9 (1867): 156–60.

Wawro, Geoffrey. 2003. The Franco-Prussian war: the German conquest of France in 1870–1871. Cambridge: Cambridge University Press.


Mimicry in Lepidoptera.

Sexual selection.

The Franco-Prussian war.

Letter details

Letter no.
Charles Robert Darwin
Johann Friedrich Theodor (Fritz) Müller
Sent from
Source of text
The British Library (Loan MS 10 no 33)
Physical description
6pp †

Please cite as

Darwin Correspondence Project, “Letter no. 7310,” accessed on 18 April 2021,

Also published in The Correspondence of Charles Darwin, vol. 18