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Letter 7310

Darwin, C. R. to Müller, J. F. T.

28 Aug 1870


Mimicry in Lepidoptera.

Sexual selection.

The Franco-Prussian war.


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.—f1 I feel that it is quite a sin that yourletters shd. not all be published; but in truth I have no sparestrength to undertake any extra work, which though slight would followfrom seeing your letters in English through the press—not but thatyou write almost as clearly as any Englishman. This same letter alsocontained some seeds for Mr Farrer which he was very glad toreceive.f2

Your second letter of July 3d was chiefly devoted to mimickry inLepidoptera: many of your remarks seem to me so good, that I haveforwarded your letter to Mr. Bates; but he is out of London, havinghis summer holiday, & I have not yet heard from him.f3 Your remarkabout imitators & imitated being of such different sizes, & the lowersurface of wings not being altered in colour strike me as the mostcurious points. I shd. not be at all surprised if your suggestionabout sexual selection were to prove true; but it seems rather toospeculative to be introduced in my book more especially as my bookis already far too speculative.f4 The very same difficulty aboutbrightly coloured caterpillars had occurred to me, & you will see inmy Book, what I believe is the true explanation from Wallace.f5 The sameview probably applies in part to gaudy Butterflies.— My M.S. issent to Printers, & I suppose will be published in about 3 months: ofcourse I will send you a copy.f6By the way I settled with Murray recently with respect to your Book,& had to pay him only 21£“2s“3d which I consider a verysmall price for the dissemination of your views: he has 547 copiesas yet unsold.f7 This most terrible war will stop all science inFrance & Germany, for a long time: I have heard from nobody inGermany, & know not whether your Brother, Häckel, GegenbaurVictor Carus or my other friends are serving in the army.f8 Dohrnhas joined a cavalry regiment.f9 I have not yet met a soul in England,who does not rejoice in the splendid triumph of Germany over France: itis a most just retribution against that vain-glorious, war-lovingnation. As the Posts are all in confusion, I will not send thisletter through France.— The Editor has sent me duplicate copiesof the Revue des Cours Scientifiques, which contain several articelsabout my views; so I send you copies, for the chance of your likingto see them.—f10

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

British Library Board (Loan 10:33)



The letters referred to have not been found. CD had discussed thestructure of Bonatea speciosa in Orchids, pp. 87, 302–5, 330. InOrchids 2d ed., p. 76, CD added a reference to Roland Trimen’sdescription of Bonatea (Trimen 1864), but did not mention Müller’saccount.
The seeds were probably of Passiflora; Müller had sent seeds ofPassiflora for Thomas Henry Farrer with his letter of 16 February1870.
Henry Walter Bates had developed a theory about mimicry in butterfliesthat proposed that a palatable species would benefit from imitatingone that was unpalatable (Bates 1861). Müller becameinterested in mimicry after reading Wallace 1869c, and beganobserving resemblances in endemic butterflies (see letter from FritzMüller, 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 (Möllered. 1915–21, 2: 175–9). Müller suggested two points in favour ofmimicry being the result of sexual selection. Firstly, he argued, theimitated species tended to be very brightly coloured, so the colorationwas more attractive than protective. Secondly, only the upper surfacetended to be imitated, so that the imitator was still protected frompredators while not flying, since most butterflies rested with theirwings closed (see Möller ed. 1915–21, 2: 179). CD refers toDescent.
In Descent 1: 416–17, CD gave Alfred Russel Wallace’s explanationthat bright colours served as a warning to predators that acaterpillar was unpalatable.
Descent was published on 24 February 1871 (see Correspondencevol. 19,Appendix II). Müller’s name appears on CD’s presentation listfor Descent (DAR 210:11. 32; Correspondence vol. 19, Appendix IV).
CD refers to the English translation of F. Müller 1864, Facts andarguments for Darwin (Dallas trans. 1869). According to John Murray’sledger book (John Murray Archive, National Library of Scotland), 1000 copies were printed. Murray received a ten per centcommission for sales and warehousing. After one year, a loss of £212s. 3d. was recorded, but over the next ten years small profitswere 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 andthe southern states of Baden, Württemberg, and Bavaria. CD refersto Hermann Müller, Ernst Haeckel, Carl Gegenbaur, and JuliusVictor Carus. See letter from J. V. Carus, 2 October 1870.
For more on Anton Dohrn’s service in the Prussian army during theFranco-Prussian war, see Heuss 1991, pp. 104–9.
Emile Alglave was the editor of the weekly Revue des CoursScientifiques; CD’s copies of some issues of the journal are in theDarwin Pamphlet Collection–CUL. In July and August 1870, a number ofissues focused on the debate over CD’s candidacy in the zoologicalsection of the Académie des Sciences (see letter from Armand deQuatrefages, 18 July 1870). A paper by Paul Broca on transformism wasalso published in the journal (Broca 1870a; see letter from PaulBroca, 4 August 1870 and n. 2).
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