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Darwin Correspondence Project

To Fritz Müller   3 June 1868

Down Bromley Kent

June 3. 1868.

My dear Sir

I am delighted that you approve of the Translation. I have sent your errata & the additions (which latter I wish had been more copious) to Mr Dallas.1 Mr Murray has the stereotypes; so that every thing is ready; but I do not suppose Mr D. will have finished for some months, as he has much other work in hand.2 Murray also wd object to publishing in the dead months of Sept & Oct. When you next write you had better tell me how many copies to send to you &, to what other persons in Europe. I will have a few copies sent to English scientific Journals & one to Dana3 in the U. States.

Your letter of Ap. 22 has much interested me. I am delighted that you approve of my book, for I value yr opinion more than that of almost any one. I have yet hopes that you will think well of Pangenesis.4 I feel sure that our minds are somewhat alike, & I find it a great relief to have some definite, though hypothetical, view when I reflect on the wonderful transformations: of animals—the regrowth of parts,—the monstrous position of organs,—& especially the direct action of pollen on the mother-form &c. It often appears to me almost certain that the characters of the parents are “photographed” on the child, only by means of material atoms derived from each cell in both parents & developed in the child.

I am sorry about the mistake in regard to Leptotes; I dare say it was my fault, yet I took pains to avoid such blunders.5

Many thanks for all the curious facts about the unequal numbers of the sexes in Crustacea; but the more I investigate this subject the deeper I sink in doubt & difficulty.6 Thanks also for the confirmation of the rivalry of Cicadæ.7 I have often reflected with surprize on the diversity of the means for producing music with insects & still more with birds. We thus get a high idea of the importance of song in the animal kingdom. Please to tell me where I can find any account of the auditory organs in the Orthoptera? Your facts are quite new to me. Scudder has described an annectant insect in Devonian strata, furnished with a stridulating apparatus: I believe he is to be trusted, & if so the apparatus is of astonishing antiquity.8 After reading Landois paper I have been looking at the stridulating organ in the lamellicorn beetles, in expectation of finding it sexual; but I have only found it as yet in two cases, & in these it was equally developed in both sexes.9 I wish you wd. look at any of yr common Lamellicorns & take hold of both males & females & observe whether they make the squeaking or grating noise equally. If they do not, you cd perhaps send me a male & female in a light little box. How curious it is that there shd be a special organ for an object apparently so unimportant as squeaking. Here is another point; have you any Toucans; if so, ask any trustworthy hunter whether the beaks of the males, or of both sexes, are more brightly coloured during the breeding season than at other times of the year?10 Your facts about the parasites of cirripedes & Rhizocephala & of Renilla are most curious;11 but it is I think necessary to remember that when a plant is introduced into a country, insects sometimes discover that it belongs to the same family with those on which such insects habitually feed. I am sorry to say your seeds of Escholtzia were crushed & did not germinate.12 I have also to thank you for a previous letter of Ap. 3, with some interesting facts on the variation of maize, the sterility of bignonia & on conspicuous seeds.13 Heaven knows whether I shall ever live to make use of half the valuable facts which you have communicated to me. Your paper on Balanus armatus, translated by Mr Dallas, has just appeared in our annals & Mag. of Nat. Hist. & I have read it with the greatest interest   I never thought that I shd live to hear of a hybrid balanus! I am very glad that you have seen the cement tubes; they appeared to me extremely curious, & as far as I know you are the first man who has verified my observations on this point.14

After the publication of my Book a gentleman wrote to me that he had distinctly seen in his aquarium a Balanus insert its penis through the open operculum deep into an adjoining shell! I cannot just now lay my hand on this letter, but I think he saw the act repeated several times.—15

With most cordial thanks for all your kindness, My dear Sir | Yours very sincerely | C. Darwin.


See letter from Fritz Müller, 22 April 1868. William Sweetland Dallas was translating Müller’s Für Darwin (F. Müller 1866, W. S. Dallas trans. 1869).
John Murray was CD’s publisher and the publisher of W. S. Dallas trans. 1869.
James Dwight Dana.
See letter from Fritz Müller, 22 April 1868 and nn. 8–17. CD cited Müller’s remarks on the proportion of the sexes in Crustacea in Descent 1: 315.
See letter from Fritz Müller, 22 April 1868 and n. 18. CD’s cited Müller’s remarks on the musical contest between male cicadas in Descent 1: 351.
CD mentioned Samuel Hubbard Scudder’s discovery in Descent 1: 360 (see also Scudder 1865).
See Descent 1: 382. CD refers to Hermann Landois and Landois 1867.
CD discussed beaks of toucans (Ramphastidae) in Descent 2: 227.
CD refers to F. Müller 1868a, a translation of F. Müller 1867. Balanus armatus is a synonym of B. trigonus. Müller discussed the cement tubes of B. armatus in F. Müller 1868a, p. 401, referring to CD’s Living Cirripedia (1854), pl. 28, fig. 4a (see also ‘Description of plates’, p. 669).
See Correspondence vol. 6, letter from Richard Bishop to C. S. Bate, 3 December 1857.


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.

Landois, Hermann. 1867. Die Ton- und Stimmapparate der Insecten in anatomisch-physiologisher und akusticher Beziehung. Zeitschrift für wissenschaftliche Zoologie 17: 105–84.

Living Cirripedia (1854): A monograph of the sub-class Cirripedia, with figures of all the species. The Balanidæ (or sessile cirripedes); the Verrucidæ, etc. By Charles Darwin. London: Ray Society. 1854.

Müller, Fritz. 1867. Ueber Balanus armatus und einen Bastard dieser Art und des Balanus improvisus var. assimilis Darw. Archiv für Naturgeschichte 33: 329–56.

Scudder, Samuel Hubbard. 1865. On the Devonian insects of New Brunswick. [Read 2 October 1865.] Transactions of the Entomological Society of London (Journal of Proceedings) 3d ser. 2 (1864–5): 117–18.


Is glad FM approves of a translation of Für Darwin.

Hopes FM will think well of Pangenesis.

Sexual differences in insect auditory and stridulating organs.

Read FM’s paper on Balanus with great interest ["On Balanus armatus", Ann. & Mag. Nat. Hist. 4th ser. 1 (1868): 393–412].

Letter details

Letter no.
Charles Robert Darwin
Johann Friedrich Theodor (Fritz) Müller
Sent from
Source of text
The British Library (Loan MS 10 no 24)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 6224,” accessed on 18 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 16