skip to content

Darwin Correspondence Project

To Fritz Müller   9 December [1865]1

Down. | Bromley. | Kent. S.E.

Dec 9

My dear Sir

I have received your interesting letter of Oct. 10th. with its new facts on branch-tendrils.2 If the Linn. Soc. publishes your paper, as I am sure it ought to do, I will append a note with some of these new facts.3

I forwarded immediately your M.S. to Prof. Max Schultze but I did not read it, for German hand writing utterly puzzles me, & I am so weak I am capable of no exertion: I took the liberty however of asking him to send me a copy if separate ones are printed;4 & I reminded him about the spunge paper.5

I knew of the difference in the spicula, but your difficulty had not occurred to me; from analogy I should rather expect that spunges have existed with spicula of the 2 kinds, & that the one had ultimately preponderated over the other.6

You will have received before this my book on Orchids & I wish I had known that you wd have preferred the English edition. Should the German ed. fail to reach you I will send an English one.7

That is a curious observation of your daughter about the movement of the apex of the stem of Linum & wd I think be worth following out; I suspect many plants move a little, following the sun; but all do not for I have watched some pretty carefully.8

I can give you no Zoological news for I live the life of the most secluded hermit.

I occasionally hear from Ernst Haeckel who seems as determined as you are to work out the subject of the change of species. You will have seen his curious paper on certain Medusæ reproducing themselves by seminal generation at two periods of growth.9

With sincere respect | Believe me my dear Sir | Yours very truly | Ch. Darwin


The year is established by the relationship between this letter and the letter from Fritz Müller, 10 October 1865.
CD added the information on branch tendrils contained in Müller’s letter of 10 October 1865 to the paper he sent to the Linnean Society. See letter from Fritz Müller, [12 and 31 August, and 10 October 1865] and n. 1.
Müller had sent CD the manuscript of a paper on the wood of twining plants; Müller’s paper, which CD forwarded to Max Johann Sigismund Schultze, was published in Botanische Zeitung (Müller 1866). See letter from Fritz Müller, 10 October 1865 and nn. 6 and 7. CD’s letter to Schultze has not been found.
CD refers to Müller 1865c, a paper published in the journal edited by Schultze, Archiv für mikroskopische Anatomie. Müller had asked Schultze to send a copy directly to CD (see letter from Fritz Müller, 10 October 1865 and n. 8).
In his letter to CD of 10 October 1865, Müller had discussed the problem of explaining, according to Darwinian theory, the development of two types of sponges, one with calcareous spicules, the other with siliceous spicules. Müller thought it unlikely that either form was the ancestor of the other. In his paper (Müller 1865c, p. 351), Müller proposed that the sponge Darwinella aurea represented the ancestral form from which both types could have developed, because it possessed spicules composed entirely of organic fibres with no mineral component.
In his letter of 10 October 1865, Müller had requested the original English edition of Orchids. Before receiving Müller’s letter, however, CD had already sent him the German translation (Bronn trans. 1862). See letter to Fritz Müller, 20 September [1865]).
Haeckel 1865b described two species of medusae that he claimed were both capable of asexual and sexual reproduction (see letter to Ernst Haeckel, 6 December [1865] and n. 9). In his paper, Haeckel had referred to Müller 1859, which discussed different forms of a related species, Liriope catharinensis (now placed in synonymy with Liriope tetraphylla).


Has forwarded FM’s MS to Max Schultze, but did not read it.

Movement of stem apex in Linum.

Haeckel’s paper on reproduction in certain Medusae.

Letter details

Letter no.
Charles Robert Darwin
Johann Friedrich Theodor (Fritz) Müller
Sent from
Source of text
The British Library (Loan MS 10 no 4)
Physical description
LS 4pp

Please cite as

Darwin Correspondence Project, “Letter no. 4949,” accessed on 13 September 2023,

Also published in The Correspondence of Charles Darwin, vol. 13