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Darwin Correspondence Project

To Ernst Haeckel   19 July [1864]1

Down Bromley Kent

July 19

Dear Sir

I have been deeply interested by your most kind letter.—2 I naturally feel much curiosity on the progress of opinion on the descent of species, & I am delighted to hear that the subject is progressing in Germany which so abounds with great naturalists.— But what you tell me about yourself interests me the most, & I thank you sincerely for your confidence. I feel what you say in praise of my book & your intention of carrying onwards & perfecting the subject, as by far the greatest honour which could be paid me. I was shewn in London your magnificent work on Radiolariæ.3 The passage which you refer to was pointed out to me & I was struck by it & admired the boldness of your expressions.4

I am grieved to hear that you have suffered any heavy calamity;5 but at so early a period of life I cannot but hope that time, the great allayer of all evils, will do much for you. I am rendered by ill–health old for my years, which are 56,6 but I still feel a lively interest on many subjects, & your letter has delighted me. I have thought that perhaps you wd like to have a photograph of me (lately taken by one of my sons) & which I enclose.7 Some time I hope that you will have the goodness to send me your photograph, as I should much like to possess a copy.

I am very much obliged for your promised book, which I will read with care, for what you say on individual variability in the Cœlenterata is very remarkable; & this kind of variability has been greatly neglected by naturalists.8 I have however a very bad head for languages; & every German book takes me a long time which is a great evil, there is so much to read in German. I am slowly recovering from a long illness, which has quite prevented all work; but I hope soon to resume my nearly finished book on “Variation under Domestication”;9 in the mean time, I have been doing a little easy Botanical work, & one of the papers which I have prepared, will possibly interest you as it relates to reproduction & when printed I will send you a copy.10

This kind of work being in some degree new to me, I have been much struck with the interest which the theory of descent & modification gives to all researches in Natural History; for I was able to use my own views with a feeling of novelty almost as if I had only lately learnt them.

Pray present my respects to Schleicher & Gegenbaur.11 I am much pleased to know that men so distinguished agree to a large extent with my views.

Accept my cordial thanks for your long letter which has interested me in a high degree

I remain with much respect | Dear Sir | yours very sincerely | Charles Darwin


The year is established by the relationship between this letter and the letter from Ernst Haeckel, 9 [July 1864]. There is a draft of this letter in DAR 96: 18–20.
CD may have been shown Die Radiolarien (Haeckel 1862) by Thomas Henry Huxley when he visited London in 1863. Huxley had obtained a copy in October 1862 (L. Huxley ed. 1900, 1: 237). CD received his own copy from Haeckel early in 1864 (see letter to Ernst Haeckel, 3 March [1864]).
CD was 55 on 12 February 1864.
CD refers to the photograph recently taken by his son William Erasmus Darwin (see the frontispiece to this volume).
CD resumed work on the manuscript of Variation on 14 September 1864 (see ‘Journal’ (Correspondence vol. 12, Appendix II)). Variation was not published until 1868.
‘Three forms of Lythrum salicaria. Haeckel’s name appears on CD’s presentation list for the paper (see Correspondence vol. 12, Appendix III).


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 28 vols to date. Cambridge: Cambridge University Press. 1985–.

Haeckel, Ernst. 1862. Die Radiolarien. (Rhizopoda Radiaria.) Eine Monographie. 2 vols. Berlin: Georg Reimer.

‘Three forms of Lythrum salicaria’: On the sexual relations of the three forms of Lythrum salicaria. By Charles Darwin. [Read 16 June 1864.] Journal of the Linnean Society (Botany) 8 (1865): 169–96. [Collected papers 2: 106–31.]

Variation: The variation of animals and plants under domestication. By Charles Darwin. 2 vols. London: John Murray. 1868.


Thanks for praise [of Origin].

Comments on EH’s Die Radiolarien.

Grieved EH has suffered calamity [death of Anna Sethe Haeckel].

CD recovering from long illness.

Doing easy botanical work.

Mentions variability.

Discusses reception of CD’s views in Germany.

Letter details

Letter no.
Charles Robert Darwin
Ernst Philipp August (Ernst) Haeckel
Sent from
Source of text
Ernst-Haeckel-Haus (Bestand A-Abt. 1: 1-52/4)
Physical description
LS 4pp & Adraft 6pp

Please cite as

Darwin Correspondence Project, “Letter no. 4569,” accessed on 17 May 2022,

Also published in The Correspondence of Charles Darwin, vol. 12