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Darwin Correspondence Project

To Ernst Haeckel   4 July [1867]1

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

July 4.

My dear Haeckel

I heartily congratulate you on your approaching marriage.2 You have my entire sympathy & I feel sure it is the wisest step which you could take; for life without a wife to love & be loved by is a poor burthen. I trust you may pass a long & happy life, & I am sure it will be an active one, & that you will do admirable work in our beloved subject of natural history. I am sorry you will not come here this autumn, but perhaps another year you will bring your wife & shew England to her, & pay us a visit in this quiet place.

I am glad you are re-examining the Protamœba for I fully agree with you on the importance of studying these lowly organized creatures; but I am rather puzzled to think what you can find to observe.3

Many thanks for the account of your travels, but I have not read them yet, German being as you know, no easy task to me. I have written to thank for the honour of the Diploma, & likewise to Kanitz with my photograph.4

I received the other day a newspaper from N. America with an abstract of a speech by Agassiz, who seems much stirred up by your book. He says he rejoices at every new work which appears on our subject, as by this means the folly of our views will the sooner be exposed & the whole subject be quickly forgotten. He is forced to admit that no one knows better than you the structure & affinities of animals, but he is very savage at your genealogical tables & says they are flatly contradicted by paleontology. It is curious that he shd not remember that only a few years ago he maintained that a reptile cd not exist during the carboniferous period, & now he designates this very period as the Reptilian.5

Farewell my dear Haeckel with my warm wishes for your happiness in which my wife cordially joins, yours very sincerely | Charles Darwin


The year is established by the relationship between this letter and the letter from Ernst Haeckel, 28 June 1867.
Haeckel had announced his engagement to Agnes Huschke in his letter of 28 June 1867.
See letter from Ernst Haeckel, 28 June 1867. For the diploma, from the Zoological and Botanical Society in Vienna, see Correspondence vol. 15, Appendix III. CD’s letter of thanks and his letter to August Kanitz have not been found.
The newspaper and the speech by Louis Agassiz have not been identified. Haeckel’s book was his Generelle Morphologie der Organismen (Haeckel 1866); the genealogical tables, or trees, are at the end of the second volume; on these trees, see S. J. Gould 1977, pp. 76–85, 170–2 (see also letter from T. H. Huxley, [before 7 January 1867] and n. 6). Agassiz had been cautious about admitting the existence of reptiles in the Carboniferous as late as 1866; see J. L. R. Agassiz 1866–76, 1: 15, 72, 91.


Agassiz, Louis. 1866–76. Geological sketches. 2 vols. Boston: Ticknor & Fields; J. R. Osgood.

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

Gould, Stephen Jay. 1977. Ontogeny and phylogeny. Cambridge, Mass.; London: Belknap Press of Harvard University Press.

Haeckel, Ernst. 1866. Generelle Morphologie der Organismen. Allgemeine Grundzüge der organischen Formen-Wissenschaft, mechanisch begründet durch die von Charles Darwin reformirte Descendenz-Theorie. 2 vols. Berlin: Georg Reimer.


Congratulates EH on approaching marriage.

Sorry he will not visit in autumn.

Glad EH is re-examining Protoamoeba but puzzled to think what he can find.

Describes newspaper account of criticism by Agassiz of Generelle Morphologie.

Letter details

Letter no.
Charles Robert Darwin
Ernst Philipp August (Ernst) Haeckel
Sent from
Source of text
Ernst-Haeckel-Haus (Bestand A-Abt. 1-52/15)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 5578,” accessed on 27 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 15