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Darwin Correspondence Project

From Ernst Haeckel1   31 January and 1 February 1876

Jena

31. Jan 76

Hochverehrter theurer Freund!

Für Ihre beiden lieben und überaus freundlichen Briefe danke ich Ihnen herzlich. Es ist mir die grösste Freude und Genugthuung, dass Sie, als einer der genauesten Kenner und der beste Beurtheiler der Korallenbänke, mit den “Arabischen Korallen” so sehr zufrieden sind.2

Ich habe mir die möglichste Mühe gegeben, den wunderbaren Effect der herrlichen Korallenbänke und ihrer bunten Bewohner so getreu als möglich wiederzugeben.

Ich hatte Anfangs die Absicht, die prächtige Crambactis (in Fig. 2) C. Darwinii und die kleine Monoxenia (in Fig. 11) M. arabica zu nennen.3 Nachher glaubte ich aber, es würde Ihnen mehr Freude machen, wenn die letztere Ihren Namen trüge. Sie ist offenbar eine von den ältesten und primitivsten Korallen-Formen und steht (beim Mangel aller Kalktheile) wohl der hypothetischen Stammform der Octocorallen oder Alcyonarien sehr nahe (näher als Haimea und Hartea, die Spicula besitzen).4

Für den Reformator der Descendenz-Theorie ist gewiss eine solche uralte Stammform, wie Monoxenia, besonders interessant. Auch dass die ursprüngliche Gastrula-Form (Archigastrula) in ihrer Ontogenie noch heute conservirt ist, spricht für ihr sehr hohes Alter (wie bei Amphioxus).—5 Gegenwärtig arbeite ich an der III. Aufl. der “Anthropogenie”, die wesentlich verbessert wird.6

Mit den herzlichsten Grüssen | Ihr treu ergebener | Ernst Haeckel.

P. S. 1. Febr 76.

So eben erhalte ich ein neues Buch vom alten Baer in Dorpat, welches zum grössten Theile der Darwin schen Theorie gewidmet ist.7 Soweit ich eben, nach flüchtigem Durchblättern, gesehen habe, ist dasselbe sehr schwach und zeigt, dass der gute Baer (jetzt 84 Jahre alt!) nicht mehr das nöthige Urtheil und die philosophische Kritik besitzt, Ihre Theorie richtig zu verstehen und zu würdigen. Ich verehre den alten Baer ausserordentlich. Um so mehr bedaure ich, dass er jetzt noch so schlechte Sachen schreibt und seine früheren hohen Verdienste in den Schatten stellt. Ich erkläre mir das daraus, dass er seit 40 Jahren der Biologie, speciell aber der Morphologie, ganz entfremdet ist, und deren Fortschritte und neue Aufgaben nicht mehr versteht. Durch seine grosse Autoritaet wird er unserer Lehre immerhin manchen Schaden zufügen.

E. Hkl.

Footnotes

For a translation of this letter, see Appendix I.
See letters to Ernst Haeckel, 15 January [1876] and 21 January [1876]. CD had praised Haeckel’s Arabische Korallen (Arabian corals; Haeckel 1876b), a profusely illustrated book based on popular lectures with scientific explanations.
Fig. 2 in Haeckel 1876b, p. 4, is Crambactis arabica (a synonym of Entacmaea quadricolor, the bulb-tentacle sea anemone); fig. 11, p. 12, is Monoxenia darwinii; the taxon is no longer recognised. See also Correspondence vol. 23, p. 439.
Octocorallia is a subclass of Anthozoa (corals and sea anemones); Alcyonaria was an earlier name given to this group. Haimea is no longer used as a genus name in Octocorallia because of an earlier use of the name for a genus in the class Echinoidea (heart urchins, sand dollars, and sea urchins). Hartea is no longer recognised. Haeckel had grouped corals into three main divisions, of which two survived to the present day, the Hexacorallia and the Octocorallia. According to Haeckel, Monoxenia was the earliest genus of Octocorallia, dating back to the Cambrian period (see Haeckel 1876b, pp. 77–8 and plate VI).
Haeckel had hypothesised that early forms of organisms were conserved in the developmental stages of their descendents (recapitulation); he proposed that two primary cell types or germ layers were differentiated in the early embryonic development of all multicellular organisms and that the ancestral mode of germ-layer formation was by invagination to produce a functional gut. This stage in development was called gastrulation and represented the recapitulation in ontogeny of an ancient organism. Haeckel also supported the theory that Amphioxus (the lancelet; now Branchiostoma lanceolatum) was the earliest ancestral form of vertebrate (for more on the development of this theory, see Maienschein 1994).
The third edition of Haeckel’s Anthropogenie oder Entwickelungsgeschichte des Menschen (Anthropogeny, or the developmental history of humans; Haeckel 1877a) appeared in 1877. CD’s copy is in the Darwin Library–Down.
Karl Ernst von Baer had recently published the second part of his collected addresses, Studien aus dem Gebiete der Naturwissenschaften (Studies in the field of science); one of the essays included was ‘Ueber Darwin’s Lehre’ (On Darwin’s theory; Baer 1864–76, 2: 235–480). For more on Baer’s objections to CD’s theory, see Vucinich 1988, pp. 92–9; for a contemporary response to Baer’s critique, see Seidlitz 1876, pp. 39–170.

Bibliography

Baer, Karl Ernst von. 1864–76. Reden gehalten in wissenschaftlichen Versammlungen und kleinere Aufsätze vermischten Inhalts. Part 1: Reden. Part 2: Studien aus dem Gebiete der Naturwissenschaften. Part 3: Historische Fragen mit Hülfe der Naturwissenschaften. St Petersburg: H. Schmitzdorff.

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

Maienschein, Jane. 1994. ‘It’s a long way from Amphioxus’: Anton Dohrn and late nineteenth century debates about vertebrate origins. History and Philosophy of the Life Sciences 16: 465–78.

Seidlitz, Georg. 1876. Beiträge zur Descendenz-Theorie. Leipzig: W. Engelmann.

Vucinich, Alexander. 1988. Darwin in Russian thought. Berkeley: University of California Press.

Translation

From Ernst Haeckel1   31 January and 1 February 1876

Jena

31. Jan 76

Most honoured, dear friend!

For both your good and exceedingly kind letters I thank you cordially. It gives me the greatest joy and satisfaction that you, as one of the most painstaking experts and the best judge of coral reefs, are so very content with the “Arabische Korallen”.2

I have tried my utmost to capture the wonderful effect of the magnificent coral reefs and of their colourful inhabitants.

At first I intended to name the splendid Crambactis (in fig. 2) C. Darwinii and the little Monoxenia (in fig. 11) M. arabica.3 But then it occurred to me that you would like it better if the latter bore your name. It is obviously one of the oldest and most primitive coral-forms (because of its lack of calcareous parts) probably very near the hypothetical ancestral form of octocorals or Alcyonaria (closer than either Haimea or Hartea, which have spicules).4

Such an ancient ancestral form as Monoxenia surely must be of particular interest for the reformer of the theory of descent. That the ancestral gastrula form (archigastrula) is still preserved today in its ontogeny also speaks for its very great age (as in the case of Amphioxus).—5

Currently I am working on the III. ed. of “Anthropogenie”, which will be substantially improved.6

With my most cordial greetings | Yours faithfully | Ernst Haeckel.

P.S. 1 Febr 76.

Just now I received a new book from old Baer of Dorpat, which chiefly deals with the Darwinian theory.7 As far as I can see from a quick leaf through, it is very weak and shows that the good Baer (now 84 years old!) no longer has the requisite judgment and philosophical acumen properly to comprehend and appreciate your theory. I admire old Baer extremely. So I regret all the more that he now writes such a poor thing, and puts his previous high merit in the shade. I imagine this is because he has entirely lost touch with biology and especially morphology these past 40 years, and no longer understands its progress and new problems. With his great authority he will still cause our theory considerable harm. | E. Hkl.

Footnotes

For a transcription of this letter in its original German, see pp. 35–6.
See letters to Ernst Haeckel, 15 January [1876] and 21 January [1876]. CD had praised Haeckel’s Arabische Korallen (Arabian corals; Haeckel 1876b), a profusely illustrated book based on popular lectures with scientific explanations.
Fig. 2 in Haeckel 1876b, p. 4, is Crambactis arabica (a synonym of Entacmaea quadricolor, the bulb-tentacle sea anemone); fig. 11, p. 12, is Monoxenia darwinii; the taxon is no longer recognised. See also Correspondence vol. 23, p. 439.
Octocorallia is a subclass of Anthozoa (corals and sea anemones); Alcyonaria was an earlier name given to this group. Haimea is no longer used as a genus name in Octocorallia because of an earlier use of the name for a genus in the class Echinoidea (heart urchins, sand dollars, and sea urchins). Hartea is no longer recognised. Haeckel had grouped corals into three main divisions, of which two survived to the present day, the Hexacorallia and the Octocorallia. According to Haeckel, Monoxenia was the earliest genus of Octocorallia, dating back to the Cambrian period (see Haeckel 1876b, pp. 77–8 and plate VI).
Haeckel had hypothesised that early forms of organisms were conserved in the developmental stages of their descendents (recapitulation); he proposed that two primary cell types or germ layers were differentiated in the early embryonic development of all multicellular organisms and that the ancestral mode of germ-layer formation was by invagination to produce a functional gut. This stage in development was called gastrulation and represented the recapitulation in ontogeny of an ancient organism. Haeckel also supported the theory that Amphioxus (the lancelet; now Branchiostoma lanceolatum) was the earliest ancestral form of vertebrate (for more on the development of this theory, see Maienschein 1994).
The third edition of Haeckel’s Anthropogenie oder Entwickelungsgeschichte des Menschen (Anthropogeny, or the developmental history of humans; Haeckel 1877a) appeared in 1877. CD’s copy is in the Darwin Library–Down.
Karl Ernst von Baer had recently published the second part of his collected addresses, Studien aus dem Gebiete der Naturwissenschaften (Studies in the field of science); one of the essays included was ‘Ueber Darwin’s Lehre’ (On Darwin’s theory; Baer 1864–76, 2: 235–480). For more on Baer’s objections to CD’s theory, see Vucinich 1988, pp. 92–9; for a contemporary response to Baer’s critique, see Seidlitz 1876, pp. 39–170.

Bibliography

Baer, Karl Ernst von. 1864–76. Reden gehalten in wissenschaftlichen Versammlungen und kleinere Aufsätze vermischten Inhalts. Part 1: Reden. Part 2: Studien aus dem Gebiete der Naturwissenschaften. Part 3: Historische Fragen mit Hülfe der Naturwissenschaften. St Petersburg: H. Schmitzdorff.

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

Maienschein, Jane. 1994. ‘It’s a long way from Amphioxus’: Anton Dohrn and late nineteenth century debates about vertebrate origins. History and Philosophy of the Life Sciences 16: 465–78.

Seidlitz, Georg. 1876. Beiträge zur Descendenz-Theorie. Leipzig: W. Engelmann.

Vucinich, Alexander. 1988. Darwin in Russian thought. Berkeley: University of California Press.

Summary

Thanks CD for comments on Arabische Korallen [1876].

Comments on Monoenia darwinii [?] as a primitive sponge.

Discusses criticisms of CD’s theory by K. E. von Baer ["Über Darwin’s Lehre", in Reden 2 (1876): 235–480].

Letter details

Letter no.
DCP-LETT-10375
From
Ernst Philipp August (Ernst) Haeckel
To
Charles Robert Darwin
Sent from
Jena
Source of text
DAR 166: 67
Physical description
6pp (German)

Please cite as

Darwin Correspondence Project, “Letter no. 10375,” accessed on 18 April 2021, https://www.darwinproject.ac.uk/letter/DCP-LETT-10375.xml

Also published in The Correspondence of Charles Darwin, vol. 24

letter