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From Ernst Haeckel1   8 October 1873

Jena

8. Oct 73

Hochverehrter theurer Freund!

Für Ihren freundlichen Brief vom 25/Sept sowie für die gütige Übersendung der beiden Aufsätze, Ihrer “Notes on rudimentary structures” und der “Lesson in Biogenesis” sage ich Ihnen meinen herzlichsten Dank.2 Mit Ihren vortrefflichen Bemerkungen über die Ursachen der allmählichen Rückbildung der rudimentaeren Organe bin ich völlig einverstanden. Ich habe mir immer gedacht, dass die Correlation in der Ernährung der Zellen hierbei eine grosse Rolle spielt, und dass die “Natural selection” durch Benützung dieser Correlation und der damit verknüpften Verhältnisse in der Oekonomie des Organismus die allmähliche Rückbildung der nutzlosen Theile herbeiführt. Ich habe auch in der “Generellen Morphologie” ähnlich die Sache angefasst und glaube, dass sich unsere Anschauungen vollkoen decken.3

Was die “Biogenesis” betrifft, so hat mich die Mittheilung der Herren Dallinger und Drysdale sehr interessirt, dass die Keime der Monaden eine viel höhere Temperatur aushalten, als die erwachsenen Organismen.4 Im Übrigen habe ich an den Versuchen über Urzeugung kein besonders grosses Interesse, da den meisten Beobachtern viel zu sehr die Kritik und der richtige philosophische Gesichts-Punkt zu Beurtheilung der Frage fehlt. Ich glaube, dass die theoretische Haupt Schwierigkeit für die Frage von der Generatio spontanea, die im Beginne der organischen Erdgeschichte natürlich stattgefunden haben muss, durch die Entdeckung der Moneren gelösst ist.5 Ich hoffe, Sie werden mit meiner Beurtheilung dieser Verhältnisse in der natürlichen Schöpfungsgeschichte einverstanden sein, deren englische Übersetzung Sie hoffentlich bald erhalten werden. Ich weiss nicht, warum dieselbe bis jetzt noch nicht erschienen ist.6

In den letzten Monaten bin ich grösstentheils mit der weiteren Ausbildung meiner Gastrula-Theorie beschäftigt gewesen, und mit dem Nachweise, dass die beiden primaeren Keimblätter bei allen Thieren (mit Ausnahme der Protozoen) homolog sind. Je mehr ich darüber nachdenke, desto mehr bin ich überzeugt, dass diese Theorie gut ist. Die Protozoa (incl. Infusoria) haben alle noch keine Keimblätter und keinen wahren Darm. Alle übrigen Thiere (Metazoa) sind Descendenten der Gastraea (ontogen. Gastrula) haben einen wahren Darm und zwei primaere Keimblätter, Entoderm u. Exoderm.7

diagram

E. Ray-Lankester ist selbständig zur ganz ähnlichen Auffassung gelangt. Er hat einen sehr guten Aufsatz darüber in den Annals and Magaz. of nat. hist. No 65. Mai 1873 “On the primitive Cell-layers of the Embryo”8 etc. Sie haben ihn wohl gelesen?— Im September war ich 3 Wochen zu Erholung in der Schweiz wo ich zu meiner grossen Freude auch Huxley in Luzern traf. Er hat es Ihnen wohl erzält.—9 Vorgestern ist meine Familie durch einen kleinen weiblichen Anthropoiden vermehrt worden.10 Die beiden anderen praesentiren sich beifolgend.—11

Der Darwinismus hat in diesem Jahre in Deutschland sehr grosse Fortschritte gemacht. Bereits nehmen ihn die Historiker die Social-Politiker, ja sogar einige Theologen (!!) als Basis ihrer Lehren an. Hoffentlich wirkt Charles Darwin noch viele Jahre gesund und in voller Kraft für seine reformatorische Lehre.

Das ist der herzlichste Wunsch seines getreuesten Schülers und Jüngers | Ernst Haeckel

Footnotes

1
For a translation of this letter, see Appendix I.
2
See letter to Ernst Haeckel, 25 September 1873. CD had published a letter in Nature, 25 September 1873, p. 42, headed ‘On the males and complemental males of certain cirripedes, and on rudimentary structures’ (see letter to Nature, 20 September [1873]). Haeckel also refers to Dallinger and Drysdale 1873 (‘A lesson in biogenesis’).
3
In Haeckel 1866, 2: 269–72, Haeckel argued that if their conditions of life were simplified, organisms could regress to simpler forms, rather than continuing to become more complicated, and that since highly differentiated parts required extra nourishment, it was an advantage to the organism to lose them when they they were no longer required.
4
William Henry Dallinger and John James Drysdale’s finding that spores of flagellate protozoa could survive temperatures of up to 127oC challenged the theory that life could be spontaneously generated in boiled and supposedly sterile water (Dallinger and Drysdale 1873, pp. 57–8).
5
Monera, a taxon of unicellular organisms without nuclei, were part of Haeckel’s kingdom of the Protista, which contained microscopic organisms not included in the plant or animal kingdoms. Since they were structureless and homogeneous, Haeckel thought them better prototypes of the first organisms produced by spontaneous generation than more complex cells. See Haeckel 1868 and Di Gregorio 2005, pp. 430–3. Monera is now a kingdom divided into the phyla Bacteria and Cyanophycota. Haeckel included many organisms in his Monera that would not be included in the modern understanding of the term.
6
Haeckel’s Natürliche Schöpfungsgeschichte (Natural history of creation; third edition Haeckel 1872b) did not appear in English translation until 1876 (Haeckel 1876). Edwin Ray Lankester, who supervised the translation (which was made by Dora Schmitz; Lester 1995, p. 37), told Haeckel in a letter probably dated 26 November 1872 that the translation was finished and mostly printed (Di Gregorio 2005, p. 229). Haeckel’s preface to the English translation was dated 24 June 1873.
7
The term gastrula (an embryo at the stage when it transforms from a single-layered, hollow, fluid-filled ball of cells into a double-layered structure) was coined by Haeckel in Haeckel 1872a. Haeckel equated specific ontogenetic stages such as the gastrula with corresponding hypothetical ancestral organisms (in this case, Gastraea). Protozoa are single-celled animals, Metazoa many-celled animals.
8
Lankester 1873b.
9
No letter from Thomas Henry Huxley to CD concerning his meeting with Haeckel in Lucerne has been found. Huxley was on a long holiday in France, Austria, and Switzerland (L. Huxley 1900, 1: 390–7).
11
The photograph, which has not been found, was presumably of Walter and Elisabeth Haeckel, Haeckel’s son and eldest daughter.

Bibliography

Di Gregorio, Mario A. 2005. From here to eternity: Ernst Haeckel and scientific faith. Göttingen: Vandenhoeck & Ruprecht.

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.

Huxley, Leonard, ed. 1900. Life and letters of Thomas Henry Huxley. 2 vols. London: Macmillan.

Lester, Joseph. 1995. E. Ray Lankester and the making of modern British biology. Edited and with additional material by Peter J. Bowler. Oxford: British Society for the History of Science.

Translation

From Ernst Haeckel1   8 October 1873

Jena

8. Oct 73

Much esteemed dear friend!

For your kind letter of 25/Sept as well as for kindly sending me the two essays, your “Notes on rudimentary structures” and the “Lesson in Biogenesis” I thank you most cordially.2 I am wholly in agreement with your outstanding remarks on the causes of the gradual diminution of rudimentary organs. I always thought that the correlation in the nutrition of cells plays a major role in this, and that “natural selection”, by using this correlation and the conditions in the economy of the organism that are associated with it, brings about the gradual diminution of useless parts. In the “Generelle Morphologie” I approached this matter in a similar way, and I believe that our views are prefectly in accord.3

Regarding “biogenesis”, I was very interested in the communication of Mssrs Dallinger and Drysdale, namely that the germs of Monads can withstand far higher temperatures than the adult organisms.4 Incidentally, I have no special interest in the experiments on spontaneous generation, since most observers lack the critical attitude and the right philosophical outlook far too much to judge the problem. I believe that the chief theoretical difficulty for the problem of Generatio spontanea, which must have taken place naturally in the beginning of the organic history of the earth, has been solved by the discovery of the Monera.5 I hope that you will agree with my assessment of these matters in the natürliche Schöpfungsgeschichte, whose English translation you hopefully will soon receive. I have no idea why it has not yet appeared.6

In recent months I have been busy for the most part with the further development of my Gastrula-theory, and with demonstrating that the two primary germ layers are homologous in all animals (with the exception of the Protozoa). The more I reflect on it, the more I am convinced that this theory is good. The Protozoa (including Infusoria) all have not yet any germ layers or true gut. All other animals (Metazoa) descend from the Gastraea (ontogenet. Gastrula), have a genuine gut and two primary layers, entoderm and exoderm.7

diagram

E. Ray Lankester has independently arrived at quite a similar conception. He has a very good essay on this in the Annals and Magaz. of nat. hist. no. 65 May 1873, “On the primitive cell-layers of the embryo” etc.8 You have no doubt read it?— In September I spent 3 weeks on holiday in Switzerland, where to my great joy I also met Huxley in Lucerne. He probably has told you about it.—9 The day before yesterday my family was increased by a small female anthropoid.10 The two other members present themselves in the enclosed photograph.—11

This year, Darwinism has made very great progress in Germany. Historians, social-political thinkers, even a few theologians (!!) already make it the basis of their theories. Hopefully Charles Darwin will continue to work in good health and full of energy for this reformatory theory for many more years to come. That is the most heartfelt wish of his most loyal pupil and disciple | Ernst Haeckel.

Footnotes

1
For a transcription of this letter in its original German, see pp. 441–3.
2
See letter to Ernst Haeckel, 25 September 1873. CD had published a letter in Nature, 25 September 1873, p. 42, headed ‘On the males and complemental males of certain cirripedes, and on rudimentary structures’ (see letter to Nature, 20 September [1873]). Haeckel also refers to Dallinger and Drysdale 1873 (‘A lesson in biogenesis’).
3
In Haeckel 1866, 2: 269–72, Haeckel argued that if their conditions of life were simplified, organisms could regress to simpler forms, rather than continuing to become more complicated, and that since highly differentiated parts required extra nourishment, it was an advantage to the organism to lose them when they they were no longer required.
4
William Henry Dallinger and John James Drysdale’s finding that spores of flagellate protozoa could survive temperatures of up to 127oC challenged the theory that life could be spontaneously generated in boiled and supposedly sterile water (Dallinger and Drysdale 1873, pp. 57–8).
5
Monera, a taxon of unicellular organisms without nuclei, were part of Haeckel’s kingdom of the Protista, which contained microscopic organisms not included in the plant or animal kingdoms. Since they were structureless and homogeneous, Haeckel thought them better prototypes of the first organisms produced by spontaneous generation than more complex cells. See Haeckel 1868 and Di Gregorio 2005, pp. 430–3. Monera is now a kingdom divided into the phyla Bacteria and Cyanophycota. Haeckel included many organisms in his Monera that would not be included in the modern understanding of the term.
6
Haeckel’s Natürliche Schöpfungsgeschichte (Natural history of creation; third edition Haeckel 1872b) did not appear in English translation until 1876 (Haeckel 1876). Edwin Ray Lankester, who supervised the translation (which was made by Dora Schmitz; Lester 1995, p. 37), told Haeckel in a letter probably dated 26 November 1872 that the translation was finished and mostly printed (Di Gregorio 2005, p. 229). Haeckel’s preface to the English translation was dated 24 June 1873.
7
The term gastrula (an embryo at the stage when it transforms from a single-layered, hollow, fluid-filled ball of cells into a double-layered structure) was coined by Haeckel in Haeckel 1872a. Haeckel equated specific ontogenetic stages such as the gastrula with corresponding hypothetical ancestral organisms (in this case, Gastraea). Protozoa are single-celled animals, Metazoa many-celled animals.
8
Lankester 1873b.
9
No letter from Thomas Henry Huxley to CD concerning his meeting with Haeckel in Lucerne has been found. Huxley was on a long holiday in France, Austria, and Switzerland (L. Huxley 1900, 1: 390–7).
11
The photograph, which has not been found, was presumably of Walter and Elisabeth Haeckel, Haeckel’s son and eldest daughter.

Bibliography

Di Gregorio, Mario A. 2005. From here to eternity: Ernst Haeckel and scientific faith. Göttingen: Vandenhoeck & Ruprecht.

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.

Huxley, Leonard, ed. 1900. Life and letters of Thomas Henry Huxley. 2 vols. London: Macmillan.

Lester, Joseph. 1995. E. Ray Lankester and the making of modern British biology. Edited and with additional material by Peter J. Bowler. Oxford: British Society for the History of Science.

Summary

On CD’s paper ["Complemental males of certain cirripedes", Collected papers 2: 177–82].

Comments on paper by W. H. Dallinger and J. J. Drysdale ["Life history of a Cercomonad", Mon. Microsc. J. 10 (1873): 53–8].

Discusses origin of life, the Gastraea theory and concept that primary germ layers are homologous in all animals. Notes similar views of E. Ray Lankester ["On the primitive cell-layers of the embryo", Ann. & Mag. Nat. Hist. 4th ser. 11 (1873): 321–38].

Reception of Darwinism in Germany.

Letter details

Letter no.
DCP-LETT-9091
From
Ernst Philipp August (Ernst) Haeckel
To
Charles Robert Darwin
Sent from
Jena
Source of text
DAR 166: 61
Physical description
ALS 4pp (German)

Please cite as

Darwin Correspondence Project, “Letter no. 9091,” accessed on 18 April 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-9091.xml

Also published in The Correspondence of Charles Darwin, vol. 21

letter

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