Summary

Comments on CD’s health.

Discusses origin of life and differentiation of principal classes of plants and animals.

Discusses Generelle Morphologie and its chapter on embryological development.

His lectures on CD’s theory.

Asks CD for larger portrait of himself and for several copies of the small photograph. Will send photographs of German scientists in exchange.

Summary

Thanks CD for new edition of Origin [4th ed. (1866)].

Comments on CD’s criticism of the harsh tone of Generelle Morphologie. Thinks he may have harmed himself but not the cause. Believes a radical reform of the science necessary, and since most scientists take a prejudiced view of the matter, a vigorous attack is essential.

Describes his travels in Canaries, Spain, and France.

Summary

Has heard from Huxley that CD has been ill.

Progress on his book [Generelle Morphologie (1866)] has been slow.

Has been named "ordentlicher Professor". Has 150 listeners in his lectures on CD’s theory.

Thanks CD for copy [of "Climbing plants"].

Sends his book [Beiträge zur Naturgeschichte der Hydromedusen, 1. Heft: Die Familie der Rüsselquallen (Geryonidae) (1865)] and two articles.

Calls attention to a new rhizopod from Nice.

Summary

Discusses exchange of photographs with German scientists.

Comments on attitudes of German scientists toward CD’s theory.

Names several scientists who exchanged photographs: Braun, Virchow, Leydig, and Dohrn.

Summary

Has received English edition of Variation. First volume of German edition came three months ago. Comments on book.

Will send copy of recent lectures on human evolution [Entstehung des Menschengeschlechts (1868)]. Gegenbaur much interested in the subject.

Considers Selachius the ancestral form of the fish and hence of all higher vertebrates. Believes their swim-bladder became lung of amphibians.

Mentions cases of hybrid crosses between rabbits and hares producing fertile offspring.

Summary

Returns letter mailed by mistake [see 4361].

Hopes CD will accept gift of his Radiolarien [Die Radiolarien, 2 vols. (1862)].

Summary

Comments on CD’s health.

Has received gold medal from Dutch Academy of Science for Zur Entwicklungsgeschichte der Siphonophoren [1869].

His Entstehung des Menschengeschlechts [1868] has been sharply attacked by the clergy.

Summary

No book has made such a powerful impression on EH as the Origin. Most older German scholars opposed to it, but number of supporters growing among the young. Fortunately strength of religious dogmas now small among educated Germans. Situation in Jena especially favourable. Defended CD’s theory last year at Congress of German Scientists in Stettin.

Intends special study of jellyfish.

Plans general work on natural history.

Hard fate [death of Anna Sethe Haeckel] has made EH indifferent to criticism.

Colleagues August Schleicher and Carl Gegenbaur also convinced by CD’s theory.

Summary

Accepts invitation to visit Down.

Describes travel plans in Scotland.

Summary

Sends photographs of himself and his late wife [Anna Sethe]. Describes death of his wife.

Plans trip to the Alps.

Thanks CD for biographical information about himself.

Mentions Goethe as early evolutionist.

Cites Kant as early supporter of epigenesis.

Mentions criticism of CD’s theory by R. A. von Kölliker ["Über die Darwin’sche Schöpfungstheorie", Z. Wiss. Zool. 14 (1864): 174–86].

Summary

Thanks CD for notes concerning the development of his ideas about the origin of species. Says August Schleicher and Carl Gegenbaur also interested.

Names new supporters of CD’s theory, including Max Schultze, Rudolf Leuckart, and Alexander Braun. Zoologists have been more interested than botanists.

He is writing a general work on the relationships among animals [Generelle Morphologie der Organismen (1866)].

Comments on Fritz Müller’s Für Darwin [1864].

Gegenbaur is revising his Grundzüge der vergleichenden Anatomie [2d ed. (1870)] to accord with evolution.

Thanks CD for copy of book on balanids [Living Cirripedia, vol. 2].

Summary

Sends birthday wishes. Album of photographs from German admirers has been sent.

Plans trip to Mediterranean.

Summary

Sends birthday wishes.

Discusses his work on the Challenger [expedition] Radiolaria.

Summary

Sends birthday wishes.

Comments on Movement in plants.

Sends System der Ascrapeden [1880].

Describes work on Challenger Medusae.

Comments on success of CD’s theory.

Summary

Sends birthday wishes.

Discusses work on Medusae.

Recalls visit to Down.

Summary

Sends birthday wishes.

Comments on progress of CD’s theory in Germany. Mentions opposition of Rudolf Virchow and his reply Freie Wissenschaft und freie Lehre [1878].

Describes research trip to Brittany and Normandy.

Research on Challenger Radiolaria.

Summary

Is engaged to marry Agnes Huschke. Will make wedding trip to Switzerland and Italy in autumn; therefore cannot visit CD as hoped.

Discusses present research. Comments on Protoamoeba with respect to origin of life. Says it makes question of common or separate origin of phyla unimportant.

CD to receive honorary diploma from Imperial Zoological Botanical Society in Vienna.

Sends photograph of Viennese botanist, August Kanitz.

Summary

Much experiment and observation needed before spontaneous generation will be empirically advanced, but philosophically the matter is clear.

Thinks Ludwig Rütimeyer has attacked EH to satisfy pious opinion in Basel.

Will soon be finished with his monograph Die Kalkschwämme [1872].

Summary

Thanks CD for comments on Freie Wissenschaft und freie Lehre [1878].

Describes work on Medusae.

Describes work on Challenger Radiolaria and publication plans.

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].