Sends birthday wishes.

Discusses his work on the Challenger [expedition] Radiolaria.

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.

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

Describes work on Medusae.

Describes work on Challenger Radiolaria and publication plans.

Accepts invitation to visit Down.

Describes travel plans in Scotland.

Arranges to visit Down.

Sends birthday wishes.

Discusses work on Medusae.

Recalls visit to Down.

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.

Plans visit to Ceylon.

Describes rejection of his application for funds by Berlin Academy. Asks about possibility of obtaining support in England. Is writing to Lubbock and Huxley about it.

Hopes that new microscope from Zeiss is satisfactory. Ernst Abbe selected lenses.

Thanks CD for offer of financial support. Discusses application for funds for Ceylon trip.

Returns letter mailed by mistake [see 4361].

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

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.

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].

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].

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.

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.

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.

Will visit CD on Sunday, 21 October.

Will spend winter in research on Madeira and Tenerife.

CD will soon receive copy of Generelle Morphologie.

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.

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.

Describes his lectures on CD’s theory.

Thanks CD for copy of Variation. Comments on book.

Describes work of two protégés in Jena: Nicolas von Miklucho[-Maclay] and Anton Dohrn.

His cousin, Wilhelm Bleek, is sending an article about the origin of language.

Asks to keep book a few months longer but will return it if CD needs it [Webb and Berthelot, Histoire naturelle des Îles Canaries, vol. 3, pt 1: Géographie botanique (1840)].

Describes research on Siphonophora.

Describes life in Jena. Mentions alpine accident during wedding trip.