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.