Huxley had sent a copy of the English translation of Ernst Haeckel’s Freedom in science and teaching (Haeckel 1879c). CD’s copy is in the Darwin Library–Down.

The preface was written by Huxley, who condemned Rudolf Carl Virchow for suggesting in ‘grim earnest’ that evolutionary speculations generated ‘revolutionary schemes in Socialist brains’ (Haeckel 1879c, p. xx). Virchow had opposed the teaching of evolution in schools and called for moderation with respect to speculation in science; Haeckel and Virchow had clashed on this point at the 1878 meeting of the German Association of Naturalists (see Correspondence vol. 26, letter to Karl von Scherzer, 1 April 1878 and n. 2).