Thanks for copy of HS’s Principles of psychology [1855].

Thanks for HS’s Essays: [scientific, political, and speculative, vol. 1 (1858)]. Admires his general argument for the development theory.

CD is preparing an abstract on change of species. He treats subject as a naturalist, not from a general point of view. Otherwise he might have quoted HS’s argument to great advantage.

CD particularly liked articles on music and style. Expression is a favourite topic with CD. Agrees all expression is biological.

Has prepared a historical sketch [of writers on origin of species] for foreign editions of Origin. It includes HS. He was too ill to provide it for the 1st ed.

Sorry Murray has not sent HS his copy of Origin, as he was instructed.

Huxley will put CD and E. A. Darwin down for HS’s gigantic [publishing] programme. Suggests Dr Drysdale be approached about it.

CD has caused a great change in HS’s views, in showing how a great proportion of adaptation should be explained by natural selection not direct adaptation to changing conditions. HS had remarked on the survival of the best individuals as a cause of improvement in man, but he "& every one" overlooked selection of spontaneous variation. Believes so many kinds of indirect evidence must add up to a conclusive demonstration of the doctrine.

HS put the case of selection strikingly and clearly in his article [Anonymous, "A theory of population, deduced from the general law of animal fertility", Westminster Rev. 57 (1852): 468–501]. Of CD’s numerous private critics only HS has rendered the philosophy fairly: his argument is an hypothesis that explains groups of facts.

Wonders whether CD might contribute, if possible, an occasional letter to the Reader to help in their effort to establish the journal.

Asks whether CD will add his name to a list supporting them in the "[Edward John] Eyre prosecution matter".

Thanks for copy of HS’s First principles [? 2d ed. (1867)].

Comments on HS’s Principles of biology [1864, 1867].

Thanks CD for copy of Variation.

Discusses Pangenesis and considers CD’s "gemmules" comparable to his own hypothetical "physiological units" ["On alleged ""spontaneous generation"", and on the hypothesis of physiological units", appendix in The principles of biology, vol. 1 (1864)].

Thanks CD for copy of Descent; wishes it had appeared earlier so that he could have made use of the facts in his Principles of psychology [2d ed. (1870–2)].

Intends to answer Sir A. Grant’s article if CD does not. [A. Grant, "Philosophy and Mr Darwin", Contemp. Rev. 17 (1871): 274–81; H. Spencer, "Mental evolution", Contemp. Rev. 17 (1871): 461–2.]

Expresses his "unbounded admiration" for HS’s article on Martineau ["Mr Martineau on evolution", Contemp. Rev. 20 (1872): 141–54]

and his article on sociology [Contemp. Rev. 19 (1872): 701–18]. CD never believed in the reigning influence of great men on the world’s progress but could not have given his reasons. "Now every one with eyes to see and ears to hear . . . ought to bow their knee to you, as I for one do."

HS hopes in the future to show more fully "absolute emptiness" of James Martineau’s propositions; is glad CD approved of his article dealing with JM’s arguments. [J. Martineau, "The place of mind in nature", Contemp. Rev. 19 (1872): 606–23; H. Spencer, "Mr Martineau on evolution", Contemp. Rev. 20 (1872): 141–54.]

Thanks CD for Expression. Disagrees with his views on the genesis of melody; HS gives some reasons for believing it to originate in the natural cadences of emotional speech.

Wants to use CD’s support to put pressure on Michael Foster to enable Huxley to take an immediate holiday.

Thanks for copy of HS’s Descriptive sociology [1873].

Discusses adaptations in flowers and their heritability.

Mentions advertisements for HS’s book [? Study of sociology (1873)].

Thought HS would have profited by principle that a character appearing late in life is inherited at same age.

Wishes to know where, in his works, CD refers to some particular behaviour in dogs.

Mentions the sensitivity of cirripedes to passing shadows.

Thanks CD for his new volume [Insectivorous plants].

CD cannot remember whether he was on the committee of the Jamaica affair [for prosecution of Governor Eyre in 1866] but he subscribed £10.

It is curious and amusing how positivists hate all men of science, possibly because their prophet [Comte] made laughable and gigantic blunders in predicting the course of science.