Thanks for copies of FVH’s "Preliminary field report [of the U. S. Geological Survey] of Colorado and New Mexico" [Am. J. Sci. 49 (1870): 258–63] and Geological report [of the exploration] of the Yellowstone [and Missouri] River[s under the direction of Captain W. F. Reynolds (1869)].

Sends drawings of atypical Geranium and honeysuckle pollen-grains. Would they produce variation in seedlings?

Discusses flora of Sandwich Isles. "There is nothing I shd enjoy so much as to visit California, but I am growing old & my health is weak".

Expression in horses.

Crying in babies.

Sends his "Charles Darwin, eine biographische Skizze" [Das Ausland 2 Apr 1870].

About the insertion of a column on marriage of cousins in the census form.

Thanks for HHV’s interest in the census [CD’s plan to add questions on consanguineous marriage to the census] on which CD hopes to persuade Sir J. Lubbock to speak.

Good news: one little rabbit has a white forefoot.

Crossing experiments and self-sterility [in Eschscholzia].

Pangenesis.

Hermann Müller on insect adaptations for fertilisation of flowers.

CD working on book on man and sexual selection.

In a fortnight will begin to arrange notes on expression. Asks for FCD’s conclusions about the contraction of eye muscles. Is interested in abstract of FCD’s experiments on "rate of travelling of the nervous powers".

Encloses part of letter from Fritz Müller on Passiflora, with seeds.

Is endeavouring to have included in next census a question as to whether the parents in each household are cousins.

Answers to CD’s queries on expression; observations on the facial expressions of the insane.

Comments on WP’s biographical article on CD. Asks him to thank O. F. Peschel for his present of the publication [Das Ausland 2 Apr 1870].

The illness and death of his daughter have delayed his answers to CD’s queries. He has, however, worked on the circulation of the eye and has almost finished a paper on it, which he will send to CD. In general, the views of Charles Bell are confirmed.

As for CD’s second query, he doubts that the relationship exists, but will answer fully in next letter.

On death of his wife. Botany a solace.

Asks CD to review Wallace’s recent book of essays [Natural selection (1870)], particularly the new essay, which questions the applicability of natural selection to man.

Expresses sympathy [on death of FCD’s daughter].

Will be grateful for his paper and letter.

Concern over Wallace’s book [Contributions to the theory of natural selection (1870)] and its apparent backsliding from Darwinian theory. HWB suggests that only CD is capable of criticising the book.

HWB hopes not too much was made over his few comments on man in M. F. Somerville’s book [Physical geography, revised ed. (1870)].

Responds to CD’s request for Canna seeds.

Studying dichogamy in Lotus. Describes mechanism that pumps pollen on to a visiting bee. Corrects Axell on Lotus.

Announces CD’s election as Honorary Member of the Société Impériale des Naturalistes de Moscou.