Will visit JH on 27 May.

Apologizes for delay in responding to JH. Wrote to JH yesterday about AM's plan to visit Collingwood.

Thanks JH for writing. Complains of obstacles to his work. Happy to see JH recognizes work begun by Blaise Pascal and continued by famed mathematicians. Asks JH to respond to AQ's wish to dedicate his book [L'Anthropométric] to JH with only one word: 'J'accepte.'

Is working on humans and their proportions. Encloses brochures. Wishes to dedicate L'Anthropométric to JH.

Offers JH the first exemplar of AQ's work [Physique sociale]. Realizes no one will ever appreciate years of work that it has taken.

Thanks JH for accepting dedication. This has brought AQ utmost pleasure. Has dedicated few works. Expresses his esteem for JH's character and talent.

Asks whether he may see CD before leaving England.

Instances of sexual differences in viviparous fishes, suggested by reading chapters on sexual selection [in Descent] and by Mivart’s Genesis of species.

Notes on echinoderms.

Thanks for new [6th] edition of Origin.

Is working on Echini.

The more material he gets the less easy it is to diagnose a genus or species. Has little doubt that "classification is nothing but the most arbitrary convenient tool, depending upon the material at our command at a special time".

Thanks for Expression.

Has lost a year’s work in the fire that has devastated Boston.

Comments on discussion of residual organs in Descent [ch. 1].

Describes his ability to contract the platysma myoides at will.

Suggests reason for loss of voluntary movement of ears in men and monkeys.

Reply to CD’s letter of 5 Apr 1871 [7659], in which he asked HA for further details on when and how platysma myoides contracts.

Replies to CD’s questions about sources on leaf arrangement.

Gives news of speech and paper about CD.

Thanks for letter and reference to Nägeli’s observations on leaf arrangement in the bud.

A review and criticism of Chauncey Wright’s paper on phyllotaxy [Mem. Am. Acad. Arts & Sci. n.s. 9 (1867–73): 379–415]. Does not believe that the "distributive" and "cyclical" properties, which CW claims characterise the existing spiral orders of leaf arrangement, can be shown to be advantageous to plants. CW’s speculations on the origins of the spiral arrangement of leaves are purely hypothetical.

On leaf arrangement. [Badly damaged and almost illegible.]

Outlines his theory on the origin of existing orders of leaf arrangement. Believes spiral and whorled orders have evolved from a primitive distichous arrangement. These arrangements permit a compact bud form of small surface area that can withstand external changes in temperature, and in particular can tolerate frost.

Thanks CD for reading his MS [8412] and for his suggestions.

Clarifies his statement on the contraction of the bud-axis: did not mean to imply that this contraction occurred in an individual’s life-time, rather that it was the effect, after the course of ages, of successive favourable modifications.

Believes the true theory of phyllotaxy will give a convincing illustration and proof of the theory of evolution.

Discusses the significance of the node. Believes, with CD, that it has no independent importance but is merely the consequence of the presence of a leaf. Does not believe a distinction can be made between whorled and alternate leaf arrangements on the basis of the number of leaves springing from a node. The node, as the starting point of a leaf, is subject to any disarrangement which takes place among the leaves.

Corrects a factual error in his previous letter [8418].

Sends specimens illustrative of the "nodal" question.

Responds to CD’s comments on his MS on phyllotaxy.

The initial variation required by his theory would be a slight twist of the bud-axis; believes the frequent twisting of stems and branches renders such a variation possible.

Admits he placed too much emphasis on the importance of frost. He should have spoken more generally of "vicissitudes of climate".