Discusses the similarity in size, shape, and structure of the blood corpuscles of the Aves. Notes differences between the corpuscles of the domestic dog and some wild species.

Is trying to procure some cocks for CD.

Believes Scotch deerhounds are mongrels.

Thanks WBDM for his reply [missing] to CD’s previous letter [1603].

Asks for more details on the erratic blocks.

Asks also if there is good evidence that there formerly existed [in New Zealand] some animal with hair, like an otter or beaver.

Finally, do the uncivilised natives have the same ideal of [human] beauty as Europeans?

Writes of WED’s progress at school and events at home.

Discusses pigeons, with which he is "getting on splendidly".

Sends Madeira specimens, including frogs recently introduced into the island, and flourishing.

Note on cases of representative shells that are not clearly either varieties or species.

Is flattered by a proposal that he undertake some reviewing work, but has many years’ work in prospect on his present book on species and varieties.

Will attend the Philoperisteron [pigeon fanciers’ club] if he possibly can.

Thanks JMH for book of poems.

Recalls early days together. He cannot visit due to health.

Thanks WDF for his help and reports on progress in "the Cock and Hen line of business". Has written to every quarter of the world for skins of poultry and pigeons.

As for seeds, Hooker and Bentham obstinately refuse to believe they can live even a few years in the ground.

Thanks for JSH’s letter, which has been of real use.

Complains of the trouble caused by reports to Government required of Benefit Clubs.

Interested in case of Canada geese with seed in crop, because means of distribution is now a great hobby.

Delighted to hear that JD’s research is continuing. CD has heard that JD’s paper will at last be published. He is flattered by the form [as a letter addressed to CD] of communication. [See 1651a and 1819a, published in Phil. Trans. R. S. 146 (1856): 21–9 and Proc. R. S. London 8 (1856–7): 27–33.]

Encloses "notes for Mr. D" [see 1818] and a memorandum on the wild cattle of southern India [see 1819].

Breeds of silky fowl of China and Malaya. Black-skinned fowl.

Doubts any breed of canary has siskin blood; all remain true to their type.

Wild canary and finch hybrids.

Hybrids between one- and two-humped camels.

Does not regard zebra markings on asses as an indication of interbreeding but as one of the many instances of markings in the young which more or less disappear in the adult.

Crossing of Coracias species at the edges of their ranges.

Regional variations and intergrading between species of pigeons.

Regards the differences in Treron as specific [see Natural selection, p. 115 n. 1].

Gives other instances of representative species or races differing only in certain details of colouring.

Reports upon a breed of wild cattle found in southern India. The herd is reputedly descended from a wild, red bull that mated with tame cows.

[This memorandum was forwarded to CD enclosed with 1817.]

On the vitality of the ova of the Salmonidae at different stages of development.

Is attempting to get skins of poultry from all quarters of the world. Wants to inspect poultry collections.

Requests that JEG secure the assistance of Samuel Birch in regard to information about varieties of domesticated animals and plants in China. Encloses memorandum.

Has been invited to see Mr Bult’s pigeons.

Discusses chapter [6] on cleavage and foliation in South America. Notes especially cleavage where two series cross and cleavage as basis of foliation in metamorphosed rock. Notes foliation in rocks that have been liquefied by heat. Mentions case described in his "Geology of the Falkland Islands" [Collected papers 1: 203–12]. Discusses relationship of cleavage to beds. Speculations on association between grauwacke and clay-slates.

Is obliged for JEG’s assistance.