Has read FM’s paper on sponges ["Über Darwinella aurea", Arch. Miskrosk. Anat. 1 (1865): 344–53] with interest.

Has also read FM’s work on the metamorphoses of Peneus [Ann. & Mag. Nat. Hist. 3d ser. 14 (1864): 104–15], an interesting and important embryological discovery.

CD regards Louis Agassiz’s opinions as valueless.

Comments on CD’s health.

Discusses origin of life and differentiation of principal classes of plants and animals.

Discusses Generelle Morphologie and its chapter on embryological development.

His lectures on CD’s theory.

Asks CD for larger portrait of himself and for several copies of the small photograph. Will send photographs of German scientists in exchange.

Has made observations on bees’ cells. Their dimensions are not constant, nor do single bees make single cells; each one is a result of co-operation.

Gives CD reference to case of the saiga, an antelope, fearless of man.

Reports observations by New Zealander who has seen heaps of pebbles presumably voided by Dinornis.

In despair: has lost his copy of Verlot’s memoir on variations of flowers [Sur la production et la fixation des variétés (1866)]. Has JDH borrowed it?

What progress has been made with pigeon drawings for Variation?

Can WBT persuade Mr Zurhorst to repeat a pigeon experiment?

CD is happy to sign photograph. He will only require one copy of the journal.

Is in a mess with his correspondence and will get no assistance before 1 April.

Has agreed to give an address on the Darwinian theory at Nottingham [meeting of BAAS].

Thanks for the remittance.

Both WBT and Mr Zurhorst will repeat Zurhorst’s experiment to eliminate any chance of error.

Edward Blyth is writing on Indian cattle for the Field [27 (1866): 55–6, 77].

Sends copies of photographs of himself. Asks for photographs of German naturalists.

Comments on EH’s account of Protogenes primordialis.

Has found Verlot.

His sister [Emily Catherine Langton] is dying [d. 2 Feb 1866].

His stomach still very bad. Writes one or two hours and reads a little.

JDH is a wretch to remind CD of his coal-plant prophecy.

Glad JDH will give Nottingham lecture.

Welcomes ARW’s paper on pigeons ["On the pigeons of the Malay Archipelago", Ibis 1 (1865): 365–400].

Influence of monkeys on distribution of pigeons and parrots.

Asks ARW to explain a passage in his paper on Malayan Papilionidae [Trans. Linn. Soc. Lond. 25 (1866): 1–71] on how dimorphic forms are produced. CD knows of varieties "that will not blend or intermix", but which produce offspring quite like either parent.

ARW’s remarks on geographical distribution in Celebes "will give a cold shudder to the immutable naturalists".

Presses ARW to work on his travel journal.

Discusses pigeon and poultry woodcuts [for Variation].

WBT’s poultry book is at last in the hands of a solvent publisher [The poultry book (1867)].

Sorrow about Mrs Langton. Has been haunted by death these six or eight years. Now cannot bear to look at children asleep in bed – a sight he once thought the loveliest thing in creation.

Discusses exchange of photographs with German scientists.

Comments on attitudes of German scientists toward CD’s theory.

Names several scientists who exchanged photographs: Braun, Virchow, Leydig, and Dohrn.

Last fascicles of FR’s book Der Mensch [1866] being sent.

Finds roots of human race in Negroes of Africa, Bushmen of South Africa and New Guinea, and short-headed peoples of south Asia.

Has translated natural selection as natürliche Auslese.

Ludwig Rütimeyer active in developing the descent of mammals.

Sends a paper on Bombus ["On the habits of some species of humble-bees", Commun. Essex Inst. 4 (1866): 98–104].

ARW’s simple explanation of dimorphic forms is satisfactory.

On "non-blending" of certain varieties, CD thinks ARW has not understood him. He does not refer to fertility. He crossed two differently coloured varieties of peas and "got both varieties perfect, but none intermediate". Something like this must occur in ARW’s butterflies.

Thanks for photographs [of German scientists].

Thanks for all five numbers of Der Mensch [1866].

Had not known that Rütimeyer had written on modification of species.