Baffling problems with Melastoma. Appreciates ARW’s help with it and the "gorze case".

Has read report of ARW’s paper [to Newcastle BAAS meeting, "On the geographical distribution of animal life"] in the Reader [2 (1863): 352–3].

Asa Gray’s high opinion of ARW as a reviewer [reference to S. Haughton’s paper on bees’ cells, Ann. & Mag. Nat. Hist. 3d ser. 11 (1863): 415–29, reviewed by ARW in "Remarks on the Rev. S. Haughton’s paper", Ann. & Mag. Nat. Hist. 3d ser. 12 (1863): 303–9].

Remarks on ARW’s review of Samuel Haughton’s paper on bees’ cells

and Origin.

Agassiz’s strength as geologist and weakness in natural history theory.

Work problems.

His butterfly collection.

Problems with book on Malay journey.

Recommends Herbert Spencer and his Social statics.

Spencer’s "masterly" nebular hypothesis.

Has seen that ARW has read a paper to the Linnean Society.

Thinks that Herbert Spencer’s Social Statics (Spencer 1851) would be too deep for him.

On the Borneo cave exploration.

ARW will send his contribution to theory of origin of man. The vast mental and cranial differences between man and apes, whereas structural differences in other parts of body are small. The problem of explaining diversity of human races along with the stability of man’s form during all historical epochs. Discussion with "Anthropologicals" [following reading of ARW’s paper, "The origin of human races", before the Anthropological Society, 1 Mar 1864].

Response to ARW’s papers on Papilionidae ["On the phenomena of variation and geographical distribution", Trans. Linn. Soc. Lond. 25 (1866): 1–71; abstract in Reader 3 (1864): 491–3],

and man ["The origin of human races", J. Anthropol. Soc. Lond. 2 (1864): clviii–clxxxvi].

The former is "really admirable" and will be influential.

The idea of the man paper is striking and new. Minor points of difference. Conjectures regarding racial differences; the possible correlation between complexion and constitution. His Query to Army surgeons to determine this point. Offers ARW his notes on man, which CD doubts he will be able to use.

On sexual selection in "our aristocracy"; primogeniture is a scheme for destroying natural selection.

[Letter incorrectly dated March by CD.]

Argues the antiquity of the human species because natural selection acts differently with respect to men. Changes in man are largely confined to head and brain. Warfare and sex are very uncertain as means of selection.

Gives CD complete credit for theory of natural selection.

Is beginning his narrative of his travels.

Lyell argues against tracing man as far back as Miocene times. R. I. Murchison’s argument that Africa is the oldest existing land implies that Africa is the place to look for early man.

Short reply to ARW’s long letter. Reaffirms belief in sexual selection.

Postscript on M.-J.-P. Flourens’ "little dull book against me" [Examen du livre de M. Darwin (1864)].

His distress that his engagement has been broken off.

Sends copies of two papers ["On the parrots of the Malayan region", Proc. Zool. Soc. Lond. (1864): 279–97;

"On the physical geography of the Malay Archipelago", J. R. Geogr. Soc. 33 (1863): 217–34].

Commends ARW’s papers on parrots

and on the theory of geographical distribution [see 4750].

Wild pigs in Aru Islands must have been introduced and later ran wild. Does ARW have an opinion on the subject?

Sends papers with comments. Convinced that the Aru pig is a species peculiar to New Guinea fauna, not a domestic animal that ran wild.

Admires CD’s paper ["Three forms of Lythrum", Collected papers 2: 106–31].

Exchange of photographs.

Aru pigs present perplexing case, whether wild or domesticated.

Thanks CD for paper ["Climbing plants"].

Reports case of variation becoming at once hereditary – a crested blackbird with crested young.

Crests as inherited variations; domesticated birds.

Belief in value of travel journals.

Current reading.

Information concerning improvements in the Reader under new sponsorship.

Current reading and work [on pigeons for Ibis 1 (1865): 365–400, and catalogue of his collection of birds].

Book of travels postponed indefinitely.

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.

Looks forward to reading Variation.

Explains how two or more female forms occur in one species through selection. The physiological problem remains of how each produces offspring like the other without intermediates. Is not CD’s case of varieties that will not blend the physiological test of a species needed for "complete proof of the origin of species"?

"Travels" postponed.

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.

Lengthy analysis of sources of misunderstanding of natural selection. Advocacy of Spencer’s term "survival of the fittest" instead of "Natural Selection". ARW urges CD to stress frequency of variations.

CD considers "the survival of the fittest" as alternative term to "Natural Selection". Reflections upon misunderstanding and his own ambiguity.

Health improved; can now work "some hours daily".