Has FS observed the slaves of Formica sanguinea foraging outside the nest.

Reports his observations on the habits of slave-making ants (Formica sanguinea).

Charles Lyell has asked WE to pass his opinions on the MS of Origin to CD via Murray. WE is convinced of the value of CD’s researches but "to put forth the theory without the evidence", as in the MS, "would do grievous injustice to his views". The omission of these facts reduces both the philosophical and popular value of the work, by virtue of its dryness.

Supports Charles Lyell’s suggestion that CD should first publish his observations on pigeons with a theoretical outline, for "[e]very body is interested in pigeons". Such a work would generate wider interest and be better understood. A subsequent, larger book would then be approached with impartiality "not to say favour" by a wider public.

CD favours occurrence of reversions, although lack of experiments forces one to vague opinions. Reversions oppose only the inheritance not the occurrence of variation. Discusses relation of reversion, direct influence of conditions, and selection.

Discusses WED’s plans for the summer.

JDH’s comments on style of Origin MS leave CD confused.

CD advises on how to get Acacia to set seed.

CD is convinced that the suggestions [for the Origin?] of both Lyell and Whitwell Elwyn are impracticable.

Will send first six chapters of MS next week. Has taken such pains with it that he hopes corrections will not be heavy.

Sends first six chapters [of Origin] for the press. Asks JM to urge printer to keep well ahead of CD so as not to waste time. This is important for his health’s sake.

JDH finds style of CD’s MS obscure.

CD wary of JDH’s starting point on variability: it is not inherent, it does not lead necessarily to divergence, and it must be distinguished from inheritance.

Asa Gray has misread CD’s views on pre-glacial migrations and botched the subject.

Approves specimen sheet [of Origin]. Sorry book will be so long. Has now written half of last chapter; it is as long as his estimate of the entire chapter. Now thinks it will run to 6000 or 7000 words. Will do his utmost to improve his style. Anxious to publish soon; he knows of two men already writing on the subject, starting from his Linnean Society paper ["On the tendency of species to form varieties", Collected papers 2: 3–19]. Will send a diagram for the book.

Too ill to examine proofs of JDH’s Flora Tasmaniae [The botany of the Antarctic voyage, pt III].

His health has suddenly failed. He is leaving home for one week’s rest.

Has informed William Clowes that he will begin correcting on the 27th.

Returning from Moor Park. CD will take up proofs of JDH’s Flora Tasmaniae.

CD’s diagram [for chapter on "Divergence of character", Origin] is indispensable.

Finds he will have to make many corrections, his text is so obscure.

A week of hydropathy at Moor Park has done him a world of good.

THH should understand that CD’s hypothesis [natural selection] has as many flaws and holes as sound parts. The question is whether CD’s rag of a hypothesis is worth anything. A poor rag is better than nothing to carry one’s fruit to market.

Reports events at Down.

Is busy with proofs [of Origin];

is anxious to hear how WED does in his examinations.

Finds style [of Origin] incredibly bad; corrections are very heavy. Supposes it was due to his attention being fixed on general lines of argument and not on detail. Wishes to share expense of corrections.

Acknowledges receipt of £244 15s. 11d.

Extended discussion of their respective difficulties with the definition and status of species and with the extent to which the theory of transmutation may be applied.

Has rediscovered S. S. Haldeman’s 1844 paper defending the transmutation theory with great skill.

Asks for reference to Geoffroy Saint-Hilaire’s first enunciation of the progressive development and transmutation theory.

Provides requested information about certain railway shares.