Describes his lectures on CD’s theory.

Thanks CD for copy of Variation. Comments on book.

Describes work of two protégés in Jena: Nicolas von Miklucho[-Maclay] and Anton Dohrn.

His cousin, Wilhelm Bleek, is sending an article about the origin of language.

Asks to keep book a few months longer but will return it if CD needs it [Webb and Berthelot, Histoire naturelle des Îles Canaries, vol. 3, pt 1: Géographie botanique (1840)].

Describes research on Siphonophora.

Describes life in Jena. Mentions alpine accident during wedding trip.

Advance sale of Variation has exhausted the 1500 copies printed. Murray sends note for £300 author’s payment. Wants to print 1250 more immediately.

Discusses the origin and characters of sheep breeds, particularly the merino.

Reports observations on reversion to wild type in canary mules

and lists some animals that show a unique development restricted to one side of their bodies.

Would like a look at Nathusius.

Edward Blyth’s inability to recognise cats’ skulls.

Forwards a letter from Secretary of Yorkshire Philosophical Society. Hopes CD will honour them by accepting.

Has heard nothing of Variation.

Thanks for Variation.

Reports work on his travel book [The Malay Archipelago (1869)].

Colour differences in annelids and entozoa.

Thanks for loan of Variation. "The Saturday Sadducees" do not believe there are a hundred people who understand the argument. EC fancies he does.

Thanks CD for copy of Variation.

Discusses Pangenesis and considers CD’s "gemmules" comparable to his own hypothetical "physiological units" ["On alleged ""spontaneous generation"", and on the hypothesis of physiological units", appendix in The principles of biology, vol. 1 (1864)].

On the colours of the nudibranch Mollusca. [See Descent 1: 326.]

Congratulates CD on George’s success at Cambridge.

Sends prospectus of forthcoming work by his brother [Henry Trimen] and W. T. Thiselton-Dyer [Flora of Middlesex (1869)]. Hopes CD will subscribe.

Corrects some facts and gives further information on some points for the 2d ed. of Variation.

Specific distinctions among animals.

Cercopithecus of Africa contrasted with the Cebus of South America.

Notes on domestic fowls and their ancestors.

Slow growth of wild animals compared with domestic varieties.

Thanks for copy of Variation. Comments on it, especially on Pangenesis.

On the colours of sexes in Crustacea; the structure of male crabs.

WSD is delighted to hear that first edition [of Variation] has sold so well.

Has received a cheque from J. Murray for 30 guineas, double what was agreed upon. Sends a postal order for the five guineas CD sent him [see 5788].

Discusses [Fritz?] Müller’s confusion about ova and pseudova; JL’s Daphnia paper [Philos. Trans. R. Soc. Lond. 147 (1857): 79–100; see 1979] first demonstrated their structural identity.

Points out a misleading statement in Variation.

CD’s letter encourages Murray to proceed with a new edition of Variation; corrections will cost £176.

First notice has appeared in Pall Mall Gazette [7 (1868): 555].

On blind beetles [see Descent 1: 367].

Development of mandibles in Brentus.

Variability of sizes and colours in spiders; on proportion of sexes; courtship of spiders.