THH’s term "Pithecoid Man" is a theory in itself.

CD is convinced that his doctrine of a mundane period of glaciation is correct.

Henrietta’s serious illness.

Thanks for pamphlet by A. S. Taylor.

"… we have had a terrible week with my poor girl [Henrietta] on the point of death".

Discusses experiments involving placing solutions of ammonia and other substances on leaves of plants.

Discusses pamphlet by A. S. Taylor

and note by A. W. v. Hofmann concerning iodine solution.

DO’s candidacy for Professorship of Botany [at University College, London].

Henrietta’s health is better.

Paper in Botanische Zeitung [T. Nitschke, "Über die Reizbarkeit der Blätter von Drosera rotundifolia", 18: 229–34, 237–45, 245–50] missed leading point that plants close longer over animal substances. Carbonate of ammonia works on Lemna and Euphorbia roots.

Comments on relationship between eye-colour and deafness in cats [discussed in Origin]. Asks for more information.

Mentions criticism of Origin.

Thanks for information about horses.

Hopes JMR writes his book on language. Mentions Hensleigh Wedgwood’s work [A dictionary of English etymology, 3 vols. (1859–65)].

Congratulations on Professorship.

Homologies between Drosera and Dionaea. Carbonate of ammonia on roots. Wants W. H. Fitch to make drawings of Dionaea. Will copy minute structure of hairs from Trécul [see 2965].

Discusses Henrietta’s illness and their plans to return to Down.

Explains discrepancies in weights and measures caused by changes since 1836 in apothecaries’ measures.

EC has found that a discrepancy in A. W. von Hofmann’s experiments with iodine solutions resulted from an error in Hofmann’s use of decimals.

Reports S. P. Woodward’s opinion of the Origin: "a very sad book, it unsettles all one’s religious principles and the worst of it is so much of it is true".

The stone hatchets are a great muddle. Would like a copy of Jacques Boucher [de Crèvecoeur] de Perthes’s book [Antiquités Celtiques et antédiluviennes (1847–64)].

Is studying action of carbonate of ammonia on Drosera. Asks if this has been done.

On the prospectus of Natural History Review. Suggests it might offer information on whether subjects that correspondents may wish to investigate have been done already.

Henrietta still very seriously ill.

Thanks for information about the weight of water.

Describes experiments on Drosera.

Sends the tithes.

The family was detained at Eastbourne by a setback in Henrietta’s health.

Will send Leonard for tutoring on Thursday morning. Frank is doing capitally at school.

Thanks JP for copy of his Life on the earth [1860].

Is sorry, but not surprised, to see that JP is "dead against" CD on the Origin.

Sends weights of three objects (blotting paper, thread, and hair) to within 1/1000 of a grain.

Thanks THH for his lecture ["On the study of zoology", Lay sermons, addresses and reviews (1870), pp. 104–31]. Best exposé and classification of the higher objects of natural history he has ever read. On reading and observation.

Henrietta’s lack of improvement.

R. McDonnell’s work on rays and electric organs of fishes.

One thirty-thousandth of a grain of human hair inflects a single Drosera hair. Astonished by his results so he is not publishing until next summer. [Not published until 1875, Insectivorous plants. See ch. 2 for observations on inflection.]

Wants to study effects of acids on live Dionaea. Oliver should do their anatomy. Corresponding with chemical physiologists about carbonate of ammonia on roots.

Drawing up paper on Drosera but will not publish till results are tested.

Acknowledges receipt of £244 15s. 11d.

Discusses the possibility of a land-bridge connecting Biscay with Ireland and the consequent occurrence in southern Ireland of Asturian plants which are absent from England.

Asks if Hooker or anyone has criticised Edward Forbes’ botanical migration of five floras in the British Isles ["On the connexion between the distribution of existing fauna and flora of the British Isles, and the geological changes which have affected their area", Mem. Geol. Surv. G. B. 1 (1846): 336–432].