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".

Thanks for information about the weight of water.

Describes experiments on Drosera.

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].

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.

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.

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.

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

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.

The plant CD’s father called "flycatcher" was not Asclepias.

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

Welcomes JDH home from Middle Eastern expedition.

Has found some funny evidences of transmutation in Cliffortia. Sketches gradual passage "from very unlike to same" – e.g., from three-leafed form to two-leafed.

Dr Hooker has given him CD’s memorandum on the fly-catcher.

Copies out extract from Curtis’ Botanical Magazine [On Apocynum androsæmifolium, 8 (1794): tab.]: 280 and gives a further reference in Erasmus Darwin’s The loves of plants [1789]. Suggests that they look at Apocynum.

Preparing new edition of Origin and asks for JDH’s corrections and criticisms.

Encourages CD’s work in vegetable physiology.

Ascending the Lebanon JDH noted limits of plant distribution as CD requested: lower limits of a genus sharper than upper. Sharpness of boundaries related to a plant’s moisture requirement.

Impressed by "sporadic" distribution at the Jardin des Plantes in Paris.

Praise for a paper on the Entomostraca by Lubbock (Lubbock 1862). Thanks for the compliment paid to the Origin and for his general comments.

Sends the tithes.