Thanks for reference to Annales des Sciences Naturelles.

Requests DO observe rate at which Australian Drosera closes.

On detection of nitrogen in organic fluids.

Replies to WHH’s criticisms of the Origin. Is disappointed that WHH does not understand what CD means by natural selection. CD has said "ad nauseam" that selection can do nothing without previous variability. Natural selection accumulates successive variations in any profitable direction. If CD had to rewrite his book he would use "natural preservation" rather than selection. Defends his necessarily conjectural illustrations. Agrees with what WHH says on the antiquity of the world, but it makes no impression on him. Considers the difficulty of the first modification of the first protozoan. Emphasises that there is nothing in his theory "necessitating in each case progression of acquisition", nor is it the case that "a low form would never conquer a high" in the struggle for life. Attempts to explain what he means by a "dominant" group; dominance is always relative, and he does not believe any one group could be predominant. He has no objections to "sudden jumps"; they would aid him in some cases, but he has found no evidence to make him believe in them and a good deal pointing the other way.

Lists of nitrogenous organic fluids that produce contraction in Drosera, and details of how to reproduce results.

Sends address.

Instructs EN to copy and post letter [2922].

Admires DO’s correlation of spiny tree species and dry hot climate. CD suggests that spines, like strange aroma of desert plants, protect against browsing where there are few plants.

Fragrance and unisexuality.

Dimorphism in Viola tricolor.

Thinks he has worked out simple mechanism of movement in Drosera. Believes he is correct that gum has no effect.

Thanks for Trécul paper ["Organisation des glandes pédicellées de la feuille du Drosera rotundifolia", C. R. Hebd. Acad. Sci. 40: 1355–8; Ann. Sci. Nat. (Bot.) 3d ser. 3: 303–11].

Chloroform paralyses plants in 30 seconds.

Has been observing Drosera. Asks JSH whether a curious motion in the red fluid poured out from the viscid hairs is a known or common phenomenon. It surprised him, but he is "so ignorant of vegetable physiology".

Requests Dionaea now that he knows Drosera so well. Wants to compare fluids secreted; in Drosera they are acid and have antiseptic effect on meat.

Answers HGB’s criticism of Origin.

Explains HGB’s case of differences in rats by adaptation.

CD’s view explains homological and embryological resemblances of each type.

Does not believe all development is at same rate. Cites Australian forms.

Does not see force of objection that origin of life must be explained.

Asks if C. L. Brehm’s subspecies of birds are really characteristic of regions of Germany.

A poser: carbonate of soda produces inflection rather than contraction in Drosera. Possible solution: glands at end of hairs absorb as well as secrete. Fascinated by currents in cells after inflection.

Delighted to try experiments on Drosera spathulata.

Sends further details on the movement of the red fluid substance in Drosera. Will write a paper on it.

"Dr [C. R.] Bree ""pitches"" into me handsomely."

Requests DO apply carbonate of ammonia to sensitive hair of Dionaea and measure reaction time. Wants to compare Drosera and Dionaea.

Discusses letter from A. W. v. Hofmann concerning solution of iodine in water.

Has examined nearly all British orchids.

Hooker’s error on Listera.

Change in colour and consistency of Drosera hair glands after leaf inflection. Analogous structures in Dionaea. Requests Oliver confirm these observations on live plants, of which he has none.

In a muddle over the effects of salts on insectivorous plants.

Comments on Rodwell’s discussion of the “struggle for life” with reference to languages and G. H. Lewes’s article in the Cornhill Magazine (Lewes 1860, pp. 445–7). Comments on Rodwell’s account of horses affected by mildewed pasturage, and asks for more information about his white cat.

Thanks for information and extracts.

M. A. Curtis, quoted in ["Dionaea"] Penny encyclopedia [(1837) 8: 508], gives the only full account of Dionaea.

Concurs in DO’s explanation of Dionaea footstalk cells, which CD took for stomata.

Is using carbonate of ammonia as a substitute for flies and colour change in glands as index of action on Drosera. Suspects other nitrogenous compounds do not act till decomposed into carbonate of ammonia. Beginning to write Drosera paper. Action of nitrogenous compounds.

Obliged for note of 16th.

Failed to enclose letter from Hofmann.

Will be glad to read A. S. Taylor’s work [On poisons in relation to medical jurisprudence and medicine, 2d ed. (1859)].

Daughter Henrietta still weak.

Will take Natural History Review, but cannot write for it.

Has mass of notes on irritability in orchids,

but he ought to work on Variation.

Drosera was an interlude while away from home. Expectations for effect of carbonate of ammonia on Dionaea. The important phenomenon in Drosera is the segregation of the red fluid within the leaf, not action of carbonate of ammonia on the red fluid.