To Daniel Oliver 3 November 1
15 Marine Parade | Eastbourne
My dear Mr Oliver
My daughter has escaped the imminent danger she was in for a week & our minds are now tolerably at ease; & we hope to get home in a week or 10 days, if she progresses favourably.—2
I shall be anxious to hear the result of the election for the Professorship.—3
I presume your time will have been fully occupied in this important matter, & you will not have had time for any experiments on Dionæa with the C. of Ammonia; nor had time to look at the moving red matter in the Hairs of Drosera.—4 I am so greatly obliged to you for taking so much trouble to copy the extract from Bot. Zeitung.5 I presume there is a paper in extenso.— Is this so? The author has missed the point which seems to me most interesting, viz that though the Hairs close equally (or nearly so) over animal, vegetable & inorganic dry substances; they remain closed much longer over animal than over other substances. This fact led me to try the nitrogenous & non-nitrogenous fluids; for somehow the plant knows well when it has caught good food.— You were right in anticipating (as I believe you did) that C. of Ammonia acts on the fluid in cells of other plants, as in case of Drosera; I find it so with Lemna & almost as quickly with the roots of a little Euphorbia, as with the hairs of Drosera.6 I have asked Daubeny whether the action of C. of Amm. on the sap of plants was known; & he says he does not remember having heard of it.7
Yours very sincerely | C. Darwin
P.S.8 There is something which looks odd to me in the roots of the Duck-weed;9 a new root seems formed within the old one; at least an old outer cylinder is cast off in pieces; but it is out of my line.
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.
Please cite as
Darwin Correspondence Project, “Letter no. 2975,” accessed on 21 January 2017, http://www.darwinproject.ac.uk/DCP-LETT-2975