Ɛpsilon

To Jeffries Wyman   8 October [1865]1

Down Bromley | Kent.

Oct. 8

My dear Sir

I am very much obliged for your letter.2 I have tried the little experiment with the string, & it answered well;3 as did a very long narrow strip of elastic paper after having been scraped or compressed by being rubbed over a knife. I cannot see the difficulty of the mathematicians, the slip of paper when held at both ends, tends to form a regular bow, but as every part tends to contract into a small circle, if the contraction be not quite regular one part can pass by the side of the other, & the whole will break up into a set of circles or spires, which will be reversed at the 2 ends on the self-twisting principle which I have explained.

I am aware that you are much interested on the movement of plants for I have read your excellent paper on the bursting of certain gourds.4 I suppose you know Cohn’s paper on the contraction of the stamens of certain Compositæ:5 I have seen the phenomenon & was much interested by the paper.

I formerly made numerous observations shewing what an extraordinary small pressure is sufficient in certain cases to excite movement & as I believe contraction in the cells of some plants; I likewise found that certain re-agents such as Strychnine &c had a powerful influence on the movements.6 But my health has been so weak for several years that I have not been able to publish these observations,7 & I hardly know why I have mentioned them to you.

With many thanks for your note; & with sincere respect believe me | My dear Sir | Yours sincerely | Charles Darwin

LS(A)

1
The year is established by the relationship between this letter and the letter from Jeffries Wyman, 22 September 1865.
3
Wyman had described a method whereby the spiral coiling of a tendril could be demonstrated; CD had written a lengthy account of the phenomenon in ‘Climbing plants’, pp. 95–8 (see letter from Jeffries Wyman, 22 September 1865 and n. 3).
4
CD refers to Wyman 1854, a short paper on contractility in the capsules of two plants (see Correspondence vol. 11, letter to Daniel Oliver, [before 27 November 1863] and n. 2).
5
CD refers to the article by Ferdinand Julius Cohn, ‘Ueber contractile Gewebe im Pflanzenreich’ (Cohn 1860). CD’s heavily annotated copy of the article is in the Darwin Pamphlet Collection–CUL. An English abstract of the article was published in the Annals and Magazine of Natural History 11 (1863): 188–202. CD referred to both the original article and the abstract in Insectivorous plants, pp. 256, 364.
6
CD is probably referring to his experiments with the insectivorous plant Drosera rotundifolia, which he began in 1860 (see Correspondence vol. 8). In 1862 he performed experiments to test the effect of various chemicals, including strychnine, on leaf movement (see Correspondence vol. 10, letter to J. D. Hooker, 26 September [1862] and n. 1). CD’s notes on the 1862 experiments are in DAR 54: 29–49.
7
CD returned to his work on insectivorous plants in 1872 (LL 3: 322), and published his findings in 1875 as Insectivorous plants.

Manuscript Alterations and Comments

1.6 can] in CD’s hand above del ‘will’
1.8 self-twisting] interl in CD’s hand
2.1 on the movement of plants] interl in CD’s hand

Please cite as “DCP-LETT-4912,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-4912