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Darwin Correspondence Project

From Francis Darwin   [before 7 July 1878]1

My dear Father,

I have been talking to Sachs about sleeping plants that move with & without growth & it appears he fully agrees that the cause of the movement is the same in both. He has expressed this in the 4th edition of his book which you have—it is at p 852.2 He says he doesn’t agree with Pfeffer about these things—3 He thinks that the cause lies in the protoplasm which causes variations in the turgescence, & that the growth along the convex side is only in consequence of the increased turgescence which precedes it. I am glad to find he doesn’t think very much of Pfeffer, that is he says he is very learned & does very good work, but he doesn’t think clearly. Sachs seemed to think any work in cutting sections asleep & awake would be useless, as there was no doubt about it that whether there was a joint or / not the cause was the same in principle—4 I send the extract from Cieselski—5 Many thanks for the splendid twisters, the beast of a Sipho wont act with hot & cold water   I must try the tamus— I find Convulvulus arvensis is most splendidly twisted.6 I have talked to Sachs about the oats, & he thinks the best way will be to cut the tips off & extract them in alcohol.7 My elasticity of wet & dry wood experiments seem likely to fail, but it is worth going on at.8 I can always do some microscoping if it fails quite   The Sunday Society want me to lecture, are they supposed to be done for a charity? if so I feel as if I ought to do it, but if they pay I wont, would you tell me, or send a post card addressed to me to Uncle Ras for him to write on it “paid” or “not paid”9

Yr affec | FD

CD annotations

1.2 it appears … things— 1.4] double scored red crayon
1.6 the growth … precedes it. 1.7] double scored red crayon
1.11 Many thanks … paid” 1.20] crossed blue crayon


The date is established by the relationship between this letter and the letter to Francis Darwin, 7 [July 1878].
The fourth edition of Julius Sachs’s Lehrbuch der Botanik (Textbook of botany; Sachs 1868) was published in late 1874 (Sachs 1874). CD cited it in Movement in plants, p. 2 n., but there is no longer a copy of this edition in the Darwin Library–CUL. CD also cited the English translation (Sachs 1875), which had been made from the third German edition (Sachs 1873), with some additional material from Sachs 1874 added in notes (see Sachs 1875, Translator’s preface). Sachs claimed that the cause of change in turgescence during plant growth was the same as that which caused movement in a mature plant, the only difference being that growth-related changes resulted in a permanent change in cell volume, while those related to movement in a mature plant did not (Sachs 1874, p. 852).
Wilhelm Pfeffer, a former student of Sachs, had argued that increased turgescence during growth was triggered internally (or was autonomous) while that related to movement resulted from external triggers (or was induced). See Pfeffer 1877, pp. 205–7. It is unclear whether the ‘cause’ refers to the cause of the turgor or whether the cause was the turgor, which was related to both growth and movement.
CD had suggested that Francis compare the size of cells in the pulvinus of a leaf when awake or asleep to determine whether there was a loss in cell turgor on one side of the organ (see letter to Francis Darwin, 29 [June 1878]).
Francis probably sent a copy of Theophil Ciesielski’s doctoral dissertation (Ciesielski 1871); it was also published in Beiträge zur Biologie der Pflanzen without the introductory historical review of the literature (Ciesielski 1872). CD’s heavily annotated copy of Ciesielski 1871 is in the Darwin Pamphlet Collection–CUL. CD wanted to account for the conflicting experimental results of Ciesielski and Julius Sachs (letter from Francis Darwin, [22 June 1878] and n. 4).
Francis had received small lengths of stems from CD, including those of Aristolochia sipho (Dutchman’s pipe) and Tamus communis (black bryony). See letter to Francis Darwin, 29 [June 1878]. Convolvulus arvensis (‘Convulvulus’ is a misspelling) is field bindweed.
CD asked Francis to try to determine whether chlorophyll was present in cotyledons of oats (Avena sativa; see letter to Francis Darwin, 26 June [1878] and n. 3).
Francis was attempting to determine whether the strength and elasticity of woody stems changed as they dried out (letter from Francis Darwin, [22 June 1878]).
The Sunday Lecture Society, founded in 1869 as a successor to the Sunday Evenings for the People, held talks on science, literature, and the arts at St George’s Hall, Langham Place, Regent Street, London; CD was a supporter of the society (see Barton 2014, p. 204). Erasmus Alvey Darwin was probably also a supporter, as he had supported the more controversial Sunday Evenings for the People in 1866 (ibid., pp. 191–2).


Barton, Ruth. 2014. Sunday lecture societies: naturalistic scientists, Unitarians, and secularists unite against Sabbatarian legislation. In Victorian scientific naturalism: community, identity, continuity, edited by Gowan Dawson and Bernard Lightman. Chicago: University of Chicago Press.

Ciesielski, Theophil. 1871. Untersuchungen über die Abwärtskrümmung der Wurzel. Inaugural-Dissertation welche mit Genehmigung philosophischen Facultät der königl. Universität zu Breslau zur Erlangung der Doctorwürde. Breslau: R. Nischkowsky.

Ciesielski, Theophil. 1872. Untersuchungen über die Abwärtskrümmung der Wurzel. Beiträge zur Biologie der Pflanzen 1 (1870–5) Heft 2: 1–30.

Movement in plants: The power of movement in plants. By Charles Darwin. Assisted by Francis Darwin. London: John Murray. 1880.

Pfeffer, Wilhelm. 1877. Osmotische Untersuchungen. Studien zur zellmechanik. Leipzig: Wilhelm Engelmann.


He has been talking to Julius von Sachs about sleeping plants that move with and without growth.

Letter details

Letter no.
Francis Darwin
Charles Robert Darwin
Source of text
DAR 274.1: 57
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 11593F,” accessed on 16 August 2022,