To Francis Darwin   12 July [1879]1

Down, | Beckenham, Kent. | Railway Station | Orpington. S.E.R.

July 12th

My dear F.

I am glad you have tried touching cells, for I shd. never have rested until hearing a result of some kind.2 Was the point kept in contact for some little time? It rejoices me that the Phys. (I forget name) has looked at Dipsacus; I have always thought that you ought to go with that subject.—3 Wd. it worth while to show him aggregated matter in Drosera in movement, ie in early stage of aggregation? I doubt whether you will succeed in Drosera by contact, as gland only sensitive part & seat of movement chiefly at base of filament.

I have tried in peat radicles of Pisum with caustic above & below. There was no difference between the 10 control & 10 touched above in their geotropism; but I hardly looked early enough. But of the 10 touched below, 3 curved in opposition to geotropism—2 or 3 were straight & 5 or 6 geotropic in slight degree; so contest wonderfully great.4

I can see it will be impossible to try gold-beaters skin on mustard radicles.5 It has pleased me that I think I fully understand cause of “Sachs’ curvature” of radicles— too long to explain by letter.6

I have finished long chapter on Sleeping Plants & sent it to Mr Norman to copy & diagrams to Mr Cooper.—7

I am now looking over piles of notes on Heliotropism. By the way I am becoming frightened at changing so well-known a term as Heliotropism & cannot bring myself yet to write “Helism”. or “Proshelism”..8

I am more perplexed than ever about life of Dr. D: Hen thinks it very dull, & wants it much shortened & otherwise arranged. Erasmus likes it. Your mother wants parts shortened.— I shall take it on Aug. 1st to Lakes & finish it there.9

I am tired— Ever yours | C. Darwin

(What are your plans, if you have any, you degenerate Darwin.)10

Abbadabba flourishing & Dumming11

1
The year is established by the relationship between this letter and the letter from Francis Darwin, 9 July 1879.
3
Francis had not mentioned observations by a physician on Dipsacus (the genus of teasel), but CD probably refers to Wilhelm Hofmeister’s observation of the cells of the stamen hairs of Tradescantia virginica (a synonym of T. virginiana, Virginia spiderwort; see letter from Francis Darwin, 9 July 1879 and n. 2).
4
CD described these experiments with Pisum sativum (garden pea) in Movement in plants, pp. 163, 534–5.
5
CD and Francis had been investigating apheliotropism in radicles of Sinapis alba (white mustard; see letter from Francis Darwin, [after 16 June 1879]). In his investigations with aerial roots, CD had covered the apex of the roots with gold-beater’s skin (see letter to Francis Darwin, 25 June [1879] and n. 5).
6
On ‘Sachs’ curvature’, see the letter to Francis Darwin, 16 June [1879], n. 8.
7
The long chapter for Movement in plants became two chapters in the published version (ibid., pp. 280–417). Ebenezer Norman was CD’s copyist; James Davis Cooper made his woodcuts.
8
CD had consulted Francis on the use of new terms for plant movement towards or away from the sun (see letter to Francis Darwin, 25 June [1879] and n. 6).
9
Various members of CD’s immediate family had been asked to read the proof-sheets of CD’s biographical sketch for Erasmus Darwin; among them were Henrietta Emma Litchfield, Erasmus Alvey Darwin, and Emma Darwin. The Darwins stayed at Coniston in the Lake District from 2 to 27 August 1879 (Emma Darwin’s diary (DAR 242)).
10
CD jokingly alludes to some of the more illustrious Darwin ancestors discovered by George Howard Darwin while researching Darwin family history (see letter from G. H. Darwin, 24 June 1879).
11
Abbadabba was a pet name for Francis’s son, Bernard Darwin. ‘Dumming’: Bernard’s mispronunciation of ‘drumming’ (see letter to Francis Darwin, 4 July [1879]).

Manuscript Alterations and Comments

1.3 you] interl
1.5 Drosera] after del ‘mo’
2.1 in peat] interl
2.2 but … enough. 2.3] added
8.1 (What … Darwin.)] top of letter
9.1 Abbadabba … Dumming] top of letter, pencil

Please cite as “DCP-LETT-12152,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-12152