Ɛpsilon

From Casimir de Candolle1   30 July 1876

Malagny près Genève

30 Juillet 76

Monsieur

Je suis très-reconnaissant de ce que vous avez pris la peine de m’écrire à l’occasion de mon opuscule sur le Dionaea.2 Je regrette de n’avoir pour le moment rien de nouveau à vous communiquer à ce sujet.3 Les plantes que j’avais fait récemment venir d’Angleterre ont malheureusement trop souffert pour qu’il ne soit possible de la soumettre à aucunes experiences avant plusieurs semaines.

Il serait très-important d’etudier comme vous le conseillez l’effet que la nutrition animale peut exercer sur la fécundité de ces plantes.4 Mais ce genre de recherches éxigera une abondance de materiaux dont je ne disposerai jamais ici.

La lecture de la dernière edition de vos Climbing Plants5 vient de me suggérer une petite experience qui peut-être vous interessera.

L’ingénieuse explication que vous donnez du mode d’enroulement en spires multiples des vrilles des cucurbitacees m’avait depuis longtemps frappé.

Or je trouve qu’en fixant l’extrémité de ces vrilles avec des fils de coton parfaitement fléxibles ces organes, en particulier, ceux du Bryonia dioica, ne s’enroulent plus que dans un seul sens.6

J’obtiens le même résultat en faisant tenir ces vrilles à des branchilles horizontales à suspension bifilaire fonctionnant comme des balances de torsion.

J’espere, cher Monsieur, que vous ne me trouverez pas indiscret de vous avoir répondre si longuement et que vous me continuerez votre bienveillances qui m’honore à un tant degré

Mon père7 me charge de vous transmettre ses compliments les plus empressés et vous me permettrez, j’éspère, d’y assurer aussi les miens | C. de Candolle

1
For a translation of this letter, see Appendix I.
2
CD’s letter has not been found; Candolle had sent a copy of his paper ‘Sur la structure et les mouvements des feuilles du Dionæa muscipula’ (On the structure and movement of the leaves of Dionaea muscipula; C. de Candolle 1876). CD’s inscribed annotated copy is in the Darwin Pamphlet Collection–CUL.
3
In Insectivorous plants, pp. 317–18, CD had shown that cells on the upper leaf surface of Dionaea contracted when the leaf trap shut. Candolle showed that this contraction was due to changes in turgor in cells of the parenchyma of upper and lower leaf surfaces (C. de Candolle 1876, pp. 420–2).
4
Candolle had observed that there was no apparent difference in the size of different parts of plants of Dionaea that had been allowed flies or other animal matter and those that had not; he noted that this was unsurprising since the plant was fully mature before the leaves were able to capture insects (C. de Candolle 1876, p. 402).
5
Climbing plants 2d ed. was published in November 1875 (Publishers’ circular, 16 November 1875, p. 932).
6
CD had observed that caught tendrils of Bryonia dioica (white bryony) always had an equal number of spiral turns in opposite directions, regardless of the total number of spirals (Climbing plants 2d ed., pp. 165–6). Candolle later published his observations on the twining of tendrils (C. de Candolle 1877).

From Casimir de Candolle1   30 July 1876

Malagny near Geneva

30 July 76

Sir

I very much appreciate that you have taken the trouble to write to me on the occasion of my little work on Dionaea.2

I am sorry not to have anything new to communicate to you on this subject.3 The plants which I had recently ordered from England have unfortunately suffered so much that it may not be possible to submit them to any experiments for several weeks.

It would be very important to study how you consider the effect that animal nutrition has on the fertility of these plants.4 But this type of research requires an abundance of material which I will never have available here.

Reading the latest edition of your Climbing Plants5 suggests to me a little experiment which perhaps will interest you.

The clever explanation which you give of the way in which the tendrils of cucurbitaceae wind in multiple spirals had struck me a long time ago.

Now I find by fixing the ends of these tendrils with completely pliant cotton thread these organs, particularly those of Bryonia dioica, no longer wind only in one direction.6

I get the same result by fastening the tendrils to some horizontal branchlets with the two stranded suspension acting like a torsion balance.

I hope, dear Sir, that you will not find me imprudent in having taken so long to reply to you and that you will continue your goodwill towards me which honours me to such a great extent

My father7 instructs me to pass his most assiduous compliments to you and you will permit me, I hope, to assure you also of my own | C. de Candolle

1
For a transcription of this letter in its original French, see Transcript.
2
CD’s letter has not been found; Candolle had sent a copy of his paper ‘Sur la structure et les mouvements des feuilles du Dionæa muscipula’ (On the structure and movement of the leaves of Dionaea muscipula; C. de Candolle 1876). CD’s inscribed annotated copy is in the Darwin Pamphlet Collection–CUL.
3
In Insectivorous plants, pp. 317–18, CD had shown that cells on the upper leaf surface of Dionaea contracted when the leaf trap shut. Candolle showed that this contraction was due to changes in turgor in cells of the parenchyma of upper and lower leaf surfaces (C. de Candolle 1876, pp. 420–2).
4
Candolle had observed that there was no apparent difference in the size of different parts of plants of Dionaea that had been allowed flies or other animal matter and those that had not; he noted that this was unsurprising since the plant was fully mature before the leaves were able to capture insects (C. de Candolle 1876, p. 402).
5
Climbing plants 2d ed. was published in November 1875 (Publishers’ circular, 16 November 1875, p. 932).
6
CD had observed that caught tendrils of Bryonia dioica (white bryony) always had an equal number of spiral turns in opposite directions, regardless of the total number of spirals (Climbing plants 2d ed., pp. 165–6). Candolle later published his observations on the twining of tendrils (C. de Candolle 1877).

Please cite as “DCP-LETT-10567,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-10567