Thinks he has worked out simple mechanism of movement in Drosera. Believes he is correct that gum has no effect.
Thanks for Trécul paper ["Organisation des glandes pédicellées de la feuille du Drosera rotundifolia", C. R. Hebd. Acad. Sci. 40: 1355–8; Ann. Sci. Nat. (Bot.) 3d ser. 3: 303–11].
Chloroform paralyses plants in 30 seconds.
15 Marine Parade | Eastbourne
My dear Sir
Your note of 25
I will give you no more trouble, except that I earnestly hope you will try again the
old gum; & if it acts, endeavour to find out certainly its
composition. Thank you for the pretty leaf of the Australian Drosera; & for
paper with gum; but I have a horrid cold & must stop to another day to try it: a
large drop or
M. Trecul (I am so much obliged to you for telling me of that paper) disbelieves in any movement & accounts for flies being caught by their crawling under the gumy incurved hairs! But he kept the plants in a green-house or hot-house. Could this have paralysed them? I suppose not: anyhow hot-sunshine seems to make them act better. I imagine he looked out for sudden movement. Vapour of Chloroform for 30 seconds paralyses them completely.—
Thank you much for details of the unnamed Australian species. I will with permission quote your observations. Neither D. spathulata or the other species or D. longifolia seem to move quicker than D. rotundifolia.—
I am very glad to hear that you intend to attack spiny plants. Your note shows that it is a complex problem.—
With many thanks. My dear Sir | Yours sincerely | C. Darwin
I have just received a cargo by Post of living plants of Drosera from Down & I will try more gum & starch myself.—
In the unnamed Australian Drosera the incurvation of the leaf itself was terminal I suppose by your sketch. In D. rotundifolia, sometimes the incurvation is terminal; sometimes lateral; & sometimes termino-lateral, so as to be quite variable: as far as I saw in D. longifolia it was always terminal
- f1 2965.f1Dated by the relationship to the letter from Daniel Oliver, 25 September 1860.
- f2 2965.f2CD cited Tr´ecul 1855 in Insectivorous plants, p. 1 n. Oliver supplied the reference in a letter that is now missing (see letter to Daniel Oliver, 15 [September 1860]). Oliver's note giving the reference is in DAR 60.1: 66.
- f3 2965.f3Oliver's observations were given in the letter from Daniel Oliver, 25 September 1860. They were not cited in Insectivorous plants.
- f4 2965.f4Letter from Daniel Oliver, 25 September 1860.
- f5 2965.f5Notes on CD's experiment, dated `Sunday 30
th' and headed `Mr Olivers Gum from Kew, which will have caused contraction.—', are in DAR 60.1: 110.