RECORD: Darwin, C. R. [1872-1873]. ['On the movement of the leaves of Drosera'], folio 11. CUL-DAR61.17. (John van Wyhe ed., 2002-. The Complete Work of Charles Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Transcribed and edited by John van Wyhe 2.2026. RN1

NOTE: See record in the Darwin Online manuscript catalogue, enter its Identifier here. Reproduced with permission of the Syndics of Cambridge University Library and William Huxley Darwin. The volumes CUL-DAR 54-61 contain material for Darwin's book Insectivorous plants (1875).

The volume CUL-DAR61 contains Darwin's draft essay 'On the movement of the leaves of Drosera', written 1872-1873. He intended to publish this with a revised edition of Climbing plants before commencing a larger book draft in April 1874 which became Insectivorous plants. See the introduction to this essay by John van Wyhe.

Draft partly corresponds to Insectivorous plants, p. 24 'The Inflection of the Exterior Tentacles as directly caused by Objects left in Contact with their Glands.'


[17]

(11

on the centres of these leaves: after 19 hours one the hairs on one leaf closed seized tolerably well over to [illeg] morsel; but hardly [illeg] a hair closed over the other two bits of [illeg] by a touch I removed the two bits of [illeg] & placed two recently killed flies on them leaves two less active leaves to next morning (after a period 13 additional hours) I found the hairs & edges of these (two leaves, which were not active enough to earlier consider,) & thus they remained for several days

Where two more very active leaf which had in 19 hours tolerably well clasped to consider [2 words illeg] this time, namely after 40 hours, the [2 words illeg] prey to roll off.

act of clasping (ie in 52° hours after the fragment had [illeg] first prest on) bits of [illeg]

These facts show conclusively that the leaves [illeg] differently, more especially in regard to the time of release, according to the nature of the substances placed on them.)    (See separate pages marked 11A, 11.B &c)

[page excised and new sheet fragment pasted below:]

(I tried the following series of experiments with minute atoms of various substances cautiously placed by aid of a lens on a single glands. – Atom fresh raw meat caused in some cases the marginal [illeg] hair to be greatly inflected to to nearly ie centre of the leaf in five or six minutes which is by far the most rapid movement which I have witnessed.   In case I call [words illeg]    I observed one case with particular care. For ten seconds a slight but distinct change of position was visible, through a lens: in 2° 30" the pedical had curved through about 45 degrees: in 5' through about 90 degrees, & the glands & uppermost part of pedical was arched over towards the centre; when I looked again in 10' the atoms of meat were in the centre of the leaf. The movement as watched through a lens was like that of the minute hand of a clock.— This atom of meat was several hours afterwards embraced by all the hairs of the leaf.—


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Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)

File last updated 23 February, 2026