RECORD: Darwin, C. R. [1872-1873]. ['On the movement of the leaves of Drosera'], folios 118-122. CUL-DAR61.109-113. (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. 206.


[109]

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Acetate of Morphia.— A the same Minute drops wh of a solution of three grains to the ounce was brought into contact with the varied secretions of round three glands; so that each gland on an average could have received only the 1/43,200 of a grain. After an interval of 6' atoms of meat   If inflected [words illeg] tooted.  were placed on their glands, & for comparison on two other undoctored glands, the latter reached the centre in 11'. Whereas these previously treated with with the morphic    did not move in to best for 2°; & when I looked

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again after an interval of 3° 35' from the time when the meat was put on, one tentacle had become inflected, which had not reached the centre. After an interval of 8° 35' these two latter tentacles had become greatly inflected, but even yet had not reached the centre. The experiment was repeated in exactly the same manner, ; & on the three th tentacles which had been treated with morphic had not moved after an interval did not move for during of 1° 51' ; but after 3°. 16' two had become much curved ; after 4°. 16' all these had reached the water. The experiment was again repeated on two glands, with nearly the same result; as for there was no movement for 1° 39', but both had reached the centre after 4°. 16'.—

Thus all eight tentacles glands (not the reaction from other tried at about time)  ultimately carried their atoms of meat to the centre; but they never would did not move for quickly & performed this for some a [illeg] times, & took no effective moved the works very much slower than the understood glands tried at the same time & on every other

 Occasions    It is [illeg] certain the acetate of morphia [words illeg] such to glands temporarily [illeg].      It may be each have to repeat this I often added

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in the same manner minute drops of the same size of pure water to glands & no effect relative was produced, with no retardation of their  subsequent account atoms of meat were subsequently placed on them. I also placed extremely minute particles of opium on four several glands, & after leaving them for 5' to 10' feet or atoms of meat; & with nearly the same results followed as when the solution of acetate of morphic was given used.)

Extract of Hyoscyamus. One grain of the damp extract, c[4 words illeg] used sold for medical purposes, were added to ounce of water; & half minim drops of this colation were placed on the discs of seven leaves. No inflation of the tentacles were caucal ensued in the course of two days. After the drops of had been left for 30' on to discs, [illeg] of the marginal tentacles, the glands of which had not received any, were tried with meat & were found quite sensitive. To the ration of atoms of next. On the other hand when atoms of meat were placed on some of the some sub-marginal tentacles, which had had been immersed for about 1° into solution taking first began to  showed only a trace of inflection after after

Effect of immersion

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One space inserted of 3° 15', [illeg] became considerably curved after 4° 15' from the time when the [illeg] was put on. So hyoscyamus, like morphia, renders the tentacles temporarily torpid, to the action of meat.—

Strong infusion of Tea.— Half-minum drops placed on the discs of two leaves caused no inflection. Minute drops were added to the secretion of round several glands, & after an interval of 10' atoms of meat were placed on them. These tentacles moved more slowly than others undoctored ones, tried at the same time, & two did not immerse at all.

/Immersion/

Hence it would appear that a strong infusion of tea acts like a narcotic.

Extract of Belladonna (Atropa Belladonna) One grain of the extract, sold for medical purposes, was added to an ounce of water. Half-minim drops were placed on the discs of six leaves; & in the course of 25' the tentacles of course were a little inflected. After at interval of 8° 15' the sub-marginal tentacles of all the leaves were much inflected, as was the lamina itself on one leaf. The next day

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After 23° 30', the submarginal tentacles were closely inflected. But after 48° almost all the tentacles on all the leaves were fully re reexpanded; but to lamina of the one leaf were being however only partially reexpanded. All the leaves now appeared perfectly healthy, as they did after 48° on a previous trial. So that the extract of the Atropa does not act as a poison, only like but as a stimulant like milk or an insect a solution of gelatine.)

Extract of Digitaline. A small portion (as sold for medical purposes) was infused in water, & minute drops were added to the viscid secretion round 4 ten     (Calchine also) Digitaline also.   Glands. Then ten tentacles moved as quickly & as energetically, as if no drops of the any animal fluid had been given them.

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minim: "The smallest unit of fluid measure, about equivalent to one drop of liquid; the sixtieth part of a fluid drachm." OED.


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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