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Darwin Correspondence Project

To Daniel Oliver   15 [September 1860]1

Down Bromley Kent


My dear Sir

I am very much obliged for your information. I will look to Annales des Sienc.2 & have ordered the German Book.—3

With respect to the Australian Drosera, the rate or quickness of closing is the point, on which I am very anxious to have a few observations. I shall be surprised, judging from my observations, if the Australian Drosera can distinguish dry organic & inorganic substances. I found that they closed equally (or nearly so) over any substance, but they released vegetable or inorganic substances much more quickly than flies or meat.—4

The most curious results which I have arrived at, is the recognition by the leaves of fluids containing nitrogen & not containing nitrogen. This power of detecting nitrogen in fluids seems to me quite remarkable.—

Lindley does not refer to Buchanan or Wight, but he speaks in Veg. Kingdom p. 433 bottom of the movement of the Indian Drosera lunata; & I see in Steudel’s Nomenclator the names of Buchanan & Wight in relation to this species.—5

I am surprised, if my instructions were followed by Croker that Leschenaultia has not made pods.—6

I am sorry to hear that the plants in the “isosceles beds” have not seeded better. All experiments require a tantalising amount of patience.

With sincere thanks for all your kindness | Believe me, My dear Sir | Yours sincerely | C. Darwin

It might be worth if you like the job while to put a small drop of milk & of saliva on a leaf of the Australian Drosera. Our Drosera likes milk better than any other drink.—7


Dated by the relationship to the letter to Daniel Oliver, 11 September [1860].
The reference is probably to two papers about the leaves and glands of Drosera rotundifolia published in the Annales des Sciences Naturelles (Botanique) in 1855 (Groenland 1855 and Trécul 1855). These papers are both cited in Insectivorous plants, pp. 1 n., 5 n. See also letter to Daniel Oliver, 27 [September 1860].
The reference is probably to the book written by Theodor Rudolf Joseph Nitschke on the physiology of D. rotundifolia (Nitschke 1859). CD seems never to have obtained a copy of this work. In Insectivorous plants, p. 1 n., he cited papers by Nitschke from the Botanische Zeitung for 1860 and 1861. Nitschke wrote two papers on D. rotundifolia in each of these volumes (Nitschke 1860a, 1860b, 1861a, and 1861b) that CD believed were ‘by far the most important ones’ to have been published on Drosera.
CD’s experiments on Australian Drosera are reported in Insectivorous plants, pp. 280–1, 281–3.
Charles William Crocker was foreman of the propagating department at the Royal Botanic Gardens, Kew. See letter to Daniel Oliver, 11 September [1860].
Milk and saliva were among the first nitrogenous fluids that CD used in experiments to test the response of D. rotundifolia to various chemicals (Insectivorous plants, pp. 79–80). CD stated that he carried out these experiments because he ‘was led to believe that the leaves absorbed nutritious matter from the insects which they captured’ (Insectivorous plants, p. 76). His notes from this period on the effects of various substances on Drosera are in DAR 60.1.


Insectivorous plants. By Charles Darwin. London: John Murray. 1875.

Trécul, Auguste. 1855. Organisation des glandes pédicellées des feuilles du Drosera rotundifolia. Annales des sciences naturelles (botanique) 4th ser. 3: 303–11.


Thanks for reference to Annales des Sciences Naturelles.

Requests DO observe rate at which Australian Drosera closes.

On detection of nitrogen in organic fluids.

Letter details

Letter no.
Charles Robert Darwin
Daniel Oliver
Sent from
Source of text
DAR 261.10: 10 (EH 88205994)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 2917,” accessed on 18 April 2021,

Also published in The Correspondence of Charles Darwin, vol. 8