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Darwin Correspondence Project

To W. W. Baxter   17 September [1872?]1

Mr 〈    〉

Please send me about 12 oz of Sulphuric Œther & about 12 oz of Nitric Œther, both as pure as possible, for experimental purposes, in bottles with corks, as I shall use them immediately2

C. Darwin

Down | Sept 17th.—

Also about a drachm of Chloroform (I have some at Home but it has been kept long & I am afraid of its purity)

Also about a drachm of Prussic Acid of Pharmacopœa (please mark proportion of Prussic acid to water on Label)

Also 20 or 30 drops of pure, concentrated Prussic Acid.3



The year is conjectured from the likelihood that the letter was written after the resumption of CD’s work on Drosera on 23 August 1872 (CD’s ‘Journal’ (Appendix II)), and from the relationship between this letter and the letter to W. W. Baxter, 4 September [1872?].
In Insectivorous plants, pp. 219 and 220, CD recorded his experiments on the action of sulphuric ether and nitric ether (now known as ethyl sulfate and ethyl nitrate) on Drosera. Ethyl nitrate is highly volatile.
In Insectivorous plants, pp. 217, 304, and 305, CD recorded his experiments on the action of chloroform on Drosera and Dionaea, and the action of hydrocyanic acid (another name for prussic acid, now more commonly known as hydrogen cyanide) on Dionaea.


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


Orders sulphuric ether, nitric ether, chloroform, and prussic acid [for Drosera experiments? See Insectivorous plants, pp. 209, 219].

Letter details

Letter no.
Charles Robert Darwin
William Walmisley Baxter
Sent from
Source of text
Cleveland Health Sciences Library (Robert M. Stecher collection)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 8523,” accessed on 22 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 20