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Darwin Correspondence Project

From W. W. Baxter   [after 23 August 1872?]1

Wm. W. Baxter begs his respects to C. Darwin Esqre & has sent two essential Oils— They are very sparingly soluble in water something like one part in 1000 or more.2

W W B has sent some Opium by post which he hopes will be suitable3

&c &c &c


The date is conjectured from the fact that CD had evidently requested materials for his work on Drosera rotundifolia, the sundew. CD had worked on Drosera earlier (see Correspondence vol. 10, letter to J. D. Hooker, 26 September [1862] and n. 1), but he commenced another series of experiments on 23 August 1872, after finishing correcting the proofs of Expression (CD’s ‘Journal’ (Appendix II)). This letter is in the Darwin Archive–CUL among CD’s notes on Drosera; notes immediately before and after it are written on the back of corrected proof-sheets of Expression. CD’s research on Drosera was published in 1875 in Insectivorous plants.
The two essential oils were probably oil of cloves and oil of caraway (Insectivorous plants, pp. 211–12). CD repeated Baxter’s information about their solubility in water in ibid., p. 211. ‘Sparingly soluble’ refers to solubilities of 0.5 grams per litre or lower.
CD found in 1862 that opium placed on the glands of Drosera effectively put the plant to sleep; see Correspondence vol. 10, letter to Daniel Oliver, [17 September 1862]. In Insectivorous plants, he reported only on the results he achieved with acetate of morphia, a mixture of morphia (an extract of opium) and acetic acid (Insectivorous plants, p. 205).


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 28 vols to date. Cambridge: Cambridge University Press. 1985–.

Expression: The expression of the emotions in man and animals. By Charles Darwin. London: John Murray. 1872.

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


Informs CD that he has forwarded some oils and opium.

Letter details

Letter no.
William Walmisley Baxter
Charles Robert Darwin
Sent from
Source of text
DAR 60.2: 86
Physical description
AL 1p

Please cite as

Darwin Correspondence Project, “Letter no. 9793,” accessed on 18 May 2022,

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