To Edward Frankland 14 May [1874]1
Down, | Beckenham, Kent.
May 14th
My dear Prof. Frankland
I find that I have leaves enough to try Sewage water.2 Will you therefore be so kind as to send me some: of such strength as you wd. feel some surprise at being detected by any one except by a chemist. Perhaps the best plan would be to send only 1 or 2 ounces, & this cd be sent in bottle in little box by post, which wd. save much delay & putrification, as Railway to here is slow.— You could say whether I ought to add twice or thrice as much water to what you send, so as to get the proper dilution.
If what you consider to be weak should act, I could then still further dilute it. I shd use only 1 dr or dr. to each leaf. so very little is wanted. If the fluid contains Phosphate of Ammonia it will certainly act, & almost certainly if it contains the Nitrate of ammonia.—3
In next Nature you will see that I have used your information, & quoted your excellent illustration.4
Yours very sincerely | Ch. Darwin
P.S. If by any chance you have any Oleic Acid in your Laboratory, will you send 3 or 4 gr. if solid or a few drops if liquid. But not worth preparing on purpose I now suspect that this is cause of Olive oil acting on Drosera; many acids, even such as Benzoic acid, are astonishingly powerful poisons on Drosera & cause inflection; some few acids have no such effect. Acetic acid is powerful.—5
Footnotes
Bibliography
Insectivorous plants. By Charles Darwin. London: John Murray. 1875.
Summary
Requests sewage water (and oleic acid) for experiments to determine sensitivity of leaves [of Drosera].
Letter details
- Letter no.
- DCP-LETT-9460A
- From
- Charles Robert Darwin
- To
- Edward Frankland
- Sent from
- Down
- Source of text
- The John Rylands Library, The University of Manchester
- Physical description
- ALS 4pp
Please cite as
Darwin Correspondence Project, “Letter no. 9460A,” accessed on 19 March 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-9460A.xml
Also published in The Correspondence of Charles Darwin, vol. 22