To Edward Frankland   31 August 1874

Down, | Beckenham, Kent.

Aug 31 1874

My dear Professor Frankland

I hope that you will forgive me for once again troubling you.1 I am experimenting on Utricularia, which catches vast numbers of minute fresh water Crustaceans, which rot in the bladders. It cannot digest; but I find nitrate of Ammonia & urea act powerfully on it. Now what I want to know is whether towards the close of the putrefaction of flesh, skin &c, any substance is produced before the final resolution of the matter into gasses & salts of ammonia. I believe that Urea holds this position with respect to the living body; & it wd be very interesting to me to try any such substance (if such exists & can be procured) with Utricularia; As I am led to believe that the plant absorbs such products of decomposition.2

I wrote some time ago to you about the specific gravity of common phosphate of ammonia.3 As I did not hear in answer, I have used such information as I could get from Watts’ Dict., & I daresay this will be accurate enough for my purpose4

Pray believe | yours very sincerely | Ch. Darwin

LS(A)

1
Frankland had been helping CD with his work on insectivorous plants; see, most recently, the letter to Edward Frankland, 22 July 1874.
2
CD discussed Utricularia (bladderwort) in Insectivorous plants, pp. 395–453.
4
Frankland had not answered CD’s letter because he was travelling in Europe (see letter from Edward Frankland, 9 October 1874). CD’s annotated copy of Henry Watts’s Dictionary of chemistry (see Marginalia 1: 195–6) consists of the first three volumes of the second edition (Watts 1872–4), volumes four and five of an 1871 reprint of the first edition (Watts 1863–8), and a supplement to the first edition dated 1872 (Darwin Library–Down). In Insectivorous plants, p. 173 n., CD gave the specific gravity of phosphate of ammonia as 1.678, a figure given both by Frankland in his letter of 9 October 1874, and in Watts 1863–8, 4: 553.

Manuscript Alterations and Comments

2.3 , & I daresay … purpose] interl in CD’s hand

Please cite as “DCP-LETT-9614A,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-9614A