From J. D. Hooker   25 October 1873

Royal Gardens Kew

Oct 25th/73

Dear Darwin

Dyer & I have been busy over Nepenthes & have produced an analogous action to that in the cells of Drosera, in those of the glands of Nepenthes— viz a decided aggregation of protoplasm on application of the Ammon. Carb.—1

We are now trying the egg process. The pieces I put into old pitchers last night were unaffected this morning. Did I understand you that the pieces should be 120 in square? I put in big lumps. We have still a great deal to do before ⁠⟨⁠ar⁠⟩⁠riving at any satisfactory results. The constant presence of insects in all open pitchers is a draw back: & we are going to experiment on virgin pitchers.

I thought I had in my last letter referred you to Voelcker’s analysis of the fluid at Kew in 1849.2

CD annotations

2.2 Did I understand] cross in left margin, ink
2.4 The constant … draw back: 2.5] scored red crayon; ‘Roast meat’ left margin, blue crayon
Top of letter: ‘Suspend one & let one fall to bottom | So with [roast meat] | Cubes’ blue crayon; ‘Desmodium with 3 leaflets’ blue crayon
First page, left margin: ‘Cutting strike in a month or two’3blue crayon
Bottom of second page, left margin: illeg blue crayon del blue crayon
1
Hooker refers to William Turner Thiselton-Dyer. CD discussed the effect of carbonate of ammonia on Drosera rotundifolia (the common or round-leaved sundew) in Insectivorous plants, pp. 43–8. He did not mention the effect of carbonate of ammonia (now usually referred to as ammonium carbonate) on Nepenthes (the tropical pitcher-plant).
2
See letter from J. D. Hooker, 20 October 1873, and letter from W. T. Thiselton-Dyer, [after 20 October 1873?]. Some of the plants that Augustus Voelcker experimented on were from the Royal Botanic Gardens, Kew (Voelcker 1849, p. 238).
3
CD’s annotations are notes for his letter to Hooker of 26 October [1873].

Please cite as “DCP-LETT-9113,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-9113