From J. D. Hooker   3 July 1874

Royal Gardens Kew

July 3d/74

Dear Darwin

I have been going on with Nepenthes, despairing altogether of Dyer who has more irons in the fire than I have!1 I have 3 plants set out in an inviolable place a very sanctum & shall make a point now of going on—all other duties social, scientific, & parental notwithstanding.

I have made out

I That the structure is acid before the pitcher opens.

II That other parts of the plant are also acid.

III That the secretion is renewed from the glandular surface below the middle of the pitchers, after all has been withdrawn from an unopened pitcher.

IV That a sugary secretion is sometimes given off by the gland on the undersurface of the lid of the pitcher—& in considerable quantity too. But unaccountably I very rarely find it—only once in fact, viz my sanctum, but it was so copious that I cannot doubt but that it was normal.

Any hints for observations most gratefully received.— I note carefully what I do.—

Ever yours affec | J D Hooker

NB. I have your notes about meats to work with.2

CD annotations

6.2 lid of the pitcher] ‘Coloured’ pencil
6.3 only … normal. 6.4] ‘sun-light’ pencil
William Turner Thiselton-Dyer had been assisting Hooker in researching the digestive power of the tropical pitcher-plant, Nepenthes (see letter from J. D. Hooker, 1 July 1874 and n. 3).
In a letter of 31 October 1873 (Correspondence vol. 21), CD suggested that Hooker try an infusion of raw meat and mechanical irritation to see whether it increased the acid in a pitcher of Nepenthes.

Please cite as “DCP-LETT-9530,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-9530