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Darwin Correspondence Project

To J. D. Hooker   [before 25 October 1873]

Try Fibrin (as standard test)

— cartilage (for effect)

— fibro-cartilage, as will not fully digest, but rendered hyaline by Drosera.

Inset in secretion and water for some time

Pour out of virgin pitcher some secretion in water glass and with it digest a 1/20th of inch cube of albumen. If not, then try the same with some secretion from a pitcher which is in the act of Digestion. Seems to me very important, whether the ferment is secreted only from a stimulus. I understand secretion of virgin pitcher is acid. We could try citric acid wth pepsin if we knew proportion of citric acid in the secretion.

Will you put 6 cabbage-seeds and 3 Peas in secretion and in water for 4 days, and then lay on damp sand under cover in your room and see if they equally germinate. If the Nepenthes seeds do germinate see whether edge of cotyledons &c. are browned and injured.


Suggests experiments to try [with Nepenthes].

Asks JDH to test whether cabbage seeds and peas exposed to the ferment germinate.

Cancel: same as 9523.

Letter details

Letter no.
Charles Robert Darwin
Joseph Dalton Hooker
Sent from
Source of text
DAR 151: 330
Physical description
1p inc

Please cite as

Darwin Correspondence Project, “Letter no. 9112,” accessed on 4 December 2021,

Also published in The Correspondence of Charles Darwin, vol. 21