To J. D. Hooker [before 15 July 1874]1
Try Fibrin, (as standard test)
— Cartilage (for effect)
— fibro-cartilage, as will not fully digest, but rendered hyaline by Drosera—
Insect in secretion & water for some time
Pour out of virgin pitcher some secretion in watch glass and with it digest a th 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 with pepsin, if we knew proportion of citric acid in the secretion—2
Will you put 6 cabbage-seeds and 3 Peas in secretion & in water for 4 days, & then lay on damp sand under cover in your room & see if they equally germinate. If the Nepenthes seeds do germinate—see whether edge of cotyledons &c are browned & injured.
Please send in tin box with damp moss a piece of the Tropical aerial Epiphytic Utricularia, to look at the bladders3
Suggests experiments to try [with Nepenthes]. Asks JDH to test whether cabbage seeds and peas exposed to the ferment germinate.
- Letter no.
- Darwin, C. R.
- Hooker, J. D.
- Sent from
- Source of text
- Royal Botanic Gardens, Kew (JDH/3/6 Insectivorous plants 1873–8: 38–9)
- Physical description
Please cite as
Darwin Correspondence Project, “Letter no. 9523,” accessed on 9 December 2016, http://www.darwinproject.ac.uk/DCP-LETT-9523