RECORD: Darwin, C. R. [1873].09.25. Lactic / malic / iodic / phosphoric / uric / hipparic / hydriolic acids. CUL-DAR56.66-68. (John van Wyhe ed., 2002-. The Complete Work of Charles Darwin Online, http://darwin-online.org.uk/)
REVISION HISTORY: Text prepared and edited by John van Wyhe. RN2
NOTE: See record in the Darwin Online manuscript catalogue, enter its Identifier here. Reproduced with permission of the Syndics of Cambridge University Library and William Huxley Darwin. The volumes CUL-DAR 54-61 contain material for Darwin's book Insectivorous plants (1875).
66
(6D
Lactic Acid Sept 21' 8. 27' 3 leaves old red 1 gr to 1 oz (1 & 1/2 dr in all cases )
(9. 15 (+) 33 (=) 48 fluid coloured pink )
(4° 50', one leaf made a little inflection; the others fully expanded, but all glands so very pale pink colour — I think leaf killed—
put into Phosphate of Ammonia 1 gr to 20 oz— after washing it.—
Fluid coloured strong pink — I never saw colour extracted before without inflection)
Sept 22d 8. 20' glands in the same state; but I think there has been a little inflect from the Phosphate, for all 3 leaves show some inflection, but no segregation.) (23d same state— a very few tents of which glands not injured are segregated)
21' 8. 34 Malic A same strength & leaves
4° 55' no clear effect
(Sept 22d 8. 35', 2 leaves with much inflection, the 3d with some;— segregation — more inflection than can be accounted for by water — no changing mucus
Put into pure water) (Sept 23d 4° same state)
(Sept 24th 9. all 3 leaves pretty fully expanded glands darkened) so clearly not killed
8. 30; Iodic A do do do do do
(10. 34', after 2h, 2 die 2 leaves decidedly inflected) (11. 20', aft 3h strongly inflected)
(12. 30 aft 4 tentacles of glands dark brown & not black as is common)
(5. do 8h 30' d0— flaccid— fluid not coloured — most closely inflected
4 put into pure water) I do not doubt dead)
Sept 23d 8. 35' dark leaves, tentacles pales leaves evidently dead
67
(6E
Sept 21 8. 45' Phosphoric A 1 gr to 1 oz 1 & 1/2 dr 3 red leaves
2. 15' a good deal of inflection, some glands pale
(5. closely inflected — fluid pink — many glands pale pink, put into pure water), a good many more glands not inflected.)
(Sept 22d. 8. 40 — still closely inflected — all the glands, except some on disc quit pale) (23rd same state)
(Sept 24' 9. same state I do not doubt killed)
437.7 (x) 2 (=) 875.0
21' 8. 53' Uric Acid 1 gr to 2 oz, but not all dissolved, so gave 3 leaves 3 dr of the solution (sol milk warm)— 3 very good leaves
9. 15 decided inflection (12. 35' — inflection not very energetic)
5. sub-inflected — marginals not inflected, sub-marginals & outer discals inflected — glands not discoloured — water not coloured — put into pure water — great quantity of mucus secreted
Sept 22d 8. 40' — all 3 leaves almost fully reexpanded, exciting the outer part of disc which in water are so often inflected
Sept 22d 8. 20' Hipparic A (Dr Moore) — 4 leaves 1 g to 1 oz 2. dr of do — (2 leaves pale & 2 red.
(10. 15' fluid pink glands somewhat discoloured — no inflection)
(11. O) inflection glands very pale)
(2. 30' 1 leaf much inflected, 2 considerably, one very little)
(5°. (illegible) day 2 considerably & 2 very little)
(5. all 4 leaves all much inflected, & 2 closely— very much mucus secreted washed & put into pure water — glands all very pale
(Sept 24th 9. do do do glands excessively pale I do not doubt killed)
68
(6F
Hydriodic A. Sept 25' 10 18' — 3 red leaves in sol. 1 gr to 1 oz water
(10. 40' ,O) (11°, O inflection fluid pinkish, glands discoloured)
(12. 50', some inflection of sub-marginals — they look finer than those were in Benzoic A) wonderful lot of mucus secreted) (3. closely inflected all 3 leaves.) glands colourless.)
(5. immense mucus— washed & put into pure water)
(Sept 26th 8. closely inflected)
― 30th do evidently quite long dead
do. A. 10. 23' 4 3 red leaves in sol of 1 gr to 2 oz of water
(11., O effect) (11. 30' a trace of pink in fluid
(12°, 40' a trace of inflection mucus as above in sub-marginals, fluid pink.)
(3°, some slight, but decided inflection; glands colourless except those on centre of discs, which are still red in all 3 leaves — showing that these have some different property from the outer ones)
(5. very slightly sub-inflected — some glands in very centre still red)
Sept 26. 8. a m all 4 leaves closely inflected, in one leaf few glands in centre still red; fluid pink— very much mucus— put into fresh water)
Sept 30' same as above— a great contrast to Hydrochloric Acid
Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)
File last updated 8 January, 2026