RECORD: Darwin, C. R. n.d. Temp 38° 40° C / Hydrochloric / Propionic / Butyric / Valerianic acids. CUL-DAR60.2.50. (John van Wyhe ed., 2002-. The Complete Work of Charles Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 12.2022. 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).

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Temp 38° 40° C. Hydrochloric assured at 100 points

                Proprionic    Batyric    Valerianic 
                 14.0   35.4   30.2
                 16.5   24.7   16.1
                 16.8   35.8   17.8
                   
Mean.   15.8   32.0   21.4
────────── ──────── ──────────
at ordinary Temperature
as 100 : 44.9 [x-w] :: 32 : 14.37

 

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From these experiments

We see that both with [Hydro] & Butyric acid the powers of digestion is less than half of what it is at a temp of 38°-40°; & we speaking roughly these 3 acids are of with the acetic series are about one third as powerful for digestion as Hydrochloric acid

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Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)

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