From S. W. Moore   [1 October 1873]1

(1) With respect to chondrine & gelatin it has been decided that they have no nutrient properties; this conclusion is derived from the fact that dogs fed exclusively on them die of starvation; a recent experimentalist has opened up the question again & he declares that death occurs from starvation when an animal is fed exclusively with anything say fibrin, but the question is still in debateable ground.2 Gelatin is a stationary product occupying a purely mechanical position in the economy, i.e. as the basis of bones tendons etc; chondrin on the contrary is an active body which becomes converted to other tissue, in fact, fibrin stands first, then the transition to chondrin that to gelatin & this to bone by deposition of lime & conversion to uses etc of the animal parts.

(2) Artificial gastric juice consists of pepsin 3.0 to the 1000, hydrochloric acid 0.2 to the 1000 (water) about 20. to the 1000 of your dilute Hydrochloric Acid.3

(3) The boiled cabbage gives up all its salts to the water with probably a little albumen, but the infusion would contain more albumin than the boil’d solution; tea infusion would contain no albumin from the fact that by drying it is rendered insoluble; the green peas act, I should think, from the presence of Chlorophyll, I will prepare a little if you would like to try it, the grass acts less energetically because the peas are a convertible albumin while the grass is formed,4

AL incomplete

CD annotations

1.1 (1) … formed, 3.6] crossed pencil
1.1 (1) … parts. 1.10] ‘Digestion of Gelatin & Chondrin’ added blue crayon
3.1 (3) … formed, 3.6] ‘Cabbage—Peas & Grass’ added blue crayon
3.6 while the grass is formed,] ‘Cellulin’5 added ink
Top of letter: ‘Dr Moore Oct 1. 73’ ink
1
The date is established by CD’s annotation.
2
No letters from CD to Moore have been found. For CD’s initial contact with Moore, see the letter from Francis Darwin, [19 September 1873]. CD had asked Moore to prepare animal substances for his experiments on insectivorous plants (see letter to Edward Frankland, 21 September [1873], and Insectivorous plants, pp. 102, 112, 115, 120, 122–5). CD’s experiments suggested that Drosera responded to a solution of chondrin more readily than it responded to pure gelatine, but CD admitted that contamination by albumin could have affected the results. In 1870, William Bernhard Tegetmeier had stated, ‘The most nutritive materials, such as albumen, fibrin, gluten—to say nothing of such substances as starch or sugar—all equally fail to support life when given alone’ (Tegetmeier 1870).
3
In Insectivorous plants, p. 104, CD wrote that his son Francis prepared some artificial gastric juice. Instructions for the preparation are given in Klein et al. 1873, 1: 480–2.
4
In Insectivorous plants, pp. 78, 82–4, CD described the effects on the plants of an infusion and decoction of tea, a decoction of green peas, a decoction and infusion of cabbage, and a decoction of grass leaves.
5
Cellulin is an old name for cellulose. The missing end of the sentence probably noted that grass was formed mostly of cellulin, which animals could not digest.

Please cite as “DCP-LETT-9082,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-9082