Summary

Note on the chemical composition of teeth.

Summary

Sends his MS on Dionaea and hopes it may be useful for JSBS’s lecture ["On the mechanism of the leaf of Dionaea muscipula", Not. Proc. R. Inst. G. B. 7 (1874): 332–5].

Summary

Thanks for MS which he intends to read while on a week’s holiday.

Sends thanks for Francis Darwin’s offer of help and says that Francis’s experiments on digestion are complete.

Summary

Sends results of experiments on digestion. Encloses two sets of notes: "Experiments on the digestibility of certain preparations sent by Mr Darwin" and "Note for Mr Darwin" [marked by CD for insertion in ch. 6 of Insectivorous plants].

Summary

Thanks for the careful experiments, particularly on organic acids.

Summary

Purpose of experiments was to determine digestive activity of liquids containing pepsin. Gives required amounts of hydrochloric, propionic, butyric and valerianic acids. Describes experiment and gives results. Also experimented on digestive activity of butyric acid at greater temperatures than the termperature of the body.

Summary

Thanks for the acid digestion experiments, which can be printed as they are. CD trying Drosera on dentine and enamel.

Summary

Reports results of experiments comparing digestibility of gluten and fibrin for CD’s work on Drosera.

Summary

Discusses digestion by insectivorous plants, asks JSBS to try same experiments using pepsin as the digestive agent to see how the results compare with CD’s observations on digestive power of Drosera.

Summary

Sends CD provisional information that artificial gastric juice dissolves bone entirely and that gluten and fibrin are completely dissolved in hydrochloric, propionic, and butyric acids. [See Insectivorous plants, pp. 118–19.]

Summary

Thanks JSBS for his work. CD concludes the ferment of Drosera must differ from pepsin.

Summary

JSBS’s article in Nature ["Venus’s fly-trap", 10 (1874): 105–7, 127–8] could not have been better done.

Has found another plant, Pinguicula, which can catch and digest flies.

Summary

Sends cartilage from cat’s ear, the elastic fibres of which will probably resist digestion [by Drosera]. Is preparing fibro-cartilage, which he expects will be digested easily. [See Insectivorous plants, p. 104.]

Summary

Thanks for fibrin. Drosera and Pinguicula dissolve it thoroughly.

Summary

Is delighted to hear that Pinguicula and Drosera digest fibrin. Suggests diluting gluten in weak hydrochloric acid to remove starch. Enamel was nearly digested [by Drosera] overnight. Would like to try separating the digestive ferment of Pinguicula.

Summary

Reports difficulties in experiments on digestion of fibro-cartilage. Asks about JSBS’s experiments with artificial digestive fluids.

JSBS must read Hooker’s address at Belfast [Rep. BAAS 44 (1874): 103–16] to see what a magnificent digester Nepenthes is.

Summary

Will prepare experiments with the fatty acids on digestion of gluten. Has found it is digested slowly, but entirely, with pepsin and hydrochloric acid.

Summary

Has been testing the digestive powers of Drosera; wants to know whether a group of substances that elicit similar responses are related.

Summary

Suggests an explanation for difference in excitability of Drosera leaves to meat and albumen on the one hand and, on the other, fibrin, areolar tissue, gelatin, and fibrous basis of bone.

Summary

Discusses the powers of digestion of Drosera and why certain substances produce less excitement in the plant than others.