# To J. D. Hooker   26 October [1873]1

Down, | Beckenham, Kent.

Oct. 26th

My dear Hooker

I am extremely glad to hear about the aggregation in the Nepenthes glands.— It is possible, judging from Drosophyllum, that there may be secreting glands distinct from absorbent glands; if so the former will be little affected by C. of Ammonia.—2

I strongly think you do not give the experiment with the cubes of albumen a fair chance by trying pitchers including dead insects. Considering size of the pitchers, I shd. think you had better suspend cubes $\frac{1}{10}$ of an inch in size. I wd. let one lie at bottom & another suspended in the middle of fluid. Cubes of roast meat, not overdone, are also excellent for trial, but I wd. try them in distinct virgin pitcher.—

Many thanks for the analysis; of secretion of Nepenthes, it is quite sufficient, as of course I do not touch on Nepenthes.3

I fear Acacia farnesiana is much too big to send: A fresh leaf, of A. farnesianum sent damp could tell me something.—

Could you strike a cutting or graft one on any common species for me; & then perhaps it wd. form new leaves in 2 or 3 months; & so, with Mimosa albida.—4 If this can be done, there is no time to be lost. I fear that you have no species living of Desmodium with 3 leaflets (whether or not all 3 leaflets are of same size); I long to examine such a species.— I have told Frank to look out for any dried Desmodium with tendrils: I see such names as D. volubile, adscendens, adhæsivum, prehensile, uncinatum, retinens, & spirale.— What is D. gyroides, I fancied it might be near gyrans.— But Frank will be able to tell me something.5

Huxley is here & is wonderfully pleasant & jolly— He says that he is quite well; but his face is very thin, & he eats surprisingly little.6

Your troublesome friend | Ch Darwin

## Footnotes

The year is established by the relationship between this letter and the letter from J. D. Hooker, 25 October 1873.
Nepenthes is the tropical pitcher-plant. See letter from J. D. Hooker, 25 October 1873. In Insectivorous plants, CD concluded that both the sessile glands in Drosophyllum lusitanicum and the ones on pedicels were capable of secretion and absorption (see ibid., p. 334). The secretion of Drosophyllum lusitanicum, the Portuguese sundew or dewy pine, was not increased when particles of carbonate of ammonia were placed on the glands (ibid., p. 335).
CD made only brief references to Nepenthes in Insectivorous plants, citing in particular Hooker’s discovery that the fluid in the pitchers possessed an extraordinary power of digestion, but only when the pitchers had been stimulated (ibid., p. 97).
CD mentioned Acacia farnesiana (now Vachellia farnesiana) and Mimosa albida in Movement in plants.
CD had arranged for Francis Darwin to visit Kew and look at the Desmodium collection (letter to J. D. Hooker, 23 October [1873]). For the Desmodium species that CD marked in Steudel 1841, see letter to Francis Darwin, 22 October 1873 and n. 4. Desmodium volubile is not listed in Steudel 1841 or discussed in Movement in plants.
Thomas Henry Huxley arrived at Down on 25 October 1873 (Emma Darwin’s diary (DAR 242)). He had been ill earlier in the year (letter to J. D. Hooker, [6 April 1873]).

## Bibliography

Insectivorous plants. By Charles Darwin. London: John Murray. 1875.

Movement in plants: The power of movement in plants. By Charles Darwin. Assisted by Francis Darwin. London: John Murray. 1880.

Steudel, Ernst Gottlieb. 1841. Nomenclator botanicus: seu: synonymia plantarum universalis, enumerans ordine alphabetico nomina atque synonyma, tum generica tum specifica, et a Linnaeo et a recentioribus de re botanica scriptoribus plantis phanerogamis imposita. 2d edition. 2 parts. Stuttgart and Tübingen: J. G. Cotta.

## Summary

Extremely glad to hear of the aggregation in Nepenthes glands. Advises on experimenting with cubes of albumen – gives sizes, also suggests cubes of roast meat. Thanks for analyses of secretion of Nepenthes.

Asks for cutting of Acacia farnesiana.

Longs to examine a species of Desmodium with three leaflets. Has asked Frank [Darwin] to look for species of Desmodium with tendrils.

## Letter details

Letter no.
DCP-LETT-9114
From
Charles Robert Darwin
To
Joseph Dalton Hooker
Sent from
Down
Source of text
DAR 95: 284–5
Physical description
4pp