My dear Sir, yours sincerely.
Insectivorous Plants.
In the summer of 1860 he was staying at the house of his sister-in-law, Miss Wedgwood, in Ashdown Forest whence he wrote (July 29, 1860), to Sir Joseph Hooker:—
"Latterly I have done nothing here; but at first I amused myself with a few observations on the insect-catching power of Drosera:[297] and I must consult you some time whether my 'twaddle' is worth communicating to the Linnean Society."
In August he wrote to the same friend:—
"I will gratefully send my notes on Drosera when copied by my copier: the subject amused me when I had nothing to do."
He has described in the Autobiography (p. 47), the general nature of these early experiments. He noticed insects sticking to the leaves, and finding that flies, &c., placed on the adhesive glands, were held fast and embraced, he suspected that the captured prey was digested and absorbed by the leaves. He therefore tried the effect on the leaves of various nitrogenous fluids—with results which, as far as they went, verified his surmise. In September, 1860, he wrote to Dr. Gray:—
"I have been infinitely amused by working at Drosera: the movements are really curious; and the manner in which the leaves detect certain nitrogenous compounds is marvellous. You will laugh; but it is, at present, my full belief (after endless experiments) that they detect (and move in consequence of) the 1/2880 part of a single grain of nitrate of ammonia; but the muriate and sulphate of ammonia bother their chemical skill, and they cannot make anything of the nitrogen in these salts!"
Later in the autumn he was again obliged to leave home for Eastbourne, where he continued his work on Drosera.
On his return home he wrote to Lyell (November 1860):—