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 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!"

1

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):"I will and must finish my Drosera MS., which will take me a week, for, at the present moment, I care more about Drosera than the origin of all the species in the world. But I will not publish on Drosera till next year, for I am frightened and astounded at my results. I declare it is a certain fact, that one organ is so sensitive to touch, that a weight seventyeight-times less than that, viz., Too of a grain, which will move the best chemical balance, suffices to cause a conspicuous movement. Is it not curious that a plant should be far more sensitive to the touch than any nerve in the human body? Yet I am perfectly sure that this is true. When I am on my hobby-horse, I never can resist telling my friends how well my hobby goes, so you must forgive the rider."

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The work was continued, as a holiday task, at Bournemouth, where he stayed during the autumn of 1862.

A long break now ensued in his work on insectivorous plants, and it was not till 1872 that the subject seriously occupied him again. A passage in a letter to Dr. Asa Gray, written in 1863 or 1864, shows, however, that the question was not altogether absent from his mind in the interim:

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Depend on it you are unjust on the merits of my beloved Drosera; it is a wonderful plant, or rather a most sagacious animal. I will stick up for Drosera to the day of my death.

Heaven knows whether I shall ever publish my pile of experiments on it."

He notes in his diary that the last proof of the Expression of the Emotions was finished on August 22, 1872, and that he began to work on Drosera on the following day.

C. D. to Asa Gray [Sevenoaks], October 22 [1872].

I have worked pretty hard for four or five weeks on Drosera, and then broke down; so that we took a house near Sevenoaks for three weeks (where I now am) to get complete rest. I have very little power of working now, and must put off the rest of the work on Drosera till next spring, as my plants are dying. It is an endless subject, and I must cut it short, and for this reason shall not do much on Dionæa. The point which has interested me most is tracing the nerves! which follow the vascular bundles. By a prick with a sharp lancet at a certain point, I can paralyse one-half the leaf, so that a stimulus to the other half causes no movement. It is just like dividing the spinal marrow of a frog:-no stimulus can be sent from the brain or anterior part of the spine to the hind legs but if these latter are stimulated, they move by reflex action. I find my old results about the astonishing sensitiveness of the nervous system (!?) of Drosera to various stimulants fully confirmed and extended. . .

...

C. D. to Asa Gray, Down, June 3 [1874].

I am now hard at work getting my book on Drosera & Co. ready for the printers, but it will take some time, for I am always finding out new points to observe. I think you will be interested by my observations on the digestive process in Drosera; the secretion contains an acid of the acetic series, and some ferment closely analogous to, but not identical with, pepsine; for I have been making a long series of comparative trials. No human being will believe what I shall publish about the smallness of the doses of phosphate of ammonia which act. . . .

The manuscript of Insectivorous Plants was finished in March 1875. He seems to have been more than usually oppressed by the writing of this book, thus he wrote to Sir J. D. Hooker in February:

"You ask about my book, and all that I can say is that I am ready to commit suicide; I thought it was decently written,

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but find so much wants rewriting, that it will not be ready to go to printers for two months, and will then make a confoundedly big book. Murray will say that it is no use publishing in the middle of summer, so I do not know what will be the upshot; but I begin to think that every one who publishes a book is a fool."

The book was published on July 2nd, 1875, and 2700 copies were sold out of the edition of 3000.

The Kew Index of Plant-Names.

Some account of my father's connection with the Index of Plant-Names, now (1892) being printed by the Clarendon Press, will be found in Mr. B. Daydon Jackson's paper in the Journal of Botany, 1887, p. 151. Mr. Jackson quotes the following statement by Sir J. D. Hooker :

Shortly before his death, Mr. Charles Darwin informed Sir Joseph Hooker that it was his intention to devote a considerable sum of money annually for some years in aid or furtherance of some work or works of practical utility to biological science, and to make provisions in his will in the event of these not being completed during his lifetime.

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Amongst other objects connected with botanical science, Mr. Darwin regarded with especial interest the importance of a complete index to the names and authors of the genera and species of plants known to botanists, together with their native countries. Steudel's Nomenclator is the only existing work of this nature, and although now nearly half a century old, Mr. Darwin had found it of great aid in his own researches. It has been indispensable to every botanical institution, whether as a list of all known flowering plants, as an indication of their authors, or as a digest of botanical geography."

Since 1840, when the Nomenclator was published, the number of described plants may be said to have doubled, so that Steudel is now seriously below the requirements of botanical work. To remedy this want, the Nomenclator has been from time to time posted up in an interleaved copy in the Herbarium at Kew, by the help of "funds supplied by private liberality." *

My father, like other botanists, had, as Sir Joseph Hooker points out, experienced the value of Steudel's work. He obtained plants from all sorts of sources, which were often incorrectly named, and he felt the necessity of adhering to

*Kew Gardens Report, 1881, p. 62.

the accepted nomenclature so that he might convey to other
workers precise indications as to the plants which he had studied.
It was also frequently a matter of importance to him to know
the native country of his experimental plants. Thus it was
natural that he should recognise the desirability of completing
and publishing the interleaved volume at Kew. The wish to help
in this object was heightened by the admiration he felt for the
results for which the world has to thank the Royal Gardens at
Kew, and by his gratitude for the invaluable aid which for so
many years he received from its Director and his staff. He
expressly stated that it was his wish "to aid in some way the
scientific work carried on at the Royal Gardens " *—which
induced him to offer to supply funds for the completion of the
Kew Nomenclator.

The following passage, for which I am indebted to Professor
Judd, is of interest, as illustrating, the motives that actuated
father in this matter. Professor Judd writes:-

my

"On the occasion of my last visit to him, he told me that his
income having recently greatly increased, while his wants re-
mained the same, he was most anxious to devote what he could
spare to the advancement of Geology or Biology. He dwelt in
the most touching manner on the fact that he owed so much
happiness and fame to the natural history sciences, which had
been the solace of what might have been a painful existence ;-
and he begged me, if I knew if any research which could be
aided by a grant of a few hundreds of pounds, to let him know,
as it would be a delight to him to feel that he was helping in
promoting the progress of science. He informed me at the
same time that he was making the same suggestion to Sir
Joseph Hooker and Professor_Huxley with respect to Botany
and Zoology respectively. I was much impressed by the
earnestness, and, indeed, deep emotion, with which he spoke
of his indebtedness to Science, and his desire to promote its
interests."

The plan of the proposed work having been carefully con-
sidered, Sir Joseph Hooker was able to confide its elaboration
in detail to Mr. B. Daydon Jackson, Secretary of the Linnean
Society, whose extensive knowledge of botanical literature
qualifies him for the task. My father's original idea of
producing a modern edition of Steudel's Nomenclator has been
practically abandoned, the aim now kept in view is rather to
construct a list of genera and species (with references) founded
on Bentham and Hooker's Genera Plantarum. Under Sir

* See Nature, January 5, 1882.

Joseph Hooker's supervision, the work, carried out with admirable zeal by Mr. Jackson, goes steadily forward. The colossal nature of the undertaking may be estimated by the fact that the manuscript of the Index is at the present time (1892) believed to weigh more than a ton.

The Kew Index,' will be a fitting memorial of my father: and his share in its completion illustrates a part of his character his ready sympathy with work outside his own lines of investigation and his respect for minute and patient labour in all branches of science.