penetrated by the tubes of the one and not by those of the other; nor
are the tubes exserted. Or (which is the same thing) the stigma of the
one form acts on and is acted on by pollen, which produces not the
least effect on the stigma of the other form. Taking sexual power as the
criterion of difference, the two forms of this one species may be said
to be generically distinct.")

[On the same subject he wrote to Sir Joseph Hooker in August 1862:--

"Is Oliver at Kew? When I am established at Bournemouth I am completely
mad to examine any fresh flowers of any Lythraceous plant, and I would
write and ask him if any are in bloom."

Again he wrote to the same friend in October:--

"If you ask Oliver, I think he will tell you I have got a real odd case
in Lythrum, it interests me extremely, and seems to me the strangest
case of propagation recorded amongst plants or animals, viz. a necessary
triple alliance between three hermaphrodites. I feel sure I can now
prove the truth of the case from a multitude of crosses made this
summer."

In an article, 'Dimorphism in the Genitalia of Plants' ('Silliman's
Journal,' 1862, volume xxxiv. page 419), Dr. Gray pointed out that the
structural difference between the two forms of Primula had already been
defined in the 'Flora of North America,' as DIOECIO-DIMORPHISM. The
use of this term called forth the following remarks from my father. The
letter also alludes to a review of the 'Fertilisation of Orchids' in the
same volume of 'Silliman's Journal.']

CHARLES DARWIN TO ASA GRAY. Down, November 26 [1862].

My dear Gray,

The very day after my last letter, yours of November 10th, and the
review in 'Silliman,' which I feared might have been lost, reached me.
We were all very much interested by the political part of your letter;
and in some odd way one never feels that information and opinions
painted in a newspaper come from a living source; they seem dead,
whereas all that you write is full of life. The reviews interested me
profoundly; you rashly ask for my opinion, and you must consequently
endure a long letter. First for Dimorphism; I do not AT PRESENT like the
term "Dioecio-dimorphism;" for I think it gives quite a false notion,
that the phenomena are connected with a separation of the sexes.
Certainly in Primula there is unequal fertility in the two forms, and I
suspect this is the case with Linum; and, therefore I felt bound in
the Primula paper to state that it might be a step towards a dioecious
condition; though I believe there are no dioecious forms in Primulaceae
or Linaceae. But the three forms in Lythrum convince me that the
phenomenon is in no way necessarily connected with any tendency to
separation of sexes. The case seems to me in result or function to be
almost identical with what old C.K. Sprengel called "dichogamy," and
which is so frequent in truly hermaphrodite groups; namely, the pollen
and stigma of each flower being mature at different periods. If I am
right, it is very advisable not to use the term "dioecious," as this at
once brings notions of separation of sexes.

... I was much perplexed by Oliver's remarks in the 'Natural History
Review' on the Primula case, on the lower plants having sexes more often
separated than in the higher plants,--so exactly the reverse of what
takes place in animals. Hooker in his review of the 'Orchids' repeats
this remark. There seems to be much truth in what you say ("Forms which
are low in the scale as respects morphological completeness may be
high in the scale of rank founded on specialisation of structure and
function."--Dr. Gray, in 'Silliman's Journal.'), and it did not occur to
me, about no improbability of specialisation in CERTAIN lines in lowly
organised beings. I could hardly doubt that the hermaphrodite state is
the aboriginal one. But how is it in the conjugation of Confervae--is
not one of the two individuals here in fact male, and the other female?
I have been much puzzled by this contrast in sexual arrangements
between plants and animals. Can there be anything in the following
consideration: By ROUGHEST calculation about one-third of the British
GENERA of aquatic plants belong to the Linnean classes of Mono and
Dioecia; whilst of terrestrial plants (the aquatic genera being
subtracted) only one-thirteenth of the genera belong to these two
classes. Is there any truth in this fact generally? Can aquatic plants,
being confined to a small area or small community of individuals,
require more free crossing, and therefore have separate sexes? But to
return to our point, does not Alph. de Candolle say that aquatic plants
taken as a whole are lowly organised, compared with terrestrial; and may
not Oliver's remark on the separation of the sexes in lowly organised
plants stand in some relation to their being frequently aquatic? Or is
this all rubbish?

... What a magnificent compliment you end your review with! You and
Hooker seem determined to turn my head with conceit and vanity (if not
already turned) and make me an unbearable wretch.

With most cordial thanks, my good and kind friend, Farewell, C. DARWIN.

[The following passage from a letter (July 28, 1863), to Prof.
Hildebrand, contains a reference to the reception of the dimorphic work
in France:--

"I am extremely much pleased to hear that you have been looking at the
manner of fertilisation of your native Orchids, and still more pleased
to hear that you have been experimenting on Linum. I much hope that you
may publish the result of these experiments; because I was told that the
most eminent French botanists of Paris said that my paper on Primula was
the work of imagination, and that the case was so improbable they did
not believe in my results."]

CHARLES DARWIN TO ASA GRAY. April 19 [1864].

... I received a little time ago a paper with a good account of your
Herbarium and Library, and a long time previously your excellent review
of Scott's 'Primulaceae,' and I forwarded it to him in India, as it
would much please him. I was very glad to see in it a new case of
Dimorphism (I forget just now the name of the plant); I shall be
grateful to hear of any other cases, as I still feel an interest in
the subject. I should be very glad to get some seed of your dimorphic
Plantagos; for I cannot banish the suspicion that they must belong to a
very different class like that of the common Thyme. (In this prediction
he was right. See 'Forms of Flowers,' page 307.) How could the
wind, which is the agent of fertilisation, with Plantago, fertilise
"reciprocally dimorphic" flowers like Primula? Theory says this cannot
be, and in such cases of one's own theories I follow Agassiz and
declare, "that nature never lies." I should even be very glad to examine
the two dried forms of Plantago. Indeed, any dried dimorphic plants
would be gratefully received...

Did my Lythrum paper interest you? I crawl on at the rate of two hours
per diem, with 'Variation under Domestication.'

CHARLES DARWIN TO J.D. HOOKER. Down, November 26 [1864].

... You do not know how pleased I am that you have read my Lythrum paper;
I thought you would not have time, and I have for long years looked at
you as my Public, and care more for your opinion than that of all the
rest of the world. I have done nothing which has interested me so much
as Lythrum, since making out the complemental males of Cirripedes.
I fear that I have dragged in too much miscellaneous matter into the
paper.

... I get letters occasionally, which show me that Natural Selection is
making GREAT progress in Germany, and some amongst the young in France.
I have just received a pamphlet from Germany, with the complimentary
title of "Darwinische Arten-Enstehung-Humbug"!

Farewell, my best of old friends, C. DARWIN.

CHARLES DARWIN TO ASA GRAY. September 10, [1867?].

... The only point which I have made out this summer, which could
possibly interest you, is that the common Oxlip found everywhere, more
or less commonly in England, is certainly a hybrid between the primrose
and cowslip; whilst the P. elatior (Jacq.), found only in the
Eastern Counties, is a perfectly distinct and good species; hardly
distinguishable from the common oxlip, except by the length of the
seed-capsule relatively to the calyx. This seems to me rather a horrid
fact for all systematic botanists...

CHARLES DARWIN TO F. HILDEBRAND. Down, November 16, 1868.

My dear Sir,

I wrote my last note in such a hurry from London, that I quite forgot
what I chiefly wished to say, namely to thank you for your excellent
notices in the 'Bot. Zeitung' of my paper on the offspring of dimorphic
plants. The subject is so obscure that I did not expect that any one
would have noticed my paper, and I am accordingly very much pleased
that you should have brought the subject before the many excellent
naturalists of Germany.

Of all the German authors (but they are not many) whose works I have
read, you write by far the clearest style, but whether this is a
compliment to a German writer I do not know.

[The two following letters refer to the small bud-like "Cleistogamic"
flowers found in the violet and many other plants. They do not open and
are necessarily self-fertilised:]

CHARLES DARWIN TO J.D. HOOKER. Down, May 30 [1862].

... What will become of my book on Variation? I am involved in a
multiplicity of experiments. I have been amusing myself by looking at
the small flowers of Viola. If Oliver (Shortly afterwards he wrote:
"Oliver, the omniscient, has sent me a paper in the 'Bot. Zeitung,' with
most accurate description of all that I saw in Viola.") has had time to
study them, he will have seen the curious case (as it seems to me) which
I have just made clearly out, viz. that in these flowers, the FEW pollen
grains are never shed, or never leave the anther-cells, but emit long
pollen tubes, which penetrate the stigma. To-day I got the anther with
the included pollen grain (now empty) at one end, and a bundle of tubes
penetrating the stigmatic tissue at the other end; I got the whole under
a microscope without breaking the tubes; I wonder whether the stigma
pours some fluid into the anther so as to excite the included grains. It
is a rather odd case of correlation, that in the double sweet violet
the small flowers are double; i.e., have a multitude of minute scales
representing the petals. What queer little flowers they are.

Have you had time to read poor dear Henslow's life? it has interested me
for the man's sake, and, what I did not think possible, has even exalted
his character in my estimation...

[The following is an extract from the letter given in part above, and
refers to Dr. Gray's article on the sexual differences of plants:]

CHARLES DARWIN TO ASA GRAY. NOVEMBER 26 [1862].

... You will think that I am in the most unpleasant, contradictory,
fractious humour, when I tell you that I do not like your term of
"precocious fertilisation" for your second class of dimorphism [i.e. for
cleistogamic fertilisation]. If I can trust my memory, the state of
the corolla, of the stigma, and the pollen-grains is different from the
state of the parts in the bud; that they are in a condition of special
modification. But upon my life I am ashamed of myself to differ so much
from my betters on this head. The TEMPORARY theory (This view is now
generally accepted.) which I have formed on this class of dimorphism,
just to guide experiment, is that the PERFECT flowers can only be
perfectly fertilised by insects, and are in this case abundantly
crossed; but that the flowers are not always, especially in early
spring, visited enough by insects, and therefore the little imperfect
self-fertilising flowers are developed to ensure a sufficiency of seed
for present generations. Viola canina is sterile, when not visited by
insects, but when so visited forms plenty of seed. I infer from the
structure of three or four forms of Balsamineae, that these require
insects; at least there is almost as plain adaptation to insects as in
the Orchids. I have Oxalis acetosella ready in pots for experiment
next spring; and I fear this will upset my little theory... Campanula
carpathica, as I found this summer, is absolutely sterile if insects are
excluded. Specularia speculum is fairly fertile when enclosed; and this
seemed to me to be partially effected by the frequent closing of the
flower; the inward angular folds of the corolla corresponding with the
clefts of the open stigma, and in this action pushing pollen from the
outside of the stigma on to its surface. Now can you tell me, does S.
perfoliata close its flower like S. speculum, with angular inward folds?
if so, I am smashed without some fearful "wriggling." Are the IMPERFECT
flowers of your Specularia the early or the later ones? very early or
very late? It is rather pretty to see the importance of the closing of
flowers of S. speculum.

['Forms of Flowers' was published in July; in June, 1877, he wrote to
Professor Carus with regard to the translation:--

"My new book is not a long one, viz. 350 pages, chiefly of the larger
type, with fifteen simple woodcuts. All the proofs are corrected except
the Index, so that it will soon be published.

"... I do not suppose that I shall publish any more books, though perhaps
a few more papers. I cannot endure being idle, but heaven knows whether
I am capable of any more good work."

The review alluded to in the next letter is at page 445 of the volume of
'Nature' for 1878:]

CHARLES DARWIN TO W. THISELTON DYER. Down, April 5, 1878.

My dear Dyer,

I have just read in 'Nature' the review of 'Forms of Flowers,' and I am
sure that it is by you. I wish with all my heart that it deserved one
quarter of the praises which you give it. Some of your remarks have
interested me greatly... Hearty thanks for your generous and most kind
sympathy, which does a man real good, when he is as dog-tired as I am at
this minute with working all day, so good-bye.

C. DARWIN.

CHAPTER 2.XIII. -- CLIMBING AND INSECTIVOROUS PLANTS.

[My father mentions in his 'Autobiography' (volume i.) that he was led
to take up the subject of climbing plants by reading Dr. Gray's paper,
"Note on the Coiling of the Tendrils of Plants." ('Proc. Amer. Acad. of
Arts and Sciences,' 1858.) This essay seems to have been read in 1862,
but I am only able to guess at the date of the letter in which he asks
for a reference to it, so that the precise date of his beginning this
work cannot be determined.

In June 1863 he was certainly at work, and wrote to Sir J.D. Hooker for
information as to previous publications on the subject, being then in
ignorance of Palm's and H. v. Mohl's works on climbing plants, both of
which were published in 1827.]

CHARLES DARWIN TO J.D. HOOKER. Down [June] 25 [1863].

My dear Hooker,

I have been observing pretty carefully a little fact which has surprised
me; and I want to know from you and Oliver whether it seems new or odd
to you, so just tell me whenever you write; it is a very trifling fact,
so do not answer on purpose.

I have got a plant of Echinocystis lobata to observe the irritability
of the tendrils described by Asa Gray, and which of course, is plain
enough. Having the plant in my study, I have been surprised to find
that the uppermost part of each branch (i.e. the stem between the two
uppermost leaves excluding the growing tip) is CONSTANTLY and slowly
twisting round making a circle in from one-half to two hours; it
will sometimes go round two or three times, and then at the same rate
untwists and twists in opposite directions. It generally rests half
an hour before it retrogrades. The stem does not become permanently
twisted. The stem beneath the twisting portion does not move in the
least, though not tied. The movement goes on all day and all early
night. It has no relation to light for the plant stands in my window
and twists from the light just as quickly as towards it. This may be a
common phenomenon for what I know, but it confounded me quite, when I
began to observe the irritability of the tendrils. I do not say it is
the final cause, but the result is pretty, for the plant every one and
a half or two hours sweeps a circle (according to the length of the
bending shoot and the length of the tendril) of from one foot to twenty
inches in diameter, and immediately that the tendril touches any object
its sensitiveness causes it immediately to seize it; a clever gardener,
my neighbour, who saw the plant on my table last night, said: "I
believe, Sir, the tendrils can see, for wherever I put a plant it finds
out any stick near enough." I believe the above is the explanation, viz.
that it sweeps slowly round and round. The tendrils have some sense, for
they do not grasp each other when young.

Yours affectionately, C. DARWIN.

CHARLES DARWIN TO J.D. HOOKER. Down, July 14 [1863].

My dear Hooker,

I am getting very much amused by my tendrils, it is just the sort of
niggling work which suits me, and takes up no time and rather rests me
whilst writing. So will you just think whether you know any plant, which
you could give or lend me, or I could buy, with tendrils, remarkable in
any way for development, for odd or peculiar structure, or even for an
odd place in natural arrangement. I have seen or can see Cucurbitaceae,
Passion-flower, Virginian-creeper, Cissus discolor, Common-pea
and Everlasting-pea. It is really curious the diversification of
irritability (I do not mean the spontaneous movement, about which I
wrote before and correctly, as further observation shows): for instance,
I find a slight pinch between the thumb and finger at the end of the
tendril of the Cucurbitaceae causes prompt movement, but a pinch excites
no movement in Cissus. The cause is that one side alone (the concave) is
irritable in the former; whereas both sides are irritable in Cissus, so
if you excite at the same time both OPPOSITE sides there is no movement,
but by touching with a pencil the two branches of the tendril, in any
part whatever, you cause movement towards that point; so that I can
mould, by a mere touch, the two branches into any shape I like...

CHARLES DARWIN TO ASA GRAY. Down, August 4 [1863].

My present hobby-horse I owe to you, viz. the tendrils: their
irritability is beautiful, as beautiful in all its modifications as
anything in Orchids. About the SPONTANEOUS movement (independent of
touch) of the tendrils and upper internodes, I am rather taken aback by
your saying, "is it not wel-known?" I can find nothing in any book which
I have... The spontaneous movement of the tendrils is independent of the
movement of the upper internodes, but both work harmoniously together
in sweeping a circle for the tendrils to grasp a stick. So with all
climbing plants (without tendrils) as yet examined, the upper internodes
go on night and day sweeping a circle in one fixed direction. It is
surprising to watch the Apocyneae with shoots 18 inches long (beyond the
supporting stick), steadily searching for something to climb up. When
the shoot meets a stick, the motion at that point is arrested, but in
the upper part is continued; so that the climbing of all plants yet
examined is the simple result of the spontaneous circulatory movement of
the upper internodes. Pray tell me whether anything has been published
on this subject? I hate publishing what is old; but I shall hardly
regret my work if it is old, as it has much amused me...

CHARLES DARWIN TO ASA GRAY. May 28, 1864.

... An Irish nobleman on his death-bed declared that he could
conscientiously say that he had never throughout life denied himself any
pleasure; and I can conscientiously say that I have never scrupled to
trouble you; so here goes.--Have you travelled South, and can you tell
me whether the trees, which Bignonia capreolata climbs, are covered with
moss or filamentous lichen or Tillandsia? (He subsequently learned from
Dr. Gray that Polypodium incanum abounds on the trees in the districts
where this species of Bignonia grows. See 'Climbing Plants,' page 103.)
I ask because its tendrils abhor a simple stick, do not much relish
rough bark, but delight in wool or moss. They adhere in a curious manner
by making little disks, like the Ampelopsis... By the way, I will enclose
some specimens, and if you think it worth while, you can put them under
the simple microscope. It is remarkable how specially adapted some
tendrils are; those of Eccremocarpus scaber do not like a stick, will
have nothing to say to wool; but give them a bundle of culms of grass,
or a bundle of bristles and they seize them well.

CHARLES DARWIN TO J.D. HOOKER. Down, June 10 [1864].

... I have now read two German books, and all I believe that has been
written on climbers, and it has stirred me up to find that I have a
good deal of new matter. It is strange, but I really think no one has
explained simple twining plants. These books have stirred me up, and
made me wish for plants specified in them. I shall be very glad of those
you mention. I have written to Veitch for young Nepenthes and Vanilla
(which I believe will turn out a grand case, though a root creeper),
if I cannot buy young Vanilla I will ask you. I have ordered a
leaf-climbing fern, Lygodium. All this work about climbers would hurt
my conscience, did I think I could do harder work. (He was much out of
health at this time.)

[He continued his observations on climbing plants during the prolonged
illness from which he suffered in the autumn of 1863, and in the
following spring. He wrote to Sir J.D. Hooker, apparently in March
1864:--

"For several days I have been decidedly better, and what I lay much
stress on (whatever doctors say), my brain feels far stronger, and I
have lost many dreadful sensations. The hot-house is such an amusement
to me, and my amusement I owe to you, as my delight is to look at the
many odd leaves and plants from Kew... The only approach to work which
I can do is to look at tendrils and climbers, this does not distress my
weakened brain. Ask Oliver to look over the enclosed queries (and do you
look) and amuse a broken-down brother naturalist by answering any which
he can. If you ever lounge through your houses, remember me and climbing
plants."

On October 29, 1864, he wrote to Dr. Gray:--

"I have not been able to resist doing a little more at your godchild, my
climbing paper, or rather in size little book, which by Jove I will have
copied out, else I shall never stop. This has been new sort of work
for me, and I have been pleased to find what a capital guide for
observations a full conviction of the change of species is."

On January 19, 1865, he wrote to Sir J.D. Hooker:--

"It is working hours, but I am trying to take a day's holiday, for I
finished and despatched yesterday my climbing paper. For the last ten
days I have done nothing but correct refractory sentences, and I loathe
the whole subject."

A letter to Dr. Gray, April 9, 1865, has a word or two on the subject:--

"I have begun correcting proofs of my paper on 'Climbing Plants.' I
suppose I shall be able to send you a copy in four or five weeks. I
think it contains a good deal new and some curious points, but it is so
fearfully long, that no one will ever read it. If, however, you do not
SKIM through it, you will be an unnatural parent, for it is your child."

Dr. Gray not only read it but approved of it, to my father's great
satisfaction, as the following extracts show:--

"I was much pleased to get your letter of July 24th. Now that I can
do nothing, I maunder over old subjects, and your approbation of my
climbing paper gives me VERY great satisfaction. I made my observations
when I could do nothing else and much enjoyed it, but always doubted
whether they were worth publishing. I demur to its not being necessary
to explain in detail about the spires in CAUGHT tendrils running in
opposite directions; for the fact for a long time confounded me, and
I have found it difficult enough to explain the cause to two or three
persons." (August 15, 1865.)

"I received yesterday your article (In the September number of
'Silliman's Journal,' concluded in the January number, 1866.) on
climbers, and it has pleased me in an extraordinary and even silly
manner. You pay me a superb compliment, and as I have just said to my
wife, I think my friends must perceive that I like praise, they give me
such hearty doses. I always admire your skill in reviews or abstracts,
and you have done this article excellently and given the whole essence
of my paper... I have had a letter from a good Zoologist in S. Brazil,
F. Muller, who has been stirred up to observe climbers and gives me some
curious cases of BRANCH-climbers, in which branches are converted
into tendrils, and then continue to grow and throw out leaves and new
branches, and then lose their tendril character." (October 1865.)

The paper on Climbing Plants was republished in 1875, as a separate
book. The author had been unable to give his customary amount of care to
the style of the original essay, owing to the fact that it was written
during a period of continued ill-health, and it was now found to require
a great deal of alteration. He wrote to Sir J.D. Hooker (March 3,
1875): "It is lucky for authors in general that they do not require such
dreadful work in merely licking what they write into shape." And to Mr.
Murray in September he wrote: "The corrections are heavy in 'Climbing
Plants,' and yet I deliberately went over the MS. and old sheets three
times." The book was published in September 1875, an edition of 1500
copies was struck off; the edition sold fairly well, and 500 additional
copies were printed in June of the following year.]

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; 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' (volume i.), the general nature
of these early experiments. He noticed insects sticking to the leaves,
and finding that flies, etc., placed on the adhesive glands were held
fast and embraced, he suspected that the leaves were adapted to supply
nitrogenous food to the plant. 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! I began this work on Drosera in relation to GRADATION as throwing
light on Dionaea."

Later in the autumn he was again obliged to leave home for Eastbourne,
where he continued his work on Drosera. The work was so new to him that
he found himself in difficulties in the preparation of solutions, and
became puzzled over fluid and solid ounces, etc. etc. To a friend, the
late Mr. E. Cresy, who came to his help in the matter of weights and
measures, he wrote giving an account of the experiments. The extract
(November 2, 1860) which follows illustrates the almost superstitious
precautions he often applied to his researches:--

"Generally I have scrutinised every gland and hair on the leaf before
experimenting; but it occurred to me that I might in some way affect the
leaf; though this is almost impossible, as I scrutinised with equal care
those that I put into distilled water (the same water being used for
dissolving the carbonate of ammonia). I then cut off four leaves (not
touching them with my fingers), and put them in plain water, and four
other leaves into the weak solution, and after leaving them for an hour
and a half, I examined every hair on all eight leaves; no change on the
four in water; every gland and hair affected in those in ammonia.

"I had measured the quantity of weak solution, and I counted the glands
which had absorbed the ammonia, and were plainly affected; the result
convinced me that each gland could not have absorbed more than 1/64000
or 1/65000 of a grain. I have tried numbers of other experiments all
pointing to the same result. Some experiments lead me to believe that
very sensitive leaves are acted on by much smaller doses. Reflect
how little ammonia a plant can get growing on poor soil--yet it is
nourished. The really surprising part seems to me that the effect should
be visible, and not under very high power; for after trying a high
power, I thought it would be safer not to consider any effect which
was not plainly visible under a two-thirds object glass and middle
eye-piece. The effect which the carbonate of ammonia produces is the
segregation of the homogeneous fluid in the cells into a cloud of
granules and colourless fluid; and subsequently the granules coalesce
into larger masses, and for hours have the oddest movements--coalescing,
dividing, coalescing ad infinitum. I do not know whether you will care
for these ill-written details; but, as you asked, I am sure I am bound
to comply, after all the very kind and great trouble which you have
taken."

On his return home he wrote to Sir J.D. Hooker (November 21, 1860):--

"I have been working like a madman at Drosera. Here is a fact for you
which is certain as you stand where you are, though you won't believe
it, that a bit of hair 1/78000 of one grain in weight placed on gland,
will cause ONE of the gland-bearing hairs of Drosera to curve inwards,
and will alter the condition of the contents of every cell in the
foot-stalk of the gland."

And a few days later to Lyell:--

"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
seventy-eight times less than that, viz., 1/1000 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."

The work was continued, as a holiday task, at Bournemouth, where he
stayed during the autumn of 1862. The discussion in the following letter
on "nervous matter" in Drosera is of interest in relation to recent
researches on the continuity of protoplasm from cell to cell:]

CHARLES DARWIN TO J.D. HOOKER. Cliff Cottage, Bournemouth. September 26
[1862].

My dear Hooker,

Do not read this till you have leisure. If that blessed moment ever
comes, I should be very glad to have your opinion on the subject of this
letter. I am led to the opinion that Drosera must have diffused matter
in organic connection, closely analogous to the nervous matter of
animals. When the glands of one of the papillae or tentacles, in its
natural position is supplied with nitrogenised fluid and certain other
stimulants, or when loaded with an extremely slight weight, or when
struck several times with a needle, the pedicel bends near its base in
under one minute. These varied stimulants are conveyed down the pedicel
by some means; it cannot be vibration, for drops of fluid put on quite
quietly cause the movement; it cannot be absorption of the fluid from
cell to cell, for I can see the rate of absorption, which though quick,
is far slower, and in Dionaea the transmission is instantaneous;
analogy from animals would point to transmission through nervous matter.
Reflecting on the rapid power of absorption in the glands, the extreme
sensibility of the whole organ, and the conspicuous movement caused by
varied stimulants, I have tried a number of substances which are not
caustic or corrosive,... but most of which are known to have a remarkable
action on the nervous matter of animals. You will see the results in
the enclosed paper. As the nervous matter of different animals are
differently acted on by the same poisons, one would not expect the
same action on plants and animals; only if plants have diffused nervous
matter, some degree of analogous action. And this is partially the case.
Considering these experiments, together with the previously made remarks
on the functions of the parts, I cannot avoid the conclusion,
that Drosera possesses matter at least in some degree analogous in
constitution and function to nervous matter. Now do tell me what you
think, as far as you can judge from my abstract; of course many more
experiments would have to be tried; but in former years I tried on the
whole leaf, instead of on separate glands, a number of innocuous (This
line of investigation made him wish for information on the action
of poisons on plants; as in many other cases he applied to Professor
Oliver, and in reference to the result wrote to Hooker: "Pray thank
Oliver heartily for his heap of references on poisons.") substances,
such as sugar, gum, starch, etc., and they produced no effect. Your
opinion will aid me in deciding some future year in going on with
this subject. I should not have thought it worth attempting, but I had
nothing on earth to do.

My dear Hooker, Yours very sincerely, CH. DARWIN.

P.S.--We return home on Monday 28th. Thank Heaven!

[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:--

"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.]

CHARLES DARWIN 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 Dionaea. 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...

[His work on digestion in Drosera and other points in the physiology of
the plant soon led him into regions where his knowledge was defective,
and here the advice and assistance which he received from Dr. Burdon
Sanderson was of much value:]

CHARLES DARWIN TO J. BURDON SANDERSON. Down, July 25, 1873.

My dear Dr. Sanderson,

I should like to tell you a little about my recent work with Drosera, to
show that I have profited by your suggestions, and to ask a question or
two.

1. It is really beautiful how quickly and well Drosera and Dionaea
dissolve little cubes of albumen and gelatine. I kept the same sized
cubes on wet moss for comparison. When you were here I forgot that I had
tried gelatine, but albumen is far better for watching its dissolution
and absorption. Frankland has told me how to test in a rough way for
pepsin; and in the autumn he will discover what acid the digestive juice
contains.

2. A decoction of cabbage-leaves and green peas causes as much
inflection as an infusion of raw meat; a decoction of grass is less
powerful. Though I hear that the chemists try to precipitate all albumen
from the extract of belladonna, I think they must fail, as the extract
causes inflection, whereas a new lot of atropine, as well as the
valerianate [of atropine], produce no effect.

3. I have been trying a good many experiments with heated water... Should
you not call the following case one of heat rigor? Two leaves were
heated to 130 deg, and had every tentacle closely inflected; one was
taken out and placed in cold water, and it re-expanded; the other was
heated to 145 deg, and had not the least power of re-expansion. Is not
this latter case heat rigor? If you can inform me, I should very much
like to hear at what temperature cold-blooded and invertebrate animals
are killed.

4. I must tell you my final result, of which I am sure, [as to] the
sensitiveness of Drosera. I made a solution of one part of phosphate of
ammonia by weight to 218,750 of water; of this solution I gave so much
that a leaf got 1/8000 of a grain of the phosphate. I then counted the
glands, and each could have got only 1/1552000 of a grain; this being
absorbed by the glands, sufficed to cause the tentacles bearing these
glands to bend through an angle of 180 deg. Such sensitiveness requires
hot weather, and carefully selected young yet mature leaves. It strikes
me as a wonderful fact. I must add that I took every precaution, by
trying numerous leaves at the same time in the solution and in the same
water which was used for making the solution.

5. If you can persuade your friend to try the effects of carbonate of
ammonia on the aggregation of the white blood corpuscles, I should very
much like to hear the result.

I hope this letter will not have wearied you.

Believe me, yours very sincerely, CHARLES DARWIN.

CHARLES DARWIN TO W. THISELTON DYER. Down, 24 [December 1873?].

My dear Mr. Dyer,

I fear that you will think me a great bore, but I cannot resist telling
you that I have just found out that the leaves of Pinguicula possess
a beautifully adapted power of movement. Last night I put on a row of
little flies near one edge of two YOUNGISH leaves; and after 14 hours
these edges are beautifully folded over so as to clasp the flies, thus
bringing the glands into contact with the upper surfaces of the flies,
and they are now secreting copiously above and below the flies and no
doubt absorbing. The acid secretion has run down the channelled edge and
has collected in the spoon-shaped extremity, where no doubt the glands
are absorbing the delicious soup. The leaf on one side looks just like
the helix of a human ear, if you were to stuff flies within the fold.
Yours most sincerely,

CH. DARWIN.

CHARLES DARWIN 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, pepsin; 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.

... I began reading the Madagascar squib (A description of a carnivorous
plant supposed to subsist on human beings.) quite gravely, and when I
found it stated that Felis and Bos inhabited Madagascar, I thought it
was a false story, and did not perceive it was a hoax till I came to the
woman...

CHARLES DARWIN TO F.C. DONDERS. (Professor Donders, the well-known
physiologist of Utrecht.) Down, July 7, 1874.

My dear Professor Donders,

My son George writes to me that he has seen you, and that you have been
very kind to him, for which I return to you my cordial thanks. He
tells me on your authority, of a fact which interests me in the highest
degree, and which I much wish to be allowed to quote. It relates to the
action of one millionth of a grain of atropine on the eye. Now will you
be so kind, whenever you can find a little leisure, to tell me whether
you yourself have observed this fact, or believe it on good authority.
I also wish to know what proportion by weight the atropine bore to the
water solution, and how much of the solution was applied to the eye. The
reason why I am so anxious on this head is that it gives some support
to certain facts repeatedly observed by me with respect to the action of
phosphate of ammonia on Drosera. The 1/4000000 of a grain absorbed by
a gland clearly makes the tentacle which bears this gland become
inflected; and I am fully convinced that 1/20000000 of a grain of the
crystallised salt (i.e. containing about one-third of its weight of
water of crystallisation) does the same. Now I am quite unhappy at the
thought of having to publish such a statement. It will be of great value
to me to be able to give any analogous facts in support. The case of
Drosera is all the more interesting as the absorption of the salt or
any other stimulant applied to the gland causes it to transmit a motor
influence to the base of the tentacle which bears the gland.

Pray forgive me for troubling you, and do not trouble yourself to answer
this until your health is fully re-established.

Pray believe me, Yours very sincerely, CHARLES DARWIN.

[During the summer of 1874 he was at work on the genus Utricularia,
and he wrote (July 16th) to Sir J.D. Hooker giving some account of the
progress of his work:--

"I am rather glad you have not been able to send Utricularia, for the
common species has driven F. and me almost mad. The structure is MOST
complex. The bladders catch a multitude of Entomostraca, and larvae of
insects. The mechanism for capture is excellent. But there is much that
we cannot understand. From what I have seen to-day, I strongly suspect
that it is necrophagous, i.e. that it cannot digest, but absorbs
decaying matter."

He was indebted to Lady Dorothy Nevill for specimens of the curious
Utricularia montana, which is not aquatic like the European species,
but grows among the moss and debris on the branches of trees. To this
species the following letter refers:]

CHARLES DARWIN TO LADY DOROTHY NEVILL. Down September 18 [1874].

Dear Lady Dorothy Nevill,

I am so much obliged to you. I was so convinced that the bladders were
with the leaves that I never thought of removing the moss, and this was
very stupid of me. The great solid bladder-like swellings almost on the
surface are wonderful objects, but are not the true bladders. These I
found on the roots near the surface, and down to a depth of two inches
in the sand. They are as transparent as glass, from 1/20 to 1/100 of
an inch in size, and hollow. They have all the important points of
structure of the bladders of the floating English species, and I felt
confident I should find captured prey. And so I have to my delight in
two bladders, with clear proof that they had absorbed food from the
decaying mass. For Utricularia is a carrion-feeder, and not strictly
carnivorous like Drosera.

The great solid bladder-like bodies, I believe, are reservoirs of water
like a camel's stomach. As soon as I have made a few more observations,
I mean to be so cruel as to give your plant no water, and observe
whether the great bladders shrink and contain air instead of water; I
shall then also wash all earth from all roots, and see whether there are
true bladders for capturing subterranean insects down to the very bottom
of the pot. Now shall you think me very greedy, if I say that supposing
the species is not very precious, and you have several, will you give
me one more plant, and if so, please to send it to "Orpington Station,
S.E.R., to be forwarded by foot messenger."

I have hardly ever enjoyed a day more in my life than I have this day's
work; and this I owe to your Ladyship's great kindness.

The seeds are very curious monsters; I fancy of some plant allied to
Medicago, but I will show them to Dr. Hooker.

Your ladyship's very gratefully, CH. DARWIN.

CHARLES DARWIN TO J.D. HOOKER. Down, September 30, 1874.

My dear H.,

Your magnificent present of Aldrovanda has arrived quite safe. I have
enjoyed greatly a good look at the shut leaves, one of which I cut open.
It is an aquatic Dionaea, which has acquired some structures identical
with those of Utricularia!

If the leaves open and I can transfer them open under the microscope, I
will try some experiments, for mortal man cannot resist the temptation.
If I cannot transfer, I will do nothing, for otherwise it would require
hundreds of leaves.

You are a good man to give me such pleasure.

Yours affectionately, C. DARWIN.

[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, 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.]

CHAPTER 2.XIV. -- THE 'POWER OF MOVEMENT IN PLANTS.'

1880.

[The few sentences in the autobiographical chapter give with sufficient
clearness the connection between the 'Power of Movement,' and one of the
author's earlier books, that on 'Climbing Plants.' The central idea
of the book is that the movements of plants in relation to light,
gravitation, etc., are modifications of a spontaneous tendency to
revolve or circumnutate, which is widely inherent in the growing parts
of plants. This conception has not been generally adopted, and has not
taken a place among the canons of orthodox physiology. The book has been
treated by Professor Sachs with a few words of professorial contempt;
and by Professor Wiesner it has been honoured by careful and generously
expressed criticism.

Mr. Thiselton Dyer ('Charles Darwin' ('Nature' Series), page 41.) has
well said: "Whether this masterly conception of the unity of what has
hitherto seemed a chaos of unrelated phenomena will be sustained, time
alone will show. But no one can doubt the importance of what Mr. Darwin
has done, in showing that for the future the phenomena of plant movement
can and indeed must be studied from a single point of view."

The work was begun in the summer of 1877, after the publication of
'Different Forms of Flowers,' and by the autumn his enthusiasm for the
subject was thoroughly established, and he wrote to Mr. Dyer: "I am
all on fire at the work." At this time he was studying the movements
of cotyledons, in which the sleep of plants is to be observed in its
simplest form; in the following spring he was trying to discover what
useful purpose these sleep-movements could serve, and wrote to Sir
Joseph Hooker (March 25th, 1878):--

"I think we have PROVED that the sleep of plants is to lessen the injury
to the leaves from radiation. This has interested me much, and has cost
us great labour, as it has been a problem since the time of Linnaeus.
But we have killed or badly injured a multitude of plants: N.B.--Oxalis
carnosa was most valuable, but last night was killed."

His letters of this period do not give any connected account of
the progress of the work. The two following are given as being
characteristic of the author:]

CHARLES DARWIN TO W. THISELTON DYER. Down, June 2, 1878.

My dear Dyer,

I remember saying that I should die a disgraced man if I did not observe
a seedling Cactus and Cycas, and you have saved me from this horrible
fate, as they move splendidly and normally. But I have two questions to
ask: the Cycas observed was a huge seed in a broad and very shallow pot
with cocoa-nut fibre as I suppose. It was named only Cycas. Was it Cycas
pectinata? I suppose that I cannot be wrong in believing that what first
appears above ground is a true leaf, for I can see no stem or axis.
Lastly, you may remember that I said that we could not raise Opuntia
nigricans; now I must confess to a piece of stupidity; one did come up,
but my gardener and self stared at it, and concluded that it could not
be a seedling Opuntia, but now that I have seen one of O. basilaris, I
am sure it was; I observed it only casually, and saw movements, which
makes me wish to observe carefully another. If you have any fruit,
will Mr. Lynch (Mr. R.I. Lynch, now Curator of the Botanic Garden at
Cambridge was at this time in the Royal Gardens, Kew.) be so kind as to
send one more?

I am working away like a slave at radicles [roots] and at movements of
true leaves, for I have pretty well done with cotyledons...

That was an EXCELLENT letter about the Gardens (This refers to an
attempt to induce the Government to open the Royal Gardens at Kew in the
morning.): I had hoped that the agitation was over. Politicians are a
poor truckling lot, for [they] must see the wretched effects of keeping
the gardens open all day long.

Your ever troublesome friend, CH. DARWIN.

CHARLES DARWIN TO W. THISELTON DYER. 4 Bryanston St., Portman Square,
November 21 [1878].

My dear Dyer,

I must thank you for all the wonderful trouble which you have taken
about the seeds of Impatiens, and on scores of other occasions. It in
truth makes me feel ashamed of myself, and I cannot help thinking: "Oh
Lord, when he sees our book he will cry out, is this all for which I
have helped so much!" In seriousness, I hope that we have made out some
points, but I fear that we have done very little for the labour which
we have expended on our work. We are here for a week for a little rest,
which I needed.

If I remember right, November 30th, is the anniversary at the Royal, and
I fear Sir Joseph must be almost at the last gasp. I shall be glad when
he is no longer President.

Yours very sincerely, CH. DARWIN.

[In the spring of the following year, 1879. When he was engaged in
putting his results together, he wrote somewhat despondingly to Mr.
Dyer: "I am overwhelmed with my notes, and almost too old to undertake
the job which I have in hand--i.e. movements of all kinds. Yet it is
worse to be idle."

Later on in the year, when the work was approaching completion, he wrote
to Prof. Carus (July 17, 1879), with respect to a translation:--

"Together with my son Francis, I am preparing a rather large volume on
the general movements of Plants, and I think that we have made out a
good many new points and views.

"I fear that our views will meet a good deal of opposition in Germany;
but we have been working very hard for some years at the subject.

"I shall be MUCH pleased if you think the book worth translating, and
proof-sheets shall be sent you, whenever they are ready."

In the autumn he was hard at work on the manuscript, and wrote to Dr.
Gray (October 24, 1879):--

"I have written a rather big book--more is the pity--on the movements
of plants, and I am now just beginning to go over the MS. for the second
time, which is a horrid bore."

Only the concluding part of the next letter refers to the 'Power of
Movements':]

CHARLES DARWIN TO A. DE CANDOLLE. May 28, 1880.

My dear Sir,

I am particularly obliged to you for having so kindly send me your
'Phytographie' (A book on the methods of botanical research, more
especially of systematic work.); for if I had merely seen it advertised,
I should not have supposed that it could have concerned me. As it is, I
have read with very great interest about a quarter, but will not
delay longer thanking you. All that you say seems to me very clear
and convincing, and as in all your writings I find a large number of
philosophical remarks new to me, and no doubt shall find many more. They
have recalled many a puzzle through which I passed when monographing the
Cirripedia; and your book in those days would have been quite invaluable
to me. It has pleased me to find that I have always followed your plan
of making notes on separate pieces of paper; I keep several scores of
large portfolios, arranged on very thin shelves about two inches apart,
fastened to the walls of my study, and each shelf has its proper name
or title; and I can thus put at once every memorandum into its proper
place. Your book will, I am sure, be very useful to many young students,
and I shall beg my son Francis (who intends to devote himself to the
physiology of plants) to read it carefully.

As for myself I am taking a fortnight's rest, after sending a pile of
MS. to the printers, and it was a piece of good fortune that your book
arrived as I was getting into my carriage, for I wanted something to
read whilst away from home. My MS. relates to the movements of plants,
and I think that I have succeeded in showing that all the more important
great classes of movements are due to the modification of a kind of
movement common to all parts of all plants from their earliest youth.

Pray give my kind remembrances to your son, and with my highest respect
and best thanks,

Believe me, my dear Sir, yours very sincerely, CHARLES DARWIN.

P.S.--It always pleases me to exalt plants in the organic scale, and if
you will take the trouble to read my last chapter when my book (which
will be sadly too big) is published and sent to you, I hope and think
that you also will admire some of the beautiful adaptations by which
seedling plants are enabled to perform their proper functions.

[The book was published on November 6, 1880, and 1500 copies were
disposed of at Mr. Murray's sale. With regard to it he wrote to Sir J.D.
Hooker (November 23):--

"Your note has pleased me much--for I did not expect that you would have
had time to read ANY of it. Read the last chapter, and you will know the
whole result, but without the evidence. The case, however, of radicles
bending after exposure for an hour to geotropism, with their tips (or
brains) cut off is, I think, worth your reading (bottom of page 525); it
astounded me. The next most remarkable fact, as it appeared to me (page
148), is the discrimination of the tip of the radicle between a slightly
harder and softer object affixed on opposite sides of tip. But I will
bother you no more about my book. The sensitiveness of seedlings to
light is marvellous."

To another friend, Mr. Thiselton Dyer, he wrote (November 28, 1880):--

"Very many thanks for your most kind note, but you think too highly of
our work, not but what this is very pleasant... Many of the Germans are
very contemptuous about making out the use of organs; but they may sneer
the souls out of their bodies, and I for one shall think it the most
interesting part of Natural History. Indeed you are greatly mistaken if
you doubt for one moment on the very great value of your constant and
most kind assistance to us."

The book was widely reviewed, and excited much interest among the
general public. The following letter refers to a leading article in the
"Times", November 20, 1880:]

CHARLES DARWIN TO MRS. HALIBURTON. (Mrs. Haliburton was a daughter of my
father's early friend, the late Mr. Owen, of Woodhouse.) Down, November
22, 1880.

My dear Sarah,

You see how audaciously I begin; but I have always loved and shall
ever love this name. Your letter has done more than please me, for its
kindness has touched my heart. I often think of old days and of the
delight of my visits to Woodhouse, and of the deep debt of gratitude
I owe to your father. It was very good of you to write. I had quite
forgotten my old ambition about the Shrewsbury newspaper (Mrs.
Haliburton had reminded him of his saying as a boy that if Eddowes'
newspaper ever alluded to him as "our deserving fellow-townsman," his
ambition would be amply gratified.); but I remember the pride which I
felt when I saw in a book about beetles the impressive words "captured
by C. Darwin." Captured sounded so grand compared with caught. This
seemed to me glory enough for any man! I do not know in the least what
made the "Times" glorify me (The following is the opening sentence
of the leading article:--"Of all our living men of science none have
laboured longer and to more splendid purpose than Mr. Darwin."), for it
has sometimes pitched into me ferociously.

I should very much like to see you again, but you would find a visit
here very dull, for we feel very old and have no amusement, and lead
a solitary life. But we intend in a few weeks to spend a few days in
London, and then if you have anything else to do in London, you would
perhaps come and lunch with us. (My father had the pleasure of seeing
Mrs. Haliburton at his brother's house in Queen Anne Street.)

Believe me, my dear Sarah, Yours gratefully and affectionately, CHARLES
DARWIN.

[The following letter was called forth by the publication of a volume
devoted to the criticism of the 'Power of Movement in Plants' by an
accomplished botanist, Dr. Julius Wiesner, Professor of Botany in the
University of Vienna:]

CHARLES DARWIN TO JULIUS WIESNER. Down, October 25th, 1881.

My dear Sir,

I have now finished your book ('Das Bewegungsvermogen der Pflanzen.'
Vienna, 1881.), and have understood the whole except a very few
passages. In the first place, let me thank you cordially for the manner
in which you have everywhere treated me. You have shown how a man may
differ from another in the most decided manner, and yet express his
difference with the most perfect courtesy. Not a few English and German
naturalists might learn a useful lesson from your example; for the
coarse language often used by scientific men towards each other does no
good, and only degrades science.

I have been profoundly interested by your book, and some of your
experiments are so beautiful, that I actually felt pleasure while being
vivisected. It would take up too much space to discuss all the important
topics in your book. I fear that you have quite upset the interpretation
which I have given of the effects of cutting off the tips of
horizontally extended roots, and of those laterally exposed to moisture;
but I cannot persuade myself that the horizontal position of lateral
branches and roots is due simply to their lessened power of growth. Nor
when I think of my experiments with the cotyledons of Phalaris, can I
give up the belief of the transmission of some stimulus due to light
from the upper to the lower part. At page 60 you have misunderstood my
meaning, when you say that I believe that the effects from light
are transmitted to a part which is not itself heliotropic. I never
considered whether or not the short part beneath the ground was
heliotropic; but I believe that with young seedlings the part which
bends NEAR, but ABOVE the ground is heliotropic, and I believe so from
this part bending only moderately when the light is oblique, and bending
rectangularly when the light is horizontal. Nevertheless the bending of
this lower part, as I conclude from my experiments with opaque caps,
is influenced by the action of light on the upper part. My opinion,
however, on the above and many other points, signifies very little, for
I have no doubt that your book will convince most botanists that I am
wrong in all the points on which we differ.

Independently of the question of transmission, my mind is so full of
facts leading me to believe that light, gravity, etc., act not in a
direct manner on growth, but as stimuli, that I am quite unable to
modify my judgment on this head. I could not understand the passage at
page 78, until I consulted my son George, who is a mathematician. He
supposes that your objection is founded on the diffused light from the
lamp illuminating both sides of the object, and not being reduced, with
increasing distance in the same ratio as the direct light; but he doubts
whether this NECESSARY correction will account for the very little
difference in the heliotropic curvature of the plants in the successive
pots.

With respect to the sensitiveness of the tips of roots to contact, I
cannot admit your view until it is proved that I am in error about bits
of card attached by liquid gum causing movement; whereas no movement
was caused if the card remained separated from the tip by a layer of the
liquid gum. The fact also of thicker and thinner bits of card attached
on opposite sides of the same root by shellac, causing movement in one
direction, has to be explained. You often speak of the tip having been
injured; but externally there was no sign of injury: and when the tip
was plainly injured, the extreme part became curved TOWARDS the injured
side. I can no more believe that the tip was injured by the bits of
card, at least when attached by gum-water, than that the glands of
Drosera are injured by a particle of thread or hair placed on it, or
that the human tongue [is so] when it feels any such object.

About the most important subject in my book, namely circumnutation, I
can only say that I feel utterly bewildered at the difference in our
conclusions; but I could not fully understand some parts which my
son Francis will be able to translate to me when he returns home. The
greater part of your book is beautifully clear.

Finally, I wish that I had enough strength and spirit to commence
a fresh set of experiments, and publish the results, with a full
recantation of my errors when convinced of them; but I am too old for
such an undertaking, nor do I suppose that I shall be able to do much,
or any more, original work. I imagine that I see one possible source of
error in your beautiful experiment of a plant rotating and exposed to a
lateral light.

With high respect and with sincere thanks for the kind manner in which
you have treated me and my mistakes, I remain, my dear Sir, yours
sincerely,

CHARLES DARWIN.

CHAPTER 2.XV. -- MISCELLANEOUS BOTANICAL LETTERS.

1873-1882.

[The present chapter contains a series of miscellaneous letters on
botanical subjects. Some of them show my father's varied interests in
botanical science, and others give account of researches which never
reached completion.]

BLOOM ON LEAVES AND FRUIT.

[His researches into the meaning of the "bloom," or waxy coating found
on many leaves, was one of those inquiries which remained unfinished at
the time of his death. He amassed a quantity of notes on the subject,
part of which I hope to publish at no distant date. (A small instalment
on the relation between bloom and the distribution of the stomata on
leaves has appeared in the 'Journal of the Linnean Society,' 1886.
Tschirsch ("Linnaea", 1881) has published results identical with
some which my father and myself obtained, viz. that bloom diminishes
transpiration. The same fact was previously published by Garreau in
1850.)

One of his earliest letters on this subject was addressed in August,
1873, to Sir Joseph Hooker:--

"I want a little information from you, and if you do not yourself know,
please to enquire of some of the wise men of Kew.

"Why are the leaves and fruit of so many plants protected by a thin
layer of waxy matter (like the common cabbage), or with fine hair, so
that when such leaves or fruit are immersed in water they appear as if
encased in thin glass? It is really a pretty sight to put a pod of the
common pea, or a raspberry into water. I find several leaves are thus
protected on the under surface and not on the upper.

"How can water injure the leaves if indeed this is at all the case?"

On this latter point he wrote to Sir Thomas Farrer:--

"I am now become mad about drops of water injuring leaves. Please ask
Mr. Paine (Sir Thomas Farrer's gardener.) whether he believes, FROM
HIS OWN EXPERIENCE, that drops of water injure leaves or fruit in his
conservatories. It is said that the drops act as burning-glasses; if
this is true, they would not be at all injurious on cloudy days. As
he is so acute a man, I should very much like to hear his opinion. I
remember when I grew hot-house orchids I was cautioned not to wet their
leaves; but I never then thought on the subject.

"I enjoyed my visit greatly with you, and I am very sure that all
England could not afford a kinder and pleasanter host."

Some years later he took up the subject again, and wrote to Sir Joseph
Hooker (May 25, 1877):--

"I have been looking over my old notes about the "bloom" on plants,
and I think that the subject is well worth pursuing, though I am very
doubtful of any success. Are you inclined to aid me on the mere chance
of success, for without your aid I could do hardly anything?"]

CHARLES DARWIN TO ASA GRAY. Down, June 4 [1877].

... I am now trying to make out the use or function of "bloom," or the
waxy secretion on the leaves and fruit of plants, but am VERY doubtful
whether I shall succeed. Can you give me any light? Are such plants
commoner in warm than in colder climates? I ask because I often walk out
in heavy rain, and the leaves of very few wild dicotyledons can be here
seen with drops of water rolling off them like quick-silver. Whereas in
my flower garden, greenhouse, and hot-houses there are several. Again,
are bloo-protected plants common on your DRY western plains? Hooker
THINKS that they are common at the Cape of Good Hope. It is a puzzle
to me if they are common under very dry climates, and I find bloom very
common on the Acacias and Eucalypti of Australia. Some of the Eucalypti
which do not appear to be covered with bloom have the epidermis
protected by a layer of some substance which is dissolved in boiling
alcohol. Are there any bloo-protected leaves or fruit in the Arctic
regions? If you can illuminate me, as you so often have done, pray do
so; but otherwise do not bother yourself by answering.

Yours affectionately, C. DARWIN.

CHARLES DARWIN TO W. THISELTON DYER. Down, September 5 [1877].

My dear Dyer,

One word to thank you. I declare had it not been for your kindness, we
should have broken down. As it is we have made out clearly that with
some plants (chiefly succulent) the bloom checks evaporation--with
some certainly prevents attacks of insects; with SOME sea-shore plants
prevents injury from salt-water, and, I believe, with a few prevents
injury from pure water resting on the leaves. This latter is as yet
the most doubtful and the most interesting point in relation to the
movements of plants...

CHARLES DARWIN TO F. MULLER. Down, July 4 [1881].

My dear Sir,

Your kindness is unbounded, and I cannot tell you how much your last
letter (May 31) has interested me. I have piles of notes about the
effect of water resting on leaves, and their movements (as I supposed)
to shake off the drops. But I have not looked over these notes for a
long time, and had come to think that perhaps my notion was mere fancy,
but I had intended to begin experimenting as soon as I returned home;
and now with your INVALUABLE letter about the position of the leaves of
various plants during rain (I have one analogous case with Acacia from
South Africa), I shall be stimulated to work in earnest.

VARIABILITY.

[The following letter refers to a subject on which my father felt the
strongest interest:--the experimental investigation of the causes of
variability. The experiments alluded to were to some extent planned out,
and some preliminary work was begun in the direction indicated below,
but the research was ultimately abandoned.]

CHARLES DARWIN TO J.H. GILBERT. (Dr. Gilbert, F.R.S., joint author
with Sir John Bennett Lawes of a long series of valuable researches in
Scientific Agriculture.) Down, February 16, 1876.

My dear Sir,

When I met you at the Linnean Society, you were so kind as to say that
you would aid me with advice, and this will be of the utmost value to me
and my son. I will first state my object, and hope that you will excuse
a long letter. It is admitted by all naturalists that no problem is so
perplexing as what causes almost every cultivated plant to vary, and no
experiments as yet tried have thrown any light on the subject. Now
for the last ten years I have been experimenting in crossing and
self-fertilising plants; and one indirect result has surprised me much;
namely, that by taking pains to cultivate plants in pots under glass
during several successive generations, under nearly similar conditions,
and by self-fertilising them in each generation, the colour of the
flowers often changes, and, what is very remarkable, they became in some
of the most variable species, such as Mimulus, Carnation, etc., quite
constant, like those of a wild species.

This fact and several others have led me to the suspicion that the cause
of variation must be in different substances absorbed from the soil by
these plants when their powers of absorption are not interfered with
by other plants with which they grow mingled in a state of nature.
Therefore my son and I wish to grow plants in pots in soil entirely, or
as nearly entirely as is possible, destitute of all matter which plants
absorb, and then to give during several successive generations to
several plants of the same species as different solutions as may be
compatible with their life and health. And now, can you advise me how
to make soil approximately free of all the substances which plants
naturally absorb? I suppose white silver sand, sold for cleaning
harness, etc., is nearly pure silica, but what am I to do for alumina?
Without some alumina I imagine that it would be impossible to keep the
soil damp and fit for the growth of plants. I presume that clay washed
over and over again in water would still yield mineral matter to the
carbonic acid secreted by the roots. I should want a good deal of soil,
for it would be useless to experimentise unless we could fill from
twenty to thirty moderately sized flower-pots every year. Can you
suggest any plan? for unless you can it would, I fear, be useless for us
to commence an attempt to discover whether variability depends at all
on matter absorbed from the soil. After obtaining the requisite kind of
soil, my notion is to water one set of plants with nitrate of potassium,
another set with nitrate of sodium, and another with nitrate of lime,
giving all as much phosphate of ammonia as they seemed to support, for
I wish the plants to grow as luxuriantly as possible. The plants watered
with nitrate of Na and of Ca would require, I suppose, some K; but
perhaps they would get what is absolutely necessary from such soil as I
should be forced to employ, and from the rain-water collected in tanks.
I could use hard water from a deep well in the chalk, but then all the
plants would get lime. If the plants to which I give Nitrate of Na and
of Ca would not grow I might give them a little alum.

I am well aware how very ignorant I am, and how crude my notions are;
and if you could suggest any other solutions by which plants would be
likely to be affected it would be a very great kindness. I suppose that
there are no organic fluids which plants would absorb, and which I could
procure?

I must trust to your kindness to excuse me for troubling you at such
length, and,

I remain, dear Sir, yours sincerely, CHARLES DARWIN.

[The next letter to Professor Semper (Professor of Zoology at Wurzburg.)
bears on the same subject:]

FROM CHARLES DARWIN TO K. SEMPER. Down, July 19, 1881.

My dear Professor Semper,

I have been much pleased to receive your letter, but I did not expect
you to answer my former one... I cannot remember what I wrote to you,
but I am sure that it must have expressed the interest which I felt in
reading your book. (Published in the 'International Scientific Series,'
in 1881, under the title, 'The Natural Conditions of Existence as they
affect Animal Life.') I thought that you attributed too much weight to
the DIRECT action of the environment; but whether I said so I know not,
for without being asked I should have thought it presumptuous to have
criticised your book, nor should I now say so had I not during the last
few days been struck with Professor Hoffmann's review of his own work in
the 'Botanische Zeitung,' on the variability of plants; and it is really
surprising how little effect he produced by cultivating certain plants
under unnatural conditions, as the presence of salt, lime, zinc, etc.,
etc., during SEVERAL generations. Plants, moreover, were selected which
were the most likely to vary under such conditions, judging from the
existence of closely-allied forms adapted for these conditions. No
doubt I originally attributed too little weight to the direct action of
conditions, but Hoffmann's paper has staggered me. Perhaps hundreds of
generations of exposure are necessary. It is a most perplexing subject.
I wish I was not so old, and had more strength, for I see lines of
research to follow. Hoffmann even doubts whether plants vary more
under cultivation than in their native home and under their natural
conditions. If so, the astonishing variations of almost all cultivated
plants must be due to selection and breeding from the varying
individuals. This idea crossed my mind many years ago, but I was
afraid to publish it, as I thought that people would say, "how he does
exaggerate the importance of selection."

I still MUST believe that changed conditions give the impulse to
variability, but that they act IN MOST CASES in a very indirect manner.
But, as I said, it is a most perplexing problem. Pray forgive me for
writing at such length; I had no intention of doing so when I sat down
to write.

I am extremely sorry to hear, for your own sake and for that of Science,
that you are so hard worked, and that so much of your time is consumed
in official labour.

Pray believe me, dear Professor Semper, Yours sincerely, CHARLES DARWIN.

GALLS.

[Shortly before his death, my father began to experimentise on the
possibility of producing galls artificially. A letter to Sir J.D. Hooker
(November 3, 1880) shows the interest which he felt in the question:--

"I was delighted with Paget's Essay ('Disease in Plants,' by Sir
James Paget.--See "Gardeners' Chronicle", 1880.); I hear that he has
occasionally attended to this subject from his youth... I am very glad he
has called attention to galls: this has always seemed to me a profoundly
interesting subject; and if I had been younger would take it up."

His interest in this subject was connected with his ever-present wish
to learn something of the causes of variation. He imagined to himself
wonderful galls caused to appear on the ovaries of plants, and by these
means he thought it possible that the seed might be influenced, and thus
new varieties arise. He made a considerable number of experiments by
injecting various reagents into the tissues of leaves, and with some
slight indications of success.]

AGGREGATION.

[The following letter gives an idea of the subject of the last of his
published papers. ('Journal of the Linnean Society.' volume xix, 1882,
pages 239 and 262.) The appearances which he observed in leaves and
roots attracted him, on account of their relation to the phenomena of
aggregation which had so deeply interested him when he was at work on
Drosera:]

CHARLES DARWIN TO S.H. VINES. (Reader in Botany in the University of
Cambridge.) Down, November 1, 1881.

My dear Mr. Vines,

As I know how busy you are, it is a great shame to trouble you. But you
are so rich in chemical knowledge about plants, and I am so poor, that
I appeal to your charity as a pauper. My question is--Do you know of
any solid substance in the cells of plants which glycerine and water
dissolves? But you will understand my perplexity better if I give you
the facts: I mentioned to you that if a plant of Euphorbia peplus is
gently dug up and the roots placed for a short time in a weak solution
(1 to 10,000 of water, suffices in 24 hours) of carbonate of ammonia the
(generally) alternate longitudinal rows of cells in every rootlet, from
the root-cap up to the very top of the root (but not as far as I have
yet seen in the green stem) become filled with translucent, brownish
grains of matter. These rounded grains often cohere and even become
confluent. Pure phosphate and nitrate of ammonia produce (though more
slowly) the same effect, as does pure carbonate of soda.

Now, if slices of root under a cover-glass are irrigated with glycerine
and water, every one of the innumerable grains in the cells disappear
after some hours. What am I to think of this.?...

Forgive me for bothering you to such an extent; but I must mention
that if the roots are dipped in boiling water there is no deposition of
matter, and carbonate of ammonia afterwards produces no effect. I should
state that I now find that the granular matter is formed in the cells
immediately beneath the thin epidermis, and a few other cells near the
vascular tissue. If the granules consisted of living protoplasm (but
I can see no traces of movement in them), then I should infer that
the glycerine killed them and aggregation ceased with the diffusion of
invisibly minute particles, for I have seen an analogous phenomenon in
Drosera.

If you can aid me, pray do so, and anyhow forgive me. Yours very
sincerely, CH. DARWIN.

MR. TORBITT'S EXPERIMENTS ON THE POTATO-DISEASE.

[Mr. James Torbitt, of Belfast, has been engaged for the last twelve
years in the difficult undertaking, in which he has been to a large
extent successful, of raising fungus-proof varieties of the potato. My
father felt great interest in Mr. Torbitt's work, and corresponded with
him from 1876 onwards. The following letter, giving a clear account of
Mr. Torbitt's method and of my father's opinion of the probability of
its success, was written with the idea that Government aid for the work
might possibly be obtainable:]

CHARLES DARWIN TO T.H. FARRER. Down, March 2, 1878.

My dear Farrer,

Mr. Torbitt's plan of overcoming the potato-disease seems to me by far
the best which has ever been suggested. It consists, as you know
from his printed letter, of rearing a vast number of seedlings from
cross-fertilised parents, exposing them to infection, ruthlessly
destroying all that suffer, saving those which resist best, and
repeating the process in successive seminal generations. My belief in
the probability of good results from this process rests on the fact of
all characters whatever occasionally varying. It is known, for instance,
that certain species and varieties of the vine resist phylloxera better
than others. Andrew Knight found in one variety or species of the apple
which was not in the least attacked by coccus, and another variety has
been observed in South Australia. Certain varieties of the peach resist
mildew, and several other such cases could be given. Therefore there is
no great improbability in a new variety of potato arising which would
resist the fungus completely, or at least much better than any existing
variety. With respect to the cross-fertilisation of two distinct
seedling plants, it has been ascertained that the offspring thus raised
inherit much more vigorous constitutions and generally are more prolific
than seedlings from self-fertilised parents. It is also probable that
cross-fertilisation would be especially valuable in the case of the
potato, as there is reason to believe that the flowers are seldom
crossed by our native insects; and some varieties are absolutely sterile
unless fertilised with pollen from a distinct variety. There is some
evidence that the good effects from a cross are transmitted for several
generations; it would not, therefore be necessary to cross-fertilise the
seedlings in each generation, though this would be desirable, as it is
almost certain that a greater number of seeds would thus be obtained. It
should be remembered that a cross between plants raised from the tubers
of the same plant, though growing on distinct roots, does no more good
than a cross between flowers on the same individual. Considering the
whole subject, it appears to me that it would be a national misfortune
if the cros-fertilised seeds in Mr. Torbitt's possession produced by
parents which have already shown some power of resisting the disease,
are not utilised by the Government, or some public body, and the process
of selection continued during several more generations.

Should the Agricultural Society undertake the work, Mr. Torbitt's
knowledge gained by experience would be especially valuable; and
an outline of the plan is given in his printed letter. It would be
necessary that all the tubers produced by each plant should be collected
separately, and carefully examined in each succeeding generation.

It would be advisable that some kind of potato eminently liable to the
disease should be planted in considerable numbers near the seedlings so
as to infect them.

Altogether the trial would be one requiring much care and extreme
patience, as I know from experience with analogous work, and it may be
feared that it would be difficult to find any one who would pursue the
experiment with sufficient energy. It seems, therefore, to me highly
desirable that Mr. Torbitt should be aided with some small grant so as
to continue the work himself.

Judging from his reports, his efforts have already been crowned in so
short a time with more success than could have been anticipated; and
I think you will agree with me, that any one who raises a fungus-proof
potato will be a public benefactor of no common kind.

My dear Farrer, yours sincerely, CHARLES DARWIN.

[After further consultation with Sir Thomas Farrer and with Mr. Caird,
my father became convinced that it was hopeless to attempt to obtain
Government aid. He wrote to Mr. Torbitt to this effect, adding, "it
would be less trouble to get up a subscription from a few rich leading
agriculturists than from Government. This plan I think you cannot object
to, as you have asked nothing, and will have nothing whatever to do with
the subscription. In fact, the affair is, in my opinion, a compliment
to you." The idea here broached was carried out, and Mr. Torbitt was
enabled to continue his work by the aid of a sum to which Sir T. Farrer,
Mr. Caird, my father, and a few friends, subscribed.

My father's sympathy and encouragement were highly valued by Mr.
Torbitt, who tells me that without them he should long ago have given up
his attempt. A few extracts will illustrate my father's fellow feeling
with Mr. Torbitt's energy and perseverance:--

"I admire your indomitable spirit. If any one ever deserved success,
you do so, and I keep to my original opinion that you have a very good
chance of raising a fungus-proof variety of the potato.

"A pioneer in a new undertaking is sure to meet with many
disappointments, so I hope that you will keep up your courage, though we
have done so very little for you."

Mr. Torbitt tells me that he still (1887) succeeds in raising varieties
possessing well-marked powers of resisting disease; but this immunity is
not permanent, and, after some years, the varieties become liable to the
attacks of the fungus.]

THE KEW INDEX OF PLANT-NAMES, OR 'NOMENCLATOR DARWINIANUS.'

[Some account of my father's connection with the Index of Plant-names
now (1887) in course of preparation at Kew will be found in Mr. B.
Daydon Jackson's paper in the 'Journal of Botany,' 1887, page 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.

"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 the 'Nomenclator'
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." (Kew Gardens Report, 1881, page 62.)

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 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 recognize 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" (Kew Gardens
Report, 1881, page 62.)--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
much interest, as illustrating the motives that actuated my father in
this matter. Professor Judd writes:--

"On the occasion of my last visit to him, he told me that his income
having recently greatly increased, while his wants remained 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 of 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."

Sir Joseph Hooker was asked by my father "to take into consideration,
with the aid of the botanical staff at Kew and the late Mr. Bentham, the
extent and scope of the proposed work, and to suggest the best means of
having it executed. In doing this, Sir Joseph had further the advantage
of the great knowledge and experience of Professor Asa Gray, of
Cambridge, U.S.A., and of Mr. John Ball, F.R.S." ('Journal of Botany,'
loc. cit.)

The plan of the proposed work having been carefully considered, 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.' The colossal nature
of the work in progress at Kew may be estimated by the fact that the
manuscript of the 'Index' is at the present time (1887) believed to
weigh more than a ton. Under Sir Joseph Hooker's supervision the work
goes steadily forward, being carried out with admirable zeal by Mr.
Jackson, who devotes himself unsparingly to the enterprise, in which,
too, he has the advantage of the active interest in the work felt by
Professor Oliver and Mr. Thiselton Dyer.

The Kew 'Index,' which will, in all probability, be ready to go to press
in four or five years, 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.]

CHAPTER 2.XVI. -- CONCLUSION.

Some idea of the general course of my father's health may have been
gathered from the letters given in the preceding pages. The subject of
health appears more prominently than is often necessary in a Biography,
because it was, unfortunately, so real an element in determining the
outward form of his life.

During the last ten years of his life the condition of his health was a
cause of satisfaction and hope to his family. His condition showed
signs of amendment in several particulars. He suffered less distress
and discomfort, and was able to work more steadily. Something has
been already said of Dr. Bence Jones's treatment, from which my father
certainly derived benefit. In later years he became a patient of Sir
Andrew Clark, under whose care he improved greatly in general health. It
was not only for his generously rendered service that my father felt
a debt of gratitude towards Sir Andrew Clark. He owed to his cheering
personal influence an ofte-repeated encouragement, which laterally added
something real to his happiness, and he found sincere pleasure in Sir
Andrew's friendship and kindness towards himself and his children.

Scattered through the past pages are one or two references to pain or
uneasiness felt in the region of the heart. How far these indicate that
the heart was affected early in life, I cannot pretend to say; in any
case it is certain that he had no serious or permanent trouble of
this nature until shortly before his death. In spite of the general
improvement in his health, which has been above alluded to, there was
a certain loss of physical vigour occasionally apparent during the last
few years of his life. This is illustrated by a sentence in a letter
to his old friend Sir James Sulivan, written on January 10, 1879: "My
scientific work tires me more than it used to do, but I have nothing
else to do, and whether one is worn out a year or two sooner or later
signifies but little."

A similar feeling is shown in a letter to Sir J.D. Hooker of June 15,
1881. My father was staying at Patterdale, and wrote: "I am rather
despondent about myself... I have not the heart or strength to begin any
investigation lasting years, which is the only thing which I enjoy, and
I have no little jobs which I can do."

In July, 1881, he wrote to Mr. Wallace, "We have just returned home
after spending five weeks on Ullswater; the scenery is quite charming,
but I cannot walk, and everything tires me, even seeing scenery... What
I shall do with my few remaining years of life I can hardly tell. I
have everything to make me happy and contented, but life has become very
wearisome to me." He was, however, able to do a good deal of work, and
that of a trying sort (On the action of carbonate of ammonia on roots
and leaves.), during the autumn of 1881, but towards the end of the year
he was clearly in need of rest; and during the winter was in a lower
condition than was usual with him.

On December 13 he went for a week to his daughter's house in Bryanston
Street. During his stay in London he went to call on Mr. Romanes, and
was seized when on the door-step with an attack apparently of the same
kind as those which afterwards became so frequent. The rest of the
incident, which I give in Mr. Romanes' words, is interesting too from a
different point of view, as giving one more illustration of my father's
scrupulous consideration for others:--

"I happened to be out, but my butler, observing that Mr. Darwin was ill,
asked him to come in, he said he would prefer going home, and although
the butler urged him to wait at least until a cab could be fetched, he
said he would rather not give so much trouble. For the same reason he
refused to allow the butler to accompany him. Accordingly he watched him
walking with difficulty towards the direction in which cabs were to be
met with, and saw that, when he had got about three hundred yards from
the house, he staggered and caught hold of the park-railings as if
to prevent himself from falling. The butler therefore hastened to his
assistance, but after a few seconds saw him turn round with the evident
purpose of retracing his steps to my house. However, after he had
returned part of the way he seems to have felt better, for he again
changed his mind, and proceeded to find a cab."

During the last week of February and in the beginning of March, attacks
of pain in the region of the heart, with irregularity of the pulse,
became frequent, coming on indeed nearly every afternoon. A seizure of
this sort occurred about March 7, when he was walking alone at a short
distance from the house; he got home with difficulty, and this was the
last time that he was able to reach his favourite 'Sand-walk.' Shortly
after this, his illness became obviously more serious and alarming, and
he was seen by Sir Andrew Clark, whose treatment was continued by Dr.
Norman Moore, of St. Bartholomew's Hospital, and Mr. Alfrey, of St.
Mary Cray. He suffered from distressing sensations of exhaustion and
faintness, and seemed to recognise with deep depression the fact that
his working days were over. He gradually recovered from this condition,
and became more cheerful and hopeful, as is shown in the following
letter to Mr. Huxley, who was anxious that my father should have closer
medical supervision than the existing arrangements allowed:

Down, March 27, 1882.

My dear Huxley,

Your most kind letter has been a real cordial to me. I have felt better
to-day than for three weeks, and have felt as yet no pain. Your plan
seems an excellent one, and I will probably act upon it, unless I get
very much better. Dr. Clark's kindness is unbounded to me, but he is
too busy to come here. Once again, accept my cordial thanks, my dear old
friend. I wish to God there were more automata (The allusion is to Mr.
Huxley's address 'On the Hypothesis that Animals are Automata, and its
History,' given at the Belfast meeting of the British Association in
1874, and republished in 'Science and Culture.') in the world like you.

Ever yours, CH. DARWIN."

The allusion to Sir Andrew Clark requires a word of explanation. Sir
Andrew Clark himself was ever ready to devote himself to my father, who,
however, could not endure the thought of sending for him, knowing how
severely his great practice taxed his strength.

No especial change occurred during the beginning of April, but on
Saturday 15th he was seized with giddiness while sitting at dinner in
the evening, and fainted in an attempt to reach his sofa. On the 17th
he was again better, and in my temporary absence recorded for me the
progress of an experiment in which I was engaged. During the night of
April 18th, about a quarter to twelve, he had a severe attack and passed
into a faint, from which he was brought back to consciousness with great
difficulty. He seemed to recognise the approach of death, and said, "I
am not the least afraid to die." All the next morning he suffered from
terrible nausea and faintness, and hardly rallied before the end came.

He died at about four o'clock on Wednesday, April 19th, 1882, in the
seventy-fourth year of his age.

I close the record of my father's life with a few words of retrospect
added to the manuscript of his 'Autobiography' in 1879:--

"As for myself, I believe that I have acted rightly in steadily
following, and devoting my life to Science. I feel no remorse from
having committed any great sin, but have often and often regretted that
I have not done more direct good to my fellow creatures."

APPENDIX I.

THE FUNERAL IN WESTMINSTER ABBEY.

On the Friday succeeding my father's death, the following letter, signed
by twenty members of Parliament, was addressed to Dr. Bradley, Dean of
Westminster:--

HOUSE OF COMMONS, April 21, 1882.

Very Rev. Sir,

We hope you will not think we are taking a liberty if we venture to
suggest that it would be acceptable to a very large number of our
fellow-countrymen of all classes and opinions that our illustrious
countryman, Mr. Darwin, should be buried in Westminster Abbey.

We remain, your obedient servants,

JOHN LUBBOCK, NEVIL STOREY MASKELYNE, A.J. MUNDELLA, G.O. TREVELYAN,
LYON PLAYFAIR, CHARLES W. DILKE, DAVID WEDDERBURN, ARTHUR RUSSEL, HORACE
DAVEY, BENJAMIN ARMITAGE, RICHARD B. MARTIN, FRANCIS W. BUXTON, E.L.
STANLEY, HENRY BROADHURST, JOHN BARRAN, F.J. CHEETHAM, H.S. HOLLAND, H.
CAMPBELL-BANNERMAN, CHARLES BRUCE, RICHARD FORT.

The Dean was abroad at the time, and telegraphed his cordial
acquiescence.

The family had desired that my father should be buried at Down: with
regard to their wishes, Sir John Lubbock wrote:--

HOUSE OF COMMONS, April 25, 1882.

My dear Darwin,

I quite sympathise with your feeling, and personally I should greatly
have preferred that your father should have rested in Down amongst us
all. It is, I am sure, quite understood that the initiative was not
taken by you. Still, from a national point of view, it is clearly right
that he should be buried in the Abbey. I esteem it a great privilege to
be allowed to accompany my dear master to the grave.

Believe me, yours most sincerely,

JOHN LUBBOCK.

W.E. DARWIN, ESQ.

The family gave up their first-formed plans, and the funeral took place
in Westminster Abbey on April 26th. The pall-bearers were:--

  SIR JOHN LUBBOCK,
  MR. HUXLEY,
  MR. JAMES RUSSELL LOWELL (American Minister),
  MR. A.R. WALLACE,
  THE DUKE OF DEVONSHIRE,
  CANON FARRAR,
  SIR J.D. HOOKER,
  MR. WM. SPOTTISWOODE (President of the Royal Society),
  THE EARL OF DERBY,
  THE DUKE OF ARGYLL.

The funeral was attended by the representatives of France, Germany,
Italy, Spain, Russia, and by those of the Universities, and learned
Societies, as well as by large numbers of personal friends and
distinguished men.

The grave is in the North aisle of the Nave close to the angle of the
choir-screen, and a few feet from the grave of Sir Isaac Newton. The
stone bears the inscription--

CHARLES ROBERT DARWIN. Born 12 February, 1809. Died 19 April, 1882.

APPENDIX II.

I.--LIST OF WORKS BY CHARLES DARWIN.

Narrative of the Surveying Voyages of Her Majesty's Ships 'Adventure'
and 'Beagle' between the years 1826 and 1836, describing their
examination of the Southern shores of South America, and the 'Beagle's'
circumnavigation of the globe. Volume iii. Journal and Remarks,
1832-1836. By Charles Darwin. 8vo. London, 1839.

Journal of Researches into the Natural History and Geology of the
countries visited during the Voyage of H.M.S. 'Beagle' round the world,
under the command of Captain Fitz-Roy, R.N. 2nd edition, corrected, with
additions. 8vo. London, 1845. (Colonial and Home Library.)

A Naturalist's Voyage. Journal of Researches, etc., 8vo. London, 1860.
[Contains a postscript dated February 1, 1860.]

Zoology of the Voyage of H.M.S. 'Beagle.' Edited and superintended
by Charles Darwin. Part I. Fossil Mammalia, by Richard Owen. With a
Geological Introduction, by Charles Darwin. 4to. London, 1840.

--Part II. Mammalia, by George R. Waterhouse. With a notice of their
habits and ranges, by Charles Darwin. 4to. London, 1839.

--Part III. Birds, by John Gould. An "Advertisement" (2 pages) states
that in consequence of Mr. Gould's having left England for Australia,
many descriptions were supplied by Mr. G.R. Gray of the British Museum.
4to. London, 1841.

--Part IV. Fish, by Rev. Leonard Jenyns. 4to. London, 1842.

--Part V. Reptiles, by Thomas Bell. 4to. London, 1843.

The Structure and Distribution of Coral Reefs. Being the First Part of
the Geology of the Voyage of the 'Beagle.' 8vo. London, 1842.

The Structure and Distribution of Coral Reefs. 2nd edition. 8vo. London,
1874.

Geological Observations on the Volcanic Islands, visited during the
Voyage of H.M.S. 'Beagle.' Being the Second Part of the Geology of the
Voyage of the 'Beagle.' 8vo. London, 1844.

Geological Observations on South America. Being the Third Part of the
Geology of the Voyage of the 'Beagle.' 8vo. London, 1846.

Geological Observations on the Volcanic Islands and parts of South
America visited during the Voyage of H.M.S. 'Beagle.' 2nd edition. 8vo.
London, 1876.

A Monograph of the Fossil Lepadidae; or, Pedunculated Cirripedes of
Great Britain. 4to. London, 1851. (Palaeontographical Society.)

A Monograph of the Sub-class Cirripedia, with Figures of all the
Species. The Lepadidae; or, Pedunculated Cirripedes. 8vo. London, 1851.
(Ray Society.)

--The Balanidae (or Sessile Cirripedes); the Verrucidae, etc. 8vo.
London, 1854. (Ray Society.)

A Monograph of the Fossil Balanidae and Verrucidae of Great Britain.
4to. London, 1854. (Palaeontographical Society.)

On the Origin of Species by means of Natural Selection, or the
Preservation of Favoured Races in the Struggle for Life. 8vo. London,
1859. (Dated October 1st, 1859, published November 24, 1859.)

--Fifth thousand. 8vo. London, 1860.

--Third edition, with additions and corrections. (Seventh thousand.)
8vo. London, 1861. (Dated March, 1861.)

--Fourth edition with additions and corrections. (Eighth thousand.) 8vo.
London, 1866. (Dated June, 1866.)

--Fifth edition, with additions and corrections. (Tenth thousand.) 8vo.
London, 1869. (Dated May, 1869.)

--Sixth edition, with additions and corrections to 1872. (Twenty-fourth
thousand.) 8vo. London, 1882. (Dated January, 1872.)

On the various contrivances by which Orchids are fertilised by Insects.
8vo. London, 1862.

--Second edition. 8vo. London, 1877. [In the second edition the word
"On" is omitted from the title.]

The Movements and Habits of Climbing Plants. Second edition. 8vo.
London, 1875. [First appeared in the ninth volume of the 'Journal of the
Linnean Society.']

The Variation of Animals and Plants under Domestication. 2 volumes. 8vo.
London, 1868.

--Second edition, revised. 2 volumes. 8vo. London, 1875.

The Descent of Man, and Selection in Relation to Sex. 2 volumes. 8vo.
London, 1871.

--Second edition. 8vo. London, 1874. (In 1 volume.)

The Expression of the Emotions in Man and Animals. 8vo. London, 1872.

Insectivorous Plants. 8vo. London, 1875.

The Effects of Cross and Self Fertilisation in the Vegetable Kingdom.
8vo. London, 1876.

--Second edition. 8vo. London, 1878.

The different Forms of Flowers on Plants of the same Species. 8vo.
London, 1877.

--Second edition. 8vo. London, 1880.

The Power of Movement in Plants. By Charles Darwin, assisted by Francis
Darwin. 8vo. London, 1880.

The Formation of Vegetable Mould, through the Action of Worms, with
Observations on their Habits. 8vo. London, 1881.

II.--LIST OF BOOKS CONTAINING CONTRIBUTIONS BY CHARLES DARWIN.

A Manual of scientific enquiry; prepared for the use of Her Majesty's
Navy: and adapted for travellers in general. Edited by Sir John F.W.
Herschel, Bart. 8vo. London, 1849. (Section VI. Geology. By Charles
Darwin.)

Memoir of the Rev. John Stevens Henslow. By the Rev. Leonard Jenyns.
8vo. London, 1862. [In Chapter III., Recollections by Charles Darwin.]

A letter (1876) on the 'Drift' near Southampton published in Prof. J.
Geikie's 'Prehistoric Europe.'

Flowers and their unbidden guests. By A. Kerner. With a Prefatory Letter
by Charles Darwin. The translation revised and edited by W. Ogle. 8vo.
London, 1878.

Erasmus Darwin. By Ernst Krause. Translated from the German by W.S.
Dallas. With a preliminary notice by Charles Darwin. 8vo. London, 1879.

Studies in the Theory of Descent. By August Weismann. Translated and
edited by Raphael Meldola. With a Prefatory Notice by Charles Darwin.
8vo. London, 1880--.

The Fertilisation of Flowers. By Hermann Muller. Translated and edited
by D'Arcy W. Thompson. With a Preface by Charles Darwin. 8vo. London,
1883.

Mental Evolution in Animals. By G.J. Romanes. With a posthumous essay on
instinct by Charles Darwin, 1883. [Also published in the Journal of the
Linnean Society.]

Some Notes on a curious habit of male humble bees were sent to Prof.
Hermann Muller, of Lippstadt, who had permission from Mr. Darwin to make
what use he pleased of them. After Muller's death the Notes were given
by his son to Dr. E. Krause, who published them under the title,
"Ueber die Wege der Hummel-Mannchen" in his book, 'Gesammelte kleinere
Schriften von Charles Darwin.' (1886).

III.--LIST OF SCIENTIFIC PAPERS, INCLUDING A SELECTION OF LETTERS AND
SHORT COMMUNICATIONS TO SCIENTIFIC JOURNALS.

Letters to Professor Henslow, read by him at the meeting of the
Cambridge Philosophical Society, held November 16, 1835. 31 pages. 8vo.
Privately printed for distribution among the members of the Society.

Geological Notes made during a survey of the East and West Coasts of
South America in the years 1832, 1833, 1834, and 1835; with an account
of a transverse section of the Cordilleras of the Andes between
Valparaiso and Mendoza. [Read November 18, 1835.] Geology Society Proc.
ii. 1838, pages 210-212. [This Paper is incorrectly described in Geology
Society Proc. ii., page 210 as follows:--"Geological notes, etc., by F.
Darwin, Esq., of St. John's College, Cambridge: communicated by Prof.
Sedgwick." It is Indexed under C. Darwin.]

Notes upon the Rhea Americana. Zoology Society Proc., Part v. 1837.
pages 35-36.

Observations of proofs of recent elevation on the coast of Chili, made
during the survey of H.M.S. "Beagle," commanded by Captain Fitz-Roy.
[1837.] Geological Society Proc. ii.1838, pages 446-449.

A sketch of the deposits containing extinct Mammalia in the
neighbourhood of the Plata. [1837.] Geological Society Proc. ii. 1838,
pages 542-544.

On certain areas of elevation and subsidence in the Pacific and
Indian oceans, as deduced from the study of coral formations. [1837.]
Geological Society Proc. ii. 1838, pages 552-554.

On the Formation of Mould. [Read November 1, 1837.] Geological Society
Proc. ii. 1838, pages 574-576; Geological Society Transactions v. 1840,
pages 505-510.

On the Connexion of certain Volcanic Phenomena and on the formation of
mountain-chains and the effects of continental elevations. [Read March
7, 1838.] Geological Society Proc. ii. 1838, pages 654-660; Geological
Society Transactions v. 1840, pages 601-632. [In the Society's
Transactions the wording of the title is slightly different.]

Origin of saliferous deposits. Salt Lakes of Patagonia and La Plata.
Geological Society Journal ii. (Part ii.), 1838, pages 127-128.

Note on a Rock seen on an Iceberg in 16 deg South Latitude. Geographical
Society Journal ix. 1839, pages 528-529.

Observations on the Parallel Roads of Glen Roy, and of other parts of
Lochaber in Scotland, with an attempt to prove that they are of marine
origin. Phil. Trans. 1839, pages 39-82.

On a remarkable Bar of Sandstone off Pernambuco, on the Coast of Brazil.
Phil. Mag. xix. 1841, pages 257-260.

On the Distribution of the Erratic Boulders and on the Contemporaneous
Unstratified Deposits of South America. [1841.] Geological Society Proc.
iii. 1842, pages 425-430; Geological Society Transactions vi. 1842,
pages 415-432.

Notes on the Effects produced by the Ancient Glaciers of
Caernarvonshire, and on the Boulders transported by Floating Ice. London
Philosophical Magazine volume xxi. page 180. 1842.

Remarks on the preceding paper, in a Letter from Charles Darwin, Esq.,
to Mr. Maclaren. Edinburgh New Philosophical Journal xxxiv. 1843,
pages 47- 50. [The "preceding" paper is: "On Coral Islands and Reefs as
described by Mr. Darwin. By Charles Maclaren, Esq., F.R.S.E."]

Observations on the Structure and Propagation of the genus Sagitta.
Annals and Magazine of Natural History xiii. 1844, pages 1-6.

Brief descriptions of several Terrestrial Planariae, and of some
remarkable Marine Species, with an Account of their Habits. Annals and
Magazine of Natural History xiv. 1844, pages 241-251.

An account of the Fine Dust which often falls on Vessels in the Atlantic
Ocean. Geological Society Journal ii. 1846, pages 26-30.

On the Geology of the Falkland Islands. Geological Society Journal ii.
1846, pages 267-274.

A review of Waterhouse's 'Natural History of the Mammalia.' [Not
signed.] Annals and Magazine of Natural History 1847. Volume xix. page
53.

On the Transportal of Erratic Boulders from a lower to a higher level.
Geological Society Journal iv. 1848, pages 315-323.

On British fossil Lepadidae. Geological Society Journal vi. 1850, pages
439-440. [The G.S.J. says "This paper was withdrawn by the author with
the permission of the Council."]

Analogy of the Structure of some Volcanic Rocks with that of Glaciers.
Edinburgh Royal Society Proc. ii. 1851, pages 17-18.

On the power of Icebergs to make rectilinear, uniformly-directed Grooves
across a Submarine Undulatory Surface. Philosophical Magazine x. 1855,
pages 96-98.

Vitality of Seeds. "Gardeners' Chronicle", November 17, 1855, page 758.

On the action of Sea-water on the Germination of Seeds. [1856.] Linnean
Society Journal i. 1857 ("Botany"), pages 130-140.

On the Agency of Bees in the Fertilisation of Papilionaceous Flowers.
"Gardeners' Chronicle", page 725, 1857.

On the Tendency of Species to form Varieties; and on the Perpetuation of
Varieties and Species by Natural Means of Selection. By Charles Darwin,
Esq., F.R.S., F.L.S., and F.G.S., and Alfred Wallace, Esq. [Read
July 1st, 1858.] Journal of the Linnean Society 1859, volume iii.
("Zoology"), page 45.

Special titles of Charles Darwin's contributions to the foregoing:--

i. Extract from an unpublished work on Species by Charles Darwin Esq.,
consisting of a portion of a chapter entitled, "On the Variation of
Organic Beings in a State of Nature; on the Natural Means of Selection;
on the Comparison of Domestic Races and true Species."

ii. Abstract of a Letter from C. Darwin, Esq., to Professor Asa Gray, of
Boston U.S., dated September 5, 1857.

On the Agency of Bees in the Fertilisation of Papilionaceous Flowers,
and on the Crossing of Kidney Beans. "Gardeners' Chronicle", 1858, page
828 and Annals of Natural History 3rd series ii. 1858, pages 459-465.

Do the Tineina or other small Moths suck Flowers, and if so what
Flowers? "Entomological Weekly Intelligencer" volume viii. 1860, page
103.

Note on the achenia of Pumilio Argyrolepis. "Gardeners' Chronicle",
January 5, 1861, page 4.

Fertilisation of Vincas. "Gardeners' Chronicle", pages 552, 831, 832.
1861.

On the Two Forms, or Dimorphic Condition, in the species of Primula, and
on their remarkable Sexual Relations. Linnean Society Journal vi. 1862
("Botany"), pages 77-96.

On the Three remarkable Sexual Forms of Catasetum tridentatum, an Orchid
in the possession of the Linnean Society. Linnean Society Journal vi.
1862 ("Botany"), pages 151-157.

Yellow Rain. "Gardeners' Chronicle", July 18, 1863, page 675.

On the thickness of the Pampean formation near Buenos Ayres. Geological
Society Journal xix. 1863, pages 68-71.

On the so-called "Auditory-sac" of Cirripedes. Natural History Review,
1863, pages 115-116.

A review of Mr. Bates' paper on 'Mimetic Butterflies.' Natural History
Review, 1863, page 221-. [Not signed.]

On the existence of two forms, and on their reciprocal sexual relation,
in several species of the genus Linum. Linnean Society Journal vii. 1864
("Botany"), pages 69-83.

On the Sexual Relations of the Three Forms of Lythrum salicaria. [1864.]
Linnean Society Journal viii. 1865 ("Botany"), pages 169-196.

On the Movement and Habits of Climbing Plants. [1865.] Linnean Society
Journal ix. 1867 ("Botany"), pages 1-118.

Note on the Common Broom (Cytisus scoparius). [1866.] Linnean Society
Journal ix. 1867 ("Botany"), page 358.

Notes on the Fertilization of Orchids. Annals and Magazine of Natural
History, 4th series, iv. 1869, pages 141-159.

On the Character and Hybrid-like Nature of the Offspring from the
Illegitimate Unions of Dimorphic and Trimorphic Plants. [1868.] Linnean
Society Journal x. 1869 ("Botany"), pages 393-437.

On the Specific Difference between Primula veris, British Fl. (var.
officinalis, of Linn.), P. vulgaris, British Fl. (var. acaulis, Linn.),
and P. elatior, Jacq.; and on the Hybrid Nature of the common Oxlip.
With Supplementary Remarks on naturally produced Hybrids in the genus
Verbascum. [1868.] Linnean Society Journal x. 1869 ("Botany"), pages
437-454.

Note on the Habits of the Pampas Woodpecker (Colaptes campestris).
Zoological Society Proceedings November 1, 1870, pages 705-706.

Fertilisation of Leschenaultia. "Gardeners' Chronicle", page 1166, 1871.

The Fertilisation of Winter-flowering Plants. 'Nature,' November 18,
1869, volume i. page 85.

Pangenesis. 'Nature,' April 27, 1871, volume iii. page 502.

A new view of Darwinism. 'Nature,' July 6, 1871, volume iv. page 180.

Bree on Darwinism. 'Nature,' August 8, 1872, volume vi. page 279.

Inherited Instinct. 'Nature,' February 13, 1873, volume vii. page 281.

Perception in the Lower Animals. 'Nature,' March 13, 1873, volume vii.
page 360.

Origin of certain instincts. 'Nature,' April 3, 1873, volume vii. page
417.

Habits of Ants. 'Nature,' July 24, 1873, volume viii. page 244.

On the Males and Complemental Males of Certain Cirripedes, and on
Rudimentary Structures. 'Nature,' September 25, 1873, volume viii. page
431.

Recent researches on Termites and Honey-bees. 'Nature,' February 19,
1874, volume ix. page 308.

Fertilisation of the Fumariaceae. 'Nature,' April 16, 1874, volume ix.
page 460.

Flowers of the Primrose destroyed by Birds. 'Nature,' April 23, 1874,
volume ix. page 482; May 14, 1874, volume x. page 24.

Cherry Blossoms. 'Nature,' May 11, 1876, volume xiv. page 28.

Sexual Selection in relation to Monkeys. 'Nature,' November 2, 1876,
volume xv. page 18. Reprinted as a supplement to the 'Descent of Man,'
18..

Fritz Muller on Flowers and Insects. 'Nature,' November 29, 1877, volume
xvii. page 78.

The Scarcity of Holly Berries and Bees. "Gardeners' Chronicle", January
20, 1877, page 83.

Note on Fertilization of Plants. "Gardeners' Chronicle", volume vii.
page 246, 1877.

A biographical sketch of an infant. 'Mind,' No.7, July, 1877.

Transplantation of Shells. 'Nature,' May 30, 1878, volume xviii. page
120.

Fritz Muller on a Frog having Eggs on its back--on the abortion of the
hairs on the legs of certain Caddis-Flies, etc. 'Nature,' March 20,
1879, volume xix. page 462.

Rats and Water-Casks. 'Nature,' March 27, 1879, volume xix. page 481.

Fertility of Hybrids from the common and Chinese Goose. 'Nature,'
January 1, 1880, volume xxi. page 207.

The Sexual Colours of certain Butterflies. 'Nature,' January 8, 1880,
volume xxi. page 237.

The Omori Shell Mounds. 'Nature,' April 15, 1880, volume xxi. page 561.

Sir Wyville Thomson and Natural Selection. 'Nature,' November 11, 1880,
volume xxiii. page 32.

Black Sheep. 'Nature,' December 30, 1880, volume xxiii. page 193.

Movements of Plants. 'Nature,' March 3, 1881, volume xxiii. page 409.

The Movements of Leaves. 'Nature,' April 28, 1881, volume xxiii. page
603.

Inheritance. 'Nature,' July 21, 1881, volume xxiv. page 257.

Leaves injured at Night by Free Radiation. 'Nature,' September 15, 1881,
volume xxiv. page 459.

The Parasitic Habits of Molothrus. 'Nature,' November 17, 1881, volume
xxv. page 51.

On the Dispersal of Freshwater Bivalves. 'Nature,' April 6, 1882, volume
xxv. page 529.

The Action of Carbonate of Ammonia on the Roots of certain Plants. [Read
March 16, 1882.] Linnean Society Journal ("Botany"), volume xix. 1882,
pages 239-261.

The Action of Carbonate of Ammonia on Chlorophyll-bodies. [Read March 6,
1882.] Linnean Society Journal ("Botany"), volume xix. 1882, pages 262-
284.

On the modification of a Race of Syrian Street-Dogs by means of Sexual
Selection. By W. Van Dyck. With a preliminary notice by Charles Darwin.
[Read April 18, 1882.] Proceedings of the Zoological Society 1882, pages
367-370.

APPENDIX III.

PORTRAITS.

1838: Water-colour by G. Richmond in the possession of The Family.

1851: Lithograph by Ipswich British Association Series.

1853: Chalk Drawing by Samuel Lawrence in the possession of The Family.

1853?: Chalk Drawing (Probably a sketch made at one of the sittings
for the last mentioned.) by Samuel Lawrence in the possession of Prof.
Hughes, Cambridge.

1869: Bust, marble, by T. Woolner, R.A. in the possession of The Family.

1875: Oil Painting (A replica by the artist is in the possession of
Christ's College, Cambridge.) by W. Ouless, R.A., etched by P. Rajon, in
the possession of The Family.

1879: Oil Painting by W.B. Richmond in the possession of The University
of Cambridge.

1881: Oil Painting (A replica by the artist is in the possession of W.E.
Darwin, Esq., Southampton.) by the Hon. John Collier, in the possession
of The Linnaean Society, etched by Leopold Flameng.

CHIEF PORTRAITS AND MEMORIALS NOT TAKEN FROM LIFE.

Statue by Joseph Boehm, R.A., in the possession of Museum, South
Kensington.

Bust by Chr. Lehr, Junr.

Plaque by T. Woolner, R.A., and Josiah Wedgwood and Sons in the
possession of Christ's College, in Charles Darwin's Room.

Deep Medallion by J. Boehm, R.A. to be placed in Westminster Abbey.

CHIEF ENGRAVINGS FROM PHOTOGRAPHS.

1854?: By Messrs. Maull and Fox, engraved on wood for 'Harper's
Magazine' (October 1884).

1870?: By O.J. Rejlander, engraved on steel by C.H. Jeens for 'Nature'
(June 4, 1874).

1874?: By Captain Darwin, R.E., engraved on wood for the 'Century
Magazine' (January 1883). Frontispiece, volume i.

(The dates of these photographs must, from various causes, remain
uncertain. Owing to a loss of books by fire, Messrs. Maull and Fox can
give only an approximate date. Mr. Rejlander died some years ago, and
his business was broken up. My brother, captain Darwin, has no record of
the date at which his photograph was taken.)

1881: By Messrs. Elliott and Fry, engraved on wood by G. Kruells, for
the present work.

APPENDIX IV.

HONOURS, DEGREES, SOCIETIES, ETC.

(The list has been compiled from the diplomas and letters in my father's
possession, and is no doubt incomplete, as he seems to have lost or
mislaid some of the papers received from foreign Societies. Where the
name of a foreign Society (excluding those in the United States) is
given in English, it is a translation of the Latin (or in one case
Russian) of the original Diploma.)

ORDER.--Prussian Order, 'Pour le Merite.' 1867.

OFFICE.--County Magistrate. 1857.

DEGREES.

Cambridge: B.A. 1831 [1832]. See volume i. M.A. 1837. Hon. LL.D. 1877.

Breslau: Hon. Doctor in Medicine and Surgery. 1862.

Bonn: Hon. Doctor in Medicine and Surgery. 1868.

Leyden: Hon. M.D. 1875.

SOCIETIES.--London:

Zoological. Corresponding Member. 1831. (He afterwards became a Fellow
of the Society.) Entomological. 1833, Original Member. Geological. 1836.
Wollaston Medal, 1859. Royal Geographical. 1838. Royal. 1839. Royal
Medal, 1853. Copley Medal, 1864. Linnean. 1854. Ethnological. 1861.
Medico-Chirurgical. Hon. Member. 1868. Baly Medal of the Royal College
of Physicians, 1879.

SOCIETIES.--PROVINCIAL, COLONIAL, AND INDIAN.

Royal Society of Edinburgh, 1865. Royal Medical Society of Edinburgh,
1826. Hon. Member, 1861. Royal Irish Academy. Hon. Member, 1866.
Literary and Philosophical Society of Manchester. Hon. Member, 1868.
Watford Natural History Society. Hon. Member, 1877. Asiatic Society
of Bengal. Hon. Member, 1871. Royal Society of New South Wales. Hon.
Member, 1879. Philosophical Institute of Canterbury, New Zealand. Hon.
Member, 1863. New Zealand Institute. Hon. Member, 1872.

FOREIGN SOCIETIES.--AMERICA.

Sociedad Cientifica Argentina. Hon. Member, 1877. Academia Nacional
de Ciencias, Argentine Republic. Hon. Member, 1878. Sociedad Zoologica
Arjentina. Hon. Member, 1874. Boston Society of Natural History. Hon.
Member, 1873. American Academy of Arts and Sciences (Boston). Foreign
Hon. Member, 1874. California Academy of Sciences. Hon. Member, 1872.
California State Geological Society. Corresponding Member, 1877.
Franklin Literary Society, Indiana. Hon. Member, 1878. Sociedad de
Naturalistas Neo-Granadinos. Hon. Member, 1860. New York Academy
of Sciences. Hon. Member, 1879. Gabinete Portuguez de Leitura em
Pernambuco. Corresponding Member, 1879. Academy of Natural Sciences
of Philadelphia. Correspondent, 1860. American Philosophical Society,
Philadelphia. Member, 1869.

AUSTRIA-HUNGARY.

Imperial Academy of Sciences of Vienna. Foreign Corresponding Member,
1871; Hon. Foreign Member, 1875. Anthropologische Gesellschaft in Wien.
Hon. Member, 1872. K. k. Zoologisch-botanische Gesellschaft in Wien.
Member, 1867. Magyar Tudomanyos Akademia, Pest, 1872.

BELGIUM.

Societe Royale des Sciences Medicales et Naturelles de Bruxelles.
Hon. Member, 1878. Societie Royale de Botanique de Belgique. 'Membre
Associe,' 1881. Academie Royale des Sciences, etc., de Belgique.
'Associe de la Classe des Sciences.' 1870.

DENMARK.

Royal Society of Copenhagen. Fellow, 1879.

FRANCE.

Societe d'Anthropologie de Paris. Foreign Member, 1871. Societe
Entomologique de France. Hon. Member, 1874. Societe Geologique de France
(Life Member), 1837. Institut de France. 'Correspondant' Section of
Botany, 1878.

GERMANY.

Royal Prussian Academy of Sciences (Berlin). Corresponding Member,
1863; Fellow, 1878. Berliner Gesellschaft fur Anthropologie, etc.
Corresponding Member, 1877. Schlesische Gesellschaft fur Vaterlandische
Cultur (Breslau). Hon. Member 1878. Caesarea Leopoldino-Carolina
Academia Naturae Curiosorum (Dresden). 1857. (The diploma contains the
words "accipe... ex antiqua nostra consuetudine cognomen Forster." It was
formerly the custom in the "Caesarea Leopoldin-Carolina Academia", that
each new member should receive as a 'cognomen,' a name celebrated in
that branch of science to which he belonged. Thus a physician might be
christened Boerhave, or an astronomer, Kepler. My father seems to have
been named after the traveller John Reinhold Forster.) Senkenbergische
Naturforschende Gesellschaft zu Frankfurt am Main. Corresponding
Member, 1873. Naturforschende Gesellschaft zu Halle. Member 1879.
Siebenburgische Verein fur Naturwissenschaften (Hermannstadt). Hon.
Member, 1877. Medicinisch-naturwissenschaftliche Gesellschaft zu Jena.
Hon. Member, 1878. Royal Bavarian Academy of Literature and Science
(Munich). Foreign Member, 1878.

HOLLAND.

Koninklijke Natuurkundige Vereeniging in Nederlandsch-Indie (Batavia).
Corresponding Member, 1880. Societe Hollandaise des Sciences a Harlem.
Foreign Member, 1877. Zeeuwsch Genootschap der Wetenschappen te
Middelburg. Foreign Member, 1877.

ITALY.

Societa Geografica Italiana (Florence). 1870. Societa Italiana di
Antropologia e di Etnologia (Florence). Hon. Member, 1872. Societa dei
Naturalisti in Modena. Hon. Member, 1875. Academia de' Lincei di Roma.
Foreign Member, 1875. La Scuola Italica, Academia Pitagorica, Reale ed
Imp. Societa (Rome). "Presidente Onoraria degli Anziani Pitagorici,"
1880. Royal Academy of Turin. 1873. "Bressa" Prize, 1879.

PORTUGAL.

Sociedade de Geographia de Lisboa (Lisbon). Corresponding Member, 1877.

RUSSIA.

Society of Naturalists of the Imperial Kazan University. Hon. Member,
1875. Societas Caesarea Naturae Curiosorum (Moscow). Hon. Member, 1870.
Imperial Academy of Sciences (St. Petersburg). Corresponding Member,
1867.

SPAIN.

Institucion Libre de Ensenanza (Madrid). Hon. Professor, 1877.

SWEDEN.

Royal Swedish Academy of Sciences (Stockholm). Foreign Member, 1865.
Royal Society of Sciences (Upsala). Fellow, 1860.

SWITZERLAND.

Societe des Sciences Naturelles de Neuchatel. Corresponding Member,
1863.

INDEX.

  ABBOT, F.E., letter to.

  ACADEMY OF NATURAL SCIENCES (Philadelphia) elects Darwin a member.

  AGASSIZ, Alexander, letter to.

  AGASSIZ, Louis, Darwin's estimate of.
  Letters to.
  His attitude toward the 'Origin of Species.'
  Reviews the 'Origin of Species.'

  AGGREGATION, studied by Darwin.

  'ALMANACK, THE NATURALISTS' POCKET,' mentioned.

  ANDES, Darwin crosses the.

  'ANNALS AND MAGAZINE OF NATURAL HISTORY,' mentioned.

  ANTICIPATION of Darwin's views.

  ANTS, observations on.

  APPLETON, D., & CO., publish 'Origin of Species' in America.

  ARGYLL, Duke of, criticises the 'Origin of Species.'
  Darwin's comments on his criticisms.
  Darwin on his 'Reign of Law.'
  Reviews the 'Fertilisation of Orchids.'

  ARISTOTLE, Darwin's estimate of.

  ARRANGEMENT of leaves on the stems of plants.

  'ATHENAEUM,' Darwin on its review of the 'Origin of Species.'
  Reports British Association discussion.
  Darwin's letters to, in his own defence.
  Criticises Darwin.

  AUSTRALIA, development of animals in.

  AUSTRALIAN flora.

  AUSTRIAN expedition.

  AUTOBIOGRAPHY, extracts from.

  AVELING, Dr., on Darwin's religious views.
  Note.

  BAIN, Alexander, letter to.

  BALFOUR, Francis M., Darwin's estimate of.

  BALY medal presented to Darwin.

  BAER, K.E. von, agrees with Darwin.

  BASTIAN, H.C., Darwin on his 'Beginnings of Life.'

  BATES, H.W., Darwin on his insect fauna of the Amazon valley.
  Letters to.
  Darwin on his mimetic variations of butterflies.

  BATS.

  "BEAGLE", voyage of.
  Darwin offered an appointment to the.
  Her equipments.
  Object of her voyage.
  Her crew.

  BEETLES, collecting.

  BEHRENS, W., letter to.

  BELL, T., describes Darwin's reptiles.

  BELL-STONE of Shrewsbury mentioned.

  BELT, Thomas, Darwin on his 'Naturalist in Nicaragua.'

  BEMMELEN, A. van, letter to.

  BENTHAM, George, his silence on natural selection.
  Letter to Francis Darwin on his adoption of Darwin's views.
  His view of natural selection.
  Letters to.

  BERKELEY, Rev. M.J., reviews the 'Fertilisation of Orchids.'

  BERLIN ACADEMY OF SCIENCES elects Darwin corresponding member.

  BET made by Darwin.

  BLOMEFIELD (JENYNS), Rev. Leonard, Darwin becomes acquainted with.
  Letters to.
  Darwin on his 'Observations in Natural History.'

  BLOOM on leaves and fruit, Darwin's work on.

  BLYTH, Edward, mentioned.

  BOOLE, Mrs., her letter on natural selection and religion.
  Letter to.

  BOOTT, Francis, mentioned.

  BOTANY, Darwin's work on, and its relation to natural selection.

  BOWEN, Francis, reviews the 'Origin of Species.'

  BRACE, C.L., and wife, Darwin on their philanthropic work.

  BRAZIL, Emperor of, wishes to meet Darwin.

  BREE, C.R., his work 'Species not Transmutable.'
  Accuses Wallace of blundering, and is answered by Darwin.

  BREEDING, sources of information on.

  BRESSA prize presented to Darwin.