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More Letters of Charles Darwin Volume II by Charles Darwin

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If it were universally known that the birth of children could be prevented,
and this were not thought immoral by married persons, would there not be
great danger of extreme profligacy amongst unmarried women, and might we
not become like the "arreoi" societies in the Pacific? In the course of a
century France will tell us the result in many ways, and we can already see
that the French nation does not spread or increase much.

I am glad that you intend to continue your investigations, and I hope
ultimately may publish on the subject.

Down, January 13th, 1879.

I am much obliged for your note and for the essay which you have sent me.
I am a poor german scholar, and your german is difficult; but I think that
I understand your meaning, and hope at some future time, when more at
leisure, to recur to your essay. As far as I can judge, you have made a
great advance in many ways in the subject; and I will send your paper to
Mr. Edmund Gurney (The late Edmund Gurney, author of "The Power of Sound,"
1880.), who has written on and is much interested in the origin of the
taste for music. In reading your essay, it occurred to me that facility in
the utterance of prolonged sounds (I do not think that you allude to this
point) may possibly come into play in rendering them musical; for I have
heard it stated that those who vary their voices much, and use cadences in
long continued speaking, feel less fatigued than those who speak on the
same note.

Down, February 5th, 1880.

(420/1. Romanes was at work on what ultimately came to be a book on animal
intelligence. Romanes's reply to this letter is given in his "Life," page
95. The table referred to is published as a frontispiece to his "Mental
Evolution in Animals," 1885.)

As I feared, I cannot be of the least use to you. I could not venture to
say anything about babies without reading my Expression book and paper on
Infants, or about animals without reading the "Descent of Man" and
referring to my notes; and it is a great wrench to my mind to change from
one subject to another.

I will, however, hazard one or two remarks. Firstly, I should have thought
that the word "love" (not sexual passion), as shown very low in the scale,
to offspring and apparently to comrades, ought to have come in more
prominently in your table than appears to be the case. Secondly, if you
give any instance of the appreciation of different stimulants by plants,
there is a much better case than that given by you--namely, that of the
glands of Drosera, which can be touched roughly two or three times and do
not transmit any effect, but do so if pressed by a weight of 1/78000 grain
("Insectivorous Plants" 263). On the other hand, the filament of Dionoea
may be quietly loaded with a much greater weight, while a touch by a hair
causes the lobes to close instantly. This has always seemed to me a
marvellous fact. Thirdly, I have been accustomed to look at the coming in
of the sense of pleasure and pain as one of the most important steps in the
development of mind, and I should think it ought to be prominent in your
table. The sort of progress which I have imagined is that a stimulus
produced some effect at the point affected, and that the effect radiated at
first in all directions, and then that certain definite advantageous lines
of transmission were acquired, inducing definite reaction in certain lines.
Such transmission afterwards became associated in some unknown way with
pleasure or pain. These sensations led at first to all sorts of violent
action, such as the wriggling of a worm, which was of some use. All the
organs of sense would be at the same time excited. Afterwards definite
lines of action would be found to be the most useful, and so would be
practised. But it is of no use my giving you my crude notions.

Down, May 22nd, 1880.

(421/1. Mr. Preston wrote (May 20th, 1880) to the effect that
"self-interest as a motive for conduct is a thing to be commended--and it
certainly [is] I think...the only conceivable rational motive of conduct:
and always is the tacitly recognised motive in all rational actions." Mr.
Preston does not, of course, commend selfishness, which is not true

There seem to be two ways of looking at the case given by Darwin. The man
who knows that he is risking his life,--realising that the personal
satisfaction that may follow is not worth the risk--is surely admirable
from the strength of character that leads him to follow the social instinct
against his purely personal inclination. But the man who blindly obeys the
social instinct is a more useful member of a social community. He will act
with courage where even the strong man will fail.)

Your letter appears to me an interesting and valuable one; but I have now
been working for some years exclusively on the physiology of plants, and
all other subjects have gone out of my head, and it fatigues me much to try
and bring them back again into my head. I am, moreover, at present very
busy, as I leave home for a fortnight's rest at the beginning of next week.
My conviction as yet remains unchanged, that a man who (for instance) jumps
into a river to save a life without a second's reflection (either from an
innate tendency or from one gained by habit) is deservedly more honoured
than a man who acts deliberately and is conscious, for however short a
time, that the risk and sacrifice give him some inward satisfaction.

You are of course familiar with Herbert Spencer's writings on Ethics.

(422/1. The observations to which the following letters refer were
continued by Mr. Wallis, who gave an account of his work in an interesting
paper in the "Proceedings of the Zoological Society," March 2nd, 1897. The
results on the whole confirm the belief that traces of an ancestral pointed
ear exist in man.)

Down, March 22nd, 1881.

I am very much obliged for your courteous and kind note. The fact which
you communicate is quite new to me, and as I was laughed at about the tips
to human ears, I should like to publish in "Nature" some time your fact.
But I must first consult Eschricht, and see whether he notices this fact in
his curious paper on the lanugo on human embryos; and secondly I ought to
look to monkeys and other animals which have tufted ears, and observe how
the hair grows. This I shall not be able to do for some months, as I shall
not be in London until the autumn so as to go to the Zoological Gardens.
But in order that I may not hereafter throw away time, will you be so kind
as to inform me whether I may publish your observation if on further search
it seems desirable?

Down, March 31st, 1881.

I am much obliged for your interesting letter. I am glad to hear that you
are looking to other ears, and will visit the Zoological Gardens. Under
these circumstances it would be incomparably better (as more authentic) if
you would publish a notice of your observations in "Nature" or some
scientific journal. Would it not be well to confine your attention to
infants, as more likely to retain any primordial character, and offering
less difficulty in observing. I think, though, it would be worth while to
observe whether there is any relation (though probably none) between much
hairiness on the ears of an infant and the presence of the "tip" on the
folded margin. Could you not get an accurate sketch of the direction of
the hair of the tip of an ear?

The fact which you communicate about the goat-sucker is very curious.
About the difference in the power of flight in Dorkings, etc., may it not
be due merely to greater weight of body in the adults?

I am so old that I am not likely ever again to write on general and
difficult points in the theory of Evolution.

I shall use what little strength is left me for more confined and easy


(Mrs. Emily Talbot was secretary of the Education Department of the
American Social Science Association, Boston, Mass. A circular and register
was issued by the Department, and answers to various questions were asked
for. See "Nature," April 28th, page 617, 1881. The above letter was
published in "The Field Naturalist," Manchester, 1883, page 5, edited by
Mr. W.E. Axon, to whom we are indebted for a copy.)

Down, July 19th [1881?]

In response to your wish, I have much pleasure in expressing the interest
which I feel in your proposed investigation on the mental and bodily
development of infants. Very little is at present accurately known on this
subject, and I believe that isolated observations will add but little to
our knowledge, whereas tabulated results from a very large number of
observations, systematically made, would probably throw much light on the
sequence and period of development of the several faculties. This
knowledge would probably give a foundation for some improvement in our
education of young children, and would show us whether the system ought to
be followed in all cases.

I will venture to specify a few points of inquiry which, as it seems to me,
possess some scientific interest. For instance, does the education of the
parents influence the mental powers of their children at any age, either at
a very early or somewhat more advanced stage? This could perhaps be
learned by schoolmasters and mistresses if a large number of children were
first classed according to age and their mental attainments, and afterwards
in accordance with the education of their parents, as far as this could be
discovered. As observation is one of the earliest faculties developed in
young children, and as this power would probably be exercised in an equal
degree by the children of educated and uneducated persons, it seems not
impossible that any transmitted effect from education could be displayed
only at a somewhat advanced age. It would be desirable to test
statistically, in a similar manner, the truth of the oft-repeated statement
that coloured children at first learn as quickly as white children, but
that they afterwards fall off in progress. If it could be proved that
education acts not only on the individual, but, by transmission, on the
race, this would be a great encouragement to all working on this
all-important subject. It is well known that children sometimes exhibit,
at a very early age, strong special tastes, for which no cause can be
assigned, although occasionally they may be accounted for by reversion to
the taste or occupation of some progenitor; and it would be interesting to
learn how far such early tastes are persistent and influence the future
career of the individual. In some instances such tastes die away without
apparently leaving any after effect, but it would be desirable to know how
far this is commonly the case, as we should then know whether it were
important to direct as far as this is possible the early tastes of our
children. It may be more beneficial that a child should follow
energetically some pursuit, of however trifling a nature, and thus acquire
perseverance, than that he should be turned from it because of no future
advantage to him. I will mention one other small point of inquiry in
relation to very young children, which may possibly prove important with
respect to the origin of language; but it could be investigated only by
persons possessing an accurate musical ear. Children, even before they can
articulate, express some of their feelings and desires by noises uttered in
different notes. For instance, they make an interrogative noise, and
others of assent and dissent, in different tones; and it would, I think, be
worth while to ascertain whether there is any uniformity in different
children in the pitch of their voices under various frames of mind.

I fear that this letter can be of no use to you, but it will serve to show
my sympathy and good wishes in your researches.


Down, February 11th [1866].

I am much obliged to you for your kindness in sending me an abstract of
your paper on beauty. (425/1. A newspaper report of a communication to
the "Dumfries Antiquarian and Natural History Society.") In my opinion you
take quite a correct view of the subject. It is clear that Dr. Dickson has
either never seen my book, or overlooked the discussion on sexual
selection. If you have any precise facts on birds' "courtesy towards their
own image in mirror or picture," I should very much like to hear them.
Butterflies offer an excellent instance of beauty being displayed in
conspicuous parts; for those kinds which habitually display the underside
of the wing have this side gaudily coloured, and this is not so in the
reverse case. I daresay you will know that the males of many foreign
butterflies are much more brilliantly coloured than the females, as in the
case of birds. I can adduce good evidence from two large classes of facts
(too large to specify) that flowers have become beautiful to make them
conspicuous to insects. (425/2. This letter is published in "A Country
Schoolmaster, James Shaw." Edited by Robert Wallace, Edinburgh, 1899.)

(425/3. Mr. Darwin wrote again to Mr. Shaw in April, 1866:--)

I am much obliged for your kind letter and all the great trouble which you
have taken in sending to all the various and interesting facts on birds
admiring themselves. I am very glad to hear of these facts. I have just
finished writing and adding to a new edition of the "Origin," and in this I
have given, without going into details (so that I shall not be able to use
your facts), some remarks on the subject of beauty.

Down, February 16th [1867?]

I want to beg two favours of you. I wish to ascertain whether the Bower-
Bird discriminates colours. (426/1. Mr. Bartlett does not seem to have
supplied any information on the point in question. The evidence for the
Bower-Bird's taste in colour is in "Descent of Man," II., page 112.) Will
you have all the coloured worsted removed from the cage and bower, and then
put all in a row, at some distance from bower, the enclosed coloured
worsted, and mark whether the bird AT FIRST makes any selection. Each
packet contains an equal quantity; the packets had better be separate, and
each thread put separate, but close together; perhaps it would be fairest
if the several colours were put alternately--one thread of bright scarlet,
one thread of brown, etc., etc. There are six colours. Will you have the
kindness to tell me whether the birds prefer one colour to another?

Secondly, I very much want several heads of the fancy and long-domesticated
rabbits, to measure the capacity of skull. I want only small kinds, such
as Himalaya, small Angora, Silver Grey, or any small-sized rabbit which has
long been domesticated. The Silver Grey from warrens would be of little
use. The animals must be adult, and the smaller the breed the better. Now
when any one dies would you send me the carcase named; if the skin is of
any value it might be skinned, but it would be rather better with skin, and
I could make a present to any keeper to whom the skin is a perquisite.
This would be of great assistance to me, if you would have the kindness
thus to aid me.


(427/1. We are not aware that the experiment here suggested has ever been
carried out.)

Down, March 5th [1867].

I write on the bare and very improbable chance of your being able to try,
or get some trustworthy person to try, the following little experiment.
But I may first state, as showing what I want, that it has been stated that
if two long feathers in the tail of the male Widow-Bird at the Cape of Good
Hope are pulled out, no female will pair with him.

Now, where two or three common cocks are kept, I want to know, if the tail
sickle-feathers and saddle-feathers of one which had succeeded in getting
wives were cut and mutilated and his beauty spoiled, whether he would
continue to be successful in getting wives. This might be tried with
drakes or peacocks, but no one would be willing to spoil for a season his
peacocks. I have no strength or opportunity of watching my own poultry,
otherwise I would try it. I would very gladly repay all expenses of loss
of value of the poultry, etc. But, as I said, I have written on the most
improbable chance of your interesting any one to make the trial, or having
time and inclination yourself to make it. Another, and perhaps better,
mode of making the trial would be to turn down to some hens two or three
cocks, one being injured in its plumage.

I am glad to say that I have begun correcting proofs. (427/2. "The
Variation of Animals and Plants.") I hope that you received safely the
skulls which you so kindly lent me.

Down, March 30th [1867].

I am much obliged for your note, and shall be truly obliged if you will
insert any question on the subject. That is a capital remark of yours
about the trimmed game cocks, and shall be quoted by me. (428/1. "Descent
of Man," Edition I., Volume II., page 117. "Mr. Tegetmeier is convinced
that a game cock, though disfigured by being dubbed with his hackles
trimmed, would be accepted as readily as a male retaining all his natural
ornaments.") Nevertheless I am still inclined from many facts strongly to
believe that the beauty of the male bird determines the choice of the
female with wild birds, however it may be under domestication. Sir R.
Heron has described how one pied peacock was extra attentive to the hens.
This is a subject which I must take up as soon as my present book is done.

I shall be most particularly obliged to you if you will dye with magenta a
pigeon or two. (428/2. "Mr. Tegetmeier, at my request, stained some of
his birds with magenta, but they were not much noticed by the others."--
"Descent of Man" (1901), page 637.) Would it not be better to dye the tail
alone and crown of head, so as not to make too great difference? I shall
be very curious to hear how an entirely crimson pigeon will be received by
the others as well as his mate.

P.S.--Perhaps the best experiment, for my purpose, would be to colour a
young unpaired male and turn him with other pigeons, and observe whether he
was longer or quicker than usual in mating.

Down, April 29th [1867].

I have been greatly interested by your letter, but your view is not new to
me. (429/1. We have not been able to find Mr. Wallace's letter to which
this is a reply. It evidently refers to Mr. Wallace's belief in the
paramount importance of protection in the evolution of colour. This is
clear from the P.S. to the present letter and from the passages in the
"Origin" referred to. The first reference, Edition IV., page 240, is as
follows: "We can sometimes plainly see the proximate cause of the
transmission of ornaments to the males alone; for a pea-hen with the long
tail of the male bird would be badly fitted to sit on her eggs, and a coal-
black female capercailzie would be far more conspicuous on her nest, and
more exposed to danger, than in her present modest attire." The passages
in Edition I. (pages 89, 101) do not directly bear on the question of
protection.) If you will look at page 240 of the fourth edition of the
"Origin" you will find it very briefly given with two extreme examples of
the peacock and black grouse. A more general statement is given at page
101, or at page 89 of the first edition, for I have long entertained this
view, though I have never had space to develop it. But I had not
sufficient knowledge to generalise as far as you do about colouring and
nesting. In your paper perhaps you will just allude to my scanty remark in
the fourth edition, because in my Essay on Man I intend to discuss the
whole subject of sexual selection, explaining as I believe it does much
with respect to man. I have collected all my old notes, and partly written
my discussion, and it would be flat work for me to give the leading idea as
exclusively from you. But, as I am sure from your greater knowledge of
Ornithology and Entomology that you will write a much better discussion
than I could, your paper will be of great use to me. Nevertheless I must
discuss the subject fully in my Essay on Man. When we met at the
Zoological Society, and I asked you about the sexual differences in
kingfishers, I had this subject in view; as I had when I suggested to Bates
the difficulty about gaudy caterpillars, which you have so admirably (as I
believe it will prove) explained. (429/2. See a letter of February 26th,
1867, to Mr. Wallace, "Life and Letters" III., page 94.) I have got one
capital case (genus forgotten) of a [Australian] bird in which the female
has long tail-plumes, and which consequently builds a different nest from
all her allies. (429/3. Menura superba: see "Descent of Man" (1901),
page 687. Rhynchoea, mentioned a line or two lower down, is discussed in
the "Descent," page 727. The female is more brightly coloured than the
male, and has a convoluted trachea, elsewhere a masculine character. There
seems some reason to suppose that "the male undertakes the duty of
incubation.") With respect to certain female birds being more brightly
coloured than the males, and the latter incubating, I have gone a little
into the subject, and cannot say that I am fully satisfied. I remember
mentioning to you the case of Rhynchoea, but its nesting seems unknown. In
some other cases the difference in brightness seemed to me hardly
sufficiently accounted for by the principle of protection. At the Falkland
Islands there is a carrion hawk in which the female (as I ascertained by
dissection) is the brightest coloured, and I doubt whether protection will
here apply; but I wrote several months ago to the Falklands to make
enquiries. The conclusion to which I have been leaning is that in some of
these abnormal cases the colour happened to vary in the female alone, and
was transmitted to females alone, and that her variations have been
selected through the admiration of the male.

It is a very interesting subject, but I shall not be able to go on with it
for the next five or six months, as I am fully employed in correcting dull
proof-sheets. When I return to the work I shall find it much better done
by you than I could have succeeded in doing.

It is curious how we hit on the same ideas. I have endeavoured to show in
my MS. discussion that nearly the same principles account for young birds
not being gaily coloured in many cases, but this is too complex a point for
a note.

On reading over your letter again, and on further reflection, I do not
think (as far as I remember my words) that I expressed myself nearly
strongly enough on the value and beauty of your generalisation (429/4. See
Letter 203, Volume I.), viz., that all birds in which the female is
conspicuously or brightly coloured build in holes or under domes. I
thought that this was the explanation in many, perhaps most cases, but do
not think I should ever have extended my view to your generalisation.
Forgive me troubling you with this P.S.

Down, May 5th [1867].

The offer of your valuable notes is most generous, but it would vex me to
take so much from you, as it is certain that you could work up the subject
very much better than I could. Therefore I earnestly, and without any
reservation, hope that you will proceed with your paper, so that I return
your notes. You seem already to have well investigated the subject. I
confess on receiving your note that I felt rather flat at my recent work
being almost thrown away, but I did not intend to show this feeling. As a
proof how little advance I had made on the subject, I may mention that
though I had been collecting facts on the colouring, and other sexual
differences in mammals, your explanation with respect to the females had
not occurred to me. I am surprised at my own stupidity, but I have long
recognised how much clearer and deeper your insight into matters is than
mine. I do not know how far you have attended to the laws of inheritance,
so what follows may be obvious to you. I have begun my discussion on
sexual selection by showing that new characters often appear in one sex and
are transmitted to that sex alone, and that from some unknown cause such
characters apparently appear oftener in the male than in the female.
Secondly, characters may be developed and be confined to the male, and long
afterwards be transferred to the female. Thirdly, characters may arise in
either sex and be transmitted to both sexes, either in an equal or unequal
degree. In this latter case I have supposed that the survival of the
fittest has come into play with female birds and kept the female
dull-coloured. With respect to the absence of spurs in the female
gallinaceous birds, I presume that they would be in the way during
incubation; at least I have got the case of a German breed of fowls in
which the hens were spurred, and were found to disturb and break their eggs
much. With respect to the females of deer not having horns, I presume it
is to save the loss of organised matter. In your note you speak of sexual
selection and protection as sufficient to account for the colouring of all
animals, but it seems to me doubtful how far this will come into play with
some of the lower animals, such as sea anemones, some corals, etc., etc.
On the other hand Hackel (430/1. See "Descent of Man" (1901) page 402.)
has recently well shown that the transparency and absence of colour in the
lower oceanic animals, belonging to the most different classes, may be well
accounted for on the principle of protection.

Some time or other I should like much to know where your paper on the nests
of birds has appeared, and I shall be extremely anxious to read your paper
in the "Westminster Review." (430/2. "Westminster Review," July, 1867.)
Your paper on the sexual colouring of birds will, I have no doubt, be very
striking. Forgive me, if you can, for a touch of illiberality about your

March 19th, 1868.

(431/1. "The Variation of Animals and Plants" having been published on
January 30th, 1868, Mr. Darwin notes in his diary that on February 4th he
"Began on Man and Sexual Selection." He had already (in 1864 and 1867)
corresponded with Mr. Wallace on these questions--see for instance the
"Life and Letters," III., page 89; but, owing to various interruptions,
serious work on the subject did not begin until 1869. The following
quotations show the line of work undertaken early in 1868.

Mr. Wallace wrote (March 19th, 1868): "I am glad you have got good
materials on sexual selection. It is no doubt a difficult subject. One
difficulty to me is, that I do not see how the constant MINUTE variations,
which are sufficient for Natural Selection to work with, could be SEXUALLY
selected. We seem to require a series of bold and abrupt variations. How
can we imagine that an inch in the tail of the peacock, or 1/4-inch in that
of the Bird of Paradise, would be noticed and preferred by the female.")

In regard to sexual selection. A girl sees a handsome man, and without
observing whether his nose or whiskers are the tenth of an inch longer or
shorter than in some other man, admires his appearance and says she will
marry him. So, I suppose, with the pea-hen; and the tail has been
increased in length merely by, on the whole, presenting a more gorgeous
appearance. J. Jenner Weir, however, has given me some facts showing that
birds apparently admire details of plumage.

March 28th [1868].

I am particularly obliged to you for your observations on the stridulation
of the two sexes of Lamellicorns. (432/1. We are unable to find any
mention of F. Muller's observations on this point; but the reference is
clearly to Darwin's observations on Necrophorus and Pelobius, in which the
stridulating rasp was bigger in the males in the first individuals
examined, but not so in succeeding specimens. "Descent of Man," Edition
II., Volume I., page 382.) I begin to fear that I am completely in error
owing to that common cause, viz. mistaking at first individual variability
for sexual difference.

I go on working at sexual selection, and, though never idle, I am able to
do so little work each day that I make very slow progress. I knew from
Azara about the young of the tapir being striped, and about young deer
being spotted (432/2. Fritz Muller's views are discussed in the "Descent
of Man," Edition II., Volume II., page 305.); I have often reflected on
this subject, and know not what to conclude about the loss of the stripes
and spots. From the geographical distribution of the striped and unstriped
species of Equus there seems to be something very mysterious about the loss
of stripes; and I cannot persuade myself that the common ass has lost its
stripes owing to being rendered more conspicuous from having stripes and
thus exposed to danger.


(433/1. Mr. John Jenner Weir, to whom the following letters are addressed,
is frequently quoted in the "Descent of Man" as having supplied Mr. Darwin
with information on a variety of subjects.)

Down, February 27th [1868].

I must thank you for your paper on apterous lepidoptera (433/2. Published
by the West Kent Natural History, Microscopical and Photographic Society,
Greenwich, 1867. Mr. Weir's paper seems chiefly to have interested Mr.
Darwin as affording a good case of gradation in the degree of degradation
of the wings in various species.), which has interested me exceedingly, and
likewise for the very honourable mention which you make of my name. It is
almost a pity that your paper was not published in some Journal in which it
would have had a wider distribution. It contained much that was new to me.
I think the part about the relation of the wings and spiracles and tracheae
might have been made a little clearer. Incidentally, you have done me a
good service by reminding me of the rudimentary spurs on the legs of the
partridge, for I am now writing on what I have called sexual selection. I
believe that I am not mistaken in thinking that you have attended much to
birds in confinement, as well as to insects. If you could call to mind any
facts bearing on this subject, with birds, insects, or any animals--such as
the selection by a female of any particular male--or conversely of a
particular female by a male, or on the rivalry between males, or on the
allurement of the females by the males, or any such facts, I should be most
grateful for the information, if you would have the kindness to communicate

P.S.--I may give as instance of [this] class of facts, that Barrow asserts
that a male Emberiza (?) at the Cape has immensely long tail-feathers
during the breeding season (433/3. Barrow describes the long tail feathers
of Emberiza longicauda as enduring "but the season of love." "An Account
of Travels into the Interior of Southern Africa": London, 1801, Volume I.,
page 244.); and that if these are cut off, he has no chance of getting a
wife. I have always felt an intense wish to make analogous trials, but
have never had an opportunity, and it is not likely that you or any one
would be willing to try so troublesome an experiment. Colouring or
staining the fine red breast of a bullfinch with some innocuous matter into
a dingy tint would be an analogous case, and then putting him and ordinary
males with a female. A friend promised, but failed, to try a converse
experiment with white pigeons--viz., to stain their tails and wings with
magenta or other colours, and then observe what effect such a prodigious
alteration would have on their courtship. (433/4. See Letter 428.) It
would be a fairer trial to cut off the eyes of the tail-feathers of male
peacocks; but who would sacrifice the beauty of their bird for a whole
season to please a mere naturalist?

Down, February 29th [1868].

I have hardly ever received a note which has interested me more than your
last; and this is no exaggeration. I had a few cases of birds perceiving
slight changes in the dress of their owners, but your facts are of tenfold
value. I shall certainly make use of them, and need not say how much
obliged I should be for any others about which you feel confident.

Do you know of any birds besides some of the gallinaceae which are
polygamous? Do you know of any birds besides pigeons, and, as it is said,
the raven, which pair for their whole lives?

Many years ago I visited your brother, who showed me his pigeons and gave
me some valuable information. Could you persuade him (but I fear he would
think it high treason) to stain a male pigeon some brilliant colour, and
observe whether it excited in the other pigeons, especially the females,
admiration or contempt?

For the chance of your liking to have a copy and being able to find some
parts which would interest you, I have directed Mr. Murray to send you my
recent book on "Variation under Domestication."

P.S.--I have somewhere safe references to cases of magpies, of which one of
a pair has been repeatedly (I think seven times) killed, and yet another
mate was always immediately found. (434/1. On this subject see "Descent
of Man," Edition I., Volume II., page 104, where Mr. Weir's observations
were made use of. This statement is quoted from Jenner ("Phil. Trans."
1824) in the "Descent of Man" (1901), page 620.) A gamekeeper told me
yesterday of analogous case. This perplexes me much. Are there many
unmarried birds? I can hardly believe it. Or will one of a pair, of which
the nest has been robbed, or which are barren, always desert his or her
mate for a strange mate with the attraction of a nest, and in one instance
with young birds in the nest? The gamekeeper said during breeding season
he had never observed a single or unpaired partridge. How can the sexes be
so equally matched?

P.S. 2nd.--I fear you will find me a great bore, but I will be as
reasonable as can be expected in plundering one so rich as you.

P.S. 3rd.--I have just received a letter from Dr. Wallace (434/2. See
"Descent of Man," Edition I., Volume I., pages 386-401, where Dr. Wallace's
observations are quoted.), of Colchester, about the proportional numbers of
the two sexes in Bombyx; and in this note, apropos to an incidental remark
of mine, he stoutly maintains that female lepidoptera never notice the
colours or appearance of the male, but always receive the first male which
comes; and this appears very probable. He says he has often seen fine
females receive old battered and pale-tinted males. I shall have to admit
this very great objection to sexual selection in insects. His observations
no doubt apply to English lepidoptera, in most of which the sexes are
alike. The brimstone or orange-tip would be good to observe in this
respect, but it is hopelessly difficult. I think I have often seen several
males following one female; and what decides which male shall succeed? How
is this about several males; is it not so?

6, Queen Anne Street, Cavendish Square, W. [March 6th, 1868].

I have come here for a few weeks, for a little change and rest. Just as I
was leaving home I received your first note, and yesterday a second; and
both are most interesting and valuable to me. That is a very curious
observation about the goldfinch's beak (435/1. "Descent of Man," Edition
I., Volume I., page 39. Mr. Weir is quoted as saying that the birdcatchers
can distinguish the males of the goldfinch, Carduelis elegans, by their
"slightly longer beaks."), but one would hardly like to trust it without
measurement or comparison of the beaks of several male and female birds;
for I do not understand that you yourself assert that the beak of the male
is sensibly longer than that of the female. If you come across any acute
birdcatchers (I do not mean to ask you to go after them), I wish you would
ask what is their impression on the relative numbers of the sexes of any
birds which they habitually catch, and whether some years males are more
numerous and some years females. I see that I must trust to analogy (an
unsafe support) for sexual selection in regard to colour in butterflies.
You speak of the brimstone butterfly and genus Edusa (435/2. Colias
Edusa.) (I forget what this is, and have no books here, unless it is
Colias) not opening their wings. In one of my notes to Mr. Stainton I
asked him (but he could or did not answer) whether butterflies such as the
Fritillaries, with wings bright beneath and above, opened and shut their
wings more than Vanessae, most of which, I think, are obscure on the under
surface. That is a most curious observation about the red underwing moth
and the robin (435/3. "Descent of Man," Edition I., Volume I., page 395.
Mr. Weir describes the pursuit of a red-underwing, Triphoena pronuba, by a
robin which was attracted by the bright colour of the moth, and constantly
missed the insect by breaking pieces off the wing instead of seizing the
body. Mr. Wallace's facts are given on the same page.), and strongly
supports a suggestion (which I thought hardly credible) of A.R. Wallace,
viz. that the immense wings of some exotic lepidoptera served as a
protection from difficulty of birds seizing them. I will probably quote
your case.

No doubt Dr. Hooker collected the Kerguelen moth, for I remember he told me
of the case when I suggested in the "Origin," the explanation of the
coleoptera of Madeira being apterous; but he did not know what had become
of the specimens.

I am quite delighted to hear that you are observing coloured birds (435/4.
"Descent of Man," Edition I., Volume II., page 110.), though the
probability, I suppose, will be that no sure result will be gained. I am
accustomed with my numerous experiments with plants to be well satisfied if
I get any good result in one case out of five.

You will not be able to read all my book--too much detail. Some of the
chapters in the second volume are curious, I think. If any man wants to
gain a good opinion of his fellow-men, he ought to do what I am doing,
pester them with letters.

4, Chester Place, Regent's Park, N.W., March 13th [1868].

You make a very great mistake when you speak of "the risk of your notes
boring me." They are of the utmost value to me, and I am sure I shall
never be tired of receiving them; but I must not be unreasonable. I shall
give almost all the facts which you have mentioned in your two last notes,
as well as in the previous ones; and my only difficulty will be not to give
too much and weary my readers. Your last note is especially valuable about
birds displaying the beautiful parts of their plumage. Audubon (436/1. In
his "Ornithological Biography," 5 volumes, Edinburgh, 1831-49.) gives a
good many facts about the antics of birds during courtship, but nothing
nearly so much to the purpose as yours. I shall never be able to resist
giving the whole substance of your last note. It is quite a new light to
me, except with the peacock and Bird of Paradise. I must now look to
turkey's wings; but I do not think that their wings are beautiful when
opened during courtship. Its tail is finely banded. How about the drake
and Gallus bankiva? I forget how their wings look when expanded. Your
facts are all the more valuable as I now clearly see that for butterflies I
must trust to analogy altogether in regard to sexual selection. But I
think I shall make out a strong case (as far as the rather deceitful guide
of analogy will serve) in the sexes of butterflies being alike or differing
greatly--in moths which do not display the lower surface of their wings not
having them gaudily coloured, etc., etc.--nocturnal moths, etc.--and in
some male insects fighting for the females, and attracting them by music.

My discussion on sexual selection will be a curious one--a mere dovetailing
of information derived from you, Bates, Wallace, etc., etc., etc.

We remain at above address all this month, and then return home. In the
summer, could I persuade you to pay us a visit of a day or two, and I would
try and get Bates and some others to come down? But my health is so
precarious, I can ask no one who will not allow me the privilege of a poor
old invalid; for talking, I find by long and dear-bought experience, tries
my head more than anything, and I am utterly incapable of talking more than
half an hour, except on rare occasions.

I fear this note is very badly written; but I was very ill all yesterday,
and my hand shakes to-day.

4, Chester Place, Regent's Park, N.W., March 22nd [1868].

I hope that you will not think me ungrateful that I have not sooner
answered your note of the 16th; but in fact I have been overwhelmed both
with calls and letters; and, alas! one visit to the British Museum of an
hour or hour and a half does for me for the whole day.

I was particularly glad to hear your and your brother's statement about the
"gay" deceiver-pigeons. (437/1. Some cock pigeons "called by our English
fanciers gay birds are so successful in their gallantries that, as Mr. H.
Weir informs me, they must be shut up, on account of the mischief which
they cause.") I did not at all know that certain birds could win the
affections of the females more than other males, except, indeed, in the
case of the peacock. Conversely, Mr. Hewitt, I remember, states that in
making hybrids the cock pheasant would prefer certain hen fowls and
strongly dislike others. I will write to Mr. H. in a few days, and ask him
whether he has observed anything of this kind with pure unions of fowls,
ducks, etc. I had utterly forgotten the case of the ruff (437/2. The
ruff, Machetes pugnax, was believed by Montague to be polygamous. "Descent
of Man," Edition I., Volume I., page 270.), but now I remember having heard
that it was polygamous; but polygamy with birds, at least, does not seem
common enough to have played an important part. So little is known of
habits of foreign birds: Wallace does not even know whether Birds of
Paradise are polygamous. Have you been a large collector of caterpillars?
I believe so. I inferred from a letter from Dr. Wallace, of Colchester,
that he would account for Mr. Stainton and others rearing more female than
male by their having collected the larger and finer caterpillars. But I
misunderstood him, and he maintains that collectors take all caterpillars,
large and small, for that they collect the caterpillars alone of the rarer
moths or butterflies. What think you? I hear from Professor Canestrini
(437/3. See "Descent of Man" (1901), page 385.) in Italy that females are
born in considerable excess with Bombyx mori, and in greater excess of late
years than formerly! Quatrefages writes to me that he believes they are
equal in France. So that the farther I go the deeper I sink into the mire.
With cordial thanks for your most valuable letters.

We remain here till April 1st, and then hurrah for home and quiet work.

4, Chester Place, N.W., March 27th [1868].

I hardly know which of your three last letters has interested me most.
What splendid work I shall have hereafter in selecting and arranging all
your facts. Your last letter is most curious--all about the bird-catchers
--and interested us all. I suppose the male chaffinch in "pegging"
approaches the captive singing-bird, from rivalry or jealousy--if I am
wrong please tell me; otherwise I will assume so. Can you form any theory
about all the many cases which you have given me, and others which have
been published, of when one [of a] pair is killed, another soon appearing?
Your fact about the bullfinches in your garden is most curious on this
head. (438/1. Mr. Weir stated that at Blackheath he never saw or heard a
wild bullfinch, yet when one of his caged males died, a wild one in the
course of a few days generally came and perched near the widowed female,
whose call-note is not loud. "Descent of Man" (1901), page 623.) Are
there everywhere many unpaired birds? What can the explanation be?

Mr. Gould assures me that all the nightingales which first come over are
males, and he believes this is so with other migratory birds. But this
does not agree with what the bird-catchers say about the common linnet,
which I suppose migrates within the limits of England.

Many thanks for very curious case of Pavo nigripennis. (438/2. See
"Animals and Plants," Edition II., Volume I., page 306.) I am very glad to
get additional evidence. I have sent your fact to be inserted, if not too
late, in four foreign editions which are now printing. I am delighted to
hear that you approve of my book; I thought every mortal man would find the
details very tedious, and have often repented of giving so many. You will
find pangenesis stiff reading, and I fear will shake your head in
disapproval. Wallace sticks up for the great god Pan like a man.

The fertility of hybrid canaries would be a fine subject for careful

Down, April 4th [1868].

I read over your last ten (!) letters this morning, and made an index of
their contents for easy reference; and what a mine of wealth you have
bestowed on me. I am glad you will publish yourself on gay-coloured
caterpillars and birds (439/1. See "Descent of Man," Edition I., Volume
I., page 417, where Mr. Weir's experiments are given; they were made to
test Mr. Wallace's theory that caterpillars, which are protected against
birds by an unpleasant taste, have been rendered conspicuous, so that they
are easily recognised. They thus escape being pecked or tasted, which to
soft-skinned animals would be as fatal as being devoured. See Mr. Jenner
Weir's papers, "Transact. Entomolog. Soc." 1869, page 2; 1870, page 337.
In regard to one of these papers Mr. Darwin wrote (May 13th, 1869): "Your
verification of Wallace's suggestion seems to me to amount to quite a
discovery."); it seems to me much the best plan; therefore, I will not
forward your letter to Mr. Wallace. I was much in the Zoological Gardens
during my month in London, and picked up what scraps of knowledge I could.
Without my having mentioned your most interesting observations on the
display of the Fringillidae (439/2. "Descent of Man" (1901), page 738.),
Mr. Bartlett told me how the Gold Pheasant erects his collar and turns from
side to side, displaying it to the hen. He has offered to give me notes on
the display of all Gallinaceae with which he is acquainted; but he is so
busy a man that I rather doubt whether he will ever do so.

I received about a week ago a remarkably kind letter from your brother, and
I am sorry to hear that he suffers much in health. He gave me some fine
facts about a Dun Hen Carrier which would never pair with a bird of any
other colour. He told me, also, of some one at Lewes who paints his dog!
and will inquire about it. By the way, Mr. Trimen tells me that as a boy
he used to paint butterflies, and that they long haunted the same place,
but he made no further observations on them. As far as colour is
concerned, I see I shall have to trust to mere inference from the males
displaying their plumage, and other analogous facts. I shall get no direct
evidence of the preference of the hens. Mr. Hewitt, of Birmingham, tells
me that the common hen prefers a salacious cock, but is quite indifferent
to colour.

Will you consider and kindly give me your opinion on the two following
points. Do very vigorous and well-nourished hens receive the male earlier
in the spring than weaker or poorer hens? I suppose that they do.
Secondly, do you suppose that the birds which pair first in the season have
any advantage in rearing numerous and healthy offspring over those which
pair later in the season? With respect to the mysterious cases of which
you have given me so many, in addition to those previously collected, of
when one bird of a pair is shot another immediately supplying its place, I
was drawing to the conclusion that there must be in each district several
unpaired birds; yet this seems very improbable. You allude, also, to the
unknown causes which keep down the numbers of birds; and often and often
have I marvelled over this subject with respect to many animals.


(440/1. The following refers to Mr. Wallace's article "A Theory of Birds'
Nests," in Andrew Murray's "Journal of Travel," Volume I., page 73. He
here treats in fuller detail the view already published in the "Westminster
Review," July 1867, page 38. The rule which Mr. Wallace believes, with
very few exceptions, to hold good is, "that when both sexes are of
strikingly gay and conspicuous colours, the nest is...such as to conceal
the sitting bird; while, whenever there is a striking contrast of colours,
the male being gay and conspicuous, the female dull and obscure, the nest
is open, and the sitting bird exposed to view." At this time Mr. Wallace
allowed considerably more influence to sexual selection (in combination
with the need of protection) than in his later writings. The following
extract from a letter from Mr. Wallace to Darwin (July 23rd, 1877) fixes
the period at which the change in his views occurred: "I am almost afraid
to tell you that in going over the subject of the colours of animals, etc.,
etc., for a small volume of essays, etc., I am preparing, I have come to
conclusions directly opposed to voluntary sexual selection, and believe
that I can explain (in a general way) all the phenomena of sexual ornaments
and colours by laws of development aided by simple 'Natural Selection.'"
He finally rejected Mr. Darwin's theory that colours "have been developed
by the preference of the females, the more ornamented males becoming the
parents of each successive generation." "Darwinism," 1889, page 285. See
also Letters 442, 443, 449, 450, etc.)

Down, April 15th, [1868].

I have been deeply interested by your admirable article on birds' nests. I
am delighted to see that we really differ very little,--not more than two
men almost always will. You do not lay much or any stress on new
characters spontaneously appearing in one sex (generally the male), and
being transmitted exclusively, or more commonly only in excess, to that
sex. I, on the other hand, formerly paid far too little attention to
protection. I had only a glimpse of the truth; but even now I do not go
quite as far as you. I cannot avoid thinking rather more than you do about
the exceptions in nesting to the rule, especially the partial exceptions,
i.e., when there is some little difference between the sexes in species
which build concealed nests. I am not quite satisfied about the incubating
males; there is so little difference in conspicuousness between the sexes.
I wish with all my heart I could go the whole length with you. You seem to
think that male birds probably select the most beautiful females; I must
feel some doubt on this head, for I can find no evidence of it. Though I
am writing so carping a note, I admire the article thoroughly.

And now I want to ask a question. When female butterflies are more
brilliant than their males you believe that they have in most cases, or in
all cases, been rendered brilliant so as to mimic some other species, and
thus escape danger. But can you account for the males not having been
rendered equally brilliant and equally protected? (440/2. See Wallace in
the "Westminster Review," July, 1867, page 37, on the protection to the
female insect afforded by its resemblance either to an inanimate object or
to another insect protected by its unpalatableness. The cases are
discussed in relation to the much greater importance (to the species as a
whole) of the preservation of the female insect with her load of eggs than
the male who may safely be sacrificed after pairing. See Letter 189,
note.) Although it may be most for the welfare of the species that the
female should be protected, yet it would be some advantage, certainly no
disadvantage, for the unfortunate male to enjoy an equal immunity from
danger. For my part, I should say that the female alone had happened to
vary in the right manner, and that the beneficial variations had been
transmitted to the same sex alone. Believing in this, I can see no
improbability (but from analogy of domestic animals a strong probability)
that variations leading to beauty must often have occurred in the males
alone, and been transmitted to that sex alone. Thus I should account in
many cases for the greater beauty of the male over the female, without the
need of the protective principle. I should be grateful for an answer on
the point.

Down, April 18th [1868].

You see that I have taken you at your word, and have not (owing to heaps of
stupid letters) earlier noticed your three last letters, which as usual are
rich in facts. Your letters make almost a little volume on my table. I
daresay you hardly knew yourself how much curious information was lying in
your mind till I began the severe pumping process. The case of the
starling married thrice in one day is capital, and beats the case of the
magpies of which one was shot seven times consecutively. A gamekeeper here
tells me that he has repeatedly shot one of a pair of jays, and it has
always been immediately replaced. I begin to think that the pairing of
birds must be as delicate and tedious an operation as the pairing of young
gentlemen and ladies. If I can convince myself that there are habitually
many unpaired birds, it will be a great aid to me in sexual selection,
about which I have lately had many troubles, and am therefore rejoiced to
hear in your last note that your faith keeps staunch. That is a curious
fact about the bullfinches all appearing to listen to the German singer
(441/1. See Letter 445, note.); and this leads me to ask how much faith
may I put in the statement that male birds will sing in rivalry until they
injure themselves. Yarrell formerly told me that they would sometimes even
sing themselves to death. I am sorry to hear that the painted bullfinch
turns out to be a female; though she has done us a good turn in exhibiting
her jealousy, of which I had no idea.

Thank you for telling me about the wildness of the hybrid canaries:
nothing has hardly ever surprised me more than the many cases of reversion
from crossing. Do you not think it a very curious subject? I have not
heard from Mr. Bartlett about the Gallinaceae, and I daresay I never shall.
He told me about the Tragopan, and he is positive that the blue wattle
becomes gorged with blood, and not air.

Returning to the first of the last three letters. It is most curious the
number of persons of the name of Jenner who have had a strong taste for
Natural History. It is a pity you cannot trace your connection with the
great Jenner, for a duke might be proud of his blood.

I heard lately from Professor Rolleston of the inherited effects of an
injury in the same eye. Is the scar on your son's leg on the same side and
on exactly the same spot where you were wounded? And did the wound
suppurate, or heal by the first intention? I cannot persuade myself of the
truth of the common belief of the influence of the mother's imagination on
the child. A point just occurs to me (though it does not at present
concern me) about birds' nests. Have you read Wallace's recent articles?
(441/2. A full discussion of Mr. Wallace's views is given in "Descent of
Man," Edition I., Volume II., Chapter XV. Briefly, Mr. Wallace's point is
that the dull colour of the female bird is protective by rendering her
inconspicuous during incubation. Thus the relatively bright colour of the
male would not simply depend on sexual selection, but also on the hen being
"saved, through Natural Selection, from acquiring the conspicuous colours
of the male" (loc. cit., page 155).) I always distrust myself when I
differ from him; but I cannot admit that birds learn to make their nests
from having seen them whilst young. I must think it as true an instinct as
that which leads a caterpillar to suspend its cocoon in a particular
manner. Have you had any experience of birds hatched under a foster-mother
making their nests in the proper manner? I cannot thank you enough for all
your kindness.


(442/1. Dr. Clifford Allbutt's view probably had reference to the fact
that the sperm-cell goes, or is carried, to the germ-cell, never vice
versa. In this letter Darwin gives the reason for the "law" referred to.
Mr. A.R. Wallace has been good enough to give us the following note:--"It
was at this time that my paper on 'Protective Resemblance' first appeared
in the 'Westminster Review,' in which I adduced the greater, or rather, the
more continuous, importance of the female (in the lower animals) for the
race, and my 'Theory of Birds' Nests' ('Journal of Travel and Natural
History,' No. 2) in which I applied this to the usually dull colours of
female butterflies and birds. It is to these articles as well as to my
letters that Darwin chiefly refers."--Note by Mr. Wallace, May 27th, 1902.)

Down, April 30th [1868].

Your letter, like so many previous ones, has interested me much. Dr.
Allbutt's view occurred to me some time ago, and I have written a short
discussion on it. It is, I think, a remarkable law, to which I have found
no exception. The foundation lies in the fact that in many cases the eggs
or seeds require nourishment and protection by the mother-form for some
time after impregnation. Hence the spermatozoa and antherozoids travel in
the lower aquatic animals and plants to the female, and pollen is borne to
the female organ. As organisms rise in the scale it seems natural that the
male should carry the spermatozoa to the female in his own body. As the
male is the searcher, he has required and gained more eager passions than
the female; and, very differently from you, I look at this as one great
difficulty in believing that the males select the more attractive females;
as far as I can discover, they are always ready to seize on any female, and
sometimes on many females. Nothing would please me more than to find
evidence of males selecting the more attractive females. I have for months
been trying to persuade myself of this. There is the case of man in favour
of this belief, and I know in hybrid unions of males preferring particular
females, but, alas, not guided by colour. Perhaps I may get more evidence
as I wade through my twenty years' mass of notes.

I am not shaken about the female protected butterflies. I will grant (only
for argument) that the life of the male is of very little value,--I will
grant that the males do not vary, yet why has not the protective beauty of
the female been transferred by inheritance to the male? The beauty would
be a gain to the male, as far as we can see, as a protection; and I cannot
believe that it would be repulsive to the female as she became beautiful.
But we shall never convince each other. I sometimes marvel how truth
progresses, so difficult is it for one man to convince another, unless his
mind is vacant. Nevertheless, I myself to a certain extent contradict my
own remark, for I believe far more in the importance of protection than I
did before reading your articles.

I do not think you lay nearly stress enough in your articles on what you
admit in your letters: viz., "there seems to be some production of
vividness...of colour in the male independent of protection." This I am
making a chief point; and have come to your conclusion so far that I
believe that intense colouring in the female sex is often checked by being

That is an excellent remark of yours about no known case of male alone
assuming protective colours; but in the cases in which protection has been
gained by dull colours, I presume that sexual selection would interfere
with the male losing his beauty. If the male alone had acquired beauty as
a protection, it would be most readily overlooked, as males are so often
more beautiful than their females. Moreover, I grant that the life of the
male is somewhat less precious, and thus there would be less rigorous
selection with the male, so he would be less likely to be made beautiful
through Natural Selection for protection. (442/2. This does not apply to
sexual selection, for the greater the excess of males, and the less
precious their lives, so much the better for sexual selection. [Note in
original.]) But it seems to me a good argument, and very good if it could
be thoroughly established. I do not know whether you will care to read
this scrawl.

Down, May 5th [1868?].

I am afraid I have caused you a great deal of trouble in writing to me at
such length. I am glad to say that I agree almost entirely with your
summary, except that I should put sexual selection as an equal, or perhaps
as even a more important agent in giving colour than Natural Selection for
protection. As I get on in my work I hope to get clearer and more decided
ideas. Working up from the bottom of the scale, I have as yet only got to
fishes. What I rather object to in your articles is that I do not think
any one would infer from them that you place sexual selection even as high
as No. 4 in your summary. It was very natural that you should give only a
line to sexual selection in the summary to the "Westminster Review," but
the result at first to my mind was that you attributed hardly anything to
its power. In your penultimate note you say "in the great mass of cases in
which there is great differentiation of colour between the sexes, I believe
it is due almost wholly to the need of protection to the female." Now,
looking to the whole animal kingdom, I can at present by no means admit
this view; but pray do not suppose that because I differ to a certain
extent, I do not thoroughly admire your several papers and your admirable
generalisation on birds' nests. With respect to this latter point,
however, although, following you, I suspect that I shall ultimately look at
the whole case from a rather different point of view.

You ask what I think about the gay-coloured females of Pieris. (443/1.
See "Westminster Review," July, 1867, page 37; also Letter 440.) I believe
I quite follow you in believing that the colours are wholly due to mimicry;
and I further believe that the male is not brilliant from not having
received through inheritance colour from the female, and from not himself
having varied; in short, that he has not been influenced by selection.

I can make no answer with respect to the elephants. With respect to the
female reindeer, I have hitherto looked at the horns simply as the
consequence of inheritance not having been limited by sex.

Your idea about colour being concentrated in the smaller males seems good,
and I presume that you will not object to my giving it as your suggestion.

Down, May 7th [1868].

I have now to thank you for no less than four letters! You are so kind
that I will not apologise for the trouble I cause you; but it has lately
occurred to me that you ought to publish a paper or book on the habits of
the birds which you have so carefully observed. But should you do this, I
do not think that my giving some of the facts for a special object would
much injure the novelty of your work. There is such a multitude of points
in these last letters that I hardly know what to touch upon. Thanks about
the instinct of nidification, and for your answers on many points. I am
glad to hear reports about the ferocious female bullfinch. I hope you will
have another try in colouring males. I have now finished lepidoptera, and
have used your facts about caterpillars, and as a caution the case of the
yellow-underwings. I have now begun on fishes, and by comparing different
classes of facts my views are getting a little more decided. In about a
fortnight or three weeks I shall come to birds, and then I dare say that I
shall be extra troublesome. I will now enclose a few queries for the mere
chance of your being able to answer some of them, and I think it will save
you trouble if I write them on a separate slip, and then you can sometimes
answer by a mere "no" or "yes."

Your last letter on male pigeons and linnets has interested me much, for
the precise facts which you have given me on display are of the utmost
value for my work. I have written to Mr. Bartlett on Gallinaceae, but I
dare say I shall not get an answer. I had heard before, but am glad to
have confirmation about the ruffs being the most numerous. I am greatly
obliged to your brother for sending out circulars. I have not heard from
him as yet. I want to ask him whether he has ever observed when several
male pigeons are courting one female that the latter decides with which
male she will pair. The story about the black mark on the lambs must be a
hoax. The inaccuracy of many persons is wonderful. I should like to tell
you a story, but it is too long, about beans growing on the wrong side of
the pod during certain years.


Does any female bird regularly sing?

Do you know any case of both sexes, more especially of the female, [being]
more brightly coloured whilst young than when come to maturity and fit to
breed? An imaginary instance would be if the female kingfisher (or male)
became dull coloured when adult.

Do you know whether the male and female wild canary bird differ in plumage
(though I believe I could find this out for myself), and do any of the
domestic breeds differ sexually?

Do you know any gallinaceous bird in which the female has well developed

It is very odd that my memory should fail me, but I cannot remember
whether, in accordance with your views, the wing of Gallus bankiva (or
Game-Cock, which is so like the wild) is ornamental when he opens and
scrapes it before the female. I fear it is not; but though I have often
looked at wing of the wild and tame bird, I cannot call to mind the exact
colours. What a number of points you have attended to; I did not know that
you were a horticulturist. I have often marvelled at the different growth
of the flowering and creeping branches of the ivy; but had no idea that
they kept their character when propagated by cuttings. There is a S.
American genus (name forgotten just now) which differs in an analogous
manner but even greater degree, but it is difficult to cultivate in our
hot-house. I have tried and failed.

Down, May 30th [1868].

I am glad to hear your opinion on the nest-making instinct, for I am Tory
enough not to like to give up all old beliefs. Wallace's view (445/1. See
Letter 440, etc.) is also opposed to a great mass of analogical facts. The
cases which you mention of suddenly reacquired wildness seem curious. I
have also to thank you for a previous valuable letter. With respect to
spurs on female Gallinaceae, I applied to Mr. Blyth, who has wonderful
systematic knowledge, and he tells me that the female Pavo muticus and
Fire-back pheasants are spurred. From various interruptions I get on very
slowly with my Bird MS., but have already often and often referred to your
volume of letters, and have used various facts, and shall use many more.
And now I am ashamed to say that I have more questions to ask; but I
forget--you told me not to apologise.

1. In your letter of April 14th you mention the case of about twenty birds
which seemed to listen with much interest to an excellent piping bullfinch.
(445/2. Quoted in the "Descent of Man" (1901), page 564. "A bullfinch
which had been taught to pipe a German waltz...when this bird was first
introduced into a room where other birds were kept and he began to sing,
all the others, consisting of about twenty linnets and canaries, ranged
themselves on the nearest side of their cages, and listened with the
greatest interest to the new performer.") What kind of birds were these

2. Is it true, as often stated, that a bird reared by foster-parents, and
who has never heard the song of its own species, imitates to a certain
extent the song of the species which it may be in the habit of hearing?

Now for a more troublesome point. I find it very necessary to make out
relation of immature plumage to adult plumage, both when the sexes differ
and are alike in the adult state. Therefore, I want much to learn about
the first plumage (answering, for instance, to the speckled state of the
robin before it acquires the red breast) of the several varieties of the
canary. Can you help me? What is the character or colour of the first
plumage of bright yellow or mealy canaries which breed true to these tints?
So with the mottled-brown canaries, for I believe that there are breeds
which always come brown and mottled. Lastly, in the "prize-canaries,"
which have black wing- and tail-feathers during their first (?) plumage,
what colours are the wings and tails after the first (?) moult or when
adult? I should be particularly glad to learn this. Heaven have mercy on
you, for it is clear that I have none. I am going to investigate this same
point with all the breeds of fowls, as Mr. Tegetmeier will procure for me
young birds, about two months old, of all the breeds.

In the course of this next month I hope you will come down here on the
Saturday and stay over the Sunday. Some months ago Mr. Bates said he would
pay me a visit during June, and I have thought it would be pleasanter for
you to come here when I can get him, so that you would have a companion if
I get knocked up, as is sadly too often my bad habit and great misfortune.

Did you ever hear of the existence of any sub-breed of the canary in which
the male differs in plumage from the female?

Down, June 3rd [1868].

Your letter of April 22nd has much interested me. I am delighted that you
approve of my book, for I value your opinion more than that of almost any
one. I have yet hopes that you will think well of pangenesis. I feel sure
that our minds are somewhat alike, and I find it a great relief to have
some definite, though hypothetical view, when I reflect on the wonderful
transformations of animals, the re-growth of parts, and especially the
direct action of pollen on the mother form, etc. It often appears to me
almost certain that the characters of the parents are "photographed" on the
child, only by means of material atoms derived from each cell in both
parents, and developed in the child. I am sorry about the mistake in
regard to Leptotes. (446/1. See "Animals and Plants," Edition I., Volume
II., page 134, where it is stated that Oncidium is fertile with Leptotes, a
mistake corrected in the 2nd edition.) I daresay it was my fault, yet I
took pains to avoid such blunders. Many thanks for all the curious facts
about the unequal number of the sexes in crustacea, but the more I
investigate this subject the deeper I sink in doubt and difficulty.
Thanks, also, for the confirmation of the rivalry of Cicadae. (446/2. See
"Descent of Man," Edition I., Volume I., page 351, for F. Muller's
observations; and for a reference to Landois' paper.) I have often
reflected with surprise on the diversity of the means for producing music
with insects, and still more with birds. We thus get a high idea of the
importance of song in the animal kingdom. Please to tell me where I can
find any account of the auditory organs in the orthoptera? Your facts are
quite new to me. Scudder has described an annectant insect in Devonian
strata, furnished with a stridulating apparatus. (446/3. The insect is no
doubt Xenoneura antiquorum, from the Devonian rocks of New Brunswick.
Scudder compared a peculiar feature in the wing of this species to the
stridulating apparatus of the Locustariae, but afterwards stated that he
had been led astray in his original description, and that there was no
evidence in support of the comparison with a stridulating organ. See the
"Devonian Insects of New Brunswick," reprinted in S.H. Scudder's "Fossil
Insects of N. America," Volume I., page 179, New York, 1890.) I believe he
is to be trusted, and if so the apparatus is of astonishing antiquity.
After reading Landois' paper I have been working at the stridulating organ
in the lamellicorn beetles, in expectation of finding it sexual, but I have
only found it as yet in two cases, and in these it was equally developed in
both sexes. I wish you would look at any of your common lamellicorns and
take hold of both males and females and observe whether they make the
squeaking or grating noise equally. If they do not, you could perhaps send
me a male and female in a light little box. How curious it is that there
should be a special organ for an object apparently so unimportant as
squeaking. Here is another point: have you any Toucans? if so, ask any
trustworthy hunter whether the beaks of the males, or of both sexes, are
more brightly coloured during the breeding season than at other times of
the year? I have also to thank you for a previous letter of April 3rd,
with some interesting facts on the variation of maize, the sterility of
Bignonia and on conspicuous seeds. Heaven knows whether I shall ever live
to make use of half the valuable facts which you have communicated to me...

Down, June 18th [1868].

Many thanks. I am glad that you mentioned the linnet, for I had much
difficulty in persuading myself that the crimson breast could be due to
change in the old feathers, as the books say. I am glad to hear of the
retribution of the wicked old she-bullfinch. You remember telling me how
many Weirs and Jenners have been naturalists; now this morning I have been
putting together all my references about one bird of a pair being killed,
and a new mate being soon found; you, Jenner Weir, have given me some most
striking cases with starlings; Dr. Jenner gives the most curious case of
all in "Philosophical Transactions" (447/1. "Phil. Trans." 1824.), and a
Mr. Weir gives the next most striking in Macgillivray. (447/2.
Macgillivray's "History of British Birds," Volume I., page 570. See
"Descent of Man" (1901), page 621.) Now, is this not odd? Pray remember
how very glad we shall be to see you here whenever you can come.

Did some ancient progenitor of the Weirs and Jenners puzzle his brains
about the mating of birds, and has the question become indelibly fixed in
all your minds?

August 19th [1868].

I had become, before my nine weeks' horrid interruption of all work,
extremely interested in sexual selection, and was making fair progress. In
truth it has vexed me much to find that the farther I get on the more I
differ from you about the females being dull-coloured for protection. I
can now hardly express myself as strongly, even, as in the "Origin." This
has much decreased the pleasure of my work. In the course of September, if
I can get at all stronger, I hope to get Mr. J. Jenner Weir (who has been
wonderfully kind in giving me information) to pay me a visit, and I will
then write for the chance of your being able to come, and I hope bring with
you Mrs. Wallace. If I could get several of you together it would be less
dull for you, for of late I have found it impossible to talk with any human
being for more than half an hour, except on extraordinary good days.

(448/1. On September 16th Darwin wrote to Wallace on the same subject:--)

You will be pleased to hear that I am undergoing severe distress about
protection and sexual selection; this morning I oscillated with joy towards
you; this evening I have swung back to the old position, out of which I
fear I shall never get.


(449/1. From "Life and Letters," Volume III., page 123.)

Down, September 23rd [1868].

I am very much obliged for all your trouble in writing me your long letter,
which I will keep by me and ponder over. To answer it would require at
least 200 folio pages! If you could see how often I have rewritten some
pages you would know how anxious I am to arrive as near as I can to the
truth. I lay great stress on what I know takes place under domestication;
I think we start with different fundamental notions on inheritance. I find
it is most difficult, but not, I think, impossible to see how, for
instance, a few red feathers appearing on the head of a male bird, and
which are at first transmitted to both sexes, would come to be transmitted
to males alone. It is not enough that females should be produced from the
males with red feathers, which should be destitute of red feathers; but
these females must have a latent tendency to produce such feathers,
otherwise they would cause deterioration in the red head-feathers of their
male offspring. Such latent tendency would be shown by their producing the
red feathers when old, or diseased in their ovaria. But I have no
difficulty in making the whole head red if the few red feathers in the male
from the first tended to be sexually transmitted. I am quite willing to
admit that the female may have been modified, either at the same time or
subsequently, for protection by the accumulation of variations limited in
their transmission to the female sex. I owe to your writings the
consideration of this latter point. But I cannot yet persuade myself that
females alone have often been modified for protection. Should you grudge
the trouble briefly to tell me, whether you believe that the plainer head
and less bright colours of female chaffinch, the less red on the head and
less clean colours of female goldfinch, the much less red on the breast of
the female bullfinch, the paler crest of golden-crested wren, etc., have
been acquired by them for protection? I cannot think so, any more than I
can that the considerable differences between female and male
house-sparrow, or much greater brightness of male Parus caeruleus (both of
which build under cover) than of female Parus, are related to protection.
I even misdoubt much whether the less blackness of female blackbird is for

Again, can you give me reasons for believing that the moderate differences
between the female pheasant, the female Gallus bankiva, the female of black
grouse, the pea-hen, the female partridge, have all special references to
protection under slightly different conditions? I, of course, admit that
they are all protected by dull colours, derived, as I think, from some
dull-ground progenitor; and I account partly for their difference by
partial transference of colour from the male, and by other means too long
to specify; but I earnestly wish to see reason to believe that each is
specially adapted for concealment to its environment.

I grieve to differ from you, and it actually terrifies me and makes me
constantly distrust myself. I fear we shall never quite understand each
other. I value the cases of bright-coloured, incubating male fisher, and
brilliant female butterflies, solely as showing that one sex may be made
brilliant without any necessary transference of beauty to the other sex;
for in these cases I cannot suppose that beauty in the other sex was
checked by selection.

I fear this letter will trouble you to read it. A very short answer about
your belief in regard to the female finches and Gallinaceae would suffice.

9, St. Mark's Crescent, N.W., September 27th, 1868.

Your view seems to be that variations occurring in one sex are transmitted
either to that sex exclusively or to both sexes equally, or more rarely
partially transferred. But we have every gradation of sexual colours, from
total dissimilarity to perfect identity. If this is explained solely by
the laws of inheritance, then the colours of one or other sex will be
always (in relation to the environment) a matter of chance. I cannot think
this. I think selection more powerful than laws of inheritance, of which
it makes use, as shown by cases of two, three or four forms of female
butterflies, all of which have, I have little doubt, been specialised for

To answer your first question is most difficult, if not impossible, because
we have no sufficient evidence in individual cases of slight sexual
difference, to determine whether the male alone has acquired his superior
brightness by sexual selection, or the female been made duller by need of
protection, or whether the two causes have acted. Many of the sexual
differences of existing species may be inherited differences from parent
forms, which existed under different conditions and had greater or less
need of protection.

I think I admitted before, the general tendency (probably) of males to
acquire brighter tints. Yet this cannot be universal, for many female
birds and quadrupeds have equally bright tints.

To your second question I can reply more decidedly. I do think the females
of the Gallinaceae you mention have been modified or been prevented from
acquiring the brighter plumage of the male, by need of protection. I know
that the Gallus bankiva frequents drier and more open situations than the
pea-hen of Java, which is found among grassy and leafy vegetation,
corresponding with the colours of the two. So the Argus pheasant, male and
female, are, I feel sure, protected by their tints corresponding to the
dead leaves of the lofty forest in which they dwell, and the female of the
gorgeous fire-back pheasant Lophura viellottii is of a very similar rich
brown colour.

I do not, however, at all think the question can be settled by individual
cases, but by only large masses of facts. The colours of the mass of
female birds seem to me strictly analogous to the colours of both sexes of
snipes, woodcocks, plovers, etc., which are undoubtedly protective.

Now, supposing, on your view, that the colours of a male bird become more
and more brilliant by sexual selection, and a good deal of that colour is
transmitted to the female till it becomes positively injurious to her
during incubation, and the race is in danger of extinction; do you not
think that all the females who had acquired less of the male's bright
colours, or who themselves varied in a protective direction, would be
preserved, and that thus a good protective colouring would soon be

If you admit that this could occur, and can show no good reason why it
should not often occur, then we no longer differ, for this is the main
point of my view.

Have you ever thought of the red wax-tips of the Bombycilla beautifully
imitating the red fructification of lichens used in the nest, and therefore
the FEMALES have it too? Yet this is a very sexual-looking character.

If sexes have been differentiated entirely by sexual selection the females
can have no relation to environment. But in groups when both sexes require
protection during feeding or repose, as snipes, woodcock, ptarmigan, desert
birds and animals, green forest birds, etc., arctic birds of prey, and
animals, then both sexes are modified for protection. Why should that
power entirely cease to act when sexual differentiation exists and when the
female requires protection, and why should the colour of so many FEMALE
BIRDS seem to be protective, if it has not been made protective by

It is contrary to the principles of "Origin of Species," that colour should
have been produced in both sexes by sexual selection and never have been
modified to bring the female into harmony with the environment. "Sexual
selection is less rigorous than Natural Selection," and will therefore be
subordinate to it.

I think the case of female Pieris pyrrha proves that females alone can be
greatly modified for protection. (450/1. My latest views on this subject,
with many new facts and arguments, will be found in the later editions of
my "Darwinism," Chapter X. (A.R.W.))


(451/1. On October 4th, 1868, Mr. Wallace wrote again on the same subject
without adding anything of importance to his arguments of September 27th.
We give his final remarks:--)

October 4th, 1868.

I am sorry to find that our difference of opinion on this point is a source
of anxiety to you. Pray do not let it be so. The truth will come out at
last, and our difference may be the means of setting others to work who may
set us both right. After all, this question is only an episode (though an
important one) in the great question of the "Origin of Species," and
whether you or I are right will not at all affect the main doctrine--that
is one comfort.

I hope you will publish your treatise on "Sexual Selection" as a separate
book as soon as possible; and then, while you are going on with your other
work, there will no doubt be found some one to battle with me over your
facts on this hard problem.

Down, October 6th [1868].

Your letter is very valuable to me, and in every way very kind. I will not
inflict a long answer, but only answer your queries. There are breeds
(viz. Hamburg) in which both sexes differ much from each other and from
both sexes of Gallus bankiva; and both sexes are kept constant by
selection. The comb of the Spanish male has been ordered to be upright,
and that of Spanish female to lop over, and this has been effected. There
are sub-breeds of game fowl, with females very distinct and males almost
identical; but this, apparently, is the result of spontaneous variation,
without special selection. I am very glad to hear of case of female Birds
of Paradise.

I have never in the least doubted possibility of modifying female birds
alone for protection, and I have long believed it for butterflies. I have
wanted only evidence for the female alone of birds having had their colour
modified for protection. But then I believe that the variations by which a
female bird or butterfly could get or has got protective colouring have
probably from the first been variations limited in their transmission to
the female sex. And so with the variations of the male: when the male is
more beautiful than the female, I believe the variations were sexually
limited in their transmission to the males.

Down, October 31st, 1868.

(453/1. A short account of the Periodical Cicada (C. septendecim) is given
by Dr. Sharp in the Cambridge Natural History, Insects II., page 570. We
are indebted to Dr. Sharp for calling our attention to Mr. C.L. Marlatt's
full account of the insect in "Bulletin No. 14 [NS.] of the U.S. Department
of Agriculture," 1898. The Cicada lives for long periods underground as
larva and pupa, so that swarms of the adults of one race (septendecim)
appear at intervals of 17 years, while those of the southern form or race
(tredecim) appear at intervals of 13 years. This fact was first made out
by Phares in 1845, but was overlooked or forgotten, and was only re-
discovered by Walsh and Riley in 1868, who published a joint paper in the
"American Entomologist," Volume I., page 63. Walsh appears to have adhered
to the view that the 13- and 17-year forms are distinct species, though, as
we gather from Marlatt's paper (page 14), he published a letter to Mr.
Darwin in which he speaks of the 13-year form as an incipient species; see
"Index to Missouri Entomolog. Reports Bull. 6," U.S.E.C., page 58 (as given
by Marlatt). With regard to the cause of the difference in period of the
two forms, Marlatt (pages 15, 16) refers doubtfully to difference of
temperature as the determining factor. Experiments have been instituted by
moving 17-year eggs to the south, and vice versa with 13-year eggs. The
results were, however, not known at the time of publication of Marlatt's

I am very much obliged for the extracts about the "drumming," which will be
of real use to me.

I do not at all know what to think of your extraordinary case of the
Cicadas. Professor Asa Gray and Dr. Hooker were staying here, and I told
them of the facts. They thought that the 13-year and the 17-year forms
ought not to be ranked as distinct species, unless other differences
besides the period of development could be discovered. They thought the
mere rarity of variability in such a point was not sufficient, and I think
I concur with them. The fact of both the forms presenting the same case of
dimorphism is very curious. I have long wished that some one would dissect
the forms of the male stag-beetle with smaller mandibles, and see if they
were well developed, i.e., whether there was an abundance of spermatozoa;
and the same observations ought, I think, to be made on the rarer form of
your Cicada. Could you not get some observer, such as Dr. Hartman (453/2.
Mr. Walsh sent Mr. Darwin an extract from Dr. Hartman's "Journal of the
doings of a Cicada septendecim," in which the females are described as
flocking round the drumming males. "Descent of Man" (1901), page 433.), to
note whether the females flocked in equal numbers to the "drumming" of the
rarer form as to the common form? You have a very curious and perplexing
subject of investigation, and I wish you success in your work.

Down, June 15th [1869?].

You must not suppose from my delay that I have not been much interested by
your long letter. I write now merely to thank you, and just to say that
probably you are right on all the points you touch on, except, as I think,
about sexual selection, which I will not give up. My belief in it,
however, is contingent on my general belief in sexual selection. It is an
awful stretcher to believe that a peacock's tail was thus formed; but,
believing it, I believe in the same principle somewhat modified applied to

Down, February 13th [N.D.]

I wrote a little time ago asking you an odd question about elephants, and
now I am going to ask you an odder. I hope that you will not think me an
intolerable bore. It is most improbable that you could get me an answer,
but I ask on mere chance. Macacus silenus (455/1. Macacus silenus L., an
Indian ape.) has a great mane of hair round neck, and passing into large
whiskers and beard. Now what I want most especially to know is whether
these monkeys, when they fight in confinement (and I have seen it stated
that they are sometimes kept in confinement), are protected from bites by
this mane and beard. Any one who watched them fighting would, I think, be
able to judge on this head. My object is to find out with various animals
how far the mane is of any use, or a mere ornament. Is the male Macacus
silenus furnished with longer hair than the female about the neck and face?
As I said, it is a hundred or a thousand to one against your finding out
any one who has kept these monkeys in confinement.

Down, August 28th [1870].

I have to thank you very sincerely for two letters: one of April 25th,
containing a very curious account of the structure and morphology of
Bonatea. I feel that it is quite a sin that your letters should not all be
published! but, in truth, I have no spare strength to undertake any extra
work, which, though slight, would follow from seeing your letters in
English through the press--not but that you write almost as clearly as any
Englishman. This same letter also contained some seeds for Mr. Farrer,
which he was very glad to receive.

Your second letter, of July 5th, was chiefly devoted to mimicry in
lepidoptera: many of your remarks seem to me so good, that I have
forwarded your letter to Mr. Bates; but he is out of London having his
summer holiday, and I have not yet heard from him. Your remark about
imitators and imitated being of such different sizes, and the lower surface
of the wings not being altered in colour, strike me as the most curious
points. I should not be at all surprised if your suggestion about sexual
selection were to prove true; but it seems rather too speculative to be
introduced in my book, more especially as my book is already far too
speculative. The very same difficulty about brightly coloured caterpillars
had occurred to me, and you will see in my book what, I believe, is the
true explanation from Wallace. The same view probably applies in part to
gaudy butterflies. My MS. is sent to the printers, and, I suppose, will be
published in about three months: of course I will send you a copy. By the
way, I settled with Murray recently with respect to your book (456/1. The
translation of "Fur Darwin," published in 1869.), and had to pay him only
21 pounds 2 shillings 3 pence, which I consider a very small price for the
dissemination of your views; he has 547 copies as yet unsold. This most
terrible war will stop all science in France and Germany for a long time.
I have heard from nobody in Germany, and know not whether your brother,
Hackel, Gegenbaur, Victor Carus, or my other friends are serving in the
army. Dohrn has joined a cavalry regiment. I have not yet met a soul in
England who does not rejoice in the splendid triumph of Germany over France
(456/2. See Letter 239, Volume I.): it is a most just retribution against
that vainglorious, war-liking nation. As the posts are all in confusion, I
will not send this letter through France. The Editor has sent me duplicate
copies of the "Revue des Cours Scientifiques," which contain several
articles about my views; so I send you copies for the chance of your liking
to see them.

Holly House, Barking, E., January 27th, 1871.

Many thanks for your first volume (457/1. "The Descent of Man".), which I
have just finished reading through with the greatest pleasure and interest;
and I have also to thank you for the great tenderness with which you have
treated me and my heresies.

On the subject of "sexual selection" and "protection," you do not yet
convince me that I am wrong; but I expect your heaviest artillery will be
brought up in your second volume, and I may have to capitulate. You seem,
however, to have somewhat misunderstood my exact meaning, and I do not
think the difference between us is quite so great as you seem to think it.
There are a number of passages in which you argue against the view that the
female has in any large number of cases been "specially modified" for
protection, or that colour has generally been obtained by either sex for
purposes of protection. But my view is, as I thought I had made it clear,
that the female has (in most cases) been simply prevented from acquiring
the gay tints of the male (even when there was a tendency for her to
inherit it), because it was hurtful; and that, when protection is not
needed, gay colours are so generally acquired by both sexes as to show that
inheritance by both sexes of colour variations is the most usual, when not
prevented from acting by Natural Selection. The colour itself may be
acquired either by sexual selection or by other unknown causes.

There are, however, difficulties in the very wide application you give to
sexual selection which at present stagger me, though no one was or is more
ready than myself to admit the perfect truth of the principle or the
immense importance and great variety of its applications.

Your chapters on "Man" are of intense interest--but as touching my special
heresy, not as yet altogether convincing, though, of course, I fully agree
with every word and every argument which goes to prove the "evolution" or
"development" of man out of a lower form. My ONLY difficulties are, as to
whether you have accounted for EVERY STEP of the development by ascertained

I feel sure that the book will keep up and increase your high reputation,
and be immensely successful, as it deserves to be...

Down, March 13th, 1871.

(458/1. We are indebted to Mr. Murdoch for a draft of his letter dated
March 10th, 1871. It is too long to be quoted at length; the following
citations give some idea of its contents: "In your 'Descent of Man,' in
treating of the external differences between males and females of the same
variety, have you attached sufficient importance to the different amount
and kind of energy expended by them in reproduction?" Mr. Murdoch sums up:
"Is it wrong, then, to suppose that extra growth, complicated structure,
and activity in one sex exist as escape-valves for surplus vigour, rather
than to please or fight with, though they may serve these purposes and be
modified by them?")

I am much obliged for your valuable letter. I am strongly inclined to
think that I have made a great and complete oversight with respect to the
subject which you discuss. I am the more surprised at this, as I remember
reflecting on some points which ought to have led me to your conclusion.
By an odd chance I received the day before yesterday a letter from Mr.
Lowne (author of an excellent book on the anatomy of the Blow-fly) (458/2.
"The Anatomy and Physiology of the Blow-fly (Musca vomitaria L.)," by B.T.
Lowne. London, 1870.) with a discussion very nearly to the same effect as
yours. His conclusions were drawn from studying male insects with great
horns, mandibles, etc. He informs me that his paper on this subject will
soon be published in the "Transact. Entomolog. Society." (458/3.
"Observations on Immature Sexuality and Alternate Generation in Insects."
By B.T. Lowne. "Trans. Entomolog. Soc." 1871 [Read March 6th, 1871]. "I
believe that certain cutaneous appendages, as the gigantic mandibles and
thoracic horns of many males, are complemental to the sexual organs; that,
in point of fact, they are produced by the excess of nutriment in the male,
which in the female would go to form the generative organs and ova" (loc.
cit., page 197).) I am inclined to look at your and Mr. Lowne's view as
specially valuable from probably throwing light on the greater variability
of male than female animals, which manifestly has much bearing on sexual
selection. I will keep your remarks in mind whenever a new edition of my
book is demanded.


(459/1. The following letter refers to two letters to Mr. Darwin, in which
Mr. Fraser pointed out that illustrations of the theory of Sexual Selection
might be found amongst British butterflies and moths. Mr. Fraser, in
explanation of the letters, writes: "As an altogether unknown and far from
experienced naturalist, I feared to send my letters for publication
without, in the first place, obtaining Mr. Darwin's approval." The
information was published in "Nature," Volume III., April 20th, 1871, page
489. The article was referred to in the second edition of the "Descent of
Man" (1874), pages 312, 316, 319. Mr. Fraser adds: "This is only another
illustration of Mr. Darwin's great conscientiousness in acknowledging
suggestions received by him from the most humble sources." (Letter from
Mr. Fraser to F. Darwin, March 21, 1888.)

Down, April 14th [1871].

I am very much obliged for your letter and the interesting facts which it
contains, and which are new to me. But I am at present so much engaged
with other subjects that I cannot fully consider them; and, even if I had
time, I do not suppose that I should have anything to say worth printing in
a scientific journal. It would obviously be absurd in me to allow a mere
note of thanks from me to be printed. Whenever I have to bring out a
corrected edition of my book I will well consider your remarks (which I
hope that you will send to "Nature"), but the difficulty will be that my
friends tell me that I have already introduced too many facts, and that I
ought to prune rather than to introduce more.

Down, December 3rd, 1871.

I am much obliged to you for having sent me your two interesting papers,
and for the kind writing on the cover. I am very glad to have my error
corrected about the protective colouring of shells. (460/1. "On Adaptive
Coloration of the Mollusca," "Boston Society of Natural History Proc."
Volume XIV., April 5th, 1871. Mr. Morse quotes from the "Descent of Man,"
I., page 316, a passage to the effect that the colours of the mollusca do
not in general appear to be protective. Mr. Morse goes on to give
instances of protective coloration.) It is no excuse for my broad
statement, but I had in my mind the species which are brightly or
beautifully coloured, and I can as yet hardly think that the colouring in
such cases is protective.

Down, February 29th, 1872.

I am rejoiced to hear that your eyesight is somewhat better; but I fear
that work with the microscope is still out of your power. I have often
thought with sincere sympathy how much you must have suffered from your
grand line of embryological research having been stopped. It was very good
of you to use your eyes in writing to me. I have just received your essay
(461/1. "Ueber der Einfluss der Isolirung auf die Artbildung": Leipzig,
1872.); but as I am now staying in London for the sake of rest, and as
German is at all times very difficult to me, I shall not be able to read
your essay for some little time. I am, however, very curious to learn what
you have to say on isolation and on periods of variation. I thought much
about isolation when I wrote in Chapter IV. on the circumstances favourable
to Natural Selection. No doubt there remains an immense deal of work to do
on "Artbildung." I have only opened a path for others to enter, and in the
course of time to make a broad and clear high-road. I am especially glad
that you are turning your attention to sexual selection. I have in this
country hardly found any naturalists who agree with me on this subject,
even to a moderate extent. They think it absurd that a female bird should
be able to appreciate the splendid plumage of the male; but it would take
much to persuade me that the peacock does not spread his gorgeous tail in
the presence of the female in order to fascinate or excite her. The case,
no doubt, is much more difficult with insects. I fear that you will find
it difficult to experiment on diurnal lepidoptera in confinement, for I
have never heard of any of these breeding in this state. (461/2. We are
indebted to Mr. Bateson for the following note: "This belief does not seem
to be well founded, for since Darwin's time several species of Rhopalocera
(e.g. Pieris, Pararge, Caenonympha) have been successfully bred in
confinement without any special difficulty; and by the use of large cages
members even of strong-flying genera, such as Vanessa, have been induced to
breed.") I was extremely pleased at hearing from Fritz Muller that he
liked my chapter on lepidoptera in the "Descent of Man" more than any other
part, excepting the chapter on morals.

Down [May, 1872].

I have now read with the greatest interest your essay, which contains a
vast amount of matter quite new to me. (462/1. "Anwendung der
Darwin'schen Lehre auf Bienen," "Verhandl. d. naturhist. Vereins fur
preuss. Rheinld. u. Westf." 1872. References to Muller's paper occur in
the second edition of the "Descent of Man.") I really have no criticisms
or suggestions to offer. The perfection of the gradation in the character
of bees, especially in such important parts as the mouth-organs, was
altogether unknown to me. You bring out all such facts very clearly by
your comparison with the corresponding organs in the allied hymenoptera.
How very curious is the case of bees and wasps having acquired,
independently of inheritance from a common source, the habit of building
hexagonal cells and of producing sterile workers! But I have been most
interested by your discussion on secondary sexual differences; I do not
suppose so full an account of such differences in any other group of
animals has ever been published. It delights me to find that we have
independently arrived at almost exactly the same conclusion with respect to
the more important points deserving investigation in relation to sexual
selection. For instance, the relative number of the two sexes, the earlier
emergence of the males, the laws of inheritance, etc. What an admirable
illustration you give of the transference of characters acquired by one
sex--namely, that of the male of Bombus possessing the pollen-collecting
apparatus. Many of your facts about the differences between male and
female bees are surprisingly parallel with those which occur with birds.
The reading your essay has given me great confidence in the efficacy of
sexual selection, and I wanted some encouragement, as extremely few
naturalists in England seem inclined to believe in it. I am, however, glad
to find that Prof. Weismann has some faith in this principle.

The males of Bombus follow one remarkable habit, which I think it would
interest you to investigate this coming summer, and no one could do it
better than you. (462/2. Mr. Darwin's observations on this curious
subject were sent to Hermann Muller, and after his death were translated
and published in Krause's "Gesammelte kleinere Schriften von Charles
Darwin," 1887, page 84. The male bees had certain regular lines of flight
at Down, as from the end of the kitchen garden to the corner of the "sand-
walk," and certain regular "buzzing places" where they stopped on the wing
for a moment or two. Mr. Darwin's children remember vividly the pleasure
of helping in the investigation of this habit.) I have therefore enclosed
a briefly and roughly drawn-up account of this habit. Should you succeed
in making any observations on this subject, and if you would like to use in
any way my MS. you are perfectly welcome. I could, should you hereafter
wish to make any use of the facts, give them in rather fuller detail; but I
think that I have given enough.

I hope that you may long have health, leisure, and inclination to do much
more work as excellent as your recent essay.

2.VIII.III. EXPRESSION, 1868-1874.

Down, January 30th [1868].

I am very much obliged for your answers, though few in number (October
5th), about expression. I was especially glad to hear about shrugging the
shoulders. You say that an old negro woman, when expressing astonishment,
wonderfully resembled a Cebus when astonished; but are you sure that the
Cebus opened its mouth? I ask because the Chimpanzee does not open its
mouth when astonished, or when listening. (463/1. Darwin in the
"Expression of the Emotions," adheres to this statement as being true of
monkeys in general.) Please have the kindness to remember that I am very
anxious to know whether any monkey, when screaming violently, partially or
wholly closes its eyes.


(464/1. The late Sir W. Bowman, the well-known surgeon, supplied a good
deal of information of value to Darwin in regard to the expression of the
emotions. The gorging of the eyes with blood during screaming is an
important factor in the physiology of weeping, and indirectly in the
obliquity of the eyebrows--a characteristic expression of suffering. See
"Expression of the Emotions," pages 160 and 192.)

Down, March 30th [1868].

I called at your house about three weeks since, and heard that you were
away for the whole month, which I much regretted, as I wished to have had
the pleasure of seeing you, of asking you a question, and of thanking you
for your kindness to my son George. You did not quite understand the last
note which I wrote to you--viz., about Bell's precise statement that the
conjunctiva of an infant or young child becomes gorged with blood when the
eyes are forcibly opened during a screaming fit. (464/2. Sir C. Bell's
statement in his "Anatomy of Expression" (1844, page 106) is quoted in the
"Expression of the Emotions," page 158.) I have carefully kept your
previous note, in which you spoke doubtfully about Bell's statement. I
intended in my former note only to express a wish that if, during your
professional work, you were led to open the eyelids of a screaming child,
you would specially observe this point about the eye showing signs of
becoming gorged with blood, which interests me extremely. Could you ask
any one to observe this for me in an eye-dispensary or hospital? But I now
have to beg you kindly to consider one other question at any time when you
have half an hour's leisure.

When a man coughs violently from choking or retches violently, even when he
yawns, and when he laughs violently, tears come into the eyes. Now, in all
these cases I observe that the orbicularis muscle is more or less
spasmodically contracted, as also in the crying of a child. So, again,
when the muscles of the abdomen contract violently in a propelling manner,
and the breath is, I think, always held, as during the evacuation of a very
costive man, and as (I hear) with a woman during severe labour-pains, the
orbicularis contracts, and tears come into the eyes. Sir J.E. Tennant
states that tears roll down the cheeks of elephants when screaming and
trumpeting at first being captured; accordingly I went to the Zoological
Gardens, and the keeper made two elephants trumpet, and when they did this
violently the orbicularis was invariably plainly contracted. Hence I am
led to conclude that there must be some relation between the contraction of
this muscle and the secretion of tears. Can you tell me what this relation
is? Does the orbicularis press against, and so directly stimulate, the
lachrymal gland? As a slight blow on the eye causes, by reflex action, a
copious effusion of tears, can the slight spasmodic contraction of the
orbicularis act like a blow? This seems hardly possible. Does the same
nerve which runs to the orbicularis send off fibrils to the lachrymal
glands; and if so, when the order goes for the muscle to contract, is
nervous force sent sympathetically at the same time to the glands? (464/3.
See "Expression of the Emotions," page 169.)

I should be extremely much obliged if you [would] have the kindness to give
me your opinion on this point.


(465/1. Mr. Darwin was indebted to Sir W. Bowman for an introduction to
Professor Donders, whose work on Sir Charles Bell's views is quoted in the
"Expression of the Emotions," pages 160-62.)

Down, June 3rd [1870?].

I do not know how to thank you enough for the very great trouble which you
have taken in writing at such length, and for your kind expressions towards
me. I am particularly obliged for the abstract with respect to Sir C.
Bell's views (465/2. See "Expression of the Emotions," pages 158 et seq.:
Sir Charles Bell's view is that adopted by Darwin--viz. that the
contraction of the muscles round the eyes counteracts the gorging of the
parts during screaming, etc. The essay of Donders is, no doubt, "On the
Action of the Eyelids in Determination of Blood from Expiratory Effort" in
Beale's "Archives of Medicine," Volume V., 1870, page 20, which is a
translation of the original in Dutch.), as I shall now proceed with some
confidence; but I am intensely curious to read your essay in full when
translated and published, as I hope, in the "Dublin Journal," as you speak
of the weak point in the case--viz., that injuries are not known to follow
from the gorging of the eye with blood. I may mention that my son and his
friend at a military academy tell me that when they perform certain feats
with their heads downwards their faces become purple and veins distended,
and that they then feel an uncomfortable sensation in their eyes; but that
as it is necessary for them to see, they cannot protect their eyes by
closing the eyelids. The companions of one young man, who naturally has
very prominent eyes, used to laugh at him when performing such feats, and
declare that some day both eyes would start out of his head.

Your essay on the physiological and anatomical relations between the
contraction of the orbicular muscles and the secretion of tears is
wonderfully clear, and has interested me greatly. I had not thought about
irritating substances getting into the nose during vomiting; but my clear
impression is that mere retching causes tears. I will, however, try to get
this point ascertained. When I reflect that in vomiting (subject to the
above doubt), in violent coughing from choking, in yawning, violent
laughter, in the violent downward action of the abdominal muscle...and in
your very curious case of the spasms (465/3. In some cases a slight touch
to the eye causes spasms of the orbicularis muscle, which may continue for
so long as an hour, being accompanied by a flow of tears. See "Expression
of the Emotions," page 166.)--that in all these cases the orbicular muscles
are strongly and unconsciously contracted, and that at the same time tears
often certainly flow, I must think that there is a connection of some kind
between these phenomena; but you have clearly shown me that the nature of
the relation is at present quite obscure.

6, Queen Anne Street, W., December 19th [1870?].

I was with Mr. Wood this morning, and he expressed himself strongly about
your and your daughter's kindness in aiding him. He much wants assistance
on another point, and if you would aid him, you would greatly oblige me.
You know well the appearance of a dog when approaching another dog with
hostile intentions, before they come close together. The dog walks very
stiffly, with tail rigid and upright, hair on back erected, ears pointed
and eyes directed forwards. When the dog attacks the other, down go the
ears, and the canines are uncovered. Now, could you anyhow arrange so that
one of your dogs could see a strange dog from a little distance, so that
Mr. Wood could sketch the former attitude, viz., of the stiff gesture with
erected hair and erected ears. (466/1. In Chapter II. of the "Expression
of the Emotions" there are sketches of dogs in illustration of the
"Principle of Antithesis," drawn by Mr. Riviere and by Mr. A. May (figures
5-8). Mr. T.W. Wood supplied similar drawings of a cat (figures 9, 10),
also a sketch of the head of a snarling dog (figure 14).) And then he
could afterwards sketch the same dog, when fondled by his master and
wagging his tail with drooping ears. These two sketches I want much, and
it would be a great favour to Mr. Wood, and myself, if you could aid him.

P.S.--When a horse is turned out into a field he trots with high, elastic
steps, and carries his tail aloft. Even when a cow frisks about she throws
up her tail. I have seen a drawing of an elephant, apparently trotting
with high steps, and with the tail erect. When the elephants in the garden
are turned out and are excited so as to move quickly, do they carry their
tails aloft? How is this with the rhinoceros? Do not trouble yourself to
answer this, but I shall be in London in a couple of months, and then
perhaps you will be able to answer this trifling question. Or, if you
write about wolves and jackals turning round, you can tell me about the
tails of elephants, or of any other animals. (466/2. In the "Expression
of the Emotions," page 44, reference is made under the head of "Associated
habitual movements in the lower animals," to dogs and other animals turning
round and round and scratching the ground with their fore-paws when they
wish to go to sleep on a carpet, or other similar surface.)

Down, January 5th, [1871?]

Many thanks about Limulus. I am going to ask another favour, but I do not
want to trouble you to answer it by letter. When the Callithrix sciureus
screams violently, does it wrinkle up the skin round the eyes like a baby
always does? (467/1. "Humboldt also asserts that the eyes of the
Callithrix sciureus 'instantly fill with tears when it is seized with
fear'; but when this pretty little monkey in the Zoological Gardens was
teased, so as to cry out loudly, this did not occur. I do not, however,
wish to throw the least doubt on the accuracy of Humboldt's statement."
("The Expression of the Emotions in Man and Animals," 1872, page 137.)
When thus screaming do the eyes become suffused with moisture? Will you
ask Sutton to observe carefully? (467/2. One of the keepers who made many
observations on monkeys for Mr. Darwin.) Could you make it scream without
hurting it much? I should be truly obliged some time for this information,
when in spring I come to the Gardens.

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