Charles S. Brooks - "Journeys to Bagdad"

Gottfried Keller - "Die Leute von Seldwyla, Vol. 1"

Frederick Orin Bartlett - "The Triflers"

George Wharton Edwards - "The Book of Old English Ballads"

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More Letters of Charles Darwin Volume II

C >> Charles Darwin >> More Letters of Charles Darwin Volume II




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.

Queries:

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
spurs?

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.


LETTER 445. TO J. JENNER WEIR.
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
twenty?

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?


LETTER 446. TO F. MULLER.
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...


LETTER 447. TO J. JENNER WEIR.
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?


LETTER 448. TO A.R. WALLACE.
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.


LETTER 449. TO A.R. WALLACE.

(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
protection.

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.


LETTER 450. A.R. WALLACE TO CHARLES DARWIN.
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
protection.

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
acquired?

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
selection.

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.))


LETTER 451. A.R. WALLACE TO CHARLES DARWIN.

(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.


LETTER 452. TO A.R. WALLACE.
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.


LETTER 453. TO B.D. WALSH.
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
paper.)

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.


LETTER 454. TO A.R. WALLACE.
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
man.

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