Today | News | Books | Recipes Adventure | Science Fiction | Ghost stories | Poetry | Children | History Bookf the alpine-boreal form
bryoniae hardly differ from those of the German form (var. vernalis),
while the females are strikingly different. Thus the character of
secondary sexual differences is determined by climate.) I am, therefore,
fully prepared to admit the justness of your criticism on sexual
selection of lepidoptera; but considering the display of their beauty, I
am not yet inclined to think that I am altogether in error.
What you say about reversion (268/3. For instance, the fact that
reversion to the primary winter-form may be produced by the disturbing
effect of high temperature (page 7).) being excited by various causes,
agrees with what I concluded with respect to the remarkable effects
of crossing two breeds: namely, that anything which disturbs the
constitution leads to reversion, or, as I put the case under my
hypothesis of pangenesis, gives a good chance of latent gemmules
developing. Your essay, in my opinion, is an admirable one, and I thank
you for the interest which it has afforded me.
P.S. I find that there are several points, which I have forgotten. Mr.
Jenner Weir has not published anything more about caterpillars, but
I have written to him, asking him whether he has tried any more
experiments, and will keep back this letter till I receive his answer.
Mr. Riley of the United States supports Mr. Weir, and you will
find reference to him and other papers at page 426 of the new and
much-corrected edition of my "Descent of Man." As I have a duplicate
copy of Volume I. (I believe Volume II. is not yet published in german)
I send it to you by this post. Mr. Belt, in his travels in Nicaragua,
gives several striking cases of conspicuously coloured animals (but not
caterpillars) which are distasteful to birds of prey: he is an excellent
observer, and his book, "The Naturalist in Nicaragua," very interesting.
I am very much obliged for your photograph, which I am particularly glad
to possess, and I send mine in return.
I see you allude to Hilgendorf's statements, which I was sorry to
see disputed by some good German observer. Mr. Hyatt, an excellent
palaeontologist of the United States, visited the place, and likewise
assured me that Hilgendorf was quite mistaken. (268/4. See Letters
252-7.)
I am grieved to hear that your eyesight still continues bad, but anyhow
it has forced your excellent work in your last essay.
May 4th. Here is what Mr. Weir says:--
"In reply to your inquiry of Saturday, I regret that I have little
to add to my two communications to the 'Entomological Society
Transactions.'
"I repeated the experiments with gaudy caterpillars for years, and
always with the same results: not on a single occasion did I find richly
coloured, conspicuous larvae eaten by birds. It was more remarkable
to observe that the birds paid not the slightest attention to gaudy
caterpillars, not even when in motion,--the experiments so thoroughly
satisfied my mind that I have now given up making them."
LETTER 269. TO LAWSON TAIT.
(269/1. The late Mr. Lawson Tait wrote to Mr. Darwin (June 2nd, 1875):
"I am watching a lot of my mice from whom I removed the tails at birth,
and I am coming to the conclusion that the essential use of the tail
there is as a recording organ--that is, they record in their memories
the corners they turn and the height of the holes they pass through by
touching them with their tails." Mr. Darwin was interested in the idea
because "some German sneered at Natural Selection and instanced the
tails of mice.")
June 11th, 1875.
It has just occurred to me to look at the "Origin of Species" (Edition
VI., page 170), and it is certain that Bronn, in the appended chapter
to his translation of my book into german, did advance ears and tail of
various species of mice as a difficulty opposed to Natural Selection. I
answered with respect to ears by alluding to Schobl's curious paper (I
forget when published) (269/2. J. Schobl, "Das aussere Ohr der Mause als
wichtiges Tastorgan." "Archiv. Mik. Anat." VII., 1871, page 260.) on the
hairs of the ears being sensitive and provided with nerves. I presume
he made fine sections: if you are accustomed to such histological work,
would it not be worth while to examine hairs of tail of mice? At page
189 I quote Henslow (confirmed by Gunther) on Mus messorius (and other
species?) using tail as prehensile organ.
Dr. Kane in his account of the second Grinnell Expedition says that the
Esquimaux in severe weather carry a fox-tail tied to the neck, which
they use as a respirator by holding the tip of the tail between their
teeth. (269/3. The fact is stated in Volume II., page 24, of E.K. Kane's
"Arctic Explorations: The Second Grinnell Expedition in Search of Sir
John Franklin." Philadelphia, 1856.)
He says also that he found a frozen fox curled up with his nose buried
in his tail.
N.B. It is just possible that the latter fact is stated by M'Clintock,
not by Dr. Kane.
(269/4. The final passage is a postscript by Mr. W.E. Darwin bearing on
Mr. Lawson Tait's idea of the respirator function of the fox's tail.)
LETTER 270. TO G.J. ROMANES. Down, July 12th, 1875.
I am correcting a second edition of "Variation under Domestication," and
find that I must do it pretty fully. Therefore I give a short abstract
of potato graft-hybrids, and I want to know whether I did not send you a
reference about beet. Did you look to this, and can you tell me anything
about it?
I hope with all my heart that you are getting on pretty well with your
experiments.
I have been led to think a good deal on the subject, and am convinced
of its high importance, though it will take years of hammering before
physiologists will admit that the sexual organs only collect the
generative elements.
The edition will be published in November, and then you will see
all that I have collected, but I believe that you gave all the more
important cases. The case of vine in "Gardeners' Chronicle," which I
sent you, I think may only be a bud-variation not due to grafting. I
have heard indirectly of your splendid success with nerves of medusae.
We have been at Abinger Hall for a month for rest, which I much
required, and I saw there the cut-leaved vine which seems splendid for
graft hybridism.
LETTER 271. TO FRANCIS GALTON. Down, November 7th, 1875.
I have read your essay with much curiosity and interest, but you
probably have no idea how excessively difficult it is to understand.
(271/1. "A Theory of Heredity" ("Journal of the Anthropological
Institute," 1875). In this paper Mr. Galton admits that the hypothesis
of organic units "must lie at the foundation of the science of
heredity," and proceeds to show in what respect his conception differs
from the hypothesis of pangenesis. The copy of Mr. Galton's paper, which
Darwin numbered in correspondence with the criticisms in his letter, is
not available, and we are therefore only able to guess at some of
the points referred to.) I cannot fully grasp, only here and there
conjecture, what are the points on which we |