More Letters of Charles Darwin, vol 2 | Page 6

that all botanists would agree that many
tropical plants could not withstand a somewhat cooler climate. But I
have come not to care at all for general beliefs without the special facts.
I have suffered too often from this: thus I found in every book the
general statement that a host of flowers were fertilised in the bud, that
seeds could not withstand salt water, etc., etc. I would far more trust
such graphic accounts as that by you of the mixed vegetation on the
Himalayas and other such accounts. And with respect to tropical plants
withstanding the slowly coming on cool period, I trust to such facts as
yours (and others) about seeds of the same species from mountains and
plains having acquired a slightly different climatal constitution. I know
all that I have said will excite in you savage contempt towards me. Do
not answer this rigmarole, but attack me to your heart's content, and to
that of mine, whenever you can come here, and may it be soon.
LETTER 383. J.D. HOOKER TO CHARLES DARWIN. Kew, 1870.
(383/1. The following extract from a letter of Sir J.D. Hooker shows
the tables reversed between the correspondents.)
Grove is disgusted at your being disquieted about W. Thomson. Tell

George from me not to sit upon you with his mathematics. When I
threatened your tropical cooling views with the facts of the physicists,
you snubbed me and the facts sweetly, over and over again; and now,
because a scarecrow of x+y has been raised on the selfsame facts, you
boo-boo. Take another dose of Huxley's penultimate G. S. Address, and
send George back to college. (383/2. Huxley's Anniversary Address to
the Geological Society, 1869 ("Collected Essays," VIII., page 305).
This is a criticism of Lord Kelvin's paper "On Geological Time"
("Trans. Geolog. Soc. Glasgow," III.). At page 336 Mr. Huxley deals
with Lord Kelvin's "third line of argument, based on the temperature of
the interior of the earth." This was no doubt the point most disturbing to
Mr. Darwin, since it led Lord Kelvin to ask (as quoted by Huxley),
"Are modern geologists prepared to say that all life was killed off the
earth 50,000, 100,000, or 200,000 years ago?" Mr. Huxley, after
criticising Lord Kelvin's data and conclusion, gives his conviction that
the case against Geology has broken down. With regard to evolution,
Huxley (page 328) ingeniously points out a case of circular reasoning.
"But it may be said that it is biology, and not geology, which asks for
so much time--that the succession of life demands vast intervals; but
this appears to me to be reasoning in a circle. Biology takes her time
from geology. The only reason we have for believing in the slow rate of
the change in living forms is the fact that they persist through a series
of deposits which, geology informs us, have taken a long while to make.
If the geological clock is wrong, all the naturalist will have to do is to
modify his notions of the rapidity of change accordingly.")
LETTER 384. TO J.D. HOOKER. February 3rd [1868].
I am now reading Miquel on "Flora of Japan" (384/1. Miquel, "Flore du
Japon": "Archives Neerlandaises" ii., 1867.), and like it: it is rather a
relief to me (though, of course, not new to you) to find so very much in
common with Asia. I wonder if A. Murray's (384/2. "Geographical
Distribution of Mammals," by Andrew Murray, 1866. See
Chapter V.
, page 47. See Letter 379.) notion can be correct, that a [profound] arm
of the sea penetrated the west coast of N. America, and prevented the
Asiatico-Japan element colonising that side of the continent so much as
the eastern side; or will climate suffice? I shall to the day of my death

keep up my full interest in Geographical Distribution, but I doubt
whether I shall ever have strength to come in any fuller detail than in
the "Origin" to this grand subject. In fact, I do not suppose any man
could master so comprehensive a subject as it now has become, if all
kingdoms of nature are included. I have read Murray's book, and am
disappointed--though, as you said, here and there clever thoughts occur.
How strange it is, that his view not affording the least explanation of
the innumerable adaptations everywhere to be seen apparently does not
in the least trouble his mind. One of the most curious cases which he
adduces seems to me to be the two allied fresh-water, highly peculiar
porpoises in the Ganges and Indus; and the more distantly allied form
of the Amazons. Do you remember his explanation of an arm of the sea
becoming cut off, like the Caspian, converted into fresh-water, and then
divided into two lakes (by upheaval), giving rise to two