Today | News | Books | Recipes Adventure | Science Fiction | Ghost stories | Poetry | Children | History Bookam right (if my general principles are right), that there would
be little tendency to the formation of a new species during the period
of migration, whether shorter or longer, though considerable variability
may have supervened.)
LETTER 337. TO J.D. HOOKER. Down, December 10th [1856].
It is a most tiresome drawback to my satisfaction in writing that,
though I leave out a good deal and try to condense, every chapter
runs to such an inordinate length. My present chapter on the causes of
fertility and sterility and on natural crossing has actually run out
to 100 pages MS., and yet I do not think I have put in anything
superfluous...
I have for the last fifteen months been tormented and haunted by
land-mollusca, which occur on every oceanic island; and I thought that
the double creationists or continental extensionists had here a complete
victory. The few eggs which I have tried both sink and are killed. No
one doubts that salt water would be eminently destructive to them; and I
was really in despair, when I thought I would try them when torpid; and
this day I have taken a lot out of the sea-water, after exactly seven
days' immersion. (337/1. This method of dispersal is not given in the
"Origin"; it seems, therefore, probable that further experiments upset
the conclusion drawn in 1856. This would account for the satisfaction
expressed in the following year at the discovery of another method, on
which Darwin wrote to Sir J.D. Hooker: "The distribution of fresh-water
molluscs has been a horrid incubus to me, but I think I know my way now.
When first hatched they are very active, and I have had thirty or forty
crawl on a dead duck's foot; and they cannot be jerked off, and
will live fifteen or even twenty-four hours out of water" ("Life and
Letters," II., page 93). The published account of these experiments is
in the "Origin," Edition I., page 385.) Some sink and some swim; and in
both cases I have had (as yet) one come to life again, which has quite
astonished and delighted me. I feel as if a thousand-pound weight was
taken off my back. Adios, my dear, kind friend.
I must tell you another of my profound experiments! [Frank] said to me:
"Why should not a bird be killed (by hawk, lightning, apoplexy, hail,
etc.) with seed in its crop, and it would swim?" No sooner said than
done: a pigeon has floated for thirty days in salt water with seeds in
its crop, and they have grown splendidly; and to my great surprise even
tares (Leguminosae, so generally killed by sea-water), which the bird
had naturally eaten, have grown well. You will say gulls and dog-fish,
etc., would eat up the carcase, and so they would 999 times out of
a thousand, but one might escape: I have seen dead land-birds in
sea-drift.
LETTER 338. ASA GRAY TO CHARLES DARWIN.
(338/1. In reply to Darwin's letter given in "Life and Letters," II.,
page 88.)
Cambridge, Mass., February 16th, 1857.
I meant to have replied to your interesting letter of January 1st long
before this time, and also that of November 24th, which I doubt if I
have ever acknowledged. But after getting my school-book, Lessons in
Botany, off my hands--it taking up time far beyond what its size would
seem to warrant--I had to fall hard at work upon a collection of small
size from Japan--mostly N. Japan, which I am only just done with. As
I expected, the number of species common to N. America is considerably
increased in this collection, as also the number of closely
representative species in the two, and a pretty considerable number of
European species too. I have packed off my MSS. (though I hardly know
what will become of it), or I would refer you to some illustrations. The
greater part of the identical species (of Japan and N. America) are of
those extending to or belonging to N.W. coast of America, but there
are several peculiar to Japan and E. U. States: e.g. our Viburnum
lantanoides is one of Thunberg's species. De Candolle's remarkable case
of Phryma, which he so dwells upon, turns out, as Dr. Hooker said
it would, to be only one out of a great many cases of the same sort.
(Hooker brought Monotropa uniflora, you know, from the Himalayas; and
now, by the way, I have it from almost as far south, i.e., from St. Fee,
New Granada)...
Well, I never meant to draw any conclusions at all, and am very sorry
that the only one I was beguiled into should "rile" (338/2. "One of your
conclusions makes me groan, viz., that the line of connection of the
strictly alpine plants is through Greenland. I should extremely like
to see your reasons published in detail, for it 'riles' me (this is a
proper expression, is it not?) dreadfully" (Darwin to Gray, January 1st,
1857, "Life and Letters," II., page 89).) you, as you say it does,--that
on page 73 of my second article: for if it troubles you it is not likely
to be sound. Of course I had no idea of laying any great stress upon the
fact (at first view so unexpected to me) that one-third of our alpine
species common to Europe do not reach the Arctic circle; but the remark
which I put down was an off-hand inference from what you geologists seem
to have settled--viz., that the northern regions must have been a deal
cooler than they are now--the northern limit of vegetation therefore
much lower than now--about the epoch when it would seem probable that
the existing species of our plants were created. At any rate, during
the Glacial period there could have been no phaenogamous plants on our
continent anywhere near the polar regions; and it seems a good rule to
look in the first place for the cause or reason of what now is, in that
which immediately preceded. I don't see that Greenland could help us
much, but if there was any interchange of species between N. America and
N. Europe in those times, was not the communication more likely to be in
lower latitudes than over the pole?
If, however, you say--as you may have very good reasons for saying--that
the existing species got their present diffusion before the Glacial
epoch, I should have no answer. I suppose you must needs assume very
great antiquity for species of plants in order to account for their
present dispersion, so long as we cling--as one cannot but do--to the
idea of the single birthplace of species.
I am curious to see whether, as you suggest, there would be found a
harmony or close similarity between the geographical range in
this country of the species common to Europe and those strictly
representative or strictly congeneric with European species. If I get
a little time I will look up the facts: though, as Dr. Hooker rightly
tells me, I have no business to be running after side game of any sort,
while there is so much I have to do--much more than I shall ever do
probably--to finish undertakings I have long ago begun.
...As to your P.S. If you have time to send me a longer list of your
protean genera, I will say if they seem to be protean here. Of those you
mention:--
Salix, I really know nothing about.
Rubus, the N. American species, with one excep |