The two old parent connecting links just keep alive
in two or three areas; then we have four widely extended species, their
descendants; and from them little groups of newer descendants inhabiting
rather small areas...

LETTER 234. TO CAMILLE DARESTE. Down, November 20th, 1869.

Dear Sir,

I am glad that you are a candidate for the Chair of Physiology in Paris.
As you are aware from my published works, I have always considered your
investigations on the production of monstrosities as full of interest.
No subject is at the present time more important, as far as my judgment
goes, than the ascertaining by experiment how far structure can be
modified by the direct action of changed conditions; and you have thrown
much light on this subject.

I observe that several naturalists in various parts of Europe have
lately maintained that it is now of the highest interest for science to
endeavour to lessen, as far as possible, our profound ignorance on the
cause of each individual variation; and, as Is. Geoffroy St. Hilaire
long ago remarked, monstrosities cannot be separated by any distinct
line from slighter variations.

With my best wishes for your success in obtaining the Professorship, and
with sincere respect.

I have the honour to remain, dear sir, Yours faithfully, CHARLES DARWIN.

CHAPTER 1.V.--EVOLUTION, 1870-1882.

LETTER 235. TO J. JENNER WEIR. Down, March 17th [1870].

It is my decided opinion that you ought to send an account to some
scientific society, and I think to the Royal Society. (235/1. Mr. Jenner
Weir's case is given in "Animals and Plants," Edition II., Volume I.,
page 435, and does not appear to have been published elsewhere.
The facts are briefly that a horse, the offspring of a mare of Lord
Mostyn's, which had previously borne a foal by a quagga, showed a
number of quagga-like characters, such as stripes, low-growing mane,
and elongated hoofs. The passage in "Animals and Plants," to which he
directs Mr. Weir's attention in reference to Carpenter's objection, is
in Edition I., Volume I., page 405: "It is a most improbable hypothesis
that the mere blood of one individual should affect the reproductive
organs of another individual in such a manner as to modify the
subsequent offspring. The analogy from the direct action of foreign
pollen on the ovarium and seed-coats of the mother plant strongly
supports the belief that the male element acts directly on the
reproductive organs of the femal