d developed the greater differences. At the same time
I do _not_ say they were not sufficient. I merely urge that there is a
difference between proof and probability.--Yours very truly,

ALFRED R. WALLACE.

* * * * *

TO PROF. POULTON

_Broadstone, Wimborne. August 5, 1904._

My dear Poulton,-- ... What a miserable abortion of a theory is
"Mutation," which the Americans now seem to be taking up in place of
Lamarckism, "superseded." Anything rather than Darwinism! I am glad Dr.
F.A. Dixey shows it up so well in this week's _Nature_,[30] but too
mildly!--Yours very truly,

ALFRED R. WALLACE.

* * * * *

TO PROF. POULTON

_Broadstone, Wimborne. April 3, 1905._

My dear Poulton,--Many thanks for copy of your Address,[31] which I have
read with great pleasure and will forward to Birch next mail. You have,
I think, produced a splendid and unanswerable set of facts proving the
non-heredity of acquired characters. I was particularly pleased with the
portion on "instincts," in which the argument is especially clear and
strong. I am afraid, however, the whole subject is above and beyond the
average "entomologist" or insect collector, but it will be of great
value to all students of evolution. It is curious how few even of the
more acute minds take the trouble to reason out carefully the teaching
of certain facts--as in the case of Romanes and the "variable
protection," and as I showed also in the case of Mivart (and also
Romanes and Gulick) declaring that isolation alone, without Natural
Selection, could produce perfect and well-defined species (see _Nature_,
Jan. 12, 1899).... --Yours faithfully,

A.R. WALLACE.

* * * * *

TO SIR FRANCIS DARWIN

_Broadstone, Wimborne. October 29, 1905._

Dear Mr. Darwin,--I return you the two articles on "Mutation" with many
thanks. As they are both supporters of de Vries, I suppose they put his
case as strongly as possible. Professor Hubrecht's paper is by far the
clearest and the best written, and he says distinctly that de Vries
claims that all new species have been produced by mutations, and none by
"fluctuating variations." Professor Hubrecht supports this and says that
de Vries has proved it! And all this founded upon a few "sports" from
one species of plant, itself of doubtful origin (variety or hybrid), and
offering phenomena in no way different from scores of other cul