bridity" question. I really think I
shall be able to arrange the whole subject more intelligibly than Darwin
did, and simplify it immensely by leaving out the endless discussion of
collateral details and difficulties which in the "Origin of Species"
confuse the main issue....

The most remarkable steps yet made in advance are, I think, the theory
of Weismann of the continuity of the germ plasm, and its corollary that
acquired modifications are never inherited! and Patrick Geddes's
explanation of the laws of growth in plants on the theory of the
antagonism of vegetative and reproductive growth....--Yours very
sincerely,

ALFRED R. WALLACE.

* * * * *

TO PROF. MELDOLA

_Frith Hill, Godalming. March 20, 1888._

My dear Meldola,--I have been working away at my hybridity chapters,[15]
and am almost disposed to cry "Eureka!" for I have got light on the
problem. When almost in despair of making it clear that Natural
Selection could act one way or the other, I luckily routed out an old
paper that I wrote twenty years ago, giving a demonstration of the
action of Natural Selection. It did not convince Darwin then, but it has
convinced me now, and I think it can be proved that in some cases (and
those I think most probable) Natural Selection will accumulate
variations in infertility between incipient species. Many other causes
of infertility co-operate, and I really think I have overcome the
fundamental difficulties of the question and made it a good deal clearer
than Darwin left it.... I think also it completely smashes up
Romanes.--Yours faithfully,

ALFRED R. WALLACE.

* * * * *

The next letter relates to a question which Prof. Meldola raised as to
whether, in view of the extreme importance of "divergence" (in the
Darwinian sense) for the separation and maintenance of specific types,
it might not be possible that sterility, when of advantage as a check to
crossing, had in itself, as a physiological character, been brought
about by Natural Selection, just as extreme fecundity had been brought
about (by Natural Selection) in cases where such fecundity was of
advantage.

TO PROF. MELDOLA

_Frith Hill, Godalming. April 12, 1888._

My dear Meldola,--Many thanks for your criticism. It is a perfectly
sound one as against my view being a _complete explanation_ of the
phenomena, but that I do not claim. And I do not see any chance of the
required facts