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