rieties of
certain butterflies, except "by supposing the passive acquisition of
characters produced by the direct influence of climate."

Nevertheless in his next paragraph but one he calls such cases
"doubtful," and proposes that for the moment they should be left aside.
He accordingly leaves them, but I have not yet found what other moment he
considered auspicious for returning to them. He tells us that "new
experiments will be necessary, and that he has himself already begun to
undertake them." Perhaps he will give us the results of these
experiments in some future book--for that they will prove satisfactory to
him can hardly, I think, be doubted. He writes:--

"Leaving on one side, for the moment, these doubtful and insufficiently
investigated cases, we may still maintain that the assumption that
changes induced by external conditions in the organism as a whole are
communicated to the germ-cells after the manner indicated in Darwin's
hypothesis of pangenesis, is wholly unnecessary for the explanation of
these phenomena. Still we cannot exclude the possibility of such a
transmission occasionally occurring, for even if the greater part of the
effects must be attributable to natural selection, there might be a
smaller part in certain cases which depends on this exceptional factor."

I repeatedly tried to understand Mr. Darwin's theory of pangenesis, and
so often failed that I long since gave the matter up in despair. I did
so with the less unwillingness because I saw that no one else appeared to
understand the theory, and that even Mr. Darwin's warmest adherents
regarded it with disfavour. If Mr. Darwin means that every cell of the
body throws off minute particles that find their way to the germ-cells,
and hence into the new embryo, this is indeed difficult of comprehension
and belief. If he means that the rhythms or vibrations that go on
ceaselessly in every cell of the body communicate themselves with greater
or less accuracy or perturbation, as the case may be, to the cells that
go to form offspring, and that since the characteristics of matter are
determined by vibrations, in communicating vibrations they in effect
communicate matter, according to the view put forward in the last chapter
of my book "Luck or Cunning," {36} then we can better understand it. I
have nothing, however, to do with Mr. Darwin's theory of pangenesis
beyond avoiding the pretence that I understand either the theory itself
or what Pr