301
supposed selection, all investigation goes to prove that
there is a great deal of variation in all species, however
fixed. This fact is generally urged to show the possibility
of transmutation of species by means of Natural Selection,
in so far as it offers material for selection to act on. But
there is another way of looking at this matter. If, in
those cases in which the species has remained stable, we
take a given number of adults who have passed through
the period when destruction has been most at work—we
must look upon the relative differences as the result of the
action of Natural Selection. We do not find what we
should expect if Natural Selection were preserving the
species at its highest possible excellence ; but we do find
that enormous difference between individuals, which is
consistent with the stability of a species.
Now it follows, necessarily, that if Natural Selection has
not maintained the highest efficiency of a species, the cessa
tion of Natural Selection will not lead to that deterioration
which might otherwise have been anticipated, but rather to
that stability of species which the principle of regression
can of itself maintain.
It is interesting to note the reasons which are assigned
for the supposed deteriorating results of the cessation of
Natural Selection. It was taken for granted that there will
be phis and minus variations on either side of the average.
Mr. Herbert Spencer thereupon assumed that in the ab
sence of Natural Selection these plus and minus variations
would neutralise one another, and so the stability of the
species would be maintained. But Mr. Romanes replied
that in the absence of Natural Selection there would be
an excess of minus variations. Whereupon Mr. Spencer
asked for proofs, and Mr. Romanes adduced two.
“(i). When selection is withdrawn there will be no excessive plus
variations, because so long as selection was present the efficiency