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assume the truth of the given law which they believe
to have been already proved. Thus Mr. H. F. Osborn
says that “the law of Natural Selection is well established,
and no more under discussion.” Those who believe this
may confidently enter on a new field of enquiry, expecting
to find illustrations of the action of Natural Selection
there as elsewhere. That is the spirit in which Mr. Poulton
entered on his most valuable investigations. He says :—
“Any scientific work which I have had the opportunity of doing
has been inspired by one firm purpose—the desire to support, in
however small a degree, and to illustrate by new examples those
great principles which we owe to the life and writings of Charles
Darwin, and especially the pre-eminent principle of Natural
Selection.”—(Preface. p. xiii.)
That is the spirit which inspired Mr. Darwin when he
penned the following passage :—
“ When both sexes of birds are so obscurely coloured that it
would be rash to assume the agency of sexual selection, and when
no direct evidence can be advanced showing that such colours serve
as a protection, it is best to own complete ignorance of the cause,
or, which comes nearly to the same thing, to attribute the result
to the direct action of the conditions of life.”—(Descent of Man.
f. 4Qi.)
What is this but a predetermination to know nothing but
Selection, Natural or Sexual? Apart from one of these
explanations, we can know nothing! In the same way,
Mr. Romanes takes for granted the action of Natural
Selection in his attempt to solve the problem presented
by instinct. Moreover, it was necessary, as a mere matter
of historical sequence, that the proof of the transmutation
of species as against the fixity of species, of evolution as
against sudden creation, of transmutation of species and
organic evolution by means of Natural Selection rather
than by other means, should have been first established.
Mr. Henry Walter Bates promulgated the theory of
mimicry, having been first convinced of the truth of
