animals--the 'struggle for existence' taking the place of man, and
exerting, in the case of natural selection, that selective action which
he performs in artificial selection.

The evidence brought forward by Mr. Darwin in support of his hypothesis
is of three kinds. First, he endeavours to prove that species may be
originated by selection; secondly, he attempts to show that natural
causes are competent to exert selection; and thirdly, he tries to prove
that the most remarkable and apparently anomalous phenomena exhibited by
the distribution, development, and mutual relations of species, can be
shown to be deducible from the general doctrine of their origin, which
he propounds, combined with the known facts of geological change; and
that, even if all these phenomena are not at present explicable by it,
none are necessarily inconsistent with it.

There cannot be a doubt that the method of inquiry which Mr. Darwin has
adopted is not only rigorously in accordance with the canons of
scientific logic, but that it is the only adequate method. Critics
exclusively trained in classics or in mathematics, who have never
determined a scientific fact in their lives by induction from
experiment or observation, prate learnedly about Mr. Darwin's method,
which is not inductive enough, not Baconian enough, forsooth, for
them. But even if practical acquaintance with the process of scientific
investigation is denied them, they may learn, by the perusal of Mr.
Mill's admirable chapter "On the Deductive Method," that there are
multitudes of scientific inquiries in which the method of pure
induction helps the investigator but a very little way.

"The mode of investigation," says Mr. Mill, "which, from the proved
inapplicability of direct methods of observation and experiment,