other purposes than the good of its
possessor, have been shown by Mr. Darwin to follow the same great law of
utility. Flowers do not often need protection, but very often require
the aid of insects to fertilize them, and maintain their reproductive
powers in the greatest vigour. Their gay colours attract insects, as do
also their sweet odours and honeyed secretions; and that this is the
main function of colour in flowers is shown by the striking fact, that
those flowers which can be perfectly fertilized by the wind, and do not
need the aid of insects, _rarely or never have gaily-coloured flowers_.

This wide extension of the general principle of utility to the colours
of such varied groups, both in the animal and vegetable kingdoms,
compels us to acknowledge that the "reign of law" has been fairly traced
into this stronghold of the advocates of special creation. And to those
who oppose the explanation I have given of the facts adduced in this
essay, I would again respectfully urge that they must grapple with the
whole of the facts, not one or two of them only. It will be admitted
that, on the theory of evolution and natural selection, a wide range of
facts with regard to colour in nature have been co-ordinated and
explained. Until at least an equally wide range of facts can be shown to
be in harmony with any other theory, we can hardly be expected to
abandon that which has already done such good service, and which has led
to the discovery of so many interesting and unexpected harmonies among
the most common (but hitherto most neglected and least understood), of
the phenomena presented by organised beings.

VIII.

CREATION BY LAW.

Among the various criticisms that have appeared on Mr. Darwin's
celebrated "Origin of Species," there is, perhaps, none that will appeal
to so large a number of well educated and intelligent persons, as that
contained in the Duke of Argyll's "Reign of Law." The noble author
represents the feelings and expresses the ideas of that large class, who
take a keen interest in the progress of Science in general, and
especially that of Natural History, but have never themselves studied
nature in detail, or acquired that personal knowledge of the structure
of closely allied forms,--the wonderful gradations from species to
species and from group to group, and the infinite variety of the
phenomena of "variation" in organic beings,--which are absolutely
necessary for a full appreciation of the