taken up than any man living.
Personally and practically exercised in zoology, in minute anatomy, in
geology; a student of geographical distribution, not on maps and in
museums only, but by long voyages and laborious collection; having
largely advanced each of these branches of science, and having spent
many years in gathering and sifting materials for his present work, the
store of accurately registered facts upon which the author of the
"Origin of Species" is able to draw at will is prodigious.

But this very superabundance of matter must have been embarrassing to a
writer who, for the present, can only put forward an abstract of his
views; and thence it arises, perhaps, that notwithstanding the clearness
of the style, those who attempt fairly to digest the book find much of
it a sort of intellectual pemmican--a mass of facts crushed and pounded
into shape, rather than held together by the ordinary medium of an
obvious logical bond: due attention will, without doubt, discover this
bond, but it is often hard to find.

Again, from sheer want of room, much has to be taken for granted which
might readily enough be proved; and hence, while the adept, who can
supply the missing links in the evidence from his own knowledge,
discovers fresh proof of the singular thoroughness with which all
difficulties have been considered and all unjustifiable suppositions
avoided, at every reperusal of Mr. Darwin's pregnant paragraphs, the
novice in biology is apt to complain of the frequency of what he fancies
is gratuitous assumption.

Thus while it may be doubted if, for some years, any one is likely to be
competent to pronounce judgment on all the issues raised by Mr. Darwin,
there is assuredly abundant room for him, who, assuming the humbler,
though perhaps as useful, office of an interpreter between the "Origin
of Species" and the public, contents himself with endeavouring to point
out the nature of the problems which it discusses; to distinguish
between the ascertained facts and the theoretical views which it
contains; and finally, to show the extent to which the explanation it
offers satisfies the requirements of scientific logic. At any rate, it
is this office which we propose to undertake in the following pages.

It may be safely assumed that our readers have a general conception of
the nature of the objects to which the word "species" is applied; but it
has, perhaps, occurred to few, even of those who are naturalists _ex
prof