Darwiniana | Page 9

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 purpose 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 a few, even to those who are naturalists ex
professo, to reflect, that, as commonly employed, the term has a double
sense and denotes two very different orders of relations. When we call
a group of animals, or of plants, a species, we may imply thereby,
either that all these animals or plants have some common peculiarity of
form or structure; or, we may mean that they possess some common
functional character. That part of biological science which deals with
form and structure is called Morphology--that which concerns itself
with function, Physiology--so that we may conveniently speak of these
two senses, or aspects, of "species"--the one as morphological, the
other as physiological. Regarded from the former point of view, a
species is nothing more than a kind of animal or plant, which is
distinctly definable from all others, by certain constant, and not merely
sexual, morphological peculiarities. Thus horses form a species,
because the group of animals to which that name is applied is
distinguished from all others in the world by the following constantly
associated characters. They have--1, A vertebral column; 2, Mammae;
3, A placental embryo; 4, Four legs; 5, A single well-developed toe in
each foot provided with a hoof; 6, A bushy tail; and 7, Callosities on
the inner sides of both the fore and the hind legs. The asses, again, form
a distinct species, because, with the same characters, as far as the fifth
in the above list, all asses have tufted tails, and have callosities only on
the inner side of the fore-legs. If animals were discovered having the
general characters of the horse, but sometimes with callosities only on
the fore-legs, and more or less tufted tails; or animals having the
general characters of the ass, but with more or less bushy tails, and

sometimes with callosities on both pairs of legs, besides being
intermediate in other respects--the two species would have to be
merged into one. They could no longer be regarded as morphologically
distinct species, for they would not be distinctly definable one from the
other.
However bare and simple this definition of species may appear to be,
we confidently appeal to all practical naturalists, whether zoologists,
botanists, or palaeontologists, to say if, in the vast majority of cases,
they know, or mean to affirm, anything more of the group of animals or
plants they so denominate than what has just been stated. Even the
most decided advocates of the received doctrines respecting species
admit this.
"I apprehend," says Professor Owen, [Footnote: "On the Osteology of
the Chimpanzees