Darwinism | Page 7

quite useless to speculate as to how
far it might be possible to travel in the same direction, or where the
road would ultimately lead to.
The Problem before Darwin.
It is clear, then, that what was understood by the "origin" or the
"transmutation" of species before Darwin's work appeared, was the
comparatively simple question whether the allied species of each genus
had or had not been derived from one another and, remotely, from
some common ancestor, by the ordinary method of reproduction and by
means of laws and conditions still in action and capable of being
thoroughly investigated. If any naturalist had been asked at that day
whether, supposing it to be clearly shown that all the different species
of each genus had been derived from some one ancestral species, and
that a full and complete explanation were to be given of how each
minute difference in form, colour, or structure might have originated,
and how the several peculiarities of habit and of geographical
distribution might have been brought about--whether, if this were done,
the "origin of species" would be discovered, the great mystery solved,
he would undoubtedly have replied in the affirmative. He would
probably have added that he never expected any such marvellous
discovery to be made in his lifetime. But so much as this assuredly Mr.
Darwin has done, not only in the opinion of his disciples and admirers,
but by the admissions of those who doubt the completeness of his
explanations. For almost all their objections and difficulties apply to
those larger differences which separate genera, families, and orders
from each other, not to those which separate one species from the
species to which it is most nearly allied, and from the remaining
species of the same genus. They adduce such difficulties as the first
development of the eye, or of the milk-producing glands of the
mammalia; the wonderful instincts of bees and of ants; the complex
arrangements for the fertilisation of orchids, and numerous other points

of structure or habit, as not being satisfactorily explained. But it is
evident that these peculiarities had their origin at a very remote period
of the earth's history, and no theory, however complete, can do more
than afford a probable conjecture as to how they were produced. Our
ignorance of the state of the earth's surface and of the conditions of life
at those remote periods is very great; thousands of animals and plants
must have existed of which we have no record; while we are usually
without any information as to the habits and general life-history even of
those of which we possess some fragmentary remains; so that the truest
and most complete theory would not enable us to solve all the difficult
problems which the whole course of the development of life upon our
globe presents to us.
What we may expect a true theory to do is to enable us to comprehend
and follow out in some detail those changes in the form, structure, and
relations of animals and plants which are effected in short periods of
time, geologically speaking, and which are now going on around us.
We may expect it to explain satisfactorily most of the lesser and
superficial differences which distinguish one species from another. We
may expect it to throw light on the mutual relations of the animals and
plants which live together in any one country, and to give some rational
account of the phenomena presented by their distribution in different
parts of the world. And, lastly, we may expect it to explain many
difficulties and to harmonise many incongruities in the excessively
complex affinities and relations of living things. All this the Darwinian
theory undoubtedly does. It shows us how, by means of some of the
most universal and ever-acting laws in nature, new species are
necessarily produced, while the old species become extinct; and it
enables us to understand how the continuous action of these laws
during the long periods with which geology makes us acquainted is
calculated to bring about those greater differences presented by the
distinct genera, families, and orders into which all living things are
classified by naturalists. The differences which these present are all of
the same nature as those presented by the species of many large genera,
but much greater in amount; and they can all be explained by the action
of the same general laws and by the extinction of a larger or smaller
number of intermediate species. Whether the distinctions between the

higher groups termed Classes and Sub-kingdoms may be accounted for
in the same way is a much more difficult question. The differences
which separate the mammals, birds, reptiles, and fishes from each other,
though vast, yet seem of the same nature as those which distinguish a
mouse from an elephant or