Darwiniana | Page 4

the New
World were discovered? It is not that they were unfit for cattle, for
millions of cattle now run wild there; and the like holds good of
Australia and New Zealand. It is a curious circumstance, in fact, that
the animals and plants of the Northern Hemisphere are not only as well

adapted to live in the Southern Hemisphere as its own autochthones,
but are, in many cases, absolutely better adapted, and so overrun and
extirpate the aborigines. Clearly, therefore, the species which naturally
inhabit a country are not necessarily the best adapted to its climate and
other conditions. The inhabitants of islands are often distinct from any
other known species of animal or plants (witness our recent examples
from the work of Sir Emerson Tennent, on Ceylon), and yet they have
almost always a sort of general family resemblance to the animals and
plants of the nearest mainland. On the other hand, there is hardly a
species of fish, shell, or crab common to the opposite sides of the
narrow isthmus of Panama. [Footnote: See page 60 Note.] Wherever we
look, then, living nature offers us riddles of difficult solution, if we
suppose that what we see is all that can be known of it.
But our knowledge of life is not confined to the existing world.
Whatever their minor differences, geologists are agreed as to the vast
thickness of the accumulated strata which compose the visible part of
our earth, and the inconceivable immensity of the time the lapse of
which they are the imperfect but the only accessible witnesses. Now,
throughout the greater part of this long series of stratified rocks are
scattered, sometimes very abundantly, multitudes of organic remains,
the fossilised exuviæ of animals and plants which lived and died while
the mud of which the rocks are formed was yet soft ooze, and could
receive and bury them. It would be a great error to suppose that these
organic remains were fragmentary relics. Our museums exhibit fossil
shells of immeasurable antiquity, as perfect as the day they were
formed; whole skeletons without a limb disturbed; nay, the changed
flesh, the developing embryos, and even the very footsteps of primæval
organisms. Thus the naturalist finds in the bowels of the earth species
as well defined as, and in some groups of animals more numerous than,
those which breathe the upper air. But, singularly enough, the majority
of these entombed species are wholly distinct from those that now live.
Nor is this unlikeness without its rule and order. As a broad fact, the
further we go back in time the less the buried species are like existing
forms; and, the further apart the sets of extinct creatures are, the less
they are like one another. In other words, there has been a regular
succession of living beings, each younger set, being in a very broad and
general sense, somewhat more like those which now live.

It was once supposed that this succession had been the result of vast
successive catastrophes, destructions, and re-creations _en masse_; but
catastrophes are now almost eliminated from geological, or at least
palæontological speculation; and it is admitted, on all hands, that the
seeming breaks in the chain of being are not absolute, but only relative
to our imperfect knowledge; that species have replaced species, not in
assemblages, but one by one; and that, if it were possible to have all the
phenomena of the past presented to us, the convenient epochs and
formations of the geologist, though having a certain distinctness, would
fade into one another with limits as undefinable as those of the distinct
and yet separable colours of the solar spectrum.
Such is a brief summary of the main truths which have been established
concerning species. Are these truths ultimate and irresolvable facts, or
are their complexities and perplexities the mere expressions of a higher
law?
A large number of persons practically assume the former position to be
correct. They believe that the writer of the Pentateuch was empowered
and commissioned to teach us scientific as well as other truth, that the
account we find there of the creation of living things is simply and
literally correct, and that anything which seems to contradict it is, by
the nature of the case, false. All the phenomena which have been
detailed are, on this view, the immediate product of a creative fiat and,
consequently, are out of the domain of science altogether.
Whether this view prove ultimately to be true or false, it is, at any rate,
not at present supported by what is commonly regarded as logical proof,
even if it be capable of discussion by reason; and hence we consider
ourselves at liberty to pass it by, and to turn to those views which
profess to rest on a scientific