the origin
and development of animal life.

But for the discoveries of geology a certain philosophy might have been
content to say of the animal creation, that it was the law of nature that
life should beget life--that reproduction, like nutrition, to which it has
been assimilated, is a part of the definition of life--and that, as to a
commencement of the various tribes of animals, we are no more bound to
look for this than for the commencement of any other of the phenomena of
nature. From the researches, however, of geology, it is evident that there
was a time when this earth revolved around the sun a barren and untenanted
globe--that there was a time when life did make its first appearance, and
that in different epochs of the world's existence there have flourished
very different species of animals than those which now inhabit it. Here,
at all events, the imagination cannot gain that imperfect repose which it
finds in the contemplation of an eternal series. It is a plain historical
fact, that life had a beginning on this earth, and that from time to time
new forms of life, new species of vegetables and animals, have been
introduced upon the scene. Here are two great facts to be accounted for,
or to be left standing out, unconnected in their origin with that
interlinked series of events which creation elsewhere displays. Life
reproduces life, the plant its seed, the animal its young, each after its
kind, such is the law; but this law itself, when was it promulgated, or
when and how did it come into force and operation?

For ourselves, in the present imperfect condition of our knowledge, we are
satisfied with referring life, in all its countless forms, at once to the
interposing will of the Creator. We listen, however, with curiosity and
attention to any theory which the naturalist or physiologist may have to
propose, so he proceed in the fair road of induction. There is nothing in
the laws of life which forbids, but much, on the contrary, which invites,
to the same pains-taking examination which has been bestowed, with more or
less success, on other phenomena of nature.

But what is the resolution of this problem which the author of the
_Vestiges_ proposes? Assuredly not one which indicates the boldness of
advancing science, but one of those hardy conjectures which are permitted
to arise only in the infancy of a science, and which show how clear the
field is, hitherto, of certain knowledge--how open to the very wanton