ies was called into existence, we must be guided by the
same rules of induction as when we speculate on the state of America in
the interval that elapsed between the introduction of man into Asia, the
supposed cradle of our race, and the arrival of the first adventurers on
the shores of the New World. In that interval, we imagine the state of
things to have gone on according to the order now observed in regions
unoccupied by man. Even now, the waters of lakes, seas, and the great
ocean, which teem with life, may be said to have no immediate relation
to the human race--to be portions of the terrestrial system of which man
has never taken, nor ever can take possession; so that the greater part
of the inhabited surface of the planet may still remain as insensible to
our presence as before any isle or continent was appointed to be our
residence.

If the barren soil around Sydney had at once become fertile upon the
landing of our first settlers; if, like the happy isles whereof the
poets have given such glowing descriptions, those sandy tracts had begun
to yield spontaneously an annual supply of grain, we might then, indeed,
have fancied alterations still more remarkable in the economy of nature
to have attended the first coming of our species into the planet. Or if,
when a volcanic island like Ischia was, for the first time, brought
under cultivation by the enterprise and industry of a Greek colony, the
internal fire had become dormant, and the earthquake had remitted its
destructive violence, there would then have been some ground for
speculating on the debilitation of the subterranean forces, when the
earth was first placed under the dominion of man. But after a long
interval of rest, the volcano bursts forth again with renewed energy,
annihilates one half of the inhabitants, and compels the remainder to
emigrate. The course of nature remains evidently unchanged; and, in like
manner, we may suppose the general condition of the globe, immediately
before and after the period when our species first began to exist, to
have been the same, with the exception only of man's presence.

The modifications in the system of which man is the instrument do not,
perhaps, constitute so great a deviation from previous analogy as we
usually imagine; we often, for example, form an exaggerated estimate of
the extent of our power in extirpating some of the inferior animals, and
causing others to multiply; a power which is circumscribed within