of that colossal cataclysm; I
shall take all those for granted at present: what we are concerned with
now are the results it left behind--the changes which it wrought on
fauna and flora and on human society. Especially is it of importance in
this connection to point out that the Glacial epoch is not yet entirely
finished--if, indeed, it is ever destined to be finished. We are living
still on the fringe of the Ice Age, in a cold and cheerless era, the
legacy of the accumulated glaciers of the northern and southern
snow-fields.

If once that ice were melted off--ah, well, there is much virtue in an
_if_. Still, Mr. Alfred Russel Wallace seems to suggest somewhere that
the sun is gradually making inroads even now on those great
glacier-sheets of the northern cap, just as we know he is doing on the
smaller glacier-sheets of Switzerland (most of which are receding), and
that in time perhaps (say in a hundred thousand years or so) warm ocean
currents may once more penetrate to the very poles themselves. That,
however, is neither here nor there. The fact remains that we of
Northern Europe live to-day in a cramped, chilled, contracted world; a
world from which all the larger, fiercer, and grander types have either
been killed off or driven south; a world which stands to the full and
vigorous world of the Eocene and Miocene periods in somewhat the same
relation as Lapland stands to-day to Italy or the Riviera.

This being so, it naturally results that if we want really to
understand the history of life, its origin and its episodes, we must
turn nowadays to that part of our planet which still most nearly
preserves the original conditions--that is to say, the Tropics. And it
has always seemed to me, both _a priori_ and _a posteriori_, that the
Tropics on this account do really possess for every one of us a vast
and for the most part unrecognised educational importance.

I say 'for every one of us,' of deliberate design. I don't mean merely
for the biologist, though to him, no doubt, their value in this respect
is greatest of all. Indeed, I doubt whether the very ideas of the
struggle for life, natural selection, the survival of the fittest,
would ever have occurred at all to the stay-at-home naturalists of the
Linnaean epoch. It was in the depths of Brazilian forests, or under the
broad shade of East Indian palms, that those fertile conceptions first
flashed independently upon two southern explorers. It is very
noteworthy inde