combine for mutual
comfort and protection, would be preserved and accumulated; the better
and higher specimens of our race would therefore increase and spread,
the lower and more brutal would give way and successively die out, and
that rapid advancement of mental organization would occur, which has
raised the very lowest races of man so far above the brutes (although
differing so little from some of them in physical structure), and, in
conjunction with scarcely perceptible modifications of form, has
developed the wonderful intellect of the European races.

_Influence of external Nature in the development of the Human Mind._

But from the time when this mental and moral advance commenced, and
man's physical character became fixed and almost immutable, a new series
of causes would come into action, and take part in his mental growth.
The diverse aspects of nature would now make themselves felt, and
profoundly influence the character of the primitive man.

When the power that had hitherto modified the body had its action
transferred to the mind, then races would advance and become improved,
merely by the harsh discipline of a sterile soil and inclement seasons.
Under their influence, a hardier, a more provident, and a more social
race would be developed, than in those regions where the earth produces
a perennial supply of vegetable food, and where neither foresight nor
ingenuity are required to prepare for the rigours of winter. And is it
not the fact that in all ages, and in every quarter of the globe, the
inhabitants of temperate have been superior to those of hotter
countries? All the great invasions and displacements of races have been
from North to South, rather than the reverse; and we have no record of
there ever having existed, any more than there exists to-day, a solitary
instance of an indigenous inter-tropical civilization. The Mexican
civilization and government came from the North, and, as well as the
Peruvian, was established, not in the rich tropical plains, but on the
lofty and sterile plateaux of the Andes. The religion and civilization
of Ceylon were introduced from North India; the successive conquerors of
the Indian peninsula came from the North-west; the northern Mongols
conquered the more Southern Chinese; and it was the bold and adventurous
tribes of the North that overran and infused new life into Southern
Europe.

_Extinction of Lower Races._

It is the same great law of "the preservation