consequent paucity of life over the vast territory which fell
under my observation. And the other was, that even in those few
spots where animal life teemed in abundance, I failed to find--
although I was eagerly looking for it--that bitter struggle for
the means of existence, among animals belonging to the same
species, which was considered by most Darwinists (though not
always by Darwin himself) as the dominant characteristic of
struggle for life, and the main factor of evolution.

The terrible snow-storms which sweep over the northern
portion of Eurasia in the later part of the winter, and the
glazed frost that often follows them; the frosts and the
snow-storms which return every year in the second half of May,
when the trees are already in full blossom and insect life swarms
everywhere; the early frosts and, occasionally, the heavy
snowfalls in July and August, which suddenly destroy myriads of
insects, as well as the second broods of the birds in the
prairies; the torrential rains, due to the monsoons, which fall
in more temperate regions in August and September--resulting in
inundations on a scale which is only known in America and in
Eastern Asia, and swamping, on the plateaus, areas as wide as
European States; and finally, the heavy snowfalls, early in
October, which eventually render a territory as large as France
and Germany, absolutely impracticable for ruminants, and destroy
them by the thousand--these were the conditions under which I
saw animal life struggling in Northern Asia. They made me realize
at an early date the overwhelming importance in Nature of what
Darwin described as "the natural checks to over-multiplication,"
in comparison to the struggle between individuals of the same
species for the means of subsistence, which may go on here and