as replace the
forest. By furnishing food for such animals as the musk-ox, they are a
great help to the handful of scattered Indians who dwell on the northern
edge of the forest. In summer, when the animals grow fat on the short
nutritious grass, the Indians follow them out into the open country and
hunt them vigorously for food and skins to sustain life through the long
dreary winter. In many cases the hunters would advance much farther into
the grass-lands were it not that the abundant musk-oxen tempt the Eskimo
of the seacoast also to leave their homes and both sides fear bloody
encounters.

With the growth of civilization the advantage of the northern
grass-lands over the northern forests becomes still more apparent. The
domestic reindeer is beginning to replace the wild musk-ox. The
reindeer people, like the Indian and Eskimo hunters, must be nomadic.
Nevertheless their mode of life permits them to live in much greater
numbers and on a much higher plane of civilization than the hunters.
Since they hunt the furbearing animals in the neighboring forests during
the winter, they diminish the food supply of the hunters who dwell
permanently in the forest, and thus make their life still more
difficult. The northern forests bid fair to decline in population rather
than increase. In this New World of ours, strange as it may seem, the
almost uninhabited forest regions of the far north and of the equator
are probably more than twice as large as the desert areas with equally
sparse population.

South of the tundras the grass-lands have a still greater advantage over
the forests. In the forest region of the Laurentian highland abundant
snow lasts far into the spring and keeps the ground so wet and cold that
no crops can be raised. Moreover, because of the still greater abundance
of snow in former times, the largest of ice sheets, as we have seen,
accumulated there during the Glacial Period and scraped away most of
the soil. The grassy plains, on the contrary, are favored not only by
a deep, rich soil, much of which was laid down by the ice, but by the
relative absence of snow in winter and the consequent rapidity with
which the ground becomes warm in the spring. Hence the Canadian plains
from the United States boundary northward to latitude 57 degrees contain
a prosperous agricultural population of over a million people, while
the far larger forested areas in the same latitude support only a few
thousand.

The question is