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