more important than their immediate surroundings. In fact, the
history of North America has been perhaps more profoundly
influenced by man's inheritance from his past homes than by the
physical features of his present home. It is indeed of vast
importance that trade can move freely through such natural
channels as New York Harbor, the Mohawk Valley, and the Great
Lakes. It is equally important that the eastern highlands of the
United States are full of the world's finest coal, while the
central plains raise some of the world's most lavish crops. Yet
it is probably even more important that because of his
inheritance from a remote ancestral environment man is energetic,
inventive, and long-lived in certain parts of the American
continent, while elsewhere he has not the strength and mental
vigor to maintain even the degree of civilization to which he
seems to have risen.

Three streams of migration have mainly determined the history of
America. One was an ancient and comparatively insignificant
stream from Asia. It brought the Indian to the two great
continents which the white man has now practically wrested from
him. A second and later stream was the great tide which rolled in
from Europe. It is as different from the other as West is from
East. Thus far it has not wholly obliterated the native people,
for between the southern border of the United States on the one
hand, and the northern borders of Argentina, Chile, and Uruguay
on the other, the vast proportion of the blood is still Indian.
The European tide may in time dominate even this region, but for
centuries to come the poor, disinherited Indians will continue to
form the bulk of the population. The third stream flowed from
Africa and was as different from either of the others as South is