with endless frequency within a country that the stronger and
better-equipped element will overcome the weaker and less well-equipped.

Thus we have here a case similar to that occurring so frequently in
nature: on the same terrain where a more highly organized plant or
animal has no longer room for subsistence, others less exacting in their
demands take up their position and flourish. The coming of the new is in
fact not infrequently the cause of the disappearance of those already
there and of their withdrawal to more favorable surroundings.

If these considerations show that by no means the majority of internal
migrations find their objective point in the cities, they at the same
time prove that the trend toward the great centers of population can, in
itself be looked upon as having an extensive social and economic
importance. It produces an alteration in the distribution of population
throughout the state; and at its originating and objective points it
gives rise to difficulties which legislative and executive authority has
hitherto labored, usually with but very moderate success, to overcome.
It transfers large numbers of persons almost directly from a sphere of
life where barter predominates into one where money and credit exchange
prevail, thereby affecting the social conditions of life and the social
customs of the manual laboring classes in a manner to fill the
philanthropist with grave anxiety.

3. Demographic Segregation and Social Selection[190]

There are two ways in which demographic crystallization may have taken
place. A people may have become rigid horizontally, divided into castes,
or social strata; or it may be geographically segregated into localized
communities, varying in size all the way from the isolated hamlet to the
highly individualized nation. Both of these forms of crystallization are
breaking down today under the pressure of modern industrialism and
democracy, in Europe as well as in America.

The sudden growth of great cities is the first result of the phenomenon
of migration which we have to note. We think of this as essentially an
American problem. We comfort ourselves in our failures of municipal
administration with that thought. This is a grievous deception. Most of
the European cities have increased in population more rapidly than in
America. This is particularly true of great German urban centers. Berlin
has outgrown our own metropolis, New York, in less than a generation,
hav