es variation. Primitive
culture is loath to change; its inertia is deep-seated. Only a sharp
prod will start it moving or accelerate its speed; such a prod is found
in new geographic conditions or new social contacts. Divergence in a
segregated spot may be overdone. Progress crawls among a people too long
isolated, though incipient civilization thrives for a time in seclusion.
But in general, accessibility, exposure to some measure of ethnic
amalgamation and social contact is essential to sustained progress.[226]
As the world has become more closely populated and means of
communication have improved, geographical segregation is increasingly
rare. The earth has lost its "corners." All parts are being drawn into
the circle of intercourse. Therefore differentiation, the first effect
of the historical movement, abates; the second effect, assimilation,
takes the lead.

[Sidenote: Elimination by historical movement.]

The ceaseless human movements making for new combinations have
stimulated development. They have lifted the level of culture, and
worked towards homogeneity of race and civilization on a higher plane.
Since the period of the great discoveries inaugurated by Columbus
enabled the historical movement to compass the world, whole continents,
like North America and Australia, have been reclaimed to civilization by
colonization. The process of assimilation is often ruthless in its
method. Hence it has been attended by a marked reduction in the number
of different ethnic stocks, tribes, languages, dialects, social and
cultural types through wide-spread elimination of the weak, backward or
unfit.[227] These have been wiped out, either by extermination or the
slower process of absorption. The Indian linguistic stocks in the United
States have been reduced from fifty-three to thirty-two; and of those
thirty-two, many survive as a single tribe or the shrinking remnant of
one.[228] In Africa the slave trade has caused the annihilation of many
small tribes.[229] The history of the Hottentots, who have been passive
before the active advance of the English, Dutch and Kaffirs about them,
shows a race undergoing a widespread process of hybridization[230] and
extermination.[231]

Strong peoples, like the English, French, Russians and Chinese, occupy
ever larger areas. Where an adverse climate precludes genuine
colonization, as it did for the Spanish in Central and South America,
and for the English and Dutch in the Indies, they