limits of racial variation due to climate and the variation due to
intermingling. In the past, when scientists assumed one unvarying Negro
type, every variation from that type was interpreted as meaning mixture of
blood. To-day we recognize a broader normal African type which, as
Palgrave says, may best be studied "among the statues of the Egyptian
rooms of the British Museum; the larger gentle eye, the full but not
over-protruding lips, the rounded contour, and the good-natured, easy,
sensuous expression. This is the genuine African model." To this race
Africa in the main and parts of Asia have belonged since prehistoric
times.

The color of this variety of man, as the color of other varieties, is due
to climate. Conditions of heat, cold, and moisture, working for thousands
of years through the skin and other organs, have given men their
differences of color. This color pigment is a protection against sunlight
and consequently varies with the intensity of the sunlight. Thus in Africa
we find the blackest men in the fierce sunlight of the desert, red pygmies
in the forest, and yellow Bushmen on the cooler southern plateau.

Next to the color, the hair is the most distinguishing characteristic of
the Negro, but the two characteristics do not vary with each other. Some
of the blackest of the Negroes have curly rather than woolly hair, while
the crispest, most closely curled hair is found among the yellow
Hottentots and Bushmen. The difference between the hair of the lighter and
darker races is a difference of degree, not of kind, and can be easily
measured. If the hair follicles of a China-man, a European, and a Negro
are cut across transversely, it will be found that the diameter of the
first is 100 by 77 to 85, the second 100 by 62 to 72, while that of the
Negro is 100 by 40 to 60. This elliptical form of the Negro's hair causes
it to curl more or less tightly.