d trees, was turned aside by the impassable barriers of mountains, or
the forbidding glacier, the roaring torrent, or the limits of the ocean
itself, and spread over the accessible parts of the earth's surface
until he had covered the selected districts on the main portions of the
globe. Then came race specialization, where a group remained a long
time in the same environment and inbred in the same stock, developing
specialized racial characters. These changes were very slow, and the
wide difference to-day between the Asiatic, the African, and the
European is indicative of the long period of years which brought them
about. Certainly, six thousand years would not suffice to make such
changes.

Of course one must realize that just as, in the period of childhood,
the plastic state of life, changes of structure and appearance are more
rapid than in the mature man, after {70} traits and characters have
become more fixed, so by analogy we may assume that this was the way of
the human race and that in the earlier period changes were more rapid
than they are to-day. Thus in the cross-fertilizations and
amalgamation of races we would expect a slower development than under
these earlier conditions, yet when we realize the persistence of the
types of Irish and German, of Italian and Greek, of Japanese and
Chinese, even though the races become amalgamated, we must infer that
the racial types were very slow in developing.

If we consider the variations in the structure and appearance of the
several tribes and races with which we come in contact in every-day
life, we are impressed with the amount of time necessary to make these
changes. Thus the Anglo-American, whom we sometimes call Caucasian,
taken as one type of the perfection of physical structure and mental
habit, with his brown hair, having a slight tendency to curl, his fair
skin, high, prominent, and broad forehead, his great brain capacity,
his long head and delicately moulded features, contrasts very strongly
with the negro, with his black skin, long head, with flat, narrow
forehead, thick lips, projecting jaw, broad nose, and black and woolly
hair. The Chinese, with his yellow skin, flat nose, black, coarse
hair, and oblique, almond-shaped eyes, and round skull, marks another
distinct racial type. Other great races have different
characteristics, and among our own race we find a further separation
into two great types, the blonds and the brunettes.

What a long p