anifest though they are, they all fall far
within the limits of variation in familiar domestic animals, and also
of hereditary malformation or defect of development occurring in the
European nations, and only requiring isolation for its perpetuation as
a race. The differences in the skull merit more attention, for it is
in this and in its enclosed brain that man most markedly differs from
the lower animals, as well as race from race. It is in the form rather
than in the mere dimensions of the skull that we should look for
specific differences; and here, adopting the vertical method of
Blumenbach as the most characteristic and valuable, we find a greater
or less antero-posterior diameter--a greater or less development of
the jaws and bones of the face. The skull of the normal European, or
Caucasian of Cuvier, is round oval; and the jaws and cheek-bones
project little beyond its anterior margin, when viewed from above. The
skull of the Mongolian of Cuvier is nearly round, and the cheek-bones
and jaws project much more strongly in front and at the sides. The
Negro skull is lengthened from back to front; the jaws project
strongly, or are prognathous; but the cheek-bones are little
prominent. For the extremes of these varieties, Retzius proposed the
names of brachy-kephalic or short-headed, and dolicho-kephalic or
long-headed, which have come into general use. The differences
indicated by these terms are of great interest, as distinctive marks
of many of the unmixed races of men; but, when pushed to extremes,
lead to very incorrect generalizations--as Professor D. Wilson has
well shown in his paper on the supposed uniformity of type in the
American races--a doctrine which he fully refutes by showing that
within a very narrow geographical range this primitive and unmixed
race presents very great differences of cranial form.[169] Exclusive
of idiots, artificially compressed heads, and deformities, the
differences between the brachy-kephalic and dolicho-kephalic heads
range from equality in the parietal and longitudinal diameter to the
proportion of about 14 to 24. As stated by some ethnologists, these
differences appear quite characteristic and distinct; but, so soon as
we attempt any minute discrimination, all confidence in them as
specific characters disappears. In our ordinary European races similar
differences, and nearly as extensive, occur. The dolicho-kephalic head
is really only an immature form perpetuated; and appears