al
faculties, seems highly probable; and that a low facial angle is
frequently accompanied with inferiority of mental powers, is certain;
but the attempt to trace a gradual scale of intelligence through the
different species of animals accompanying the modifications of the form
of the scull, is a mere visionary speculation. It has been found
necessary to exaggerate the sagacity of the ape tribe at the expense of
the dog; and strange contradictions have arisen in the conclusions
deduced from the structure of the elephant; some anatomists being
disposed to deny the quadruped the intelligence which he really
possesses, because they found that the volume of his brain was small in
comparison to that of the other mammalia; while others were inclined to
magnify extravagantly the superiority of his intellect, because the
vertical height of his skull is so great when compared to its horizontal
length.

_Different races of men are all of one species._--It would be irrelevant
to our subject if we were to enter into a farther discussion on these
topics; because, even if a graduated scale of organization and
intelligence could have been established, it would prove nothing in
favor of a tendency, in each species, to attain a higher state of
perfection. I may refer the reader to the writings of Blumenbach,
Prichard, Lawrence, and more recently Latham[838], for convincing proofs
that the varieties of form, color, and organization of different races
of men, are perfectly consistent with the generally received opinion,
that all the individuals of the species have originated from a single
pair; and, while they exhibit in man as many diversities of a
physiological nature as appear in any other species, they confirm also
the opinion of the slight deviation from a common standard of which
species are capable.

The power of existing and multiplying in every latitude, and in every
variety of situation and climate, which has enabled the great human
family to extend itself over the habitable globe, is partly, says
Lawrence, the result of physical constitution, and partly of the mental
prerogative of man. If he did not possess the most enduring and flexible
corporeal frame, his arts would not enable him to be the inhabitant of
all climates, and to brave the extremes of heat and cold, and the other
destructive influences of local situation.[839] Yet, notwithstanding
this flexibility of bodily frame, we find no signs of indefinite
departure from