Professor Wagner states
that one-half weighed between 1200 and 1400 grammes, and that about
two-ninths, consisting for the most part of male brains, exceed
1400 grammes. The lightest brain of an adult male, with sound mental
faculties, recorded by Wagner, weighed 1020 grammes. As a gramme equals
15.4 grains, and a cubic inch of water contains 252.4 grains, this is
equivalent to 62 cubic inches of water; so that as brain is heavier than
water, we are perfectly safe against erring on the side of diminution in
taking this as the smallest capacity of any adult male human brain. The
only adult male brain, weighing as little as 970 grammes, is that of an
idiot; but the brain of an adult woman, against the soundness of whose
faculties nothing appears, weighed as little as 907 grammes (55.3 cubic
inches of water); and Reid gives an adult female brain of still smaller
capacity. The heaviest brain (1872 grammes, or about 115 cubic inches)
was, however, that of a woman; next to it comes the brain of Cuvier
(1861 grammes), then Byron (1807 grammes), and then an insane person
(1783 grammes). The lightest adult brain recorded (720 grammes) was
that of an idiotic female. The brains of five children, four years old,
weighed between 1275 and 992 grammes. So that it may be safely said,
that an average European child of four years old has a brain twice as
large as that of an adult Gorilla.)

No doubt, this is a very striking difference, but it loses much of its
apparent systematic value, when viewed by the light of certain other
equally indubitable facts respecting cranial capacities.

The first of these is, that the difference in the volume of the cranial
cavity of different races of mankind is far greater, absolutely, than
that between the lowest Man and the highest Ape, while, relatively,
it is about the same. For the largest human skull measured by Morton
contained 114 cubic inches, that is to say, had very nearly double the
capacity of the smallest; while its absolute preponderance, of 52 cubic
inches--is far greater than that by which the lowest adult male human
cranium surpasses the largest of the Gorillas (62 - 34 1/2 = 27 1/2).
Secondly, the adult crania of Gorillas which have as yet been measured
differ among themselves by nearly one-third, the maximum capacity being
34.5 cubic inches, the minimum 24 cubic inches; and, thirdly, after
making all due allowance for difference of size, the cranial capacities
of some of the lower A