cording to a general law in the animal kingdom,
woman being smaller, her cerebral hemispheres should be, with equal
mentality, proportionately a little larger. There are, however, female
brains larger than many male brains, and the absolute and relative
size of the cerebral hemispheres does not give a complete measure of
the productive faculties. Remarkable men have been known to possess
rather small brains and imbeciles heavy ones. We must not forget the
great importance of the hereditary or engraphic predispositions of the
nerve element or _neurone_, to certain activities and especially to
work in general, that is to say, their aptitude to produce energy, or
if one prefers it, their disposition to "will."

It is also interesting to consider the relationship of the frontal
lobe to the rest of the cerebral hemispheres, the frontal lobe being
without doubt the principal seat of intellectual activity. According
to _Meynert_, the weight of the frontal lobe in man exceeds that of
woman, not only absolutely, but relatively to the rest of the brain.
In his _resume_ of the statistical data collected on this subject and
from the results of my own material (autopsies at the asylum of
Burgholzli in Zurich), _Mercier_ has confirmed the opinion of
_Meynert_. The average weight of the hemispheres separated from the
rest of the brain is 1019 grammes in man (frontal lobe 428, the rest
591), and 930 in woman (frontal lobe 384, rest 546). Here, atrophied
brains (except general paralytics) have been weighed with others,
which lowers the average total weight without altering the proportion.
Thus, the rest of the cerebral hemispheres exceeds the frontal lobe by
163 grammes in man and 162 grammes in woman, which means that in man
the frontal lobe constitutes 42 per cent. of the cerebral hemispheres
and in woman 41.3 per cent. The difference is not great, but it is
definite, for it is based on a large number of observations.

=Mental Capacity of the Two Sexes.=--The fundamental difference
between the psychology of woman and that of man is constituted by the
irradiations of the sexual sphere in the cerebral hemispheres, which
constitute what may be called _sexual mentality_. We shall discuss
this in the following chapters, for it constitutes the foundation of
our subject. We are only concerned here with the correlative
differences.

Adhering in a general way to the main definitions of psychology, we
assert that from the purely intellectual