excite. The unconscious fires that have their seat deep down in the
recesses of the sexual organization will flame up through every
tissue, permeate every vessel, burn every nerve, flash from the eye,
tingle in the brain, and work the whole machine at highest pressure.
There need not be, and generally will not be, any low or sensual
desire in all this elemental action. It is only making youth work over
the tasks of sober study with the wasting force of intense passion. Of
course such strenuous labor will yield brilliant, though temporary,
results. The fire is kept alive by the waste of the system, and soon
burns up its source. The first sex to suffer in this exhilarating and
costly competition must be, as experience shows it is, the one that
has the largest amount of force in readiness for immediate call; and
this is the female sex. At the age of development, Nature mobilizes
the forces of a girl's organization for the purpose of establishing a
function that shall endure for a generation, and for constructing an
apparatus that shall cradle and nurse a race. These mobilized forces,
which, at the technical educational period, the girl possesses and
controls largely in excess of the boy, under the passionate stimulus
of identical co-education, are turned from their divinely-appointed
field of operations, to the region of brain activity. The result is a
most brilliant show of cerebral pyrotechnics, and degenerations that
we have described.

That undue and disproportionate brain activity exerts a sterilizing
influence upon both sexes is alike a doctrine of physiology, and an
induction from experience. And both physiology and experience also
teach that this influence is more potent upon the female than upon the
male. The explanation of the latter fact--of the greater aptitude of
the female organization to become thus modified by excessive brain
activity--is probably to be found in the larger size, more complicated