ain in the
head. The last is probably due to swelling of the pituitary beyond
the capacity of its bony container. In a good many women, nervous
and mental phenomena herald the expected menstruation because of a
complete upset of the balance between the internal secretions, with
resulting disturbance of the nervous system. Irritability, depression,
excitability, melancholia, exaltations, restlessness, hysteria, loss
of self-control, or even more marked mental aberrations may appear.
Following them, and roughly paralleling them, may come various
abnormalities of menstruation itself. The character, extent and
duration of these furnish us the best clues to the endocrine stability
or instability of the particular feminine organism.

Menstruation is simply the uterus saying: well, not this time. As the
destined ovum within its nest, the follicle, grows, its fluid affects
the interstitial cells to send their specific stuff into the blood.
There it circulates, hits this gland and that, makes some more active,
others less, transforms the chemistry of the cells, and engorges the
mucous membranes, most of all those of the nose and of the uterus. It
is all to welcome the mature ovum and its possible impregnation, to
prepare a site for its landing and settlement, blood and food for its
nutrition, safety for its development. But it is not to be. No sperm
at hand, or effective enough to penetrate that wandering ovum. Love's
labour's lost. All must return to the so-called normal, really the
intermenstrual state. The womb must surrender some of that blood,
the glands return to their routine, and a sex diastole of the whole
organism succeeds. Until again, another follicle swells, another ovum
matures, and the premenstrual state of sex high tide cycles back.

Seven to ten days before menstruation we know that sex high tide is
beginning for that is when the blood pressure goes up. As this rise of
blood pressure is probably controlled by the posterior pituitary, we
have a clue to the reason for the rhythmic variations in the rate of
production of its secretion by the ovary. For, since menstruation is
so closely connected with the phases of the moon and the tides, the
rhythmicity of the posterior pituitary may be traced to the days when
the pineal was an eye at the top of the head, and in direct relation
with the pituitary.

Menstruation has been said to be a miniature labor. It is not that
as much as it is a miniature abortion. It is an