or pituitary begins to
secrete more in her its stimulation of the thyroid is enough to tip it
over the normal line. Such a woman in the premenstrual phase becomes
irritable and restless, does not know what to do with herself, cannot
concentrate on conversation, occupation or any single activity, may
become excited to the point of mania. Hot, tremulous, sleepless, or
sleeping badly, she has a much harder time of it than her pituitary
sister.

These samples of premenstrual internal secretion reaction are the
extremes of a vast number and variety of types. There are women in an
unstable quasi-premenstrual state for the greater part of their lives.
Sometimes an infectious disease or a psychic blow will put a woman
into this class. The significance of these cyclic changes has been
tremendously increased by the recent formal admission of women to
participation in public activities on a plane of equality with men.

Evidence exists that in man, too, there is some cyclic rhythmicity of
his endocrines, which sets up a fluctuation in his physical and mental
efficiency. The curves of these variations have still to be plotted,
and will doubtless contribute no little to our knowledge of the
control of human nature. One unexpurgated fact stands out: the
reproductive mechanism of woman has rendered her whole internal
secretion system, and so her nervous system, all her organs, her mind,
definitely and sharply more tidal in their currents, more zigzag in
their phases, more angular in their ups and downs of function, and so
less predictable, reliable and dependable.

THE MASCULINOID WOMAN

The masculinoid woman, as a functional hermaphrodite, exists first
as a congenital entity, with an inborn distribution of endocrine
predominances that make for masculinity. There are also numerous
acquired forms. The infections of childhood, measles, scarlet fever,
diphtheria, and above all mumps, may so damage the hormone system
that an inversion of sex type follows. However, the stimulative and
depressive effects of environment are even more significant. The
effects of environment in producing changes in an organism, the
changes the biologist sums up as adaptation, can be tracked in many
instances to responsive reactions of the glands of internal secretion
to demands made upon them by changed external conditions. So a cold
climate, which necessitates a more voluminous hair covering for an
animal, will evoke a hypertrophy of the adrenal cortex. S