Menstruation has been said to be a miniature labor. It is not that as much as it is a miniature abortion. It is an effort of nature still-born. But nature is quite used to its disappointments and returns placidly to the daily grind. The four phases of a woman's twenty-eight day cycle succeed each other as the premenstrual, the menstrual, the postmenstrual and the intermenstrual, with the precision of pistons moving in a motor, when no interfering factor as disease, profound emotion or climate disturbances are present, affecting the endocrines.

The sequence of events appears to be about as follows: The amount of post-pituitary secretion reaches a certain concentration. This in turn stimulates the thyroid and adrenal medulla. They in turn activate the ovarian cells, which congest the uterine glands and lining membrane. The follicle bursts, the ovum is discharged and wanders, the uterus waits and wonders. Nothing happens, the curtain is lowered, the scenery is removed, the actors revert to civilian clothes. That is the story of menstruation, the central phenomenon of woman's pre-pregnancy life. One sees it clearly as a play of an internal secretion syndicate.

THE PREMENSTRUAL MOLIMINA

The premenstrual molimina is the traditional title accorded symptoms, sensations, feelings, observations of women in the premenstrual phase. In the light of endocrine analysis, they become exceedingly important indicators of the underlying constitution of the individual concerned. Indeed, the premenstrual period furnishes a direct clue to the dominating internal secretion in a woman. Moreover, these premenstrual phenomena are the shadows cast by coming events. For they mimic and prophesy the events of the last crisis of feminine sex life, the cessation of ovulation which goes by the name of menopause, gonadopause, or change of sex life. The premenstrual phenomena provide a positive film, so to speak, of the latent negative picture of the endocrine system of the girl or woman.

Thus, there is the sub-pituitary or pituitary insufficient type, in whom the excessive swelling of the gland causes headache, and a dull, heavy, tired feeling, a definite depression. Drowsiness, sleepishness, indifference to surroundings, general sluggishness of thought, feeling and reaction, a phlegmatic frilosity, all go with it. It is due to an overweighing of the pituitary, controller of good brain tone, and alive wakefulness, by the demands of the organism.

On the other hand, the hyperthyroid type of woman reacts with an exaggeration of her tendency. When the posterior 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. Secondarily other effects appear as by-products of the adaptation. The adrenal cortex makes for pugnacity, temper, animal courage, irritability and anger reactions. So a hairy animal will, in general (unless other endocrines come in to defeat the primary effect), be more pugnacious, courageous, irritable and combative. The same applies to woman. An environment which tends to encourage the masculine traits in her, to arouse repeatedly her pugnacity and combative decisions in the more rapid give and take of the masculine world, will rouse the adrenal cortex to greater activity, and so make her face hirsute, her attitudes aggressive, and perhaps render her sterile. Concomitantly there may be a disturbance of menstruation.