Furthermore, the activities of a normal woman involve a series of sex glands. Since there function, in addition to the ovaries, the glands of the uterus, the breasts or mammary glands, and the placental gland (the secreting cells of the tissue which comes out as the after-birth). Each of these contributes directly to the reproductive life of the individual. To call the ova the sex glands is to confer upon them a name which really belongs to a chain of glands. All of the members of the sex chain, including those of the thyroid, the adrenal and the pituitary, are necessary to the functions of menstruation, impregnation, settlement of fertilized ovum in the wall of the uterus, labor and lactation. A disturbance of one of them will set up disturbances all along the line, and a resonance of distress or compensation upon the part of all of them. As an interlocking directorate over the sexual functions of the female, they are members one of the other. So what helps or hurts one, helps or hurts all. THE CYCLE OF MENSTRUATION Essentially, the ovary is a collection of follicles, nests of cells, acting as safe deposit vaults for the ova that are to become candidates for fertilization. At birth, there are some 30,000 to 200,000 of these, of which a good many atrophy during childhood so that there are no more than about 30,000 left at puberty. Of the 30,000, only an élite 400 actually mature between the ages of fifteen and forty-five. About every twenty-eight days, one of the follicles swells, becomes filled with liquid, pushes or is pushed to the surface of the ovary, there to rupture and expel into the abdominal cavity the tiny ripe ovum. The rest of the torn follicle makes itself over into a peculiar yellowish body, the true corpus luteum, should pregnancy occur. If pregnancy and the consequent placenta do not occur, it shrinks and turns into a scar, the false corpus luteum. The true corpus luteum resembles closely the adrenal cortex in make-up and staining reactions. It seems as if, once successful impregnation has been achieved, the feminine organism adrenalizes itself, makes itself more masculine and less feminine, inhibiting the posterior pituitary and the adrenal medulla, as well as the ovaries. Besides, the corpus luteum stimulates the thyroid to prepare for the heavy demands to be made upon it during pregnancy.