Here are some quick tips on how to distinguish classic crystal from plain glass. 1  Hold up a glass to the light. 2  If the glass acts as a prism and you see a rainbow you are holding crystal. 3  If not, it is just plain glass. 4  When struck, crystal produces a musical ring. 5  Glass does not.
Hormonal control of menstrual cycle. The ovarian hormones circulate in the blood and are excreted in modified forms in the urine. Estimation of the urinary output by chemical methods gives an indication of the blood levels and of the total production of these substances.
To properly regulate the menstrual cycle and treat unusual stopping of the menstrual periods (amenorrhea). Progestins work by causing changes in the uterus. After the amount of progestins in the blood drops, the lining of the uterus begins to come off and vaginal bleeding occurs (menstrual period).