MENSTRUATION, the periodical dis charge of the menses or bloody fluid from the female generative organs. In women it nor, mally occurs at intervals of one lunar month, or 13 times a year (hence the use of the term menses, Latin plural of menses, month). Its first appearance marks the stage of puberty, and is usually attended by definite changes– enlargement of the breasts, showing develop ment of the mammary glands, growth of the ovaries, of the uterus and external genital organs, etc., and by other signs, physical and mental, of approaching womanhood and ma turity. It usually begins in temperate climb between the 13th and 15th year; in hot climates it is apt to commence as young as 12 years, and in very cold climates as late as 17 years: is periodic recurrences continue until the menu pause (q.v.) or final cessation of the discharge which ordinarily arrives somewhere betsiect the 45th and 52d years. The recurrent periods of its appearance, as well as their duration vary with different females, and not infre quently in the same individual; the variation, however, not always indicating abnormal o: pathological causes. The immediate cause et menstruation is the breaking away of an on or egg from one of the ovaries. (See Menstruation is often at first, and in many per sons throughout the catamenial age, attendrd by characteristic pains and symptoms, physiological and psychological conditions G: disturbance or depression, which sometimes cal' for special hygienic treatment. During preg
nancy (with exceptional cases) there is a menstrual flow, its cessation being one of the earliest signs of conception. Observance or wholesome rules of exercise, rest, etc., helps to maintain normal conditions of body and nurl the reverse of which, owing to neglect ofsud rules, so often makes the menstrual function visitation of dread and distress.
Disorders of These its elude amenorrhoea, dysmenorrhoea, menorrhap and metrorrhagia. Amenorrhea is an absence the menstrual flow from some cause other this pregnancy or the approach of the (q.v.) or tardy establishment of the function. It is a symptom of anaemia (q.v.), or may be due to a constitutional condition such profound nerve-fag or tuberculosis. Strychnine. iron and ergot may be administered internall„ or the physician may apply local treatment (See DYSMENORRHCEA). Menorrhagia is an normally profuse flow during the menstrinl period, due to one of several conditions not checked by rest, a physician is necessarl as also in metrorrhagia, which is a sangumeons flow between the menstrual periods.