There are wide physiological limits to the amount of discharge and the duration of a menstrual period. While the average time is from three to five days, and the average amount from three to five fluidounces, both these terms may be doubled, or, on the other hand, they may be diminished to a single day and a single ounce, without detriment to the health. Menorrhagia may be said to exist when the flow is in excess as compared with what is usual with the individual, or when the loss is so great as to affect her general health. The periodical return of the flow is of prime importance in establishing the existence of menorrhagia. Repetition at periods approximating the menstrual is the keynote of diagnosis. By this menorrhagia is distinguished from the hemorrhage of a miscarriage and from metrorrhagia. A profuse flow of blood after an absence of menstruation for one or two months is held by patients, in perfect good faith, to be the effect of taking cold: with almost absolute certainty such a train of events indicates an abortion. Metrorrhagia is uterine hemorrhage occurring independently of the menstrual periods. More surely indicative of organic disease than menorrhagia, it is often most closely allied to it; many cases which in the early stages present an increased menstrual flow as a symptom are at a more advanced period accompanied by metrorrhagia. Thus far the diagnosis of menorrhagia is easy. Not so that differential diagnosis upon which alone can therapeutic measures be based. This derangement depends upon as many and as widely diverse causes as the others. It is often one expression of affections of the general system, is sometimes caused by disease of organs neither pelvic nor generative, is a common symptom of a number of organic diseases of the uterus, or it may be simply functional. The necessity for a thorough physical examination is apparent. By touch, single and bimanual, by the speculum, and by the uterine sound the condition of all the pelvic organs should be investigated. These means failing to reveal the cause of the menorrhagia, the examination should be pushed farther. The cervix should be dilated by tents and the cavity of the uterus explored. Very frequently this measure, and this alone, will reveal the cause of the derangement. Such an examination is often as valuable for its negative as for its positive results. No practitioner fulfils his duty to his patient or is just to himself who treats a menorrhagia for any length of time without making a physical examination. It may seem unnecessary to emphasize so plain a duty, yet consultants very frequently find cases in {201} which palpable causes of the disease exist and where a direct examination has not even been proposed. The following schedule will indicate the widely diverse conditions which may give rise to menorrhagia, and will serve as a guide to the study of the subject: