1st. Rupture of blood-vessels in the pelvis: Utero-ovarian; Varicose veins of broad ligaments; Vessels of extra-uterine ovisac. 2d. Rupture of pelvic viscera: Ovaries; Fallopian tubes; Uterus. 3d. Reflux of blood from the uterus: Menstrual blood. 4th. Transudation from blood-vessels: Purpura; Scorbutus; Chlorosis; Hemorrhagic peritonitis. It is then clear that the mere presence of a large clot of blood in the pelvis, apart from general symptoms, is a matter of very doubtful significance, since on the one hand it may be the result of a mere regurgitation of menstrual blood due to imperviousness of the cervical or tubal canal, or on the other of the rupture of a Fallopian tube which has become the nidus of an extra-uterine foetus. Whatever be the source of the blood which escapes, it coagulates, unless very poor in fibrin, either in the most dependent part of the peritoneum or in the pelvic areolar tissue beneath it. Here the watery portions of the mass are gradually absorbed, leaving a hard, small tumor remaining; or, suppurative action being excited, the hard mass is softened down and discharged into the rectum, vagina, bladder, or peritoneum as a grumous material somewhat resembling currant-jelly in appearance. CAUSES.--These must be divided into predisposing and exciting, for it is rare to meet with the disease in a woman who has previously been in perfect health. The predisposing causes which can be cited with confidence are--the period of ovarian activity (fifteen to forty-five years); disordered blood-state, plethora or anæmia; the menstrual epoch; chronic ovarian or tubal disease; pelvic peritonitis; and the hemorrhagic diathesis. The exciting causes have been found to be sudden checking of the menstrual flow; blows or falls; excessive or intemperate coition; obstruction of cervical canal; obstruction of Fallopian tubes; violent efforts; and ectopic gestation. VARIETIES.--The two great classes of the affection are the peritoneal and the subperitoneal. In the former the blood collects in the peritoneal cavity and becomes encysted there; in the latter it collects in the cellular tissue beneath the peritoneum, and there forms a solid mass. Some authors have opposed the consideration of these two varieties under the same head; among them, Aran, Bernutz, and Voisin. But from a clinical standpoint such a consideration appears to me to be valid. Not only have distinct instances of subperitoneal hæmatocele been recorded by such observers as Barnes, Simpson, Olshausen, and Tuckwell, but {242} cases have been met with in which the subperitoneal variety has ruptured the peritoneal roof of the pelvis, and thus broken down the theoretical barrier which pathologists have been inclined to establish between the two varieties.