Blood poisoning from criminal operations contributes its share in the causation. Traumatic agencies, like blows, falls, lacerations, and other injuries during labor, may result in pelvic peritonitis. Either too hot or too cold vaginal irrigations have given rise to this affection, and injections into the cavity of the womb for medicinal purposes, in which some of the fluid escaped through the Fallopian tube into the peritoneal cavity, has caused, in several instances, fatal peritonitis. The inflammation of the womb after childbirth invariably involves the peritoneum. The course and duration of this disease is by no means uniform. The disease under consideration is an example of an acute inflammation affecting a serous membrane. I have taken pains to inform the reader that the phenomena of inflammation are always the same, but that the results are modified by the peculiarity of the structure of which the tissues are composed. A serous membrane differs completely from a mucous membrane, inasmuch as it contains neither mucous glands nor mucous cells, and for that reason can never be the seat of catarrh; instead of this, it possesses the power to secrete or transude the serous portion of the blood, hence its name. The serous membrane in a healthy condition has only a sufficient quantity of secretion to moisten the membrane, but not to furnish any appreciable quantity of fluid. If the secretion takes place as a result of congestion, especially when this congestion is due to an obstruction to the return of blood from heart or liver disease, it is secreted in such large quantities that it constitutes dropsy. Under the stimulating influence of the inflammatory process, a similar secretion is the result, only that it contains also _fibrin_, which renders the secretion or exudation spontaneously coagulable, and, further, possesses the capability of passing into the condition of an organized tissue, either fibrous or granular, and thus forming false membranes on inflamed surfaces, or solidifying into tumors or swellings. These inflammations have their various degrees of severity, from a temporary reddening of the membrane with barely enough effusion of inflammatory material to cause a thin layer of deposit, to extensive and violent attacks, that pour out enormous quantities of effusion or exudation, so as to fill the entire pelvic cavity with a solid mass. The nature of the inflammatory material may be purulent from the beginning, because its origin was of an infectious or septic nature.