Hemorrhagic Exudation is frequently seen on the peritoneum; it forms largo, saturated coagula, disposed in thick layers. Thin strata present a deep black or bluish-black discoloration, the effect of the intestinal gases.

Peritonitis occasionally terminates in suppuration or gangrenous decomposition, phthisis and gangrcena peritonaei. With the exception of those cases, in which purulent or gangrenous disorganization and perforation result from a propagation of the disease from other tissues, this termination occurs under the following conditions: a. The peritonitis itself yields a purulent exudation, and the peritoneum is destroyed by suppuration, followed by the denudation and suppuration of the subjacent tissues. This occurs chiefly in partial, circumscribed peritonitis, when the exciting causes, viz., suppurative inflammation or gangrenous infiltration of an organ, accompanied by a purulent or ichorous discharge on the peritoneal surface, continue.

b. Occasionally a certain portion of a fibrinous exudation does not become organized, but being diffused through the interstices of the adventitious membrane, melts into a creamy pus, which, being in close contact with the latter, produces at once in it and in the peritoneum suppurative inflammation and suppuration.

In either case, ulcerative perforation of the intestine or of the abdominal parietes frequently proceeds from the morbid process in the peritoneum; and when, as is sometimes the case, both occur simultaneously, fistulae result.

Partial peritonitis in many cases appears to be a molimen naturae destined to circumscribe destructive processes, to arrest imminent or existing discharges which are hostile to the integrity of the peritoneum. To these belong, first of all, the circumscribed inflammations of the peritoneum, which take place in the vicinity of approaching or existing perforations of the stomach, the colon, the vermiform process, in the vicinity of purulent accumulations external to the peritoneum, threatening perforation and discharge into the peritoneal cavity, and the like. By this means, general peritonitis, and a consequent rapid and fatal termination are frequently postponed for a long time; yet, whilst the exciting cause continues, peritoneal phthisis, with its consecutive disorganization, must ensue; or the adhesions which limit the focus of inflammation give way, and, in consequence of the free discharge of its contents, general peritonitis follows, or this may take place without the occurrence first mentioned, in consequence of the violence and extent of the inflammatory process at the original seat of the disease.

Gangrene of the peritoneum occurs as a yellow slough, in consequence of pressure or traction caused by external or internal hernia, in consequence of its being deprived of the subserous cellular tissue where it overlays perforating ulcers of the intestines and abscesses; or as gangrenous disorganization and conversion into a blackish, moist, ragged, and friable tissue.