The thickness and consistency of the hemorrhagic exudation are proportioned to the quantity and plastic properties of the fibrin it contains: it forms a peripheral coagulum, which cleaves to the walls of the serous cavity, and may contain more or less coloring matter, or may be white. The red fluid effusion is enclosed within the peripheral coagulum, and out of it further plastic ingredients are precipitated. These ingredients in process of time, are converted into a very tough leather-like layer, which undergoes very little or no organization; the fluid effusion gradually assumes a chocolate-brown, a plum-sauce, or a yeast-yellow color, and becomes fatty and glutinous; while the substance precipitated from it degenerates into a loose pulp of the same color; or it deposits its coloring matter, and becomes a clear serous fluid.

The hemorrhagic effusion is but rarely absorbed, and with much difficulty when it is. The reason of this difficulty is sometimes the continuance of a chronic inflammation, and the frequent coexistence of tubercle with it, in the stratum from which it was poured out, and sometimes the density, the impermeability, and the extremely incomplete organization, of the plastic layer that surrounds it. When it occurs on large serous membranes, it usually proves rapidly fatal by the exhaustion it produces, or by its interfering with the function of important organs; and the more rapidly in proportion to the amount of general disease that coexists with it. It is, however, sometimes borne for a long period, and under favorable general and local circumstances it may be diminished by absorption. If, in the most favorable case, it happen, that the fluid is completely removed and the peripheral laminae are agglutinated to one another, a rust-colored, or yeast-yellow layer is found interposed between them. In the peritoneum chiefly, and more particularly on that part which belongs to the intestinal canal, the plastic layers of the hemorrhagic exudation acquire a bluish color, and after a time the color of Indian ink (melanosis stratiformis). No doubt the discoloration is owing to the action of the intestinal gas.

In course of time, the fibroid exudations frequently become the seat of calcareous deposition; and yellow, grayish, or dirty white, cheesy masses of various sizes are not unfrequently found in the cellular, as well as in the fibroid, layers of exudation. They are portions of plastic exudation which have not been organized; degenerate fibrin, which, either decaying further and becoming puriform, excites inflammation and actual suppuration and ulceration in the neighboring tissues, or else changes into a chalky concretion.

The termination of inflammation of serous membranes in suppuration has been already considered.

Sloughing or necrosis of serous tissue is very rarely met with as a consequence, or degeneration, of an inflammatory process, but it frequently results from the membrane being stripped of its subserous tissue, when that has been destroyed by suppuration or sloughing; or from pressure, stretching, or strangulation of the membrane; or when adjoining structures are also sloughing, or have become gangrenous some time previously, as in the instance of gangrene of the lung. Sloughy serous tissue forms a dirty yellowish, or a whitish, soft eschar, as is seen in the case of perforating ulcers of the stomach or intestines, or of strangulated hernise; or else it is a loose shreddy, grayish, or blackish-brown, moist, infiltrated and pulpy mass, which is traversed by a dirty white thready tissue; it has the odor peculiar to slough.

The termination of inflammation in tuberculosis, or rather the metamorphosis of its product into tubercle, will be considered presently.

The state of the tissue beneath the serous membrane during inflammation is a point of considerable practical importance. The condition of the subserous cellular tissue, as has been already mentioned, is an integral part of the whole process. The more intense the inflammation is, and the longer it continues, so much the more do that and the adjoining tissues take part in it. Inflammatory products of various kinds are deposited in all of them, and become infiltrated, or give rise to diffused or circumscribed suppuration, or to chronic, and very considerable, thickening. The most important part is that which is taken by adjoining fibrous tissues, whether aponeuroses, capsules, or ligaments. Another remarkable fact is, that the tissues lose their vital contractility: muscles, under such circumstances, become paralyzed and lose their color. Very intense and chronic inflammation leads at last to atrophy of the subserous structures, partly by the change of texture which is produced by the inflammation, and partly in consequence of their protracted palsy. The viscera contained within an inflamed serous sac are displaced and compressed to a degree and extent corresponding to the quantity and the position of the exudation; and when this is long continued, they undergo various changes of texture, which may be included generally in the terms atrophy, obsolescence, obliteration.

Whichever of the forms that have been described the inflammation assume, it may be general in its extent, or only partial and circumscribed. It is remarkable to observe, that usually - though there are various exceptions to this rule - the parietal layer of serous sacs suffers more than the visceral, and that, therefore, the plastic exudations on it are the thicker.