The peritoneal coat presents, in the higher, and particularly in the highest degree of the affection, a dirty-gray discoloration, and a total absence of lustre; at intervals it presents a dilatation and injection of its capillary vessels, and is invested with a brownish, ichorous exudation; occasionally the meso-colon, and even the mesenteric laminae, that have been in contact with them, participate in the affection. This affords a means of distinguishing dysenteric disease of the intestine on its outer surface.

The glands of the meso-colon present a corresponding tumefaction; they are of a dark-blue color, congested and tumefied; but we have not succeeded in detecting in them a peculiar (specific) solid morbid product, as we have in typhus.

The mucous membrane of the colon is, as we have already observed, the seat of the dysenteric process; and we may state it as a rule, that its intensity increases from the caecal valve downwards, and consequently is met with, in the most fully-developed state, in the sigmoid flexure and in the rectum. It not unfrequently passes beyond the csecal valve, towards the ileum, but is here only seen in its mildest form.

It commonly runs an acute course, though it is frequently chronic in the milder degrees; this, however, does not materially alter its character.

The manner in which it terminates varies.

1. The disease is fatal, in consequence of the more or less rapid, or more or less penetrating destruction of tissue, and the coincident exhaustion.

2. The disease may terminate in cure, if the mucous membrane has not become disorganized in the manner above-described, the normal cohesion returning, and a new layer being generated under the desquamated epithelium.

3. In the higher degrees of the disease, when disorganization has occurred in one of the above-described processes, and the mucous membrane has suffered more or less extensive destruction, one of two results ensues:

'a. A real cure of the loss of substance, with consolidation of the abraded portions of the intestine follows; or, b. The entire process assumes a low chronic form, the specific nature of the disease is lost, and we have atonic inflammation and suppuration of the intestinal coats.

If a cure ensues, the portions of mucous membrane which were affected in a lower degree are first restored to their normal condition; between them are small patches, or more extensive spaces, with a sinuous circumference, at which the mucous membrane is deficient, and the submucous, pale, infiltrated cellular tissue is exposed. Not unfrequently we perceive detached remnants of mucous membrane adhering to these parts. The exposed submucous cellular tissue is gradually converted, as proved by cadaveric examinations at the most various periods after the cessation of dysentery, into serous tissue; this is further condensed into sero-fibrous tissue, and by it the sinuous portions of mucous membrane, at the edge of the impaired surface, are, like the isolated remnants of mucous membrane, compressed into warty, pediculated (polypous) prolongations, and thus the originally sinuous circumference obtains a fringed, dentated appearance. In cases in which the loss of substance is inconsiderable, the new tissue may contract so as to bring the edges of the mucous membrane into apposition with one another and with the polypous remnants of mucous membrane, and the cicatrix is then represented by a large number of agminated warty excrescences of the mucous membrane, between which the sero-fibrous basis from which they proceed, may be detected.

In cases of extensive destruction of substance, the approach of the edges is rendered impossible; the deeper layers of the tissue, which takes the place of the mucous membrane, is frequently condensed into fibrous bands, which form corded projections into the intestinal cavity, interlace with one another, and not unfrequently encroach upon the calibre of the intestine in the shape of valvular or annular folds, thus giving rise to a stricture in the colon of a very peculiar form. This mode of regeneration is the more remarkable, as it closely resembles that following the destruction of the oesophageal mucous membrane by mineral acids.

In the second case the specific affection terminates after having previously given rise to more or less extensive disorganization, but without being followed by the healing process just described. The entire disease now assumes a chronic character, and appears on the residual portion of mucous membrane as chronic catarrhal inflammation, the follicles being more or less prominently affected, and suppuration occurring in the shape of sinuses and abscesses under the mucous membrane, and between the external coats of the intestine; at the same time the intestinal canal contracts, its coats assume a rusty, dark-blue color; there is occasional exacerbation of the peritoneal irritation, and the intestine becomes fixed in consequence of exudation and infiltration in its cellular sheath and its mesentery. In this case the mucous membrane is found of a dull, red color, tumefied, and invested by a copious secretion of a glairy or purulent character; the follicles, particularly those at the end of the colon, are dilated, distended by a glassy pituita, or in a state of suppuration; there are small abscesses, of the size of a hemp-seed or pea, under the mucous membrane, and in the cellular tissue lying bet-ween the muscular fibres. These abscesses open upon the mucous membrane by the suppurating follicles or by other minute orifices, forming fistulous passages in various directions, and penetrating into deeper parts, so as to reach the peritoneum, and there induce inflammation; or they give rise, in the vicinity of the rectum, to the formation of large abscesses, as described by Mor-gagni.

The concurrent contraction of the intestinal tube probably causes in this case, also, a diminution of its calibre, but this form presents no peculiarity to distinguish it from the effect which may be produced in every case of catarrhal inflammation attended by repeated exacerbations. (Vide p. 60).

The dysenteric process occurs in its exquisite and primary form in the colon only, with the exception of the mucous membrane of the female sexual organs, where it affects the uterine mucous membrane in the shape of the puerperal disease.

The dysenteric process offers the greatest analogy to the corrosion of the mucous membrane produced by a caustic acid. The consequent destruction of the tissues, as well as the phenomena of reaction, present throughout a close resemblance in both cases, and the stricture produced in the oesophagus has no analogue but that resulting in the colon from the dysenteric affection.

We have found a further analogy with the dysenteric process in the erodent effect produced upon the mucous membrane of the oesophagus by the gastric juice in scirrhous stenosis of the pylorus.