The first duty of the pathological anatomist in this case, is to institute a comprehensive investigation of the local typhous processes, and we offer the results derived from the observation of normal ileo-typhus as it is presented in the indigenous form, which is commonly very defined in its localization. On account of the importance of the subject, we shall add a summary of the changes that occur in other systems and organs in typhus, as well as a synopsis of the more important anomalies of the typhous process, that we are at present acquainted with.

The Typhous Process in the Mucous Membrane of the Small

Intestine.

The typhous process of the small intestine presents four stages:

The congestive stage.

The stage of deposition of the typhous product, - of typhous infiltration; the crude stage of the deposit.

The stage of softening and rejection of the typhous deposit.

The stage of the genuine typhous ulcer.

In the first stage, which corresponds to the period of irritation with a predominance of catarrhal and gastric symptoms, we observe on the mucous membrane of the small intestine, dilatation and stasis in the venous system, with swelling, and a peculiar succulence of the mucous membrane, accompanied by opacity and slaty discoloration. The swelling of the villous layer is particularly distinct. This condition affects, more or less, the entire mucous membrane of the small intestine, but it developes itself more strongly at some parts than at others, and there generally appears to be a gradual increase from above downwards, as far as the caecal valve. The inner surface of the intestine is invested by a thick layer of dirty, yellow, gelatinous mucus.

The mesenteric glands are slightly swollen, their bloodvessels are injected, the tissue itself is elastic, soft and dark-colored.

In the second stage the congestion is diminished; the injection and reddening, and even the swelling of the mucous membrane, retract within circumscribed spaces which correspond with Peyer's agminated glands, or occasionally with solitary follicles. Rounded or more commonly elliptical tumefactions (plaques), varying in thickness from half a line to three lines, are formed, which result from the deposition of a peculiar substance in the tissue of the Peyerian plexus and of the submucous cellular tissue. They are surrounded by a vascular wreath which stops short at their circumference, and by a marginal plane which rises abruptly, or is contracted, so as to appear pediculated. In the latter case they the more resemble flat sessile fungi, as they often present an umbilical indentation at their centre. According to the amount of matter accumulated, the mucous membrane is more or less tense, being intimately blended with the deposit, as this again is firmly and immovably attached to the muscular coat of the intestines.

The typhous patches offer a gray or tawny discoloration, which is perceptible through the mucous membrane as well as through the two external coats of the intestine, and they are hard and resilient: when the discoloration is darker, and more of a bluish-red tint, they are softer and more compressible. They appear, when seen through the peritoneum, as insulated spots; they may be generally recognized by the varicose condition of the peritoneal vessels, and they are perceptible to the touch through the tumefaction on the external surface of the intestine.

The lower third of the small intestine is the common seat of typhous infiltration, and the typhous spots are placed at the side opposite to the insertion of the mesentery; they increase in number towards the caecal valve. They vary in size from that of a sixpence to half-a-crown; towards the terminal portion of the small intestine, in correspondence with the extensive glandular apparatus that exists here, they occupy a space of several inches, and end upon the ileal surface of the valve. Near and between the patches we find single, round, nodulated tumors of the size of a hempseed or pea, surrounded by a similar vascular wreath; these represent the typhous infiltration of a solitary follicle.

On minute examination of the morbid product, it proves to be deposited under the mucous membrane and in the submucous tissue, without involving the muscular coat. It presents a substance of more or less density, of a pale-red color and fibro-lardaceous texture; it is occasionally traversed by streaks of blood. The deposit very rarely extends beyond the follicular apparatus.

The swelling of the mesenteric glands also increases; they are of the size of a bean or hazelnut, blue or bluish-red, tolerably firm, and apparently infiltrated with a lardaceous mass.

The commencement of the third stage is marked by a return of violent congestion to the small intestine. The vessels, and especially the vains of the mesentery and their ramifications between the intestinal coats, are filled with dark-purple and viscid blood. The mucous membrane again swells, the villi in particular tumefy, and on pressure, exude a grayish-white opaque serum.

The most remarkable change is now effected in the typhous patches and in the mesenteric glands; they soften. The patches become more tumefied, and if the softening process does not affect them uniformly, they acquire an uneven tuberculated surface. The deposit is converted into a grayish-red medullary mass; this may, from the imbibition of bile, be at once metamorphosed into a dirty-yellow or brown slough, involving the investing mucous membrane. The slough shrivels up in a vertical and lateral direction, becoming loose at the edges and pultaceous, splitting in various directions, and detaching itself from the lowest stratum of submucous cellular tissue, by which means it is wholly or in part discharged; or the morbid product degenerates, when the epidemy is of very intense character, into a loose, vascular, fungous growth, which is traversed by streaks of extravasated blood, or is entirely saturated with blood; it is the chief source of profuse intestinal hemorrhages, and is generally discharged piecemeal without antecedent sloughing.