Independent of the degree of stricture, the degenerated portion of the intestine, owing to the adventitious growth deposited in the submucous tissue, and still more from the consequent disorganization of the muscular coat, is in a completely passive condition. The propulsion of the faeces through this portion is therefore effected by the muscular activity of the higher part of the intestine, even when the lateral position of the disease allows of dilatation. The more considerable the stricture, or the more extensive the growth, and the more copious the feculent accumulation, the more will this activity be called into play.

The contents of the intestine necessarily stagnate and accumulate in that portion which lies immediately above the diseased point, and dilate it. If the dilatation is effected suddenly, paralysis at once ensues; otherwise the accumulated masses, a certain portion of which are only propelled through the degenerated section of the intestine, give rise to reaction, hypertrophy of the membranes follows, and as these influences increase, gradual exhaustion and paralysis result. This paralyzed portion of intestine is the proximate cause of the supervening ileus. As soon as the faeces have accumulated within it to such an extent as to reach the adjacent sound portion of intestine, the latter undertakes their discharge. Its capability of effecting this will diminish in proportion to the amount of accumulation, and to the contraction of the stricture. The consequence is, that the peristaltic action is reversed, and that the antiperistaltic movement conveys the intestinal contents to the stomach, from which they are ejected by vomiting.

The coexistent intestinal inflammation, which commonly occurs as general peritonitis, also has a share in the process. It commences at that point immediately above the stricture, which has become most dilated by the accumulated contents, and it is there most intense. This portion of intestine presents a dark-blue or blackish-red discoloration, with a tinge of brown or green; its coats are infiltrated with blood; the peritoneal investment, which is covered with a dirty-green or brownish exudation, is easily detached; the muscular coat is discolored and friable; the mucous membrane, owing to its distension, is devoid of plicae, villi, or follicles; dark-red, distended at some parts with coagula, and sloughy. Sometimes all the intestinal coats are perforated at these points, and there is consequently an extravasation of the intestinal contents into the abdominal cavity.

The inflammation extends from this portion of the intestine upwards, and is followed, pari passu, by paralysis. It passes from the intestine to the mesenteries, to the omentum, and to the parietal laminae of the peritoneum.

In some cases the inflammation is the result of irritation existing in the morbid product, which is transferred to the peritoneum, and causes paralysis of the muscular coat above the stricture, dilatation of the intestine and ileus.

It follows that, to appreciate the causes of ileus arising from scirrhous strictures of the intestine correctly, we must take into consideration:

Firstly; the absolute degree of stricture.

Secondly; the degree of attachment of the affected portion of intestine, with or without dislocation and inflection.

Thirdly; the degree of the consecutive affection of the part above the stricture.

Fourthly; the degree of the inflammation present.