The frequent bowel movement in colitis is due not only to the irritation produced by the stagnation of fecal contents but to the fact that the contracted bowel relaxes at intervals and permits the passage of material which has been accumulated above it. When the bowel is completely contracted the obstruction is complete. In examining the patients suffering from colitis the writer has often noticed the complete relaxation of the bowel which but a few moments before was so contracted that it could be rolled under the finger like a piece of thick rubber tubing.

In catarrhal colitis, the stools may be either liquid, or composed of hard lumps somewhat resembling the feces of goats, or they may be mixed in character. The stools are sometimes quite watery in character, and may contain traces of blood. Patients often think that they are suffering from diarrhoea, on account of the frequent semi-liquid discharges. The cause of liquid stools is the irritation produced by the hardened and irritating feces. The irritation is not mechanical, however, but is due to the poisonous and irritating substances which are produced by the bacteria growing in the feces, in other words, by the putrefaction which is taking place.

In many cases there is a quite regular alternation of constipation and diarrhoea; the feces accumulate for several days, when the irritation becomes so great that by a profuse flow of serum and an abundant secretion of mucus occurs, the mass is softened, and temporary relief is obtained through the complete or partial unloading of the bowels by several soft stools.

This condition, which is usually associated with cumulative constipation, is often complicated by a latent constipation, which results from spastic contraction of the bowel. The most common seat of this contraction is the descending or pelvic colon; but it may often be noted in the transverse and ascending colon. In these cases, the autointoxication which is always present is more pronounced in degree, because of the more fluid character of the intestinal contents in the upper bowel. That the disease not infrequently extends to the whole colon is shown not only by the contracted condition of the ascending colon and even of the cecum, but also by the presence of masses of hardened feces which may be frequently felt in both these portions of the colon.

The ultimate effect of long-continued inflammation of the mucous membrane is the same in the colon as in the nose and other parts provided with a mucous lining. After a time, which varies according to the resistance of the individual and the intensity of the disease, degenerative changes occur in the mucous membrane; its glands disappear, and it becomes thin and parchment-like. The degeneration extends to the muscles which lie beneath the mucous membrane. The intestinal wall is thus thinned and weakened and loses its power of contractility to a large degree; it becomes distended and enlarged by gases and fecal accumulation, and thus the difficulty becomes greatly aggravated. In these cases, the colon, or at least the portion of it which is affected, becomes much like a distended bladder, losing a large part of its functions as a living muscular tube; it fails to respond to the nervous impulses by which the act of defecation is normally affected, and serves merely as a reservoir in which accumulate waste and remnants of undigested and undigestible foodstuffs, there to remain undergoing fermentation and putrefaction, developing offensive gases and irritating poisons, until removed from the body by some mechanical means. In these cases an essential part of the defecating mechanism is practically destroyed or rendered inoperative, and it becomes necessary to resort to mechanical means, as an enema of water or oil, for emptying the bowels. Lane and other surgeons have removed the colon in these cases, an operation which is doubtless sometimes necessary, although less often required than has been advocated by some, provided the patient can have the benefit of a complete regulation of the dietary, and will follow a suitable regimen.

The disastrous consequences which result from chronic catarrhal colitis are not confined to the colon. The disease often extends to the small intestine. In aggravated cases the accumulation in the cecum becomes so great that the ileocecal valve is dilated to such an extent that the contents of the cecum and small intestine intermingle. The very perfect valve arrangement provided by Nature at the junction of the small intestine with the colon, which is rendered still more effective by a sphincter muscle placed just above it, is evidently intended to prevent any possible return of matters from the colon to the small intestine. In the small intestine the presence of carbohydrates prevents the growth of putrefactive organisms, by encouraging the formation of acids. In the colon, however, especially when there is stasis or accumulation of fecal matters, the delay permits the complete absorption of starch and sugar, so that there is no material to encourage the acid-forming bacteria, and the poison-forming microbes, being unhindered, undergo rapid development, and greatly increase in virulence, finding always plenty of food material in the mucus, bile, and other intestinal secretions, as well as the larger or smaller quantities of food protein which remains undigested or unabsorbed. When these dangerous microbes are carried into the small intestine, they may continue to develop and gradually work their way up the intestine.

The cecum becomes dilated and distorted in shape, because of the weakening of its walls in consequence of the undue accumulation of its contents. The cecum may be so dilated and stretched that it is found far over toward the left side of the body, or lying deep down in the pelvis. The damaged ileocecal valve no longer controls the opening between the small intestine and the colon. The feces are no longer found exclusively in the colon. The small intestine may for several feet be filled with fecal matters of the consistency of putty, such as are normally found only in the transverse colon and beyond.

Putrefaction of the contents of the small intestine is a very much more serious matter than putrefaction in the colon, for the reason that the small intestine is much more richly supplied with absorbents, and is also less prepared to defend itself against the attacks of the virulent miscrobes which are always present in connection with putrefactive processes.

This infection of the small intestine with fecal matters introduces a whole series of troubles which unfold as the infection ascends along the intestine. The ascending infection finally reaches the duodenum, which not infrequently becomes the seat of a chronic catarrhal condition, the result of which may be ulceration. Observations of Moynihan and others have shown that duodenal ulcer is three or four times as frequent as ulcer of the stomach. Pain occurring three or four hours after meals is very frequently due to duodenal ulcer. From the duodenum, infection often travels through the bile ducts to the liver and the gall bladder. Chronic infection of the gall bladder and gall stones are thus developed. The infection may also ascend the pancreatic duct, which is closely associated with the bile duct, and may cause chronic inflammation of the pancreas, one of the results of which may be diabetes. From observations recently made respecting the causes of diabetes it is probable that inflammation of the pancreas arising in this way is among the most common causes of this disease. Observations made in the X-ray department of the Battle Creek Sanitarium indicate that the ileocecal valve is usually incompetent in diabetes. This is a most significant fact. The ileocecal valve protects the small intestine from infection; when it becomes incompetent, there is nothing to prevent the development of an ascending infectious process, which may bring about all of the conditions above mentioned.