Occasionally it happens that inflammation of the mucous membrane ,of the bladder pro-_ ceeds to gangrene, which is characterised by a change in the volume of the hypogastric tu mour, supposing the organ to be distended, the cessation of pain, the sudden prostration of the vital powers, the complete suppression of the flow of urine, the excessive distention of the bladder and the ureters, and sometimes by the escape of urine by the umbilicus;'" more frequently, however, by the rupture of the organ and the .extravasation of its contents into the abdominal or pelvic cavity. In cases which are a consequence of retention, the gan grenous points may be presented either at the fundus or at the summit of the organ hut most commonly the affection is a consequence of the irritation or pressure made upon the bladder by a foreign body, and in these the point implicated is that upon which the body has directly exercised its influence. When we examine the mucous surface of an organ so affected, we discover that the disease exists under two distinct forms, the diffuse and the circumscribed ; but the latter of the two forms is not often witnessed except as a consequence of local violence. Dr. Carswell, however, bears testimony to its occasional existence ; he states that the congestion is extreme, and often ac companied by hemorrhage, which gives to the membrane a uniform deep red colour. More over, dark brown or black patches are found to occupy portions of various extent of the mucous membrane, which, as well as the submucous tissue, is easily torn, and other portions of this membrane are seen partially detached, and converted into a soft spongy substance having a strong gangrenous odour. In the circumscribed form of gangrene, we sometimes see a number of black eschars, which are soft and nearly putrid : sometimes greyish pulpy points are presented, which appear to implicate only the mucous tunic, but in the greater number of cases we see the different stages of their progress ; they are at first whitish, they then become yellowish, grey, slate colour or brown, and blackish ; but these changes are much more marked when the organ has been subjected for a short time to the action of the atmosphere. Where the whole of the parietes are involved, the eschar is characterised by a greyish slaty tint. These eschars are frequently confounded with the violet or brown portions or patches by which they are surrounded ; these latter are simply extreme congestion, bordering, it is true, upon gangrene, but susceptible of being restored to a healthy state, whilst the death of the other points is inevitable.
When acute inflammation affects the mus cular tunic of the bladder, the organ usually becomes strongly contracted, and the parietes present an appearance of considerable thicken ing; at the same time pus is commonly in filtrated through the tissue, or it is circum scribed into the form of abscess ; the tunic is then of a dark red colour and strongly in jected. In a case which was seen by Gendrin, where the patient refused to submit to the operation for stone, the internal tunic was ulcerated and of a red-brown colour; the mus cular tunic was more than half an inch in thickness, and contained two abscesses, each of the size of a small nut. Velpeau saw in a patient who had died of a diarrhoea, the blad der reduced to the size of a small fist; it was hard and elastic ; its parietes were more than an inch thick. In the cases described by Martin Ripaux, Molat, Maret, and Berard;* the mucous membrane was not in any way implicated, the hypertrophy being entirely limited to the muscular tunic. In these cases
the bladder was reduced to very small dimen sions, and the mucous coat made many pro jections into the cavity; the summit of these projections was red and vascular. It is not unlikely but that it may be owing to the excess of extent of the mucous over the contracted muscular tissue in such cases, that the former so easily becomes engaged in the formation of appendices. The muscular tunic may be much increased in thickness in the absence of acute or even chronic inflammation of the organ ; any irritation by which a frequent con traction of the organ may be excited will most probably produce a great increase of thickness of this tunic. Among these causes we may range the existence of fistula or calculi in time organ. Sometimes the thickening is limited to the mucous tunic. M. Portal, in examining the bladder of an old man, the parietes of the organ being eight or nine lines in thickness, found the internal tunic like cartilage, and that this was the only tunic which had acquired an increase of substance ; the peritoneal tunic was in its natural state, the muscular scarcely apparent. Chopart made a similar remark with regard to the bladder of an adult. Mor gagni mentions a like Instead of either of the modifications which have been described, acute cystitis may dege nerate into a chronic form of the disease. This form of the affection does not commonly succeed to a single and simple attack of the acute affection ; almost always there will have been sundry recurrences of the acute form before this degeneration takes place. Most frequently chronic cystitis occurs without hav ing the acute disease as a precursor, and it is upon chronic inflammation that extensive dis organisations of the various tissues of the eco nomy are mainly dependent; and the altera tions of texture in the parietes of the bladder are, therefore, most commonly produced by its agency.
In such cases we may see the mucous mem brane of an uniformly dark violet colour, thick ened and unyielding, the organ so contracted as to present only a very small undilatable cavity, incapable of containing more than a few drams of fluid. Fungous excrescences are sometimes developed upon its internal surface, especially in the vicinity of the neck. In some cases ulcerations will be found to have destroyed the muscular tunic and pene trated to the peritoneum ; in others, the mucous follicles present a most exaggerated development, communicating to the membrane a considerable increase of thickness, but with out change of colour. In other cases, the muscular tunic having acted with increased energy, its fibres have become more volumi nous and project into the interior of the organ in the form of columns, between which the mucous membrane sometimes forms what is termed hernia? But the more ordinary consequence of chronic inflammation of this organ consists in the thickening and more or less uniform induration of the vesical pa rietes. The tissue of the bladder is then con verted into a homogeneous, lardaceous sub stance, similar in appearance to that of the un impregnated uterus; the vessels which surround the organ are dilated, varicose, and form on the external surface considerable plexuses, which attest the long existence of its excitation, and the continuance of the afflux of blood of which it has been the seat.