| suppurative; | Acute----| diphtheritic; 1. Cystitis mucosa | | gangrenous. | | Chronic--| catarrhal; | membranous. 2. Interstitial cystitis, where the muscular coat of the bladder is involved. 3. Peri-cystitis, para-cystitis, where the peritoneal surface or surrounding structures are inflamed. This short section upon a surgical subject, only being granted a few pages in a medical work, cannot include a description of all these conditions, or more than a general outline of acute and chronic catarrhal cystitis. Suffice it to say for the other varieties that interstitial cystitis depends upon mucous cystitis or peri-cystitis, and is an inflammation of the muscular coat of the bladder, sometimes culminating in abscess, sometimes in concentric hypertrophy--_i.e._ contracture of the bladder. Peri-cystitis and para-cystitis occur in connection with peritonitis and pelvic cellulitis, and the peripheral inflammation may extend inward and involve the muscular and later the mucous coat. {124} All these conditions are grave only in proportion to the intensity of the malady causing them and to which they are subordinate. Gangrenous cystitis occurs after injury, and occasionally in profound septicæmic conditions (puerperal) or after intense cantharidal poisoning. It is fatal. True diphtheria of the bladder occasionally, but very rarely, accompanies general diphtheritic conditions, and is a very grave malady. Membranous cystitis is less grave, may be partial or complete. I have a fibrinous cast of a female bladder which was extruded through the meatus. This malady occurs sometimes as a late complication of advanced chronic cystitis mucosa in the male. Recovery is quite possible. Cystitis mucosa is a common disorder, constantly encountered by the physician as well as the surgeon. The irritable bladder, sometimes called cystitis, demands description here, as it may go on to become subacute or even acute cystitis of the vesical neck. Irritability of the bladder is a neurotic and not an inflammatory condition, although it may lead to the latter state and terminate in it. The bladder is said to be irritable when the calls to urinate are too frequent, generally with little or no pain. As a rule, the urine is clear, containing no pus or a quantity entirely disproportionate to the frequency of the call to urinate. In true irritability of the bladder the patient sleeps all night, although he may have to empty his bladder every hour or two by day. There is sometimes a sense of weight, heat, or throbbing, more or less intense, in the perineum; the desire to urinate is normal but imperious; the satisfaction after the act is complete, and no pain accompanies its performance.