_Lesions._ Hyperæmia of the cystic mucosa, with dilation and tortuous deviations of the larger vessels, thickening of the membrane, and distension and clouding of the epithelial cells, with a thick covering of tenacious mucus containing epithelial, pus, or white blood cells. As the disease advances epithelium is desquamated abundantly, and degenerates with production of free nuclei and pus. Along with these are microbes, usually the bacillus coli communis, and various cocci. In the fully established disease there is liable to be alkaline fermentation, and the liberated ammonia dissolves the epithelial cells, leading to extensive desquamation and raw granulating surfaces, so that the disease tends to run in a vitiating circle, the alkali dissolving the epithelium and increasing the microbian development and fermentation, which in its turn produces an increasing quantity of ammonia. _Symptoms._ There is slight hyperthermia or none, stiff or straddling gait, frequent passage of urine in small quantities and cloudy, or straining without passage, the penis or clitoris is semi-erect, eversion of the lips of the vulva is frequent, and the bladder is tender (through prepubian wall, vagina or rectum). If a finger is inserted into the bladder in the mare the thickening of the walls can often be recognized. The urine often contains precipitated crystals of ammonio-magnesian phosphate, and even clots of blood. It has an alkaline reaction even in herbivora. _Treatment._ The danger centres around the bacteridian fermentations, and a main object must be to disinfect the bladder. This will be all the more effectual if the lotions used are of an acid reaction. Thus boric acid or salicylic acid in 3 per cent. solution, injected after evacuation of the bladder and repeated a number of times a day may soon establish a healthy action. If the bladder is especially irritable a boiled weak solution of gum arabic will form a suitable medium. Other antiseptics are often used as creosote (0.5:100), carbolic acid (3:100), chloride of zinc (3:100), chlorate of potash (3:100), mercuric chloride (1:5000), silver nitrate (0.5:100), or astringents are often better: PbA, ZnSO_{4} tannic acid, ferri chloridi in dilute solution so as not to cause pain. The bowels should be kept open by an occasional saline laxative, pain moderated by codeine, and abundance of pure water and a laxative diet enjoined. Linseed tea, and infusions of slippery elm or marsh mallow have long been employed, and by soothing and relaxing the bowels they act favorably on the urinary mucosa. Stimulants of the urinary track like buchu, uva ursi or copaiba in small doses, or antiseptics like creosote, boric acid, salicylic acid, piperazine, are available in slight cases or when the acute symptoms have subsided somewhat. With prior infection of the kidneys, the latter may be used. Constant drainage may be necessary to avoid distension.