This occurs most commonly in oxen from obstruction of the urethra by a calculus. Similar obstruction in the horse causes most acute symptoms, calling for immediate relief, and rupture is a comparatively rare occurrence. Pench mentions a case resulting from a fall during an attack of colic, and with a full bladder. It has happened during lithotrity, or lithotomy, and even during parturition. Perforation by parasites has been noted and in one case by an osseous tumor of the pubic symphysis. In horses a fatal result is prompt, in cattle from 6 to 48 days. Treatment surgical. EVERSION OF THE BLADDER. This is really invagination into the female urethra and bladder. It has only been seen in mares, and then by reason of the extreme dilatability of the urethra. A pyriform, red, perhaps rugose tumor shows between the lips of the vulva, during straining. It is covered by mucosa, and on its upper surface near to its neck are two small orifices from which urine oozes or comes in jets during active expulsive efforts. It soon becomes muco-purulent on the surface, and even excoriated. Urine escaping continuously trickles down the thighs with much fœtor. It occurs especially during violent expulsive efforts as in parturition or constipation. _Treatment_ essentially surgical consists in uniform compression to expel blood and exudate followed by the pushing of the fundus through the bladder and urethra. The more recent the case, the easier is the process. Pressecq claims to have cured an obstinately recurring case, by cauterizing the urethra up to the cervix vesicæ with a round iron rod an inch in diameter. The resulting loss of substance, with the neoplasia and constriction effectually prevented renewed eversion even during parturition. Other veterinarians have successfully excised the bladder, but this entailed incontinence and constant offensive soaking of the thighs with urine. HERNIA OF THE BLADDER. This is commonly seen in the mammalian female in connection with rupture of the floor of the vagina during dystokia. It has also been observed without such lesion in both male and female dogs and horses, the bladder forming a cystocele of the vagina, or bulging between the anus and the ischium. _Diagnosis_ is confirmed by careful palpation through the rectum. The folding of the bladder backward obstructs the exit of urine. _Treatment_, essentially surgical, might include replacing of the organ and suturing of the wound, or, in the absence of a wound, evacuation of the bladder by a hypodermic needle, and replacing by palpation through the vagina or rectum. Sometimes suture of the vulva is desirable. ANOMALIES OF THE BLADDER. =Persistent urachus.= Seen in the new born and mainly in males. Antiseptic closure is essential after having ascertained that the urethra is pervious.