In the cases where the injury to a ureter has been overlooked in the course of the operation many difficulties arise before the true conditions are appreciated. In some instances they soon become obvious; for example, Purcell in 1898 performed an abdominal hysterectomy, next day the patient had complete anuria. The abdomen was reopened fifty-eight hours later; a distended ureter was easily recognized behind the ligatures applied to the right and left uterine artery respectively. The ligatures were removed, the swelling quickly subsided, and urine reached the bladder. The woman recovered. When a ureter is injured in the performance of total hysterectomy, urine escapes by the vagina, and at first there may be some doubt whether the leak is due to an injury to the bladder or to the ureter. In such conditions the quantity of urine voided from the bladder is compared with that which escapes from the vagina; if the quantities are equal, or nearly equal, the leak is in a ureter. A more reliable method is to inject a solution of methylene blue into the bladder through the urethra. If the coloured fluid escapes from the vagina, the leak is in the bladder; if not, it is in the ureter. When a vaginal leakage occurs a few days after a vaginal hysterectomy, it is probably due to necrosis and sloughing of a ureter, or the duct may have been included in a ligature which has separated by sloughing. Noble, in 1902, published an interesting series of injuries to the ureter. One of these is of great value, because it proves that a ureter may be accidentally ligatured and give rise to no symptoms. A woman of thirty-three years of age was submitted to vaginal hysterectomy for cancer of the neck of the uterus, complicated with pregnancy. She died four days after the operation, and at the post-mortem examination the left ureter was found occluded with a ligature. The ureter and pelvis of the kidney were distended with urine. The urine voided during the four days amounted on the first day to 480 c.c. (16 oz.); second day, 780 c.c. (26 oz.); third day, 1,440 c.c. (48 oz.); fourth day, 960 c.c. (32 oz.). These quantities would lull suspicion in regard to any patient, but the facts of the case are sufficient to raise suspicions of another kind, namely, that it is possible and probable that a ureter has been ligatured in the course of an operation, and the patient has recovered without any one having any suspicion that such an accident has happened.