David Wilson, MD, Chief Resident, Department of Medicine, the Jewish Hospital of St. Louis, and Instructor in Medicine, Washington University School of Medicine: A 75-year-old man was hospitalized on Aug 20, 1972, for cystoscopy because of difficulty in urination. There were no systemic signs of infection, and the history was unremarkable. Results of the physical examination were within normal limits except that the prostate was enlarged and of benign consistency. On admission, complete blood cell count, blood chemistry determinations, and urine pH, glucose, and albumin values were normal. A few red and white blood cells were present on microscopic examination of urinary sediment. On Aug 21, the patient had urethral dilatation and cystoscopy, which suggested a diagnosis of benign prostatic hyperplasia. One week later, urethral dilatation was again performed, and bleeding, persisting for 24 hours, was noted around the catheter. A transurethral resection was performed on Sept 2. Hemostasis was