The two cases here reported are published because it appears that Dr. Hugh Williams' case is the first successful transplantation into the duodenum of a common duct fistula; that my case is the second, and that the method is of sufficient simplicity and value to be included in the group of operative procedures available in the treatment of common duct fistula. REPORT OF CASES Case 1. —G. E. M., aged 5 years, white, was operated on, Sept. 3, 1912, at Massachusetts General Hospital. The preoperative diagnosis was embryonic tumor of the right kidney. A large retroperitoneal cyst was found but not identified. It was sutured to the abdominal wall. A section of the cyst submitted to the pathologist was reported as suggestive of chronic inflammation of the gallbladder. The patient was discharged from the hospital, November 23, with a diagnosis of cyst of the biliary tract. He reentered the hospital,