The frequent recourse to surgery for disturbances in the function of the extrahepatic biliary tract makes imperative exact knowledge not only of the normal distribution of the bile ducts but of the variations occasionally encountered in this system. The literature contains frequent references to this fact, and many cases are reported of injuries to the biliary tract during operation on subjects in whom the arrangement of the bile ducts was atypical. Jacobson1 reported a case in which he severed the common bile duct during an operation for gallstones, because the cystic duct paralleled the hepatic duct for some distance. Many instances of similar accidents have been reported. Werelius2 and Ginsburg and Speese3 reported cases in which transection of the common duct had been caused entirely by an anomalous arrangement of the ducts. Stetten4 reported a case in which the hepatic duct was divided instead of the