The surgical therapy of carcinoma of the biliary tract is fraught with difficulties. The proximity of the biliary tree to the hepatic blood supply has long presented a formidable barrier to successful extirpation. Carcinoma of the extrahepatic biliary tree may usually be seen and felt during explorative surgery, and, although the pathological features of these tumors often vary considerably from the commonly accepted conception of malignancy,1 the obstruction to bile flow usually is obvious and proper measures are instituted. When the tumor arises from the intrahepatic part of the bile ducts, and thus is not directly accessible to visualization and palpation, the problem of detection is added. The armamentarium available to the physician for establishing the diagnosis of obstructive, or surgical, versus parenchymatous, or medical, jaundice before operation is formidable but far from specific. Diverse conditions of the liver not amenable to surgery may present the same signs and