PRONOUNCED interference with the bile flow is, as a rule, characteristic of extrahepatic biliary obstruction, usually of mechanical character, caused by stones, strictures and tumors. Hence surgical intervention is usually considered in cases of such nature. Only rarely is an intrahepatic mechanical obstruction of the larger bile ducts encountered. In contrast to earlier belief, however, interference with bile flow is met not uncommonly in cases of primary hepatitis in the acute or chronic stage. This interference may present complete biliary obstruction characterized by absence of bile from the duodenum and consequent lack of urobilinogen in the urine. In cases of primary hepatitis the phenomenon has been called intrahepatic biliary obstruction, and it has been the subject of several descriptive analyses.1 Various hypotheses as to the pathogenesis of this phenomenon have been presented.2 Recently, Watson and Hoffbauer3 described cases of temporary exclusion of bile from the duodenum in