Summary1°It is experimentally demonstrated that by stopping the bile-flow from a great part of the liver to the bowel in pigs and rabbits no icterus is produced, and that this condition is compatible with normal life.2°Furthermore it is established that the bile (eventually produced in these obstructed parts of the liver) cannot possibly escape through intrahepatic anastomoses of bile ducts (or biliary ducts ?).3°The parts of the liver in which the bile flows freely, become hyper- functional and assume entirely the assimilation of bilirubine.4°Is was established that the parts with obstructed bile ducts undergo atrophy, while a compensatory hypertrophy occurs in those where the bile can5°It is likely that these facts apply equally to man.6 This aspect of hepatic physiology has its surgical applications :a) it is possible to ligature high up in the hepatic hilus and a branch can be used for plastic interventions on the common bileduct;b) anastomosis with one of the branches of the hepatic duct is a very satisfactory intervention;c) when circumstances require it absolutely, one is justified to sacrifice one branch of the hepatic duct.