At this time there is considerable controversy throughout the surgical world regarding routine cholangiography on the operating table. There is, without doubt, an occasional need for such a procedure, which makes it justifiable for every large hospital to have the necessary equipment available. It is apparent, however, that the routine use of this method is a cumbersome and impracticable solution to the problem of diagnosis and treatment of stones in the biliary ducts. The illustrations which are here shown reveal a technique satisfactorily in use at the Massachusetts General Hospital for the past quarter of a century. That all methods of searching and flushing the ducts failed in many instances was due to the inability to remove stones hidden within the intrahepatic ramifications of the ductal system. Thus the late Czechoslovakian surgeon, J. Bakeš1 practicing in Vienna, conceived the idea of gradual instrumental dilatation of the papilla of Vater.