Considerable confusion exists at the present time as to the pathologic and the physiologic mechanism involved in inflammatory processes in the gallbladder. These difficulties have been reflected in the wide divergence of opinion relative to the treatment of these inflammatory processes in various stages. Efforts directed at the solution of the problem by clinical statistical methods have apparently added more to the confusion than to the clarification of opinion. The following studies are based on an attempt to approach a better understanding of the subject by experimental and clinical analysis of the pathologic factors involved. Any explanation of the pathogenesis of cholecystitis must take account of many unique features by which cholecystitis differs from most inflammations elsewhere in the body. These features present themselves both clinically and pathologically. In the clinical picture of cholecystitis there are many characteristics that are unusual when compared with inflammation in other organs. It is