A VARIETY of theories have been propounded on the bile flow mechanism in man, none has gained prominence in the elucidation of the mechanism which, hence, still is a matter of concern to practicing physicians as well as to basic investigators in anatomy, physiology, and pharmacology. Ishioka1 in 1959 demonstrated difference in electrical activities between the muscle of Oddi and the duodenal wall muscle in rabbits, suggesting the former to be functionally independent of the latter. The ensuing electrophysiologic studies2,3 pursued at this department produced the results purporting that the bile flow into the duodenum essentially is controlled not so much by the duodenal peristalsis as by the sphincteric activity of the muscle of Oddi. Meanwhile, Tsushima,4 in his cinecholangiographic investigation in dogs, showed that the flow of bile into the duodenum ceases with peristaltic contraction and occurs with relaxation of the duodenum, but, on occasions, bile