Various studies in connection with the physiology of the secretion of bile have clearly shown that bile is being secreted constantly. The passage of bile into the intestines, however, occurs at intervals; for the liver, unlike every other gland except the kidney, has in connection with it a reservoir, the gallbladder, in which the bile accumulates and from which it is only expelled periodically.
One must, therefore, clearly understand and distinguish the bilesecreting from the bile-expelling mechanism. Heretofore, investigators attempting to study these two phases of secretion and expulsion have limited themselves to the response obtained after oral administration of different foods and chemicals. With the aid of the dye method, which visualizes the gallbladder, one is able to demonstrate the rate of filling and emptying of this reservoir following the intake of various foods and drugs. It is difficult to tell, however, whether the flow of bile thus obtained