A Physiologic Consideration of the Sphincter of the Ductus Choledochus.

The presence of a sphincteric mechanism at the duodenal end of the common bile duct, in relation to the functioning of the biliary tract, has never been conclusively proved. More recently, in the light of newer studies upon the physiology of the gall bladder, it has been questioned. The muscle tone of the duodenum, together with the peristaltic waves of the gastro-intestinal tract have again been ascribed as essential factors in the flow of bile.

To determine whether or not there was a localized mechanism at the duodenal end of the common duct capable, upon stimulation, of stopping the flow of bile, the following series of experiments were performed. Under ether anesthesia, the biliary tract of a dog was exposed and a cannula inserted into the common duct with the point directed towards the duodenum; and the lower intra-mural portion of the duct was carefully dissected away as closely as possible from the wall of the duodenum. All tissue as nearly as could be determined with the naked eye, not of the duct itself, was carefully teased away. The cannula was then connected to a pressure bottle containing Ringer's solution, kept at a constant body temperature; while the intra-mural portion of the duct was carefully placed upon the points of an electrode. In this position Ringer's solution was allowed to pass through the duct and records were made, by both the drop and the pressure method, of the rate of flow of the fluid through the duct before, during, and after stimulation. A brief electrical stimulation applied to a restricted region of the intramural portion caused a stoppage of the flow of the fluicl through the duct, at pressures greater than the recorded pressure produced by the secretion of the liver, or the contraction of the gall bladder.