In the course of studies1 dealing with the physiology of the discharge of bile into the intestine, it was noted that a segment of duodenum which was completely isolated from the remainder of the gastrointestinal tract increased in activity following oral administration of food, although food or gastric secretion did not come in contact with it. Increase of duodenal secretion and vascularity of the segment were also noted. Because there was no mechanical distention or direct stimulation of this segment by food or gas, the increased activity must have arisen from a nervous or circulatory stimulus. To investigate these observations further, studies were made of the activity of various segments of small bowel, isolated from the remainder of the intestinal tract and sutured to the abdominal wall. These segments soon recovered a healthy appearance and gradually resumed activity. Such preparations permitted direct observations on the activity of these segments