Four years ago, during an investigation of movements of the esophagus after total vagus section, I was struck by the difference between the primary and the secondary results of the operation. The primary result, seen during the first twenty-four hours after the esophagus is isolated from the central nervous system, is apparently a complete paralysis. Food, pushed onward by the still efficient cervical gullet, accumulates in a widely distending mass in the lower esophagus and may stagnate there for hours with no indication of any reaction of the encircling wall. In a few days, however, a remarkable recovery of function occurs in the lowest part of the tube, which is provided with smooth muscle. Contraction and peristalsis now appear in this region when food accumulates. An important factor for arousing these activities seems to be the stretching of the esophageal wall. For example, in the