IT has always been quite simple, with the aid of a thick barium mixture, to obtain satisfactory radiographs of the obstructed, or partially obstructed, esophagus, but the normal or unobstructed esophagus has presented a more difficult problem. In view of these difficulties, various devices have been instituted such as having the patient swallow the barium mixture while in the horizontal position or the more elaborate procedure of introducing a fish skin filled with barium into the esophagus. All of these methods having been productive of more or less indifferent and uncertain results, it occurred to us that there might be some procedure by which at least a partial voluntary control of the so-called “cardiac sphincter” could be brought about. With these thoughts in mind we set about accomplishing this result, with what, we feel, is a gratifying degree of success. From long experience in esophagoscopic examinations, one of us (E. B. F.) was forcibly impressed by the fact that, in almost every instance, while viewing the cardiac opening through the esophagoscope, it was seen to open and close rhythmically, synchronous with respiratory action. With this fact in mind, we set about making extensive fluoroscopic studies of the swallowing act, using a rather thick barium mixture. The subjects upon which these studies were made were persons who had never had the slightest suggestion of dysphagia or even a history of temporary cardiospasm. Of course, it is axiomatic that respirations must be suspended in order to accomplish the deglutitory act; also, it must be understood that all of these studies were made with the patient in the erect position. The results revealed some very interesting facts which may be briefly stated. 1. Barium swallowed at the end of a full forced inspiration passes at a leisurely rate through the cardia into the stomach. 2. Barium swallowed when respiration is suspended in the midst of a normal inspiration or expiration passes very rapidly through the esophagus and cardia in a thin stream, the organ itself being in a more or less collapsed condition. 3. Barium swallowed when respiration is momentarily suspended at the end of a forced expiration is held in the esophagus for several seconds and causes a rather remarkable dilatation of the organ, which, in some cases, is almost as marked as is seen in early cardiospasm. Of course, if too much fluid is swallowed, even following forced expiration, the temporary sphincteric action is overcome by sheer weight and volume and the whole mass rushes precipitously into the stomach. We have usually found that two or three moderate swallows of fluid were sufficient to produce the desired result and yet not enough to overcome the sphincteric action. Procedure.—Having completed our fluoroscopic studies, we proceeded to attempt to obtain satisfactory radiographs of the normal esophagus.