A Study of the Sensory Areas Eliciting the Swallowing Reflex

Since the introduction of the use of iodized oil by Sicard and Forestier in 1922 (1) in clinical medicine, extensive use has been made of this radio-opaque substance in accurately outlining the bronchial tree in the roent-genographic diagnosis of certain bronchopulmonic lesions. A number of different methods have been described and are in common use for the administration of this iodized oil, but perhaps one of the most satisfactory methods, because it obviates the use of the bronchoscope and other in-tratracheal instruments, is the one (2) by which the oil is allowed to descend supraglottically into the trachea, aided by gravity and aspiration, after the widespread application of cocaine to the pharyngeal regions. The well-known demonstration of the reflex character of the deglutory act and its dependence on afferent impulses from different areas in the mouth and pharynx by Wassilieff (3) naturally suggests that the administration of cocaine to the pharyngeal regions in the administration of lip-iodal owes its effectiveness to the depression or elimination of the swallowing reflex, and that this has been brought about by the paralysis of the sensory areas in the natural food passages. The considerable impetus that has been given to the use of iodized oil in studies of pulmonary diseases by the supraglottic method, has therefore aroused the question if there might not be a specific area, or a few limited areas, stimulation of which alone is uniformly responsible for inducing the swallowing reflex. A study undertaken lowing reflex is elicited to determine the relative ease with which the swal-from the various regions in the throat of man should possess not only general physiological interest but clinical significance as well. Should specific areas be found which are always responsible for the initiation of the swallowing reflex, the amount of cocainization could be greatly reduced. This would be a very desirable thing in view of the not infrequent occurrence of cocaine intoxication following the application of this drug to mucous surfaces. We wish to thank Dr. for suggesting this problem. As far as known no detailed observations on man have been made with reference to the most sensitive sites in the throat for inducing the swallow-36