IN 1931, I performed an autopsy on a five-month-old baby who had had wheezing respirations since birth and had recently developed difficulty in swallowing. At this examination a ring of blood vessels was found encircling the intrathoracic portion of the esophagus and trachea in such a way that the esophagus was indented from behind, whereas the trachea was compressed on its anterior surface. The pathological findings at once suggested that a division of some part of the so-called "vascular ring" during life would probably have relieved the pressure on the constricted esophagus and trachea.The above-mentioned case aroused my curiosity, . . .