The incidence of esophagitis, in comparison to other diseases, has always been comparatively small. Nevertheless, there has been observed at postmortem examinations at the Mayo Clinic during the past few years an apparent increase in the incidence of inflammation involving the esophagus. The purpose of our inquiry was to determine whether there has been a real increase in the incidence of esophagitis, to study the nature of the condition and, if possible, to ascertain the factor or factors responsible for this increase, apparent or real.
EMBRYOLOGY
In the 4.2 mm. embryo, according to Prentiss1 (1922), the foregut is differentiated into the pharynx, trachea, lungs, esophagus, stomach, small gut and digestive glands (liver and pancreas).
In about the 6 mm. pig embryo the bronchial arches converge caudad, and the pharyngeal pouch narrows rapidly and is differentiated into the trachea and esophagus. Soon the trachea separates from the esophagus, and