Abstract
It seems that a Chairman of this Section, in his address, has the prerogative of choosing whether he wishes to present scientific or clinical observations; to discuss philosophic attitudes in medical practice; aspects of medical education, undergraduate or graduate; or historical matters related to internal medicine. I have chosen to use my allotted time for the posing of several speculative questions about an intriguing group of diseases. Though I will provide no answers, it is my hope that these questions will help the clinician to keep an open mind and make him hesitate in accepting and acting upon a rigid set of criteria for certain apparent clinical entities. As the problems of episodic medicine, in the main acute infectious disease, have become more or less resolved by chemotherapy, attention has been directed to illnesses having a progressive and prolonged clinical course. Among these have appeared an apparently ever-increasing number of