In 1928 Guttmann and List1reported on studies of the pathophysiologic and topographic conditions of sweat secretion. Since, there have been numerous publications and additional presonal experiences which warrant a new discussion of certain aspects of the problem. DIAGNOSTIC METHODS DEMONSTRATING CUTANEOUS SYMPATHETIC INNERVATION The ever increasing interest in the sympathetic nervous system has made it necessary to devise objective diagnostic methods which analyze its functions under normal and pathologic conditions. When one reviews the functions of the sympathetic nervous system one must admit that scarcely any adequate clinical methods have been devised to study the innervation of visceral organs. However, practical diagnostic methods are available for analysis of the sympathetic cutaneous innervation, namely (1) the vasomotor, (2) the pilomotor and (3) the sweating responses. 1. The study of vasomotor function affords only limited and indirect information. Not only are the vasomotor tests complicated and dependent on many factors