Hypoglycemia manifests itself chiefly by symptoms due to disturbances of the autonomic and central nervous systems. In their monographs Sigwald1and Wilder2gave detailed descriptions of all neurologic and psychic symptoms to be noted during a hypoglycemic state, and it may be stated without hesitation that there is no neurologic or psychic abnormality which has not been observed either separately or in combination. Given susceptibility of the central nervous system to insulin, it is surprising that fatal damage of the central nervous system so seldom occurs in sufferers from diabetes treated with insulin. In 1932 Sigwald 1 gave short descriptions of 24 cases of fatal hypoglycemic coma known to him. In addition, Rathéry3reported a very instructive fatal case in 1938. Fortunately, however, the fatal cases are rare. The hypoglycemic symptoms as a rule disappear when the blood sugar has been raised to the normal level through