When in the year 1917 Dr. Wagner-Jauregg, Chief of the Psychiatric Clinic of Vienna, inoculated nine patients suffering from general paralysis with the blood of a case of benign tertian malaria, he was only testing a theory he had formed many years previously. In the interval he had been treating his cases of general paralysis by injections of tuberculin, typhus vaccine, etc., and with encouraging results. Remissions produced by these efforts were more frequent and more lasting than those which occurred in untreated cases, but a lasting remission only rarely followed.