During the past two and one-half years we have treated thirteen cases of Addison's disease by means of the suprarenal cortical extract made according to the method of Swingle and Pfiffner. The diagnosis of each of these cases we have regarded as unequivocal. We have had seven deaths (table 1), and six of our patients are now living (table 2). All of the seven fatal cases have come to autopsy, and the clinical diagnosis of Addison's disease has in each been proved correct. Four were due to cortical atrophy. Of the three due to tuberculosis, case 1 (table 1) was the first one in which treatment was given, and in the light of our later experience, adequate amounts of extract were not administered. The other two patients had advanced tuberculous lesions elsewhere in the body which probably caused death. An earlier report appeared inThe Journala year ago.1