As a result of the original concepts of Volhard and Fahr,1a malignant (bösartig) form of hypertension was separated from the general group in 1914. In 1924, however, Wagener and Keith2described a syndrome of malignant hypertension and showed that this condition deserves the distinction of an entity, differing from chronic glomerulitis and benign hypertension on the basis of age incidence, a characteristic retinal picture, absence of anemia and frequent persistence of adequate renal function. This clinical concept of Wagener and Keith was further developed in investigations at the Mayo Clinic, the results of which were published in 1927,31928,41929,5and 1931,6and various pathologic studies of this disease have been reported from this institution by Cain,7Morlock8and Odel.9None of these works included any comprehensive data regarding the brain. The purpose of the present study has been to survey the brain in cases of malignant hypertension, to