There are few chapters of wider interest in pathology than that of hypertension in its relation to cardiovascular-renal lesions, and particularly to hemorrhage of the brain. Traube1 (1856) first submitted important experimental evidence to show that increased blood pressure is a consequence of arteriosclerosis, and this was generally accepted till the end of the last century, when more accurate methods of recording the blood pressure were devised. These methods led to renewed interest in hypertension and its associated anatomic lesions. Subsequently, there appeared occasional records of cases of elevated blood pressure in which there was observed no demonstrable arteriosclerosis and no lesion of the kidneys or brain at autopsy. The results of investigation centered in two schools during the early part of this century. One expressed the belief that hypertension is secondary to local or general vascular disease; the other assumed that it is primary and independent of regressive