Abstract
Hypertension, particularity hyperplasia or "essential" hypertension, has plagued clinicians and scientists alike since medical observation first determined that an elevated blood pressure was not inseparably associated with nephritis and arteriosclerosis. But as F.D. Murphy states (1): | "Despite the progidious literature and extensive research en the subject*—the etiology, pathogenesis, and clinical course are not known with any certainty, (and) the treatment is still empirical. We are in a paradoxical situation, for, even though we have more knowledge, we still have little clear understanding." | That is the essence of our present day knowledge of hypertension. Throughout the world groups are intensively studying the problem each arriving at different answers or shades of different meanings of the same answer. Most of the work in the past two decades has been in observing experimentally produced or clinical diagnosed hypertension. An ever increasing minority of workers, however, are attempting to produce the picture in normal normotensive experimental animals without the aid of drugs or surgical procedures. In short they are trying to determine what physiological or physio—chemical alterations occur in a normotensive animal or human that will make his blood pressure rise temporarily or especially permanently.