THE EFFECTS of gradual or incomplete occlusion of the renal arteries or their branches are not as well known as are those of sudden complete blockage of the arterial circulation. Whereas the latter situation leads to acute necrosis and, if enough renal parenchyma is destroyed, to death of the organism, lower degrees of arterial obstruction may permit survival of tissue elements but in time will lead to atrophy and other retrogressive changes. In a recent paper, Christofersen and Hirsch1 have called attention to this sequence of events which may result from a variety of pathological processes associated with gradual occlusion of intrinsic renal arteries. In such a kidney the nephrons decrease in size and ultimately revert to fetal characteristics. The loss of function of the atrophic nephrons leads to progressive renal failure and death in uremia.
One may postulate that the nephrons of a kidney in which the blood