These experiments indicate that, in dogs at least, ischemia localized to the kidneys is a sufficient condition for the production of persistently elevated systolic blood pressure. When the constriction of both main renal arteries is made only moderately severe in the beginning, the elevation of systolic blood pressure is unaccompanied by signs of materially decreased renal function. In this respect the hypertension in these animals resembles the hypertension which is associated with so called benign nephrosclerosis in man. Subsequent increase of the constriction of the main renal arteries does not materially damage renal function, probably because of adequate development of accessory circulation. More delicate methods for detecting a change may yet prove that some damage does occur. Almost complete constriction of both main renal arteries, from the beginning, results in great elevation of systolic blood pressure which is accompanied by severe disturbance of renal function and uremia. This resembles the type of hypertension which is associated with so called malignant nephrosclerosis, in the sense of Fahr (17). In several of the animals with persistent elevation of systolic blood pressure, anatomical changes were observed in the glomeruli, vessels and parenchyma of the kidneys which are most probably directly referable to the ischemia.

It is hoped that these investigations will afford a means of studying the pathogenesis of hypertension that is associated with renal vascular disease.