It is coming to be realized that bacterial infection of the kidneys—pyelonephritis—plays an important role in initiating and continuing pathologic processes which can result in death by uremia and also that many of these cases are first seen by the internist as arteriosclerotic, cardiovascular renal disease and hypertension. A definite etiologic factor is thus injected into a percentage of the large group of diseases classed as degenerative. This places before medicine the theoretical possibility of diagnosing and curing bacterial infection of the kidneys in the early stage. In the late stage it appears to be impossible to change the trend of these pathologic processes. Longcope and Winkenwerder1in 1933 and Longcope2in 1937 stressed the destructive effects of pyelonephritis on the functional efficiency of the kidneys. They reported 22 cases in which the age varied from 15 to 58 years and nonobstructive pyelonephritis had been present for periods