The possible influence of distorted plasma and fluid composition of tissue on the recovery of damaged kidneys is of concern in the management of acute renal failure and has a distinct bearing on the application of extracorporeal dialysis in this condition. We sought in this study to evaluate the results of repeated hemodialysis applied to dogs rendered uremic by severe experimental renal damage. Renal ischemia produced by occlusion of the renal artery has been shown to produce a lesion resembling that of the so-called crush syndrome, described by Oliver as acute ischemuric tubular necrosis.1In our hands, three hours of arterial occlusion, associated with the division of capsular vessels and perirenal sympathectomy, was followed by the spontaneous recovery of function of the kidney so treated. Van Slyke has reported a similar experience.2Six hours of occlusion under these conditions was followed by almost total infarction of the kidney