Following the development of refined methods for studying various phases of kidney function, much progress has been made in the diagnosis and treatment of renal disease. Through functional procedures we are able to detect renal pathologic changes fairly early, to estimate the severity of the condition, and to study the course of the disease and the effect of therapeutic measures on it. Many problems in liver physiology, however, remain as yet obscure, and our studies in liver function have hitherto been of little value in diagnosis and prognosis and not at all adequate to indicate to us the severity of liver disease or the influence of treatment on it. For this reason we have, in the clinic, come to rely chiefly on symptoms and physical signs, often relatively late evidence, in the diagnosis of hepatic disease, and our therapy has been scanty and often empiric. An example of our lack