In 1960, Belding Scribner introduced hemodialysis as a treatment for chronic renal failure. Now, 50 years later, it has become quite clear that while some features of uremia (acidosis, hyperkalemia, neurologic abnormalities, and uremia-related bone disease) are corrected or improved by hemodialysis, several important features of chronic renal failure (namely the greatly increased incidence of cardiovascular disease and the inexorable progression of renal scarring and loss of function) do not seem to be affected by hemodialysis. Perhaps the time has come to reexamine what we have learned about uremia during this half century. The ability to sustain life in patients with little or no renal function was a very great achievement, both technical and (with the recognition by Congress that the treatment of patients with chronic renal failure was a condition that could only be achieved with the financial support of the U.S. government), social (1). This legislation resulted in an explosion of biotechnology in this country. The development of new and better dialyzers and dialysis membranes with different qualities in regard to porosity and biologic reactivity became a major industry and was paralleled by the appearance and rapid proliferation of a new category of physicians—dialysis physicians joined the small ranks of Ode to the anglerfish