There is an old aphorism that every successful research project raises more questions than it answers. Since dialysis for chronic uremia involves the application of dramatic techniques to terminal patients in an emotionally charged atmosphere requiring the mobilization of great scientific and material resources, it is hardly unexpected that a host of problems have arisen. General questions have ranged from "can it be done" to "should it be done" and "will it be done." Having addressed ourselves to the clinical, methodological, and biochemical experiences of the chronic dialysis program, it seems natural to consider here, at least briefly, the related