1. We have not observed gross increases in plasma volume in glomerulonephritis, nephrosis, or nephrosclerosis, even when the concentration of plasma proteins was much below normal. Our results indicate the probability that "hydremic plethora" does not occur.
2. The low protein concentration frequently observed in the plasma in nephritis is not due to increased plasma volume but to a decrease of the total amount of plasma protein in the body.
3. Changes in plasma volume showed no constant relationship to changes in edema.