In the course of nephritis severe acidosis may develop. Although all the usual evidences of acidosis are present, there is no increase in the ammonia of the urine. To this extent it differs from the acidosis resulting from the ingestion of strong mineral acids or from the overproduction of organic acids in the body such as beta-oxybutyric and aceto-acetic acids. Henderson and Palmer1 have pointed out that the titratable acidity of the urine in the acidosis of nephritis may be normal in amount though the total excretion of acid is low, due to "a never failing deficit in urinary ammonia." These observations would indicate that the acid responsible for the disturbance of the acid base equilibrium in nephritis is distinctly different in character from those acids causing acidosis in other conditions. We have previously demonstrated2 that an accumulation of inorganic phosphate occurs in the blood plasma of nephritics coincident with