In the first paper (1) of this series, the composition of the plasma was studied in cases of "acidosis" due chiefly to diarrhea and anhydremia. In contributing to the disturbances in the acid-base balance, the following factors were considered significant: (a) loss of BHCO3 from the plasma by way of the pancreatic and intestinal secretions and diarrheal stools; (b) functional renal insufficiency (depending presumably chiefly on anhydremia and oliguria) leading to diminished excretion of acid neutralized by ammonia, and consequent failure to support diminished plasma BHCO3, and (c) the excretion of BHCO3 as such into the urine during periods of increased osmotic pressure in the plasma due either to loss of plasma water resulting from diarrhea or to salt administration or both. Effective treatment of severe cases of acidosis of this type seemed to require alkali as well as water administration. Salt administration was considered contraindicated in the presence of high plasma chloride and low bicarbonate.In the second paper (2) the composition of the plasma in cases of nephritis was studied. It was concluded that when marked changes from the normal occurred in acute hemorrhagic nephritis, such symptoms as vomiting and diarrhea, edema and oliguria, and convulsions were responsible. In cases of chronic nephritis with renal damage, the characteristic plasma changes seemed due to a faulty secretion of urine, which led to a retention of phosphoric and sulfuric acid and a loss of plasma BCI and BHCO3. The resultant low electrolyte con-257