In investigating the mechanism of edema formation, we have made a study of the relations of sodium and potassium to the water in muscles of animals suffering from nutritional edema, in order to learn whether these relations provide evidence as to the validity of the hypothesis that fluid retention associated with hypoproteinemia is simply an accumulation of an ultrafiltrate from the circulating plasma. These relations might also indicate whether sodium has any role in the production of edema other than that of being the chief base of plasma filtrate, this question having been often raised by the observed necessity of ingested sodium for the formation of experimental plasmapheresis edemas in dogs (1, 2, 3), and for the occurrence of nutritional (4) and nephrotic (5) edemas in man. A nutritional edema in white rats resulting from a protein-poor carrot diet (6, 7) and shown to be accompanied by low serum proteins (8, 9) was decided upon as a practical experimental setting for the problem.
DIETSKohman (6) demonstrated that the edema in her animals had not resulted from the lack of any of the vitamins then known, and was presumably the result of protein deficiency in the diet. Vitamin G had not then been identified and may not have been supplied in sufficient quantity to Kohman's rats by the wheat-germ extract. We have sought to learn whether such deficiency could have had any effect on the course of the -edema. Accordingly, a group of five animals was placed on the Kohman wet diet to which was added daily, in a separate dish, 0.05 gram of a yeast concentrate powder