As the result of past metabolic studies, especially those of Henderson and Palmer (12) it is known that the non-volatile acids produced in excess of fixed base by human metabolism are excreted in the urine in two forms, viz., as free acids, and as ammonium salts.Since the kidney is unable to form urine with a pH much lower than 5.0, it can excrete, in significant amounts, free acids of only the weak buffer type. In this class fall acid phosphates and the various organic adds. It appears, however, that free acid excretion may assist also in elimination of strong acids, which can react with buffer salts (e.g., HC + Na2HPO4 = H(NaHPO4) + NaCl), the free buffer acid being excreted in place of the strong acid. Thus Marriott and Howland (19)

No abstract

No abstract

No abstract

It has been known for some time that in some cases of nephritis there is an increase in the blood lipoids, sometimes to the extent of 100 per cent or more above the normal. A review of the literature to 1917 has been given by Bloor (1). Later investigations confirmed these results. Epstein and Rothschild (2) thought the high lipoids in nephritis represented a condition of fat non-utilization. Bloor (1) regarded the abnormalities in blood lipoids in severe nephritis as the result of a retarded assimilation of fat in the blood, which he thought to be one manifestation of a general metabolic disturbance.We have approached the subject by an attempt to discover whether the heaping up of lipoids in the blood is due to a retarded rate of fat combustion, or to a retardation of its deposition from the blood into the tissues. Fat metabolism experiments were planned, both on normal individuals and on nephritics with and without high blood lipoids. Summary of Previous Literature.The Effect of Fat Ingestion on the Total Metabolism.-Koraen (3) and Johansson and Koraen (4) concluded that there was no increase in metabolism as a result of the ingestion of fat. Gigon (5) did not always find an increase in the total metabolism, except when large amounts of fat were given, but he found an increase in the fat metabolism. Von Voit (6) stated that when 100 per cent of the basal requirement was fed to a dog in the form of fat, the total amount of protein and fat burned remained the same after ingestion of fat as during fasting. The fat ingested merely replaced the body fat in metabolism. Magnus-Levy (7), in experiments on dogs and on man, found an increase in total metabolism as a result of fat ingestion, and furthermore showed that the degree of increase was dependent on the amount of fat ingested. Rubner (8), Staehelin (9), Bartmann (10), Murlin and Lusk (11), and Benedict and Carpenter (12) all reported an increase in total metabolism after fat ingestion. 931 (21) and of Neisser and Braeuning (22), who reported an increase in fatty substances in the blood after fat ingestion determined by the ultramicroscopic method; those of Cowie and Hoag (23), who corroborated the results of Bloor on dogs by feeding cream to five children and three adults; and those of Bang (17), who found only slight changes in the fat content of the blood of human subjects after fat ingestion, as compared with the striking increase in the dog. EXPERIMENTAL.Methods.-The basal metabolism determinations were made by the Tissot spirometer method (24). The gas analyses were made with the Henderson modification of the Haldane gas analysis apparatus (25). The protein metabolism was determined by analysis of urinary nitrogen by the Kjeldahl method. When protein was present in the urine, this was removed by heating the urine and adding trichloroacetic acid until no further precipitation occurred. The mixture was diluted to a volume, filtered, and portions of the non-protein solution used for Kjeldahl determinations. All respiratory quotients given are non-protein.The ...