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In several recent publications (14) it has been reported that dietary aminopterin produces a marked decrease in rat liver choline oxidase activity as measured by the whole homogenate technique. A simple folic acid deficiency, however, has been shown to produce only slight changes in the activity of this enzyme (5). It was probable that a simple folic acid deficiency did not deplete the tissues of folic (and folinic) acid to a great enough extent to produce much change in the activity of the whole homogenate. If only minute amounts of a folic acid cofactor were needed by the enzyme, a whole liver homogenate, even from deficient animals, might contain enough of the cofactor to maintain the normal activity of the enzyme. The choline oxidase system of rat liver has been shown to be located in the mitochondrial fraction of liver (6-S). Therefore, the authors felt that, if the mitochondria were isolated, washed, and thus freed of extraneous folic acid, folinic acid, or cofactor containing either of these in bound form, the effects of a simple folic acid deficiency could be demonstrated more clearly. In the present investigation not only the effect of a simple folic acid deficiency on the choline oxidase of isolated mitochondria has been studied, but also a comparison has been made with the effects on the mitochondrial activity of the enzyme produced by feeding aminopterin to rats. In order to complement the enzyme results, and to study the correlation of the eneyme activity with folic acid and folinic acid’ concentration in the tissues, all of the samples used for the enzyme determinations were assayed microbiologically for both folic acid and folinic acid. In the course of these

PEROSIS, an anatomical deformity of the leg bones of young chicks, was first described by Hunter and Funk (1930). The condition is associated with a high intake of calcium and phosphorus, and a low intake of manganese (Hunter et al., 1931; Milby, 1934; Wilgus et al., 1936–1937; Clifcorn et al., 1938). Later, the work of Wiese et al. (1939) showed that the blood and bone phosphatase activity of perotic birds was lower than that of chicks receiving an adequate amount of manganese in their diet. As the leg bones of chicks with perosis are bent and twisted from their normal shape it was thought that there might be an abnormal distribution of the enzyme phosphatase in the bones of these chicks. In this paper we wish to report the results we have observed on the distribution of this enzyme in the leg bones of perotic and normal chicks. EXPERIMENTAL

1. Our data indicate that the effectiveness of whole liver in the treatment of nutritional anemia in rats induced by a milk diet is directly proportional to its available iron and copper content. The other constituents in liver are not needed for maximum hemoglobin regeneration on a diet of milk, iron, copper, and manganese. 2. Commercial preparations of liver products with iron or iron and copper vary greatly in their hemoglobin-regenerating efficiency in rats with nutritional anemia. The variation is correlated directly with the iron and copper content of the preparation. When the copper-iron ratio was too wide hemoglobin regeneration was checked, although the iron supply was sufficient for optimum regeneration.

AFTER the discovery of the high requirement of the chick for arginine (Arnold et al., 1936) and glycine (Almquist et al., 1940; Hegsted et al, 1941a) certain diets containing 18% casein were found to be primarily deficient in these two amino acids (Hegsted et al., 1941b) Subsequently Briggs and his associates (1942) showed that 10% of gelatin would satisfy the requirement of the chick for arginine and glycine and that no growth difference could be demonstrated at 4 weeks of age between groups of chicks receiving free arginine and glycine and those receiving gelatin. These workers used dextrin as the carbohydrate in all of their diets. During the course of a study on the effect of the type of dietary carbohydrate on the growth of chicks, it was noted that the substitution of arginine and glycine for gelatin in the 18% casein-sucrose diets usually promoted more rapid growth during the …