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Editor's Note: This paper from Professor Elvehjem's group at the University of Wisconsin was the first to demonstrate the essentiality of copper for hemopoiesis in an animal. Forty years later Professor George Graham's group at Johns Hopkins University found signs of copper deficiency in malnourished infants.

SummaryRaw whole milk is a good source of the monkey anti-anemia factor. Pasteurization of the milk seems to reduce the amount of this factor in milk to some extent. This factor can be differentiated from the guinea pig anti-stiffness factor by the fact that raw cream possesses little activity while the raw skim milk accounts for the greater portion of the activity in whole milk. Raw whey, made by enzymatic treatment of raw skim milk, is also a good source of the monkey anti-anemia factor.

SummaryThe influence of pyridoxine, inositol, and biotin deficiencies on the susceptibility of mice to experimental poliomyelitis has been studied in more than 1400 animals. No striking or consistent difference with reference to susceptibility to either Lansing strain poliomyelitis or Theiler's encephalomyelitis was noted between animals fed diets deficient or optimum in these vitamins.

SummaryThe influence of the level of 6 common minerals on the susceptibility of Swiss mice to Theiler's GDVII virus has been investigated in more than 1100 animals.No demonstrable effect on the susceptibility to this infection was found by varying the level of calcium, magnesium or chlorine in the diet, some effect was noted with sodium, while striking results were obtained with potassium and phosphorus.A progressively decreased resistance was observed as the amount of potassium or of phosphorus was increased in the diets up to the optimal levels.

SummaryA practical meatless ration for trout containing 55% plant material is described which is essentially equivalent to a standard liver, canned carp diet so far as growth and hemoglobin levels are concerned.The effect of various substitutes in the ration is described.Although this ration contains 45% carbohydrate, liver enlargement was not noted except when sprouted soybeans or poor quality yeast were included. Large scale field trials indicated that Ration C was superior to pork spleen, and equivalent to pork spleen supplemented with canned carp, as a diet for yearling brook trout on the basis of both growth and mortality.

One might define, as the optimum goal of the nutritional biochemist, the development of a diet which supplies all nutrients in respect to kind and amount and in proper state of combination for all physiologic processes from conception to the death of the organism. In addition, the adequate diet must contain a minimum of injurious (toxic) tactors. Such a diet would indeed be balanced, and any important deviation downward from the proper amount of a nutrient would lead to one well known kind of imbalance, reflected as. deficiency disease. Since much has been written concerning this kind of imbalance, it will be considered here only incidentally. It is primarily when and where a variety and abundance of foodstuffs are available that one can apply the criteria of a balanced diet as far as knowledge permits. Any situation, whether due to economic, political, geographic or climatic reasons, which limits the food

SummaryA method of obtaining electroencephalograms in dogs has been described. When rations which contained casein were fed no abnormalities were observed. After wheat gluten was substituted for casein epileptiform seizures and concomitant abnormalities in the E.E.G. developed which were comparable to those seen in cases of human epilepsy.

Isoleucine was found to be limiting for the growth of rats fed corn diets supplemented with lysine, tryptophan, valine, and threonine or 24% zein diets supplemented with most of the essential amino acids. Since phenylalanine, which is known to be present in zein at quite a high level, was also found to be limiting for the growth of rats fed 21% of zein, it was suggested that all of the essential amino acids in zein were utilized poorly. This was further substantiated when rats fed diets containing alcohol-extracted corn showed a much greater growth response to a level of isoleucine equivalent to that supplied by the zein extracted than to the zein itself. When the level of leucine supplied by the zein was also added, no growth depression was obtained.

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