In the previous papers', the authors reported the relation between vitamin B12-deficiency in cattle and the vitamin-forming microflora (Actinomycetes) ; and also discussed the vitamin B12-requirement for the growth of chicks from the detective failure of any vitamin B12-producing microbes in poultry. In 1950, R. W . Vilter et al. suggested a probable schematic representation of a chemical-chain-relation between nucleic acid and vitamin B12 in vivo. In 1951, at Nagoya University, S. Ito observed

more »

... the simultaneous increase of both ATP and red blood cell counts in bone marrow test. From these interesting communications, and from the fact that vitamin D is an important factor in the phosphorus metabolic system, the present authors attempted to study a biochemical chain-relation between vitamin B12 and phosphate metabolic system and the effect of vitamin B12 upon the value of vitamin D determined biologically. Biological Determination of Vitamin D with Rats fed on Sterolfree Synthetic Diets containing Animal Protein: Based on the experimental evidence that the sterols may be eventually proved to be the mother substance of vitamin D, and that when cholesterol tagged with deuterium is fed to women, pregnandiol containing the isotope could be recovered from the urine, the authors used the synthetic diet completely freed from sterols and accurate results for the bioassay of vitamin D were obtained. The composition of the diet containing animal protein (purified horse meat meal) is shown in Table I . It was found that 5~7 r of vitamin B12 were contained in 100g of purified horse meat meal when tested by Euglena assay after digestion with pancreatin. Ordinary Steenbock's diet from vegetable source, however, contained no vitamin B12 when tested in the same manner. Vitamin B12 on Healing of Rickets in Rats in Prophylactic Test: The expreriments were carried out with ordinary Steenbock's diet composed of a mixture of American yellow corn meal 76, dried wheat gluten meal 20, CaCO3 3, and NaCI 1.