FURTHER EVIDENCE THAT SMALL QUANTITIES OF COPPER, MANGANESE AND ZINC ARE FACTORS IN THE METABOLISM OF ANIMALS

Abstract

Different groups of normal albino rats were fed synthetic diets containing or lacking one or all of the metals Cu, Zn, and Mn. The animals were confined in cages made of glass, aluminum and. Monel metal. Tables are presented of weight gained and of the mineral matter contained in the carcasses of the 18 rats of the experiment and 17 other rats of various ages. Most of the rats had died by the end of 17 weeks except those fed Mn; the survivors were chloroformed at this time. Animals receiving Mn seemed to show the greater average weight gain. The author tabulates the findings of other workers and himself in the analysis of rat carcasses for various minerals. He concludes that Mn is probably of more importance than Cu and Zn in animal metabolism and assumes that the potency of these elements is of a higher degree in fresh vegetable matter than when given as chemical compounds in synthetic diets.