Biochemists are reaching an increasingly greater accord in the belief that bone derived from any part of the skeleton has a rather constant inorganic composition. At any rate the "minerals" do not represent a widely variable mixture. X-ray spectrums, which afford one of the newer methods of scientific examination supplementing direct chemical analysis, indicate in a general way that bone has a crystalline structure like some of the familiar minerals.1 Tooth enamel is similar, the general formula being of the type CaCO3.nCa3(PO4)2. From this it is obvious what elements are concerned in maintenance of the integrity of such structures.
Ever since the discovery of vitamin D as an essential factor in physiologic well being, attention has been directed to its potent influence on the metabolism of the inorganic elements involved in the bones; namely, calcium and phosphorus. Analyses of the bones, in