STUDIES OF CALCIUM AND PHOSPHORUS METABOLISM XVIII. ON TEwPORARY FLUCTUATIONS IN THE LEVEL OF CALCIUM AND INORGANIC PHOSPHORUS IN BLOOD SERUM OF NORMAL INDIVIDUALS

In the investigation of various problems of calcium and phosphorus metabolism, it has been found that great changes in the volume and direction of the calcium and phosphorus stream may occur without any notable difference in the serum levels of these elements. In hyperthyroidism the calcium excretion in the urine is relatively huge and there are large negative balances of calcium and phosphorus, yet the serum calcium and serum phosphorus ' remain within normal limits (1). Moreover, there is no appreciable change in the serum levels of healthy people when, by changing the calcium intake, a positive balance is shifted to a negative one or vice versa. Yet the actual and relative amounts of calcium and phosphorus in the serum is of the utmost importance in certain abnormal conditions. MacCallum and Voegtlin (2) described the low blood and tissue calcium associated with tetany after removal of the parathyroids. Greenwald (3) later demonstrated the associated rise in serum phos