Abstract
The calcium-phosphate ion product of blood plasma "is normally as high as it is possible for it to be without initiating spontaneous precipitation of calcium phosphate salts." Its maintenance by a balance of absorption, excretion, hormones (particularly from the parathyroid, thyroid, pituitary, and sex glands), vitamins (particularly C and D), and the supply of calcium and phosphorus is analyzed in the light of more than 250 references, most of them published since 1935, when the review of Schmidt and Greenberg appeared.