Diffusible Calcium of the Blood Stream

The use of agents capable of influencing the calcium content of the blood in the treatment of many pathologic conditions has become a widespread medical procedure. 1 When there is any rational basis at all, the purpose of these reagents is to counteract a deficiency, presumed or real, in blood or tissue calcium. In some instances, it is true, the treatment is given, not for the direct effect on calcium, but for secondary effects such as to decrease hemorrhagic tendencies or to relieve edema. A sound rational basis for calcium therapy depends on an extensive knowledge of the influence of the agents commonly employed on the biochemistry of the body calcium and other bodily constituents that are interrelated with the calcium. Since it is naturally difficult to study the whole of the body calcium, attention has been given mainly to the effect on the blood calcium. Many studies have been