THE ACCELERATING EFFECT OF CALCIUM AND OTHER CATIONS ON THE CONVERSION OF FIBRINOGEN TO FIBRIN 1

Abstract
When ionic strength was maintained constant, Ca, Sr, Ba, Mg, Mn and ammonium salts accelerated the conversion of fibrinogen to fibrin by thrombin. Mercuric, cupric, cobaltous, nickelous, and ferric chlorides accelerated the clotting of fibrinogen by thrombin in low concns. but caused precipitation, presumably of proteins, in higher concns. Studies with labelled Ca indicate that this acceleration of clotting is not accompanied by the formation of a firm bond between the Ca ions and the fibrin clot.