Wooldridge (1, 2), in 1886, produced intravascu- taner (7-9) prepared cephalin free of lecithin
and existed in plasma("Fibr Page 1 PLATELET PHOSPHATIDES: THEIR SEPARATION,
IDENTIFICATION, AND CLOTTING ACTIVITY1 By AARON J. MARCUS 2 AND THEODORE' H.
SPAET (From the Department of Hematology, Division of Laboratories, Montefiore Hospital,
New York, NY) (Submitted for publication June 19, 1958; accepted August 18, 1958) Agents
capable of accelerating the conversion of prothrombin into thrombin in the presence of Ca+ …