Margaret Hurn

Observations on the Conversion of Prothrombin to Thrombin

Summary Fresh plasma, serum and platelet extracts contain a material which potentiates the action of tissue thromboplastin on stored plasma. Platelet extract apparently contains a greater degree of this activity than plasma or serum and potentiates the action of tissue thromboplastin on fresh plasma. This factor favoring prothrombin conversion apparently is present in the circulating blood.

Species Specificity of Thromboplastin Role of the Cothromboplastin Reaction

Summary Species specificity of thromboplastin is largely eliminated by brief treatment of the thromboplastin with dilute homologous serum. This appears to be an example of the cothromboplastin reaction.

Relation of Complement to Blood Coagulation

Summary Inactivation of the complement of plasma by aging or by treatment with zymin or with ammonia blocks conversion of prothrombin to thrombin while leaving ample reactive prothrombin.