Species specificity of thromboplastin. A phylogenetic study.

Having studied the influence of thromboplastin preparations derived from cold and warm-blooded species on the plasma of 12 vertebrates (carp, frog, turtle, hen, rabbit, rat, mouse, guinea-pig, ground squirrel, dog, sheep and man) we have established that among the species far from each other phylogenetically, the phenomenon of species specificity could be demonstrated in general. It was found that the extrinsic coagulation system measured by Quick times can well be activated in every examined species. Simultaneously, in plasmas of turtle and hen the intrinsic clotting system proved to be deficient.