The effect of glass upon the activity of the various plasma clotting factors.

'LFulbright Research Scholar, Department of Medicine, Oslo University, 1953-1954. 2 Present Address: Hematology Section, Veterans Administration Hospital, Long Beach, California. There is no standard nomenclature for the newer clotting factors. The following terms are used in this paper. Blood thromboplastin is used in its classic meaning of an activity which arises during clotting and which is equivalent in effect to the clotting activity of aqueous tissue extracts. Antihemophilic A factor is the name used for the plasma thromboplastin precursor present in Seitz filtered or barium carbonate absorbed fresh normal plasma, absent from the plasma of most patients with hemophilia and not found in aged normal serum; syno-