1. The special effect of calcium for the activation: of prothrombin into thrombin is shared by strontium.
2. Calcium accelerates the coagulation of blood not only through the activation of prothronzbin into thrombin, but by promoting the formation of fibrin from. fibrinogen by thrombin.
3. Thrombin is stable at the temperature below the body temperature. Its activity is maximum at body tem-perature.
4. The identification of tissue throniboplastic substance with kephalin was confirmed.
5. Kephalin maintains its thromboplastic character in full by the heating below 120°C. At higher temperature the activity is partly decreased.
6. The hydrogenation has no effect on the thromboplastic activity of kephalin.
7. The treatment of kephalin by nitrous acid or formalin causes the decrement of activity of kephalin as throznbo-kinase.
8. By the complete hydrolysis kephalin lost its thrombo-plastic activity. Out of its decomposition products glycerin-phosphoric acid and aminoethylalcohol reveal no thrombo-plastic action. Stearate and aininoethylstearate especially the latter, promote, however, the coagulation of fibrinogen a great deal.
9. Cholesterol exerts no influence upon the coagulation of plasma. Cholic acid in a great amount retards the coagulation both in presence and absence of kephalin.
10. The influence of albumin in different concentrations on the velocity of coagulation in the absence and presence of kephalin in varying amount envea.ls a complicate, but regular relation, which needs a further study.
11. The treatment of peptone plasma with trypsin induces the coagulation, the rate increasing tip to a certain point with the concentration of trypsin. This effect seems to lie in the hydrolysis of some inhibiting substance by trypsin. Further increase in trypsinn inhibit however the coagulation, possibly by its hydrolytic action on fibrinogen.
12. Kephalin has no effect on the coagulation of fibrinogen by thrombin but in a large excess it tends to decrease the coagulation velocity.
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