COAGULATION OF THE BLOOD. 309 



coagulation du fibrinogene par la thrombine les affinites restees libres 

 de celle-ci peuvent s'assouvir; le compose moins sature se transforme 

 en un compose plus sature.") The formation of fibrin from fibrinogen 

 is not, according to NOLF, an enzymotic process. 



In NOLF'S opinion the thrombogen is probably formed in the liver 

 and found to a large extent in all plasma. The thrombozym is 

 secreted by the leucocytes and the endothelial cells. It is also a normal 

 constituent of the blood plasma circulating in the living body. Most 

 tissues, on the contrary, contain no thrombozym. The tissue extracts, 

 NOLF believes, also contain no substances absolutely necessary for the 

 coagulation, but only bodies which can have a powerful accelerating 

 action, the thromboplastic substances. The circulating blood plasma 

 contains all the bodies directly necessary in the coagulation, namely,, 

 fibrinogen, thrombogen, thrombozym and lime salts. Besides these it 

 also contains a substance that inhibits coagulation, antithrombin, which 

 is formed in the liver and which NOLF now considers as a special sub- 

 stance and not as he formerly believed, an excess of thrombogen. There 

 exists, if the author understands the work of NOLF, a labile equilibrium 

 between the various constituents of the plasma, and this equilibrium is 

 destroyed in coagulation. The first impulse to coagulation is given by 

 the thromboplastic substances. 



NOLF considers as thromboplastic active any influence of a physical 

 or chemical nature which, be it produced by the walls of the vessel, a 

 suspended body, a solvent or a dissolved body, a colloid or crystalloid, 

 a molecule or an ion, makes the combination of the three above colloids 

 possible. To the thromboplastic agents belong the walls of a glass 

 vessel, finely powdered glass, the precipitates of calcium oxalate or 

 calcium fluoride, also living protoplasm, aqueous tissue extracts, the 

 alcohol soluble zymoplastic substances of ALEX. SCHMIDT, and other 

 substances. All these agents in some way or other may serve as points 

 of precipitation; but unfortunately it is not clear how this thrombo- 

 plastic action is brought about. 



An important side of NOLF'S theory of coagulation is also the fibrinol- 

 ysis which is brought about by the thrombin. The proteolytic action 

 of the thrombin is due only to the thrombozym contained therein, and 

 it has a proteolytic action only upon fibrin and not upon fibrinogen. 

 Apcording to NOLF, coagulation is merely a preparation for the prote- 

 olysis, and is a nutrition phenomenon, and in addition is of special 

 importance, in arresting hemorrhage. In order to prevent a rapid 

 fibrinoylsis, the plasma also contains one or more antifibrinolytic sub- 

 stances, which are secreted by the liver. 



What has been given contains the chief points in NOLF'S theory of 

 coagulation, and it is impossible in a text-book to enter more into detail 



