1886.] 



On the Coagulation of the Blood. 



321 



essential point in the coagulation of the blood is a loss of lecithin on 

 the part of A-fibrinogen, and a gain of lecithin on the part of 

 B-fibrinogen. A-fibrinogen loses some of its lecithin to B-fibrinogen, 

 and the result is that in the place of the two fibrinogens we have 

 fibrin. Previous authors have all regarded coagulation as essentially 

 a fermentative process. 



The author regards the fibrin ferment as purely subsidiary, and 

 considers that coagulation is nearly allied to crystallisation. 



3. In the fluid of lymph glands from which all the cellular elements 

 have been removed, another form of fibrinogen exists closely allied to 

 and probably the precursor of the A-fibrinogen of the blood. It 

 differs from the latter in causing intravascular clotting,* whereas 

 A-fibrinogen only causes under normal conditions clotting in shed 

 blood. 



It is a proteid-lecithin compound, and its action can be shown to 

 depend on the lecithin it contains. It has a wide distribution apart 

 from lymph glands. 



In the fluid of serous cavities of certain animals, the only coagulable 

 body present is C-fibrinogen, and since the blood of these animals 

 contains both A- and B-fibrinogen, the vascular wall either only 

 allows C-fibrinogen to pass, or changes A- and B-fibrinogen into 

 C-fibrinogen in their passage through. 



* Vide " Proc. Eoy. Spc," vol. 40, p. 134. 



