CHAP, i.] BLOOD. 23 



no fibrin-ferment, but that when the equilibrium of blood is 

 disturbed, either by the shedding of the blood or by injury to the 

 blood-vessels or by the introduction of foreign bodies, fibrin-ferment 

 is discharged into the plasma, as the result of changes taking 

 place in certain corpuscles. 



With regard to the other fibrin-factors our knowledge is at 

 present deficient. As we shall have to state presently, paraglo- 

 bulin apparently exists in serum and therefore in plasma, in very 

 considerable quantity; and to say nothing of the doubt as to 

 whether paraglobulin has any share in forming fibrin, it seems 

 extremely unlikely that the whole of this large quantity could 

 have come from disintegrating corpuscles. Fibrin ogen is generally 

 supposed to be pre-existent in the plasma; but there do not 

 appear to be adequate reasons for this view; and it is quite 

 possible that it too, like the ferment, comes from the corpuscles. 

 But this is almost tantamount to saying that the whole fibrin 

 comes from the corpuscles, and indeed it has been argued that the 

 white corpuscles are in part bodily converted into fibrin. 



The whole matter needs further investigation, and when 

 we remember that fibrin-ferment and even masses of white 

 corpuscles injected into the living blood-vessels do not necessarily 

 bring about coagulation, it is clear that we have much yet to 

 learn. Moreover we have reason, as we shall see, to think that 

 corpuscles are continually dying in the body, and therefore continu- 

 ally setting free fibrin-factors ; and these, unless we suppose that 

 a certain quantity of fibrin can exist scattered so to speak in the 

 blood, must be made away with or at least prevented from giving 



risetoclots - 



