26 A Manual of Veterinary Physiology. 



It will be most convenient to deal with these in the 

 order in which they are given. 



The Liquor Sanguinis, or Plasma, forms about GO per 

 cent, of the total blood ; it is a yellow albuminous fluid, 

 containing at least three proteids, one of which may by 

 certain processes be shown to be composed of two or three 

 others. The proteids are : 



Serum albumin, consisting of «, /8, and y albumins. 



Serum globulin. 



Fibrinogen. 



During the life of the blood the liquor sanguinis is 

 termed the plasma, but after it has been shed from the 

 body, and coagulation has occurred, it is no longer described 

 as plasma, but as serum ; Serum is, therefore, plasma which 

 is modified as the result of coagulation, and as this latter 

 process is attended by the production of fibrin, we may 

 say that serum is plasma minus the fibrin-forming 

 elements. 



The Proteids of Serum are serums albumin and globu- 

 lin, and in addition there is the ferment produced as the 

 result of coagulation ; fibrinogen, having been used up in 

 the process of coagulation, does not occur. The following 

 table from Halliburton exhibits these points very clearly : 



Proteids of the Plasma. Proteids of the Serum. 



Fibrinogen. Serum globulin. 



Serum globulin. Serum albumin. 



Serum albumin. Fibrin ferment. 



It has been shown that the proportion in which serum 

 globulin and serum albumin exists in the blood varies in 

 different animals ; in the horse and ox the globulins are 

 in excess of the albumins ; in man and the rabbit this 

 is reversed. The following table from Gamgee,* after 

 Hammarsten, will render this clear : 



* ' Physiological Chemistry.' 



