

COAGULATION OF THE BLOOD. 243 



the corpuscles are displaced and escape into the serum, which is 

 thus stained and cannot be seen in its clear transparent state. 



If brisk agitation with a glass rod or better, a bundle of 

 twigs be commenced the moment the blood is drawn, the fibrin 

 is formed more rapidly, but the corpuscles are not entangled in 

 its meshes, for as quickly as the elastic threads are formed they 

 adhere firmly to the rod or twigs. Thus the fibrin is formed very 

 rapidly, and the ordinary blood-clot, consisting of fibrin and the 

 corpuscles, does not appear, for the fibrin is separated from the 

 latter during the coagulation. We then have what is commonly 

 spoken of as " defibrinated blood," which does not give a clot. 

 Not that the clotting has been prevented, but the material essen- 

 tial for the formation of a clot has been removed as quickly as 

 formed, and instead of catching the corpuscles in the meshes of its 

 delicate fibrils to form the clot in the ordinary way, the stringy 

 shreds of fibrin cling around the beating-rod as a jagged mass. 

 The following tables show the relation of the different constituents 

 of coagulated and defibrinated blood respectively: 



f Serum (appearing as clear 

 T . . -pi i f Plasma | J fluid). 



= I Corpuscles }' FibriJ 1 BIoodclot . 

 ^Corpuscles j 



f Fibrin (removed on the 



Living Blood = \ fc to ^ s ) .= Defib "! 



I 



Corpuscles 



Many circumstances influence the rapidity with which a blood 

 clot is formed. Speaking generally, the removal of the blood from 

 its normal supply of nutrition and from the opportunity of pre- 

 serving the necessary equilibrium of chemical interchange be- 

 tween the corpuscles, the plasma, and the tissues in short, cir- 

 cumstances which tend to injure the corpuscles or the plasma, 

 and promote the changes resulting in their death must hasten 

 coagulation ; while, on the other hand, the conditions which pro- 

 tect the corpuscles and impede the stages in fibrin formation must 

 retard coagulation. 



