BLOOD. 45 



resembling the white corpuscles. The spleen is the organ in which they 

 are finally destroyed. 



The white corpuscles originate from the leucocytes of the adenoid tissue, 

 and subsequently give rise to the red corpuscles and partly to new tissues 

 that result from inflammatory action. 



COAGULATION OF THE BLOOD. 



When blood is withdrawn from the body and allowed to remain at rest, 

 it becomes somewhat thick and viscid in from three to five minutes ; this 

 viscidity gradually increases until the entire volume of blood assumes a 

 jelly-like consistence, which occupies from five to fifteen minutes. 



As soon as coagulation is completed, a second process begins, which 

 consists in the contraction of the coagulum and the oozing of a clear, 

 straw-colored liquid, the serum, which gradually increases in quantity as 

 the clot diminishes in size, by contraction, until the separation is completed, 

 which occupies from 12 to 24 hours. 



The changes in the blood are as follows : 



Before coagulation. 



f Liq. Sanguinis 1 f Water. 



& /-. L - r Albumen. 



T . 1 1 i or > Consisting of 4 ^. u . 



Living blood. \ pl | Fibrmogen. 



I Salts 

 [ Corpuscles. Red and white. 



After coagulation. 



f Crassamentum. "I r . . f Fibrin. 



I Clot or coagulum. } Containing <{ Corpuscles. 

 Dead blood. { f Water. 



Serum. Containing -j Albumen. 



( Salts. 



The serum, therefore, differs from the Liquor Sanguinis in not containing 

 fibrin. 



In from 12 to 24 hours the upper surface of the clot presents a grayish 

 appearance, the huffy coat, which is due to the rapid sinking of the red 

 corpuscles beneath the surface, permitting the fibrin to coagulate without 

 them, which then assumes a grayish -yellow tint. Inasmuch as the white 

 corpuscles possess a lighter specific gravity than the red, they do not sink 

 so rapidly, and becoming entangled in the fibrin, assist in forming the buffy 

 coat. Continued contraction gives a cupped appearance to the surface of 

 the clot. 



Inflammatory shites of the blood produce a marked increase in the 



