158 



APPLIED PHYSIOLOGY 



the lungs, where it is breathed out from the body. 

 Some of the mineral matter of the blood enters into the 

 composition of the cells of the body, especially of bone 

 cells. 



The albumin is the substance out of which all of the 

 cells of the body are mainly built. It is formed by 

 the liver out of the peptone which was absorbed from the 

 intestine. A little pressure causes the solution of albumin 

 and minerals to flow through the sides of the capillaries ; 

 and thus it reaches the separate cells of the body. Waste 

 matters are continually being poured into the plasma, but 

 they are removed as fast as they enter, so that carbonic 

 acid is the only one to be found except by the most deli- 

 cate tests. 



277. Clotting. When blood is drawn from the body it 

 soon becomes a jelly like mass, called a clot. After a longer 

 time the clot becomes firmer and smaller, squeezing out a 

 clear, straw-colored liquid, called serum. The process of 

 changing blood from a liquid to a jelly like form is coagu- 

 lation, or clotting: In the process a part of the albumin 

 becomes solidified in small interlacing strings, called 

 fibrin, which entangles the rest of the blood into its 

 meshes. The network soon contracts, squeezing out the 

 serum, and retaining the corpuscles. The serum is com- 

 posed of all the materials of the plasma, excepting the 

 fibrin. The process may be represented thus : 

 ' albumin ) f f albumin 



Plasma or 



mineral matter 



I water 

 Corpuscles . . . 



Serum, or 



Clot, or 



mineral matter 



+ 



water 

 ( fibrin 



+ 

 [ corpuscles 



