168 



THE BLOOD. 



nutrition of the organic nitrogenized elements of the tissues. 

 Its diminution in the blood to any considerable extent de- 

 termines defective nutrition. It is probable that all the other 

 organic nitrogenized principles are formed from it. 



In the blood, part of the albumen is transformed into 

 fibrin, which exists in small quantity, and does not appear 

 to bear any relation to nutrition. Its peculiar property of 

 spontaneous coagulation gives it a most important conser- 

 vative function in the arrest of hemorrhage. Ammonia, which 

 is contained in the blood, has the property of maintaining its 

 fluidity ; but on exposure to air, or in rupture of vessels, we 

 have an escape of ammonia, and the fibrin by its coagulation 

 reduces the whole mass of blood to a semi-solid consistence. 

 The proportion of fibrin in the blood bears no relation to the 

 function of nutrition. Its occasional absence only induces 

 obstinate hemorrhage on the division of vessels, even of very 

 small size. 



Fat, which exists in small quantity in the blood, and sugar, 

 which exists only in certain parts of the circulatory system, 

 disappear in the organism in a way which is not at present 

 understood. They are concerned in, and necessary to, the 

 processes of nutrition ; but the exact nature of their function 

 is unknown. 



The inorganic constituents of the body are found in vary- 

 ing proportions in the plasma, and have varied functions. 

 Their presence tends to preserve the proper constitution of 

 the corpuscles, which are dissolved and lost in pure water. 



The water which does not enter into the constitution of 

 the albumen and fibrin serves to hold the various salts in 

 solution, and cannot vary much in quantity from a certain 

 standard. 



Some of the inorganic salts, the chlorides particularly, 

 seem to regulate, to a certain extent, the processes of nutri-. 

 tion, are found most abundantly in the fluids, and apparently 

 do not form a very essential portion of the tissues themselves. 

 A tendency to an excess in the blood is relieved by discharge 



