SUMMARY OF PROPERTIES AND FUNCTIONS. 167 



Summary of the Properties and Functions of the Blood. 



The blood, constituting as nearly as can be estimated one- 

 eighth of the weight of the body, is the great nutritive fluid ; 

 its presence being necessary to life, and its normal constitution 

 and circulation essential to the performance of all the func- 

 tions. 



Anatomically, its most important elements are a clear 

 plasma and the red corpuscles, these existing in about equal 

 proportions. The corpuscles are intimately connected with 

 the function of respiration. Their chief office seems to be to 

 carry oxygen from the lungs to the tissues. Their presence 

 is immediately essential to life, and their normal proportion 

 essential to health. They are organized anatomical elements, 

 capable of self-regeneration from principles contained in the 

 plasma. They contain all the principles which exist in the 

 plasma, with the difference that the fibrin and albumen of 

 the latter are replaced by globuline, and a coloring matter, 

 hematine, is superadded. The plasma seems to be the part 

 chiefly employed in the nourishment of the tissues, some of 

 which, as cartilage, do not receive any of the corpuscular 

 elements of the blood. 



Chemically r , the plasma contains all the elements which 

 are necessary for the regeneration of all parts of the body. 

 These are continually being used tip in nutrition, but are 

 replaced by the absorption of articles of food after they have 

 undergone the preparation of digestion. In the deposition 

 of new matter in the regeneration of the tissues, the organic 

 and inorganic constituents of the plasma are deposited to- 

 gether ; the inorganic elements of the tissues receiving, as it 

 were, the vital properties of self-regeneration, which we sup- 

 pose to reside particularly in organic principles, from the 

 fact of their molecular union with these organic principles. 



Of the organic constituents, albumen constitutes by far 

 the greater proportion, and is the one chiefly used in the 



