CHAPTER V. 

 THE BLOOD. 



General Characteristics. The blood is a red, opaque and 

 viscid fluid having a characteristic stale odor and a salty 

 taste. The blood is heavier than water, having a specific 

 gravity in the adult male of 1.041 to 1.067, tne average being 

 about 1.055. 



The reaction of the blood is neutral. The nature of the 

 diet, either meat or vegetable, causes this neutrality to turn 

 to either an acid or an alkaline reaction. 



The blood temperature is that of the body. In the periphery 

 it is about 99 F. ; in deeper vessels it varies from 100 F. 

 to 107 F. ; and in the hepatic veins it is about 107 F. 



The Function of the Blood. The most important physio- 

 logical functions of the blood are: (i) It carries to the tis- 

 sues food-stuffs after they have been digested, (2) it trans- 

 ports to the tissues oxygen which it has absorbed from the 

 air in the lungs, (3) it carries off from the tissues the waste 

 products of metabolism, (4) it transmits the internal secre- 

 tions of glands to the different parts of the body, and (5) it 

 aids in equalizing -the body temperature. 



Quantity and Distribution of the Blood. The quantity of 

 the blood in the body is estimated at about 7.5 per cent, of 

 the body weight. A man weighing 150 pounds has a fraction 

 over eleven pounds of blood, which is about one-thirteenth 

 of the body weight. 



The distribution is generally given as, one-fourth in the 

 heart, large arteries, lungs, and veins ; one-fourth in the liver ; 

 one- fourth in the muscles attached to the skeleton ; and the 

 other one- fourth variously distributed to the other organs of 

 the body. 



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