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 tissues 

 food-stuffs after they have been digested, (2) it transports 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 secretions of glands to the differ- 

 ent 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 body 

 weight. A man weighing 150 pounds has a fraction over eleven 

 pounds of blood, which is about one-twelfth 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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