CHAPTER IX. 



DISEASES OP THE HEAET AND BLOOD-VESSELS. 



The heart is the great central organ for the propulsion of 

 the blood to the various parts of the body ; it is placed in the 

 middle space of the cavity of the chest. Its form is that of 

 a blunt cone, the base being turned upward, suspended from 

 the third to the sixth dorsal vertebrae by the venous and 

 arterial trunks which spring from it. It is a most beautiful, 

 but complex arrangement, for the propulsion of the blood 

 through the system. It is enclosed in a double membranous 

 sac callft^J^s pericardium. Its average weight is from six 



to seven pounds. .^. . ■,-■• ;--•--; --..^ ,^ 



From the important functions of this organ, and its intri- 

 cate connexion with every part of the body, through the 

 minute distribution of its blood-vessels, it naturally sjnnpa- 

 thises with even the slightest derangement of the system or 

 other organs ; hence we find in most diseases its functions 

 are either increased or diminished, consequently we make 

 use of the action of the heart to determine the state of the 

 system. 



THE PULSE. 



The arteries are the vessels which convey the blood from 

 the heart to the system. " The blood nowhere passes through 

 an artery so rapidly as it is forced into it by the ventricles of 

 the heart, on account of the resistance offered by all the 



