INFI^AMMATIONS IN THE HEART. 



These are among the most common diseases of this organ and 

 moreover lead to many of the changes in structure to be hereafter 

 noticed so that it is convenient to treat of them here. According 

 to their relative frequency they may be ranged : — ist. Inflamma- 

 tion of the external covering of the heart — pericarditis ; 2d. In- 

 flammation of the internal lining membrane of the heart — endo- 

 carditis ; and 3d. Inflammation of the muscular substance of the 

 heart — myocarditis. 



440 



