446 



THE CIRCULATOJRY SYSTEM. 



3". Chronic Endocarditis may succeed acute endocarditis, or the inflam- 

 mation may be chronic from the outset. It affects most frequently the 

 aortic and mitral valves, and the endocardium of the left auricle and 

 ventricle ; similar changes in the right side of the heart being much less 

 frequent. 



There are two main anatomical varieties of chronic endocarditis, which 

 may occur separately or together. 



(1) The endocardium is thick and dense, its surfaces are smooth or 

 covered with small, hard vegetations or ridges (Figs. 239 and 240), it is 

 often infiltrated with the salts of lime. 



(2) There is a growth of connective-tissue cells in the endocardium, 



FIG. 244. CHRONIC ENDOCARDITIS. 

 Showing fibrous " vegetation " on the mitral valve. With a large blood clot formed upon Jt. 



with a splitting-tip of the basement substance. Some of the new cells 

 continue to live, others degenerate. By the combination of such a cell 

 growth and destruction the endocardium is in some places destroyed, in 

 others changed into projecting vegetations (see Fig. 243). Fibrin is 

 deposited on the roughened surfaces (Fig. 244). After a time the con- 

 dition may be further complicated by the shrinkage and deposition of 

 the salts of lime in the new tissue and in the endocardium (Fig. 241). 

 All these changes may extend to the wall of the heart beneath the endo- 

 cardium. 



The most important result of chronic endocarditis is its effect on 

 the heart valves, producing insufficiency and stenosis (Fig. 242). The 

 changes in the valves are followed by changes in the walls and 



