THE CIRCULATORY SYSTEM. 



439 



This gradually grows deiise, shrinks, aud assumes the characters of cica- 

 tricial tissue. 



This may occur in any part of the heart wall or in the papillary mus- 

 cles, but is most common in the region supplied by the anterior coronary 

 arteries. When the heart wall is involved the new -formed connective 



FIG. 234. CHRONIC INTERSTITIAL MYOCARDITIS (Fibrous Replacement Hyperplasia) . 



tissue may yield to the blood pressure from within and aneurism of the 

 heart be formed. 



Impaired nutrition of a portion of the heart wall as the result of nar- 



FIG. 235. CHRONIC INTERSTITIAL MYOCARDITIS. 



Showing transverse section of a portion of a papillary muscle. The nbrous tissue is dense and the muscle 

 fibres are atrophied. 



rowing or obliteration of the coronary arteries or their branches, whether 

 it lead to such extreme lesions as those just described, or to fatty degene- 

 ration, or to atrophy of the muscle cells with a production of new con- 



