MYOCARDITIS. 323 



frequently associated with pernicious anemia, leukaemia, 

 phthisis and other wasting diseases ; and with arsenic- and 

 phosphorus-poisoning. 



The macroscopic appearance of the heart is quite character- 

 istic. It is usually pale, flabby, and dilated. The degene- 

 rative change generally occurs in patches, the matted appear- 

 ance produced thereby being most readily seen from within, 

 beneath the endocardium. When the process is diffuse the 

 cardiac muscle has a uniform yellowish hue. 



Myomalacia cordis is a localized softening a necrosis of 

 the heart-wall due to embolic or thrombotic obstruction of the 

 coronary arteries. The area from which the blood is cut off 

 is often wedge-shaped, pale yellow in color, and depressed 

 below the surface. 



Amyloid and hyaline degenerations are sometimes noted. 

 Calcareous infiltration of the myocardium occurs, but is ex- 

 tremely rare. 



INFLAMMATIONS. 



Myocarditis. 



Inflammation of the heart-muscle may be primary, but is 

 much more frequently secondary to a peri- or endocarditis. 

 It occurs in the course of acute infectious fevers, as typhoid, 

 diphtheria, scarlet fever, smallpox, and puerperal septicaemia. 

 The heart-muscle is friable and has a yellowish-red and 

 matted appearance ; the cavities are usually dilated. Micro- 

 scopically, there is noted in addition to the cloudy swelling 

 of the muscle-fibres a round-celled infiltration of the sup- 

 porting connective-tissue framework ; some are proliferated 

 connective-tissue cells, the majority, however, being migrated 

 leukocytes. Abscesses, appearing macroscopically on section 

 of the heart-wall as yellowish-white spots, may occur. They 

 are most frequent in the anterior wall of the left ventricle, and 

 vary from the size of a pinhead to that of a cherry. 



In fibrous or chronic myocarditis there is a great increase in 

 the interstitial connective tissue. This fibroid change -or 

 substitution may be diffuse or circumscribed. Diffuse inter- 

 muscular sclerosis is often associated with general arterio- 



