MYOCARDITIS. 355 



primitive fasciculi are filled up by connective tissue, and thus a scar is 

 formed in the heart-wall ; or else the perimysium breaks down simul- 

 taneously with the muscular fibrillse, and a mass of debris collects in 

 the substance of the wall. This is called an abscess of the heart. 



Myocarditis is not a rare affection, and we find post-mortem signs 

 of its former existence in many cases of valvular disease of the heart 

 resulting from endocarditis. Indeed, the etiology of myocarditis is, in 

 a great measure, identical with that of endocarditis, acute articular 

 rheumatism acting most frequently as the cause in either disease. 

 Myocarditis, thus excited, usually appears in the form of mere circum- 

 scribed spots, which terminate in scar-like alterations of a portion of the 

 cardiac wall ; but in more rare instances it may result either in extensive 

 degeneration, which may give rise to a chronic aneurism of the heart, 

 or else may produce cardiac abscess. In most cases we may regard 

 nyocarditis accompanying acute rheumatism as an extension of a con- 

 comitant endo- or pericarditis. In other cases, however, the disease 

 runs a more independent course, is more extensive than any attendant 

 endo- or pericarditis, which, in their turn, may then be considered as de- 

 pending upon the inflammation of the heart's substance. 



Chronic disease of the heart, particularly valvular disease, leads to 

 myocarditis, and to formation of scars in the heart quite as often as 

 to endocarditis. 



Emboli, proceeding from gangrenous lungs, not unfrequently enter 

 the coronary arteries of the heart, and we then see numerous abscesses 

 in its wall, as well as abscesses in many other organs of the aortic 

 circulation. 



Septicaemia, protracted typhus, tedious and malignant scarlatina, 

 even though the occurrence of embolism be not proved, nay, though it 

 be very unlikely, may also give rise to abscess of the heart. The 

 pathogeny of such abscesses is obscure. 



In the second volume we shall treat of syphilitic myocarditis, when 

 we come to treat of syphilis in general. Traumatic myocarditis, like 

 traumatic endocarditis, is one of the greatest of rarities. 



ANATOMICAL APPEARANCES. The seat of myocarditis is almost ex- 

 clusively the left ventricle, especially the apex ; but quite as frequently 

 (according to Dittrich) it occurs in the septum just below the aorta. 

 The papillary muscles, however, are often affected by the disease, 

 which fact is of importance to the pathogeny of deformity of the valves, 



At the outset of the malady, the muscular substance appears of a 

 dark bluish-red hue. Soon, however, the injection disappears, and dis- 

 coloration of the muscular fibre arises, the diseased place becoming of 

 a grayish color and softened. Under the microscope, after the trans- 

 and longitudinal striae have disappeared, we see the fibrillae 



