ENDOCARDITIS. 347 



defined losses of substance in the endocardium, which, immediately 

 around the ulcer, is swollen and thickened. The floor of the ulcer 

 is formed by the muscular substance of the heart, which is infiltrated 

 with pus. 



Endocarditis is accompanied by myocarditis, that is to say, the car- 

 diac muscles take part in the inflammation with far greater frequence 

 than was formerly supposed. At other times, the inner layers of the 

 cardiac wall which lie next to the inflamed endocardium become the 

 seat of infiltration, which fully explains why the cardiac wall loses 

 its tone, and why endocarditis is apt to be followed by dilatation of the 

 heart. 



The fibrinous deposits, which almost always cover the vegetations 

 upon the valves, may, if broken loose by the current of the blood, occa- 

 sion disorder of a different kind ; and baneful as the ulterior effects of 

 endocarditis are upon the system, yet almost the only source of dan- 

 ger, during the height of the disease, consists in the liability of these 

 little coagula (emboli) to wash away. Should any of them be broken 

 off by the current and borne into the circulation, hgemorrhagic infarction 

 and metastatic abscess will be the result. We have discussed the pa- 

 thogeny of these processes in detail, while treating of metastasis into the 

 lung. Here, however, it is not the lungs in which the infarctions arise, 

 but, in the vast majority of cases, the embolus gets into the artery of the 

 spleen, blocks up some one of its minuter branches, and, a wedge- 

 shaped spot, with the apex pointing inward and the base outward, is 

 established, which is at first of a blackish red, afterward assumes a 

 yellow hue, and passes into a state of caseous degeneration. 



We sometimes see spots of this kind in the kidney ; but they are 

 far more rare than hasmorrhagic infarction of the spleen, which is met 

 with post mortem, with extraordinary frequence. In the liver they 

 are still less common, and, as we have just observed, they are rarest 

 of all in the lungs. In the two latter organs indeed, one could hardly 

 conceive of the occurrence of infarction, unless a branch of the hepatic 

 artery or bronchial artery, but not of the portal vein or pulmonary 

 artery, were to be obstructed. 



That abscesses, instead of infarction, should be so rarely found i:; 

 endocarditis, is explained from what we have said already upon the 

 pathogeny of metastasis. The embolus which here obstructs the 

 artery does not come from a collection of putrefying material, as 

 emboli of the lungs so often do, but consists of coagulated fibrin, a 

 fact which is unfavorable for the conversion of the infarction into an 

 abscess. 



Should a somewhat large fibrinous clot pass into one of the caro- 

 tids, or vertebral arteries, then, accordingly as the artery of the brain is 



