OCCURRENCE OF CAUSATIVE AGENTS. 149 



demonstration of diphtheria-bacilli, has been recorded in 

 the literature. 



Almost equally as uncommon as diphtheric endocarditis 

 is also true typhoid endocarditis that is, that caused by the 

 Gaffky-Eberth bacillus. 



Tuberculous endocarditis has long been known. It attacks 

 with a certain degree of exclusiveness the thin margins of 

 the mitral leaflets, and particularly on their auricular sur- 

 face. Tubercle-bacilli have been repeatedly demonstrated 

 in the lesions. 



True gonorrhea! endocarditis is dependent upon the activ- 

 ity of the gonococcus, whose presence in the endocarditic 

 vegetations has been demonstrated by Leyden. 



The causative agent of the endocarditis following measles, 

 scarlet fever, smallpox, as well as the causes of the primary 

 disease, are still unknown. 



The endocarditis complicating acute nephritis is generally 

 caused by the same microorganisms (the exciting agents of 

 suppuration and inflammation) that give rise to the primary 

 morbid process in the kidneys. 



It is, however, to be emphasized that in all of the dis- 

 eases named, as well as in malaria and in carcinoma, the 

 concomitant endocarditis need not be due to the original 

 infecting pathogenic germ, but it may be the expression of 

 a secondary or of a mixed infection that has been engrafted 

 upon the endocardium, whose resistance has been lowered 

 by reason of the primary infection. Under such circum- 

 stances staphylococci, streptococci, diplococci, or the bac- 

 terium coli commune will be foun'd in the vegetations upon 

 the valves : in short, those microorganisms that have re- 

 peatedly been shown to be the cause of secondary infection. 



So-called malignant, ulcerative endocarditis is etiologi- 

 cally and clinically only a variety of ordinary endocarditis 

 pursuing a malignant course, and giving rise to necrosis of 

 the vegetations. If it is due to the common exciting agents 

 of inflammation staphylococci, streptococci, pneumococci, 

 or the bacterium coli commune it may be viewed as a 

 special form of pyemia, characterized by the localization 

 of the metastases on the valves of the heart. In isolated 

 c.ases of this kind the microorganisms were demonstrated 

 in the circulating blood during life. 



Experimental Development of Endocarditis by Means 

 Of Bacteria. After a previous lesion of the valves (through 



