PYOGENIC BACTERIA. 285 



Ulcerative endocarditis has been shown by the researches of 

 numerous bacteriologists to be occasionally accompanied by a mycotic 

 invasion of the affected tissues by the golden staphylococcus ; in 

 other cases Streptococcus pyogenes is present. The researches of 

 Weichselbaum, and of E. Frankel and Sanger, also show that it is 

 present in a certain proportion of the cases, at least, of endocarditis 

 verrucosa, although in smaller numbers. That the diseased condi- 

 tion of the cardiac valves in ulcerative endocarditis is due to mycotic 

 invasion is now generally admitted and is supported by experimental 

 evidence. Rosenbach first (1873) produced an endocarditis in lower 

 animals by mechanical injury to the cardiac valves, effected by in- 

 troducing a sound through the aorta. Following his method, Wys- 

 sokowitsch (1885), after injuring the cardiac valves in rabbits, in- 

 jected into the circulation pure cultures of various bacteria. He 

 obtained positive results with Staphylococcus aureus and Strepto- 

 coccus pyogenes only. When these micrococci were injected into 

 the trachea or subcutaneously the result was negative, as was the 

 case when very few cocci were injected into a vein, or when two 

 days or more were allowed to elapse after injury to the cardiac 

 valves. Subsequently Weichselbaum, Prudden, and Frankel and 

 Sanger obtained confirmatory results, thus establishing the fact that 

 when the valves are first injured mechanically (or chemically 

 Prudden) the injection into a vein of a pure culture of Staphylococcus 

 aureus gives rise to a genuine ulcerative endocarditis. It has been 

 further shown by Ribbert that the same result may be obtained with- 

 out previous injury to the valves by injecting into a vein the staphy- 

 lococcus from a potato culture suspended in water. In his experi- 

 ments not only the micrococci from the surface but the superficial 

 layer of the potato was scraped off with a sterilized knife and mixed 

 with distilled water ; and the successful result is ascribed to the fact 

 that the little agglomerations of micrococci and infected fragments 

 of potato attach themselves to the margins of the valves more readily 

 than isolated cocci would do. In these experiments the mitral and 

 tricuspid valves were affected, while the semilunar valves remained 

 intact. In ulcerative endocarditis it is evident that cocci detached 

 from the diseased valves must find their way into the circula- 

 tion. As a matter of fact, masses of micrococci are carried away by 

 the blood stream and form emboli in various parts of the body, which 

 become secondary foci of infection and give rise to local necrotic 

 changes and accumulations of pus. While this undoubtedly occurs, 

 it is generally admitted that the mycotic infection of the cardiac 

 valves is usually a secondary affection, resulting from the transpor- 

 tation of micrococci in the blood current from some other infected 

 focus. But there is no general development of micrococci in the cir- 



