280 STREPTOCOCCUS-PNEUMOCOCCUS GROUP 



tissues and the portal of entry play a prominent part in determining 

 both the type of lesion which will result from invasion of the body 

 by streptococci, and the modification in virulence they may undergo 

 in man or animal as the struggle between host and invader is extended 

 in time. 



Prophylaxis. General surgical aseptic methods. Autogenous vac- 

 cines have been extensively used in streptococcus infections, but with 

 less favorable results than autogenous staphylococcus vaccines. 



The Streptococcus Einheit or Vielheit. Considerable discussion 

 has arisen concerning the unity or the plurality of types included 

 within the organism known as Streptococcus pyogenes. Marmorek 1 

 and others have stoutly maintained the Einheit theory. Considerable 



FIG. 36. Pneumococcus mucosus showing capsule. X 1000. 



evidence in favor of this view was advanced by Koch and Petruschky, 2 

 who showed that a streptococcus obtained from a fatal puerperal 

 sepsis caused erysipelas in a rabbit when it was injected subcutaneously, 

 peritonitis when injected intraperitoneally, and septicemia when 

 introduced intravenously. The organisms freshly isolated caused a 

 rapidly fatal septicemia when introduced through the blood stream, 

 but the virulence was gradually lost following cultivation on artificial 

 media; the septicemic phenomena diminished in intensity and there 

 was evidence of a localization of the organisms. Their conclusions 

 were that the type of lesion produced by Streptococcus pyogenes 

 depended largely upon the virulence of the culture, the tissue invaded, 

 and the number of organisms. With a comparatively slight loss in 

 virulence the endocardium appeared to be somewhat more frequently 



1 Berl. klin. Wchnschr., 1902, xxxix, 299. 



2 Loc. cit. 



