PATHOGENIC BACTERIA 



159 



Streptococcus Pyogenes (Rosenbach) ; Streptococcus 

 erysipelatis (Fehleisen) . Origin. Fehleisen discovered this 

 microbe in the lymphatics of the skin in erysipelas, and he 

 thought it the cause of the same. Under the name Streptococcus 

 pyogenes, Rosenbach described an identical coccus which has 

 been found in nearly all suppurative 

 conditions. 



Form. Small cocci singly and in 

 chain-like groups. Spores have not 

 been found, though it is supposed, 

 because of their permanency, that 

 spores are present. 



Properties. They are immotile; do 

 not liquefy gelatin. 



Fig. 94. Streptococcus 

 pyogenes: culture upon agar- 

 agar two days old (Frankel 

 and Pfeiffer). 



Fig. 95. Streptococcus pyogenes 

 (Jakob). 



Growth. They grow slowly, usually on the surface, and best 

 at higher temperatures. 



Colonies. In three days a very small grayish speck, which 

 hardly ever becomes much larger than a pin-head; under 

 microscope, looking yellowish, finely granular, the edges well 

 defined. 



Stab-cidtures . Along the needle-track little separated col- 



