PATHOGENIC BACTERIA. 



117 



antiseptic precaution has been taken ; but such a discharge is 

 free from bacteria, and no more like pus than a benign growth 

 is like a malignant one. 



Streptococcus Pyogenes. (Bosenbach.) Streptococcus erysipe- 

 latis. (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, Kosenbach 



FIG. 62. 



Streptococcus pyogenes in section of skin. 



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 gelatine. 



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 micro- 

 scope, looking yellowish, finely granular, the edges quite defined. 



Stab Cultures. Along the needle-track little separated colonies 

 like strings of beads, which after a time become one solid white 

 string. 



Stroke Culture. Little drops, never coalescing, having a bluish 

 tint. 



