138 



ESSENTIALS OF BACTERIOLOGY. 



FIG. 74. 



the formation of pus cannot be ascribed to any particular one 

 alone ; some, more common than others, are found in nearly all 

 forms of suppuration ; others give rise to special types. 



Wounds are often irritated by for- 

 eign bodies and chemicals, and a dis- 

 charge occurs in them even when 

 every aseptic and antiseptic precau- 

 tion has been taken ; but such a dis- 

 charge is free from bacteria, and no 

 more like pus than a benign growth 

 is like a malignant one. 



FIG. 75. 



Streptococcus pyogenes: cult- 

 ure upon agar-agar two days old 

 (Frankel and Pfeiffer). 



Streptococcus pyogenes (Jakob). 



Streptococcus Pyogenes. (Bosenbach.) Streptococcus erysipe- 

 latis. (Fehleisen.) 



Oi'igin. 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 



