Streptococcus Pyogenes 309 



study because of still existing uncertainty as to whether there is a 

 single species or whether there are various species, but opinion, at 

 present, seems in favor of the opinion that there is but one strep- 

 tococcus whose various manifestations depend upon its virulence, 

 upon the resistance of the host, upon its avenue of entrance, and 

 the associated micro-organisms with which it happens to engage. 



Streptococci may be primary pathogenic agents, or they may be 

 secondary agents whose activities complicate, modify and sometimes 

 outweigh in importance those of the primary agents. 



They are the primary infecting agents in many inflammatory, 

 purulent and septicemic disturbances — erysipelas, cellulitis, phleg- 

 mons, osteomyelitis, puerperal infection, pseudo-membranous angina, 

 phlebitis, salpingitis, meningitis, endocarditis, etc. 



Fig. 109. — Streptococcus pyogenes, from the pus taken from an abscess. 

 . X 1000 (Frankel and Pfeiffer). 



Berson points out that they are secondary agents of importance 

 in all pathological conditions of the throat of whatever nature. 



Hektoen found them to be the most frequent complicating organism 

 in scarlatina and Councilman the most frequent complicating 

 organism in variola. 



The suppurative conditions for which streptococci are held to be 

 responsible, differ from those caused by staphylococci in being more 

 rapidly spreading, more locally destructive, and more prone to 

 generalized infection or septicemia. 



Morphology. — The organisms are spheric, of variable size (0.4-1 n 

 m diameter), and are constantly associated in pairs or in chains of 

 from four to twenty or more individuals. Special varieties, known 

 as Streptococcus longus (chains of more than one hundred members) 



