Streptococcus Pyogenes 351 



lesions, fifteen times alone and five times in association 

 with Staphylococcus aureus. 



Morphology. The organisms are spheric, of variable size 

 (0.4-1 [i in 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) and Streptococcus brevis 

 (chains of from four to ten), have been described by v. 

 Lingelsheim,* but do not hold as separate species. 



It is not motile and does not form endospores, though 

 sometimes large individuals much larger than the others in 



Fig. 105. Streptococcus pyogenes, from the pus taken from an ab- 

 scess. X looo (Frankel and Pfeiffer). 



the chain may be observed. Some believe these to be 

 arthrospores. 



Staining. The organisms stain well with ordinary 

 aqueous solutions of anilin dyes and by Gram's method. 



Isolation. The streptococcus can be isolated from pus 

 containing it by plating or by the inoculation of a mouse or 

 rabbit, from whose blood it may easily be secured after 

 death. 



Cultivation. The organism grows at both the room tem- 

 perature and that of incubation, its best and most rapid 

 development being at about 37 C. 



* "Zeitschrift fur Hygiene," Bd. x, 1891, p. 331; xn, 1892, p. 308. 



