STREPTOCOCCUS PYOGENES. 285 



It stains with the ordinary aniline (lyes, and is not 

 decolorized when subjected to Gram's method. 



It is not motile, and, being a micrococcus, does not 

 form endogenous spores. Under artificial conditions 

 we have no reason to believe that it enters a stage in 

 which its resistance to detrimental agencies is increased. 

 In the tissues of the body, however, it appears to pos- 

 sess marked vitality, for it is not rare to observe 

 recurrences of inflammatory conditions due to this 

 organism, often at a relatively long time after the 

 primary site of infection has healed. 



Streptococcus pyogenes is the organism most commonly 

 found in rapidly spreading suppurations, while micrococ- 

 cus aureus is most frequently found in circumscribed 

 abscess formations ; they may also be found together. 



The results of its inoculation into the tissues of 

 lower animals are described by Rosenbach and Passet 

 as protracted, progressive, erysipelatoid inflammations ; 

 and Fehleisen, who described a streptococcus in erysip- 

 elas that is in all probability identical with the strepto- 

 coccus pyogenes under consideration, stated that it pro- 

 duced in the tissues of rabbits (the base of the ear) 

 a sharply defined, migratory reddening without pus- 

 lornuition. The writer has encountered a culture of 

 this organism that possessed the property of inducing 

 erysipelas when introduced into the skin of the ear, and 

 disseminated abscess-formation when injected into the 

 circulation of rabbits. This observation has an im- 

 portant bearing upon the question concerning the iden- 

 tity of streptococci found in various inflammatory con- 

 ditions, such, for instance, as the spreading erysipelatoid 

 manifestations on the one hand, and the circumscribed 

 abscess-formations on the other. 



