STREPTOCOCCUS PYOGENES 341 



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 micrococcus 

 aureus is most frequently found in circumscribed abscess 

 formations; they may also be found together, and these 

 relationships may be reversed at times. 



The results of its inoculation into the tissues of lower 

 animals are described by Rosenbach and Passet as pro- 

 tracted, progressive, erysipelatoid inflammations; and Feh- 

 leisen, who described a streptococcus in erysipelas that is 

 in all probability identical with the streptococcus pyogenes 

 under consideration, stated that it produced in the tissues 

 of rabbits (the base of the ear) a sharply defined, migratory 

 reddening without pus-formation. The writer encountered 

 a strain 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 important 

 bearing upon the question concerning the identity of strep- 

 tococci found in various inflammatory conditions, such, 

 for instance, as the spreading erysipelatoid manifestations 

 on the one hand, and the circumscribed abscess-formations 

 on the other. 



The results that follow upon the inoculation of animals 

 with cultures of streptococci obtained from various inflam- 

 matory lesions are, as a rule, inconstant. At times cultures 

 will be encountered that are apparently without virulence, 

 no matter how tested; while again cultures from other 

 sources exhibit the most marked pathogenic properties, 

 even when employed in almost infinitesimal quantities. 



