LESS COMMON PYOOENIC ORGANISMS. 283 



It grows best at the temperature of the body (37.5° 

 C), and develops, but less rapidly, at the ordinary room- 

 temperature. When virulent this property is said by 

 Petruschky to be preserved by retaining the cultures in 

 the ice-chest after they have been growing on gelatin 

 for two days at 22° C. 



Its virulence may often be increased by passing it 

 through a series of susceptible animals. 



It is a facultative anaerobe. 



It stains with the ordinary aniline dyes, 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. 



The results of its inoculation into the tissues of 

 lower animals are described by Eosenbach 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- 

 Gocem 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- 

 formation. 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- 



