284 BACTERIOLOGY. 



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. 



The results that follow upon the inoculation of ani- 

 mals with cultures of streptococci obtained from various 

 inflammatory 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. Between these extremes every 

 gradation may be expected. The virulence of a culture 

 is not necessarily proportional to the intensity of the 

 pathological process from which it is derived. 



There is never any certainty of faithfully repro- 

 ducing, by inoculation into susceptible animals, the 

 pathological lesion from which a culture of the organ- 

 ism may have been obtained. The introduction into a 

 susceptible animal of a culture derived from either a 

 spreadiag phlegmon or an erysipelatous inflammation 

 may result in erysipelas, general septicsemia, local ab- 

 scess-formation, or, as said, may have no effect at all. 

 Cultures may be encountered that are pathogenic for 

 one susceptible species of animals and not for another. 



Under the ordinary conditions of artificial cultiva- 

 tion fully virulent varieties of streptoeooous pyogenes 

 usually lose their virulence after a short time. 

 Petruschky' preserves this property by cultivation 

 upon nutrient gelatin for two days at 22° C, keeping 



^ PetruscWty : Centralblatt f iir Bakteriologie und Parasitenkunde. 

 X895, AU\>. i, Bsindxvjj, 



