230 BACTERIOLOGY.i 



marked tenacity to vitality, for it is not rare to ob- 

 serve recurrences of inflammatory conditions due to this 

 organism, often at a relatively long time after the 

 primary site of infection is healed 



When introduced into the tissues of lower animals its 

 effects are uncertain. Rosenbach and Passet claimed 

 that protracted, progressive, erysipelatoid inflammations 

 were produced, and Fehleisen, who described a strepto- 

 coccus in erysipelas that is in all probability identical 

 with the streptococcus pyogenes now under considera- 

 tion, stated that it produced in the tissues of rabbits 

 (the base of the ear) a sharply defined migratory red- 

 dening without pus-formation. As a rule, it is difficult 

 to obtain any definite pathological alterations in the tis- 

 sues of animals through the introduction into them of 

 cultures of this organism by any of the methods of in- 

 oculation ordinarily practised. 



This is the streptococcus pyogenes, and is the organ- 

 ism most commonly found in rapidly spreading suppu- 

 ration in contradistinction to the staphylococcus pyogenes 

 aureus, which is most frequently found in circumscribed 

 abscess-formations ; they may be found together. 



If the opportunity presents, obtain cultures from a 

 case of erysipelas. Compare the organism thus obtained 

 with the streptococcus j ust mentioned. Inoculate a rabbit 

 both subcutaneously and into the circulation with about 

 0.2 c c. of a pure culture of these organisms in bouillon. 

 Do the results correspond, and do they in any way 

 suggest the results obtained with the staphylococcus 

 pyogenes aureus when introduced into animals in the 

 same way ? Do these streptococci flourish readily on 

 ordinary media? 



The organisms that have just been described are com- 



