246 BACTERIOLOGY. 



have no reason to believe that it enters a stage where its 

 resistance to detrimental agencies is increased. In the 

 tissues of the body, however, it appears to possess a 

 marked tenacity to vitality, for it is not rare to observe 

 recurrences of inflammatory conditions due to this organ- 

 ism, 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 auy 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 organism 

 most commonly found in rapidly spreading suppuration 

 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 just mentioned. Inoculate rab- 

 bits both subcutaneously and into the circulation with 

 about 0.2 c.c. of pure cultures of these organisms in 

 bouillon. Do the results correspond, and do they in 

 any way suggest the results obtained with the staphylo- 

 coccus pyogenes aureus when introduced into animals 



