224 bacteriology. 



The Less Common Pyogenic Organisms. — 

 The pus of an acute abscess in the human being may 

 sometimes contain other organisms beside the staphylo- 

 coccus pyogenes aureus. The staphylococcus pyogenes 

 albus and citreus may be found. The colonies of the 

 former are white, those of the latter are lemon-color. 

 The streptococcus pyogenes is also sometimes present. 

 The commonest of the pyogenic organisms however is 

 that just described — the staphylococcus pyogenes aureus. 



The Streptococcus Pyogenes. — From a spreading 

 phlegmonous inflammation prepare cultures. What is 

 the predominating organism ? Does it appear as irregu- 

 lar clusters of grapes, or has its individuals a definite 

 regular arrangement ? Are its colonies like those of the 

 staphylococcus pyogenes aureus ? 



Isolate this organism in pure cultures. In these cul- 

 tures it will be found to present an arrangement some- 

 what like a chain of beads. Determine its cultural 

 peculiarities and describe them accurately. 



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 just mentioned. Inoculate a rabbit 

 both subcutaneously and into the circulation with about 

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

 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? 



