CHAPTER IX. 



OTHER INTESTINAL BACTERIA. 



IT would be an obvious advantage if the evidence of 

 sewage contamination, furnished by the presence of B. o5 

 coli could be reinforced or confirmed by the discovery in ^ 

 water of other forms equally characteristic of the intestinal 2 

 canal. The attention of a few bacteriologists in England ^ 

 and America has been turned strongly in this direction 

 during the past few years; and two groups of organisms, 

 the sewage streptococci and the anaerobic spore-bearing ^ 

 bacilli, have been described as being probably significant. ^ 



The term "sewage streptococci" covers an ill-defined ^ 

 group including many organisms which do not actually 

 occur in well-marked chains. Those most commonly 

 found correspond, however, rather closely to the type of 

 Str. erysipelatos. They grow feebly on the surface of 

 ordinary nutrient agar, producing faint transparent, 

 rounded colonies, but under semi-anaerobic conditions 

 flourish better, giving a well-marked growth along the 

 gelatin stab and only a small circumscribed film on the 

 surface. They are favored by the presence of the sugars 

 and ferment dextrose and lactose, with the formation of 

 abundant acid but no gas. They are seen under the 



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