VAEIETIES OF COLON BACILLI 187 



On the whole, much of the English evidence tends to 

 the assumption that the atypical forms, or " paracolon 

 bacilli," generally represent weakened strains from the 

 intestinal B. coli stock. As Savage says, " we know 

 that nearly all the coli-like organisms in faeces are quite 

 typical B. coli, that in sewage a good many atypical 

 varieties are present, and that in contaminated water 

 and soil the proportion present is still larger." 



The data tabulated on p. 186 from Gage and Phelps 

 (1903) lead to a similar conclusion. About 60 per cent 

 of the cultures isolated from polluted river water, 

 filtered water, and sewage proved to be typical B. coli, 

 while 41 and 43 per cent of those isolated from spring 

 water and shellfish, respectively, and 48 per cent of 

 those from ice belonged in this class. 



Contradictory results, indicating a higher proportion 

 of typical forms outside the body than within it, have 

 been obtained by Konrich (1910) in the examination of 

 2387 different strains isolated in about equal propor- 

 tions from faeces, earth, and water. Of the 2387 coli- 

 like microbes studied, 308 were excluded by micro- 

 scopic examination (showing abnormal morphology or 

 positive Gram reaction) or by their liquefaction of 

 gelatin. The other 2079 strains were tested in sugar 

 media and peptone water with the results tabulated 

 on p. 188. 



We are inclined to attribute these results of Konrich's 

 largely to the technique which he employed. It seems 

 to be clearly stated in his paper that he obtained his 

 faecal cultures by direct plating on solid media, while 

 his earth and water samples were treated to preliminary 



