102 ELEMENTS OF WATER BACTERIOLOGY 



negative non-spore-forming rod, but there was unanimity 

 in no other respect; 26 of the 34 included the formation 

 of acid and gas in dextrose media, 22 the coagulation 

 of milk, 21 the formation of indol, 18 the formation 

 of acid and gas in lactose media, and 18 the failure to 

 liquefy gelatin. No other test was used by more than 

 13 out of the 34 observers. Konrich (1910) himself 

 found that of over 600 colon-like organisms from faeces, 

 all produced gas in dextrose broth, 79 per cent formed 

 acid and 77 per cent gas in lactose broth, 65 per cent 

 coagulated milk, 59 per cent fermented dextrose at 

 46, 54 per cent reduced neutral red, 38 per cent formed 

 indol. 



Ferreira, Horta and Paredes (i9o8 a ) studied 117 

 strains of lactose-fermenting bacilli from human faeces. 

 All proved to be motile and Gram negative, all coag- 

 ulated milk and produced fluorescence in neutral red 

 media, none liquefied gelatin in 15 days, all but one 

 formed indol. Dextrose, lactose, maltose, galactose, 

 and mannit were fermented by almost all strains, 

 while gas was formed in saccharose by 38 per cent, 

 in dulcite by 69 per cent and in inulin by 12 per cent 

 of the strains studied. The " Proskauer reaction " 

 (apparently the Voges-Proskauer reaction, though it 

 is not quite clearly stated) was positive only 8 times 

 out of 117 strains in dextrose, only 7 times (out of 48 

 strains tested) in galactose, and not at all in dulcite or 

 inulin; lactose and maltose, on the other hand, showed 

 it in almost every case. Copeland and Hoover (1911) 

 report that out of 3000 colon-like organisms fermenting 

 -lactose bile 65 per cent gave positive tests for B. coli 



