210 ELEMENTS OF WATER BACTERIOLOGY 



COMPARATIVE FERMENTATIVE POWER OF STREPTO- 

 COCCI FROM THE HORSE, THE COW, AND MAN 



(WiNSLow AND Palmer, 1910) 



The rarity of lactose-fermenting streptococci in the 

 horse makes it probable that this group can be used for 

 distinguishing pollution by street washings from that 

 due to domestic sewage; and the fact that a considera- 

 bly larger proportion of human strains attack mannite 

 and a considerably larger proportion of bovine strains 

 ferment raflGinose should make it possible to use the 

 ratio between results in these two media to distinguish 

 between the wash from pastures and cultivated land 

 and sewage. Clemesha (1912*) in India found that 

 both human and bovine faecal streptococci fermented 

 raflSinose, saccharose, and salicin, but not mannite. 

 Fuller and Armstrong, however (Journal of Infectious 

 Diseases, 1913, XIII, 442), confirm the results obtained 

 by Winslow and Palmer, finding that lactose-fermenting 

 streptococci of any kind are rare in horse dung, that 

 the streptococci of bovine faeces characteristically fer- 

 ment lactose and rafiinose, while the fermentation of 

 lactose and mannite is usual among human faecal 

 strains. The results of these workers were more con- 

 sistent than those tabulated above, 65 per cent of 

 the human strains being of the S. faecalis type (man- 



