242 



L. A. ROGERS, W. M. CLA.RK AND H. A. LUBS 



data, that of some 300 cultures whose characters have been tabu- 

 lated by MacConkey and the data of 117 cultures reported by 

 Levine. The results obtained by Levine show that it is safe to 

 separate MacConkey's cultures into the high and low-ratio groups 

 by means of the Voges and Proskauer test. If we exclude the 

 eight grain cultures, the agreement among the low ratio cultures 

 is as close as could be expected after making proper allowance 

 for differences in methods. The relatively low percentage of 

 indol formers among the milk cultures is probably due to the use 

 of a method which was later found to give low results. 

 ^ It will be noted that there was an appreciably higher number 



/^yG^/3^t7X>,//iCAfA/l//^£CES 



yy^VSj G/M/A/ 



rvfBjcOj a/so//^ 



Fig. 4. A Comparison of the High Ratio Cultures from Feces with 

 Two Types from Grains 



of cultures fermenting sucrose, raffinose and dulcitol among the 

 bovine feces cultures than among those from human feces. 

 MacConkey's cultures, which in this respect are intermediate 

 between the human and bovine cultures, include 138 from feces 

 of various animals. 



While Levine's results as to the relative number of sucrose 

 fermenters in feces from various animals are not conclusive on 

 account of the comparatively small number from each source, he 

 found a decidedly higher percentage of sucrose and raffinose 

 fermenters among the cultures from the lower animals than among 

 those from man. The percentages for sucrose fermentation 

 ranged from 32.3 per cent for cultures from pigs to 95.5 per cent 

 for the sheep as against only 12 per cent for man. 



