670 I. J. KLIGLER 



carbohydi'ate the organism actively attacks the nitrogenous com- 

 ponents of the medium, neutrahzing the acid and gradually 

 returning to the alkahne phase. The phosphate evidently takes 

 care of the free acid, thus keeping the ionic concentration below 

 the lethal point and enabling the organism to proceed in its 

 activity. As a result of this regulative power the amount of 

 sugar which a particular species can completely utilize varies 

 within limits with the relative amount of primary phosphate 

 salts present in the medium. Thus, in the presence of only 0.2 

 per cent phosphate, 0.3 per cent sugar is completely digested (as 

 indicated by the low hydrogen ion concentration) by only four 

 organisms (18, 24, 40 and 135) while only two (24 and 40) can 

 use up 0.4 per cent glucose. In the presence of 0.3 per cent 

 phosphate on the other hand 0.3 per cent glucose is also broken 

 down by number 19; and when 0.4 per cent phosphate is added 

 all but one are capable of completely destroying 0.3 per cent 

 sugar, while five (18, 19, 24, 40 and 135) can even use up 0.4 

 per cent glucose. On increasing the amount of sugar to 0.5 

 per cent even in the presence of 0.5 per cent phosphate only 

 19, 24 and 40 reach the alkaline phase (see table III). 



C. Amount of sugar digested by different species. Aside from 

 the effect of varying concentrations of phosphate, the different 

 types manifest specific differences in their power to digest defi- 

 nite quantities of glucose under a given set of conditions. These 

 differences are not attributable to the toxic action of the high 

 hydrogen ion concentration on the cell, alone. Why one organ- 

 ism (11, for instance) (see table IV) should not be able to use 0.3 per 

 cent glucose while number 18 will do away with 0.4 per cent 

 with the same amount of phosphate (see table IV), when both 

 reach approximately the same limiting hydrogen ion concentra- 

 tion (4.8 and 4.9, respectively, table IV, section B), is not evident 

 on the surface. The difference is partly explicable on the basis 

 that number 18 (B. enteritidis) carries the fermentation further 

 than number 11 {B. typhi), thus removing the acid and its 

 inhibitive effects. But this would not explain the differences 

 between numbers 17, 18 and 19, for instance, all gas-producing 

 forms. We must assume either that there are inhibiting factors 



