470 JAMES M. SHERMAN AND GEORGE E. HOLM 



effect varies with the nature of the salt. On the other hand, 

 a salt (e.g., Na citrate) which lowers the rate of growth also 

 narrows the limits of H-ion concentration at which Bact. coli 

 will grow. Table 4 shows the results obtained with NaCl and 

 Na citrate, as compared with pepton alone, at different H-ion 

 concentrations. These results are shown to better advantage 

 in figure 2 which brings out clearly the widening effect on the 

 limits of growth with NaCl, while Na citrate shows a decided 

 narrowing of the range. 



REFERENCE 

 Holm, G. E., andShkrman, J. M. 1921 Jour. Bact., 6,511. 



