182 MASS. EXPERIMENT STATION BULLETIN 167. 



si?:" 

 4w 



Graph i. {T>>'oTeo lysis) 



^6 



VZ 



/ZO Uci^r-s 



6 /Z /8 Z9 



Co^Trol _ ^. 



Sf-T-e/'/. e?-ysip€la^/S /??• Tryecf/'c''^ (^-7. 6S) 



Graph 1 represents the proteolysis of Streptococcus erysipelatis and 

 Streptococcus lacticus in the media of which the hydrogen ion concentra- 

 tion is (H)= 2.24X10"^ and (H)=2.40X10"^ respectively. The results 

 in these two media (the same within the limit of error) were especially 

 considered instead of the optimum hydrogen ion concentration for pro- 

 teolysis in the case of each organism. The reason for this is to be found 

 in an effort to comply with the purpose of this investigation. 



