Experiment B. The effect of hydrogen ion concentration upon the mortality of Bact. 

 typhosum for forty-eight hours in M/BOO buffer solutions at 20°C. 



Experiment 6. Mortality of Bact. typhosum in M/SOO buffer of pH S.5 at different 



temperatures 



Note: The buffer consisted of 50 cc. M /5 potassium acid phthalate plus 14.7 cc- 

 M/5 HCI in 5000 cc. distilled water. Tliis had a pH of 3.2 which shifted to 3.5 

 during sterilization. 



226 



