DISINFECTION STUDIES 



205 



The behavior of Bad. typhosum and Boot, coli at pH 3.5 at different 



temperatures 



Since it became possible to eliminate variability in the results 

 between duplicate bottles by means of control of pH, we could 

 proceed to the study of the effect of temperature upon the death 

 of these organisms. 



Fig. 6. Experiment 6. The Death Rate of Bact. ttphostjm in M/500 

 Phthalate Buffer, pH 3.5 at 0°, 10°, 20° 30°C. 



Closely parallel duplicate curves are omitted 



Experiments 6 and 7 were conducted at a comparatively high 

 acidity (pH 3.5) in order to obtain a comparison of the relative 

 rates of dying of these two organisms at 0°, 10°, 20° and 30°C. 

 Such a comparison is not feasible at less intense acidities because 

 of deviations of the disinfection curve from the simple logarithmic 

 form, due to the predominance of certain factors referable to 

 the specific peculiarities of each organism. This will be con- 

 sidered later. 



