MATILDA M. BROOKS 



Is 0.1 M the rate is normal, while in higher concentrations there is 

 a decrease in rate. These curves are selected from a number of 

 similar typical curves, and each represents one experiment. 



Rate of CO2, production 

 150^ 



o0.05n 



100 -- 



so- 



so- 



X0.inand0.0£n 



oagsM 



O0.35M 



l.OM 



— r— 

 30 



60 mm. 



Fig. 2. Curves showing the rate of respiration of Bacillus subtilis (expressed as 

 per cent of the normal) in 0.05, 0.1, 0.25, 0.35, and 1.0 m CaCb. The zero point 

 on the abscissa denotes the beginning of exposure to the salt solution; previous to 

 this the bacteria were in 0.75 per cent solution of dextrose in distilled water. 

 The normal rate (which is taken as 100 per cent) represents a change in pH value 

 from 7.78 to 7.60 in a number of seconds depending upon the amount of bacterial 

 suspension used, usually 30 seconds. Each curve represents a single typical 

 experiment. 



