Rate of COg production 



150%-, 



ton 



Fig. 2. Curve showing the rate of respiration c>l\Bacillus subtilis (expressed as 

 per cent of the normal) as affected by various concentrations of MgCl2. 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. Average^of three experiments;^probable 

 error less than 3 per cent of the mean. 



334 



