12 



STUDIES ON RESPIRATION. VIII 



Rate of CO2 production 



1507o-, 



100 



! 



0.5 



1.0 M 



Fig. 4. Curves showing the rate of respiration of Bacillus subtilis (expressed as 

 per cent of the normal) as effected by salts. 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 sec- 

 onds. Average of three experiments; probable error less than 3 per cent of the 

 mean. 



