200 



STUDIES ON RESPIRATION. Ill 



To show what effect a longer exposure to ether would have upon 

 the bacteria, another set of plates was poured in the same manner as 

 the first set except that the bacteria were allowed to remain in ether 

 for 1 hour. The solutions tried were (1) tap water, (2) saturated 

 solution of ether (about 7.3 per cent in tap water), (3) 0.85 per cent 



ETHER 



Fig. 5. Curve showing the effect of various concentrations of ether on the 

 growth of B. suhtilis. The ordinates denote the number of colonies expressed as 

 per cent of the normal, which is taken as 100 per cent. 



The figures expressing the per cent of ether should be corrected by multiplying 

 by 0.73. 



NaCl in tap water, and (4) saturated solution of ether in 0.85 per 

 cent NaCl solution. The following results were obtained, averaging 

 nine trials and counting tap water as 100 per cent. 



