HELEN S. THOMAS 



205 



In 7,3 per cent ether solutions there was an immediate increase 

 in the rate of respiration which reached a maximum of 206 per cent 

 (106 per cent increase) in 8 to 9 minutes (Fig. 1, Curve A). This 



RATE 



100MIN(7rB5 



Fig. 1. Curves showing the rate of respiration of wheat seeds in 7.3 per cent 

 ether solution (Curve A) ; in.3.65 per cent ether (Curve B) ; and in tap water (Curve 

 C). Time is reckoned from the beginning of exposure to the ether solutions. 

 The normal rate (which is taken as 100 per cent) corresponds to a change from 

 pH 7.78 to pH 7.36 in 1.93 minutes for Curve A, in 2.28 minutes for Curve B, 

 and in 1.53 minutes for Curve C. Curve A represents the average of ten, Curve 

 B of five, and Curve C of four experiments. Probable error is less than 5 per 

 cent of the mean. 



