192 



A fore-period of 1 hour has no ejffect, as might be 

 expected, because there was as yet no pure nitrogen in 

 the thermostat. With a fore-period of 3 to 4 hours a 

 weakening of the reaction is clearly seen, whilst further 

 the table shows that seedlings which hâve been for 4 

 hours without oxygen, remain upright, notwithstanding 

 stimulation. (PI. XVIII, flg. 2). 



D. Phototropic experiments with Sinapis. 



TABLE 17. 



Strength of stimulus 400 M.C.S. Température 23° C. 



Reaction-time 60 minutes. 



