193 



In this case also after a fore-period of 3 hours in 

 nitrogen a weakened reaction is seen to take place, whilst 

 it further follows from the table, that seedlings, which 

 hâve passed 4 hours in a space without oxygen are no 

 longer able to react to the stimulus. 



A comparison of the results of the experiments with 

 Avena and with Sinapis shows that, in the case of the 

 latter the reaction is indeed abolished sooner, but the 

 différences are too slight to allow of the déduction that 

 the seedlings of Avena react so much longer in conséquence 

 of the oxygen présent in the space under the coleoptile. 

 If this were the case, then the différence between the two 

 would hâve to be greater and the irritability in Sinapis 

 would hâve to disappear much earlier. I think I may 

 therefore conclude that in both cases it is due to intra- 

 molecular respiration that a stimulus can yet hâve an 

 efFect after the seedlings hâve passed a somewhat long fore- 

 period in nitrogen. 



