212 TRANSACTIONS AND PROCEEDINGS OF THE [Sess. lviii. 



The results obtained in this rather imperfect series of 

 experiments are too few in number to justify taking an 

 average. They show, broadly, for white wheat an increased 

 activity in the respiration under the influence of light ; but 

 in the case of red wheat, in the two experiments recorded,, 

 there appears to be a small increase in the oxygen absorbed 

 and carbonic anhydride excreted in favour of the samples 

 grown in darkness. 



These experiments, though they can hardly be considered 

 decisive as to the action of light, bring to notice a 

 peculiarity in the respiration of wheat which I have never 

 met with in barley, that is, the volume of carbonic anhy- 

 dride excreted generally exceeds in volume the amount of 

 oxygen absorbed by the seeds. In the case of barley there 

 is always more oxygen absorbed than carbonic anhydride 

 excreted. This peculiarity of wheat certainly deserves 

 further study. 



It is more than probable that a portion at least of the 

 oxygen absorbed by germinating wheat is retained, and does 

 not appear again as carbonic anhydride, as is the case with 

 germinating barley. If this is so, a considerable percentage 

 of the carbonic anhydride excreted by germinating wheat 

 cannot be accounted for as derived from the splitting up of a 

 carbohydrate, and we must look to more complicated bodies, 

 probably some of the nitrogenous compounds, for its source. 



As with barley, I made a few experiments to determine 

 the action of light on the respiration of germinating wheat, 

 when the carbonic anhydride excreted was allowed to- 

 remain in contact with the seeds. Contrary to expecta- 

 tion, white wheat still showed an increased activity in 

 respiration under the influence of light, and red wheat still 

 showed a little in favour of obscurity : — 



