ON AN IMPORTANT FUNCTION OF LEAVES. 



249 



V. Experiment zvith Compositae. 

 HeliantJiiis aimuiisP^ 



33 leaves. Dry weight. Ratio of dry matler. 



Evening 27.427 100.00 



Morning 24.266 88.50 



In 100 parts of dry matter. 



Evening. Morning. 



Total nitrogen 4.78 4.88 



Albuminoid nitrogen . 3.60 4.08 



Asparagine nitrogen 0.28 O.48 



Amido-nitrogen (.Ijf • • • •0-90 0.32 



Starch 8.50 7.50 



Absolute cjuantity in lOO leaves (in grams). 





Evening. 



Morning. 



Ratio. 





....3-976 



3-590 



100 : 90.3 



Albuminoid nitrogen'^^ 



2.990 



3.000 



100 : 100.3 



Asparagine nitrogen 



0.226 



0.344 



100 : 152 



Amido-nitrogen 



. . . .0.760 



0.246 



100 : 32.4 







5-535 



TOO : 78.3 



We see from the above experiments that in most cases 

 a considerable decrease of total and albuminoid nitrogen takes 

 place during tl*c night, and we observe also that the decrease of 

 proteids is greater in those cases where the decrease of carbohy- 

 drates is greater. In the experiments with Heliantlius and Pneralia 

 {Jciizit) the result differs from the other cases inasmuch as the 

 albuminoid nitrogen was found not to decrease during the night. 

 But this may be explained by the fact that the leaves gathered 

 in the evening had not been dried immediately and there- 

 fore had remained alive during the night, still carrying on 

 respiration. Thus, a splitting of proteids might have occurred 

 with accumulation of amido-compounds. Hence leaves gathered 



(I) 'I'his experiment was made on the i8th June. 



