296 SOME RECENT RESEARCHES IN PLANT PHYSIOLOGY 



TABLE LXVII. 



JUICE PRESSED FROM LARGE LEAVES OP HEALTHY BEET PLANTS AT 

 VARIOUS TIMES. 



These results apparently point to a considerable increase 

 in the amount of oxidase during the period of illumination. 



Bunzel, however, has pointed out that, when calculated 

 on a basis of the total solids in the tissue yielding the sap, 

 the oxidases are seen to fall off to about four-fifths of their 



former value, as shown in the column under - 



J 



where R denotes oxidase units and J represents the total 

 solids in the samples. This, it must be remarked, seems to 

 the writer to give an exaggerated idea of the actual decrease ; 

 for though Bunzel intends the ratio to give a measure of 

 the amount of the net loss of water by transpiration, in 

 reality it points to an erroneous value, since the total 

 solids are altered not only by this, but by storage of the 

 sucrose assimilated as shown in Bunzel's own analyses. 

 Nevertheless, there is no doubt that this does not invali- 

 date Bunzel's conclusion. In the first two experiments 

 in the preceding table, chemical analyses of the tissue 

 were not performed, but it seems likely that the apparent 

 increase in oxidase is to be accounted for by excessive 

 transpiration in their case also. 



