BACTERIA AND ENZYMES IN AGRICULTURE 269 



(a) At once ; 



(b) After treatment with invertase to hydrolyse the cane 

 sugar ; and 



(c) After complete inversion by means of hydrochloric acid. 

 In this way cane sugar, dextrose, laevulose and maltose 



were determined, and it was found in every case that the leaves 

 which had been exposed to light, under conditions where 

 assimilation processes were in the ascendant, always contained 

 cane sugar in greater proportion than any of the other sugars 

 present. 



Thus, to take one example, leaves picked at 9 A.M. on a dull 

 morning yielded the following analysis : 



Starch 3'24 



Cane sugar . . . . . . 4*94 



Dextrose 0'81 



Laevulose . . . . . . 4*78 



Maltose 1-21 



Leaves picked at 4 P.M. on the same day after seven hours 

 of sun gave : 



Starch 4'22 



Cane sugar . . . . . . 8 '02 



Dextrose O'OO 



Lsevulose . . . . . . 1*57 



Maltose 3'62 



It has been possible to synthesise in the laboratory all 

 the various sugars isolated by Brown and Morris ; but one 

 important difference exists between the products formed in 

 the laboratory, and those produced by the activity of the plant 

 cell. In all cases where a synthesis is effected in the laboratory 

 by purely chemical means, optically inactive derivatives 

 result, that is, mixtures of right-handed and left-handed forms 

 in equal proportions. It is of course possible, by methods 



