96 



Journal of Agricultural Research 



Vol. XV, No. a 



The writer has been unable to find any considerable amount of levulose 

 in cabbage leaves by microchemical means. 



The cleavage of polysaccharids yields osmotically active substances 

 which account for the lower freezing point of juices expressed from 

 hardened plants. As Schaffnit {44) has shown, the sugars produced 

 may have a considerable influence on frost resistance by allowing the 

 solution to be undercooled to a greater degree or by preventing the pre- 

 cipitation of proteins. 



The carbohydrate changes were determined also in plants kept at 

 constant temperatures in the dark to determine the relation of carbo- 

 hydrate change to the time of acquiring hardiness (Table IV). 



Table IV.- 



■Analyses of carbohydrates in cabbage plants kept at constant temperatures 

 in the dark 



From Tables III and IV it is seen that hardiness is acquired before any 

 great change occurs in the carbohydrate equilibrium. A utilization of 

 both starch and the reducing sugars in cultures kept at higher tempera- 

 tures is noticeable, as well as the lack of any great change at the lower 

 temperatures. 



Analyses of hardened and nonhardened cabbages were also made by 

 a modification of Koch's (20) method. This method involves a separation 



