THE METHOD OF MOVEMENT 191 



There were also two conditions of storage, moist and dry. 

 For the most part the data are expressed as percentages 

 of dry weight, but since the water contents are also given 

 the sugar contents per 100 g. of water can be easily calcu- 

 lated. Expressing the data in this way the freshly har- 

 vested leaves of Helianthus showed 0.643 g. sucrose and 

 0.443 g. hexose per 100 g. water in the mesophyll, and 

 0.566 g. sucrose and 1.71 g. hexose in the veins. Those 

 for Nicotiana were 0.583 g. sucrose and 0.414 g. hexose 

 in the mesophyll, and 0.502 g. sucrose and 1.58 g. hexose in 

 the veins. In the entire ten sets, five each of Helianthus 

 and Nicotiana, whether analyzed immediately or after 

 moist or dry storage and independently of whether the 

 mesophyll and principal veins were or were not isolated 

 before storage, the sucrose gradients in all but one instance 

 with Helianthus were found to lead from mesophyll to 

 veins. The hexose gradients, on the other hand, with but 

 one exception with Nicotiana, led in all cases from veins 

 to mesophyll. Maltose was found in the mesophyll in all 

 cases, but in only the entire leaves in dry storage where 

 the leaves became considerably wilted was there any 

 maltose found in the veins. 



Bruns also presents one set of analyses of variegated 

 leaves of Hedera helix in which the white parts of the leaves 

 were separated from the green. The green parts con- 

 tained a larger proportion of veins which tends to compli- 

 cate the data somewhat, as the veins have a higher water 

 content, a higher hexose content, and a lower sucrose 

 content than the mesophyll. But in spite of this the 

 sucrose per 100 g. of water in the green parts was 2.94 g., 

 while that in the white parts was only 1.19 g. The reduc- 

 ing sugars also had a higher concentration in the green 

 parts, but this may have been due in part to the greater 

 proportion of veins. 



Mass analyses of general stem or leaf tissues, however, as 

 were obtained by these investigators may give an entirely 

 wrong impression as to which of the constituents found are 

 actually being transported. The seeming gradient in one 



