Mason — Preliminary Notes on the Carbohydrates of the Musci. 23 



P. commune. 



In the above analysis the alteration in the hexose-sucrose ratio indicates 

 an inversion of sucrose, as sugar passes from the leaves to the stem. 



This inversion, which is rendered more probable by the presence of 

 invertase in the leaf, points to the carbohydrates being translocated to a 

 large extent in the hexose form. 



In considering the conditions which prevail in the leaf, it is difficult to see 

 how the hexoses can be responsible for synthesis of sucrose, as in the 

 presence of invertase a very high concentration of hexose sugars would be 

 needed to bring about its formation ; such a high concentration is negatived 

 by the foregoing results. 



The next experiment shows the way in which the sucrose in Thuidium 

 tamariscinum diminishes when the plants are kept in darkness. 



The difficulty of preparing the plants for analysis again renders it 

 necessary to express the results as ratios. 



d2 



