Mason — Inhibition of Inver'tase in the Sap of ^alanthus nivalis. 85 



Table II. 



The acid of the sap has evidently not been responsible for the rise in 

 depression observed in tlie samples which were not boiled. The increase in 

 depression in the sap pressed from untreated leaves is in this case much 

 greater than that from the frozen. 



It is clear from a survey of Tables I and II that, if the increase in 

 depressions of the sap pressed from the frozen material were an index 

 to the sucrose-content, very great fluctuations must have taken place in a 

 comparatively short time. 



It is instructive to compare the increases in depression recorded in 

 Tables I and II with those found by Dixon and Atkins (5) (Table III) on 

 storing sap pressed from untreated leaves of Syringa vulgaris. The material 

 for these experiments was collected towards the close of October ; the saps 

 were pressed from unfrozen leaves, and were filtered and stored at room- 

 temperature. 



Table TIT. 



Here similar great differences in the change in depression on storage are 

 noticeable. 



As it was considered possible that the fluctuations observed in the 



increase in depression of the freezing-points on storage might not be 



1,2 



