Dec. 20, 191S Mineral Composition of Sap, Leaves, and Stems 



535 



Table IX shows that the ratio of calcium oxid to magnesium oxid 

 is fairly constant in the different samples, while the wide variation in 

 the potassium oxid and sodium oxid from 27.5 in 1912 to 4.2 in 1914 

 would indicate that these figures were obtained from the sap of different 

 plants rather than from that of the same vine at different times. 



Table X. — Variation in percentage composition ^ of f rah sap of wild grape collected for 



id nic ' 



three successive days and nights '• 



' By volume. 



2 Nos. 902, 904, and 906 were collected on successive days; Nos. 903, 90s, and 907 were collected on succes- 

 sive nights. 



Table XI. — Percentage composition of ash of samples in Table X 



Referring to the results in Table X, it will be seen that there is a con- 

 siderable variation occurring daily in the mineral composition of the sap 

 and that, as a rule, most of its constituents are present in larger amounts 

 during the day, while, on the other hand, its composition is more constant 

 at night (Table XI). 



