W. A. Davis, A. J. Daisii and G. C. Sawyer 319 



Instead of actually observed, pentoses as arabiuose = — 0-094°, 

 and actually observed, pentoses as xylose = — 0'053°. 



Maltose. Reduction corresponding with 15 cc. A. 



After fermentation with maltase-free yeasts = 0-0134 grm. CuO 

 After fermentation with distillery yeast = 0-0127 



A = 0-0007 grm. CuO 

 The difference between the two sets of fermentations is within the 

 experimental error of the method. 



.-. Maltose = 0-00 %. 

 Starch. Exp. 1. 10-449 grms. of oven-dried leaf matter after 

 extracting sugars gave, on drying in vacuo at 110°, 9-7355 grms. 

 .-. Moisture = 6-82 %. 



The leaf material was heated with 200 cc. of water in boiling water 

 for 15 minutes and, after coolinrr, treated with 0-1 grm. taka-diastase at 

 38° for 24 hours. After boiling to destroy the enzymes, the leaf material 

 was filtered on a Buchner funnel and washed with water until the 

 washings amounted to about 450 cc. The filtrate was transferred to 

 a 500 cc. measuring flask and exactly the necessary quantity of basic 

 lead acetate solution (8-5 cc.) added to precipitate the tannins, etc. 

 The solution was then, without filtering, made up to 500 cc. at 15°. 

 After filtering, 100 cc. of the filtrate were treated with solid sodium 

 carbonate to precipitate the lead present and made up to 110 cc. After 

 filtering, 50 cc. were used to estimate the reducing power. 



Weight of CuO = 0-0000 grms. 



Polarisation in 400 mm. tube = - 0-053°. 

 The entire absence of reducing power shows the absence of maltose 

 and dextrose and hence of starch in the original material. The laevo- 

 rotation is due to the gummy matter of the leaf which is not entirely 

 precipitated by the basic lead acetate, owing to the shght solubihty of 

 its lead compound (Davis and Daish [1914]). 



Exj). 2. Gave Moisture = 6-86 %, 



Starch =0-00%. 



B. Experimental Data. 



Series I. Mangold Leaves. August 26th-27th, 1913. 



The alcoholic extract was evaporated in vacuo and made up to 

 500 cc. 440 cc. of this solution were treated with basic lead acetate 

 Journ. of Agrio. Sci. vn 22 



