586 
Philippine JourTial of Science 
1920 
(curve 2B, fig. 5) seems to furnish the concentration most fa- 
vorable for the oxidation of glucose, vrhen the amount of the 
latter in the reaction mixture does not exceed 40 milligrams. 
In the latter case 0.2 N is again the most favorable concentra- 
tion of alkali. When the concentration of alkali is 0.04 N 
(curve 5B, fig. 5) there seems to be a more uniformly rising 
curve when the amount of glucose is increased from 10 to 40 
Normality of alkali. 
0 . 04 . 0.2 0.4 06 0.8 
Fig. 1. Effect of normality of alkali on the amount of potassium permanganate in cubic 
centimeters of 0.2 N solution reduced to glucose. Curves 1, 2, 3, 4, and 5 are for 10, 20, 
30, 40, and 50 milligrams, respectively. 
milligrams. When the concentration of potassium permanga- 
nate is 0.05 N (curves C, fig. 5) the differences between the 
effects of the several concentrations of alkali tend to disappear. 
In choosing the concentrations of alkali and of potassium per- 
manganate to be used in devising a method for the quantitative 
determination of glucose and starch in agricultural products, I 
considered the following points: 
