594 Philippine Journal of Science 1920 
25 cubic centimeters of the glucose or hydrolyzed starch sofution 
in an Erlenmeyer flask, or 10 cubic centimeters of the solution 
to be analyzed and 15 cubic centimeters of distilled water, to 
make the volume exactly 100 cubic centimeters. Place the flask 
on the heating device described on page 587 with the heating 
power so regulated that its temperature is raised from 29° to 
95° C. in two minutes, and heat it for exactly two minutes after 
the temperature has reached 95°C. Remove the flask and add 
gradually 25 cubic centimeters of 28 per cent sulphuric acid and 
25 cubic centimeters of 0.1 N oxalic acid solutions. Titrate the 
excess of oxalic acid against standard potassium permanganate 
solution, adding the latter until the liquid assumes a pink color 
which it retains for a few seconds. The sum of the number of 
cubic centimeters of 0.1 N potassium permanganate used in oxi- 
dation and in titration minus the number of cubic centimeters 
of 0.1 N oxalic acid solution used gives the total number of 
cubic centimeters of 0.1 N potassium permanganate actually used 
in oxidation. 
Table 5 was prepared with pure glucose. The glucose was 
obtained by repeated crystallization of Kahlbaum’s Trauben- 
zucker from methyl alcohol. It was dissolved in the least pos- 
TABLE 5.—For calculating the weight of glucose and starch from the 
volume of 0.1 N potassium permanganate. 
0.1N po- 0.1 N po-~ 
pan ahd Glucose. | Starch. Peace Glucose. | Starch. 
ganate. : ganate. 
cc, mg. mg. cc. mg. mg. 
5.40 4 3.72 27. 88 21.39 
6.54 5 4.65 28, 48 24} 22.82 
7.68 6 5.58 29. 47 25| 28.25 
8.76 7 6.51 30. 46 26| 24.18 
9.84 8 7.44 31. 67 25.11 
11.08 9 8.39 32. 88 28} 26.04 
12,32 10 9.30 33. 81 29| 26.97 
13. 45 11| 10.28 34. 75 30] 27.90 
14.58 12{ 11.16 35. 80 81} 28.83 
15.75 13| 12.09 36. 86 32} 29.76 
16,93 14} 18.02 37.58 | 83 30.69 
17.85 15} 13,92 38. 24 84] 31.62 
18.77 16{ 14.88 39.38 35 | 82.55 
20.18 17| 15.81 40. 52 36} 33.48 
21.49 18] 16.74 41.05 87| 84.41 
22.74 19| 17.67 41.58 38 | 35.34 
23.99 20; 18.60 42, 22 39 | 36.17 | 
25.13 21; 19.68 || 42.86 40{ 37.20 | 
26, 28 22! 20.46 48. 35 41| 98.13 | 
