596 Philippine Journal of Science 1920 
Procedure.—Collect saliva by chewing a piece of paraffin. 
Filter and neutralize exactly with dilute hydrochloric acid. 
Heat the gelatinized starch to 40° C., add 25 cubic centimeters 
of saliva, and allow the solution to remain at 40° C. until a 
drop of the liquid gives no test for starch with iodine solution. 
Filter the solution, make the volume to 200 cubic centimeters 
hydrolyze by the acid hydrolysis method and determine starch 
in the hydrolysate by the alkaline potassium permanganate 
method. 
Blank determination—Take an amount of saliva equal to 
that used in the determination of starch, dilute to 200 cubic 
centimeters, and proceed as in the determination of starch as 
given above. 
E, COMPARISON OF THE MUNSON AND WALKER METHOD WITH THE 
: ONE PROPOSED 
To test the accuracy of the proposed method parallel deter- 
minations were run with it and with the Munson and Walker 
method, using pure glucose, commercial starch, and air-dry flour 
prepared from some tubers. The analyses of pure glucose are 
shown below with details given in full. The results with starch 
and flour are given in Table 6. 
ANALYSIS OF PURE GLUCOSE, BY THE MUNSON AND WALKER METHOD 
The Munson and Walker method(12) was followed. 
Sample 1.—0.4900 gram of glucose was dissolved. in 110 cubic centi- 
meters of distilled water and 10 cubic centimeter portions were taken 
for analysis. 
Weight of cuprous oxide. 
Samples. Blanks.* 
Grams. Grams. 
VSP GL) SUE a apt opt CR a: an ee a ee ere Fe 
0.2110 0.1083 
0.2116 0.1096 
0.2132 0.1070 
Cr i i ee ie 
Average, 0.2109 0.1083 
*The Rochelle salt solution used in these determinations happened to be an old one, — 
this is the reason why blanks are very high. 
Total weight of cuprous oxide from 10 cubic centimeters of glucose 
solution, 102.6 milligrams. 
102.6 milligrams cuprous oxide, 44.5 milligrams glucose. 
Glucose found by analysis, 99.89 per cent. 
Sample 2.—0.500 gram of glucose was dissolved in 100 cub 
meters of distilled water, and 10 cubic centimeter portions were take 
analysis. 
ie centi- 
n for 
