582 Philippine Journal of Science 1920 
mination of starch in starchy products, and a glucose-starch 
table, similar to the tables of Munson and Walker and of Allihn, 
was constructed. These results are given in the following pages. 
DISSOCIATION OF THE GLUCOSE MOLECULE 
According to Mathews,(8) sugars behave as weak acids; that 
is, the hydrogen of one of the hydroxyl groups dissociates into 
ion. Cohen (2) has found the dissociation constant of glucose 
to be 5.9X10—*. It is believed that the dissociating hydrogen 
is that of the hydroxyl group next to the aldehyde group. 
Nef,(10) however, believes that the dissociating hydrogen is not 
always the same. It may be the hydrogen of any of the hy- 
droxyl groups of the glucose molecule, 
In the presence of an alkali a glucose salt is formed, and this 
dissociates into a positive and the negative glucose ion. The 
latter, being unstable, undergoes a rearrangement resulting in 
the disturbance of electrical equilibrium and the subsequent 
formation of easily oxidizable compounds. 
ACTION OF THE ALKALI 
Mathews’s (8) experiments show that, under the action of an 
alkali, the glucose molecule is broken up into a number of reduc- 
ing particles. He concludes that, in thé rearrangement of the 
glucose molecule, intramolecular oxidation and reduction take 
place. These conclusions were derived from his experiments 
on the rate of formation of acids from sugars by alkalies. Ac- 
cording to these experiments, acids are formed secondarily. The 
first effect of the alkali is to produce easily oxidizable bodies, 
which in turn become acids—a result perhaps obtained “by 
intramolecular oxidation or by the reduction of some of the 
reaction products.” 
According to Witzemann’s(14) views, the alkali serves as 4 
catalyst in facilitating the oxidation of glucose and its decompo 
sition products. These views seem to be confirmed by the 
works of Nef(10) and his pupils, and by those of Mathews. (8) 
THE EFFECT OF ALKALI CONCENTRATION UPON OXIDATION 
Glucose and other sugars are easily oxidized in alkaline solu- 
tions. It has been found by Mathews and McGuingan(9) that 
the velocity of oxidation of sugars is much greater in an alkaline 
than in an acid solution, and the difference in the rate of ox 
dation of the different sugars studied, observed in the latter 
solution, disappears in the former. The velocity of oxidation 
