344 
K. MIYAKE. 
Factor for the Calculation of Galactan. 
To calculate the amount of galactose from the mucic acid obtained, the 
factor 1.33 is commonly used. Multiplying the galactose by 0.9 gives the 
quantity of galactan. The factor 1.33 is deduced from the fact that 100 
parts of galactose yield about 75 parts of mucic acid by oxidation with nitric 
acid in the manner specified elsewhere. The yield of mucic acid is not, 
however, constant but varies with the amount of substance taken and the 
method of operation, as is pointed out by Tolle ns’ 5 and Creydt 1 2) 3 . We 
have verified the same by oxidizing the different amounts of lactose with 
60 cc. nitric acid, sp. gr. 1.15. The results are shown in the following table. 
Table VIII. 
Lactose' 0 taken. Mucic 
acid obtained. 
o/oof mucic acid, 
(water free basis) 
o/o x 2. 
g 
g 
3.00 
1.0951 
38.44 
76.88 
1.00 
03446 
36.29 
72.58 
0.30 
0.0933 
32.75 
65.50 
0.10 
0.0194 
20.43 
40.86 
It will be seen from the table that the greater the amount of lactose 
taken, the higher is the percentage yield of mucic acid. It is consequently 
reasonable in the calculation of galactose to use different factors according 
to the amounts of mucic acid produced. The use of the factor 1.33, it 
should be understood, is for the sake of brevity and convenience. 
1) B. Tolle ns -Kurzes Handbuch der Kohlenhydrate, I, Breslau, 1898, P. 317. 
2) Lippmann - Chemie der Zuckerarten, I, Braunschweig, 1904, P, 1652. 
3) Lactose for the experiment contained 5.035 % of water. 
