METHOD FOR THE DETERMINATION OF GALACTAN. 
343 
Table VII. 
Method. 
Provisional 
method 
Proposed 
method 
Sample. 
Total mucic acid obtained 
from 
Diffe- 
Mucic acid 
obtained 
from 0.3 g 
lactose. 
3 g sample + 
0.3 g lactose. 
3 g sample 
alone. 
rence. 
8 
1 Natural stuff 0 0.2902 
8 
0.1G26 
g 
0.1240 
8 
0.0933 
j Natural 
stuff 0 0.1989 
0.0999 
0.0990 
1 Natural stuff 0 0.1785 
0.0575 
0.1210 
V 
| Natural 
stuff 0 0.2528 
0.1557 
0.0971 
V 
•j Natural 
stuff 0 0.1787 
0.0859 
0.0928 
V 
' Natural 
stuff« 0.1432 
0.0460 
0.0972 
V 
It will be seen from the figures that the provisional method gives mucic 
acid usually less in amount than the proposed method. In the former 
method, when the filtrate of the solution after separating the mucic acid 
and partially oxidized material, is again concentrated, a not inconsiderable 
amount of the mucic acid is recovered. In the ordinary operation of the 
method this amount is lost entirely in the filtrate. The sum of two crops 
of the mucic acid exceeds always that obtained by the proposed method. This 
difference is due, in our judgment, to the admixture of the organic substance 
dissolved out by ammonium carbonate solution. The loss of mucic acid in 
the filtrate is compensated to some extent by the dissolved organic materials. 
But the loss in the filtrate is usually too great to be counterbalanced in this 
way. It is thus seen that the results obtained by the provisional method 
are not accurate and have little value beyond the qualitative significance for 
the presence af galactan or other mucic acid yielding substances. 
1) Cotyledon of soy-bean. 
2) Cotyledon of 2 weeks seedling. 
3) Cotyledon of 4 weeks seedling. 
