340 
K. MIYAKE. 
0.30 On the following day. 
Xot crystallized even after standing 48 hours. 
) When evaporated down to one-fifth its original 
0.05 j volume the crystals began to appear after several 
days. 
It will be seen from the table that down to one gram of lactose the 
tnueic acid is precipitated immediately after evaporation. The case may or 
may not be the same, if organic matter is present in a considerable quantity 
in the solution. To tost how far the presence of organic substance affects 
the time of crystallization of mucic acid the following experiment was made. 
Table III. 
Sample. 
Natural stuff 0 3 g + Lactose 3.0 g 
” ” ” + ” 1.5 g 
” ” ” + ” 1.0 g 
Time required for crystallization 
of mucic acid. 
Immediately after evaporation. 
V V >) 
Several hours after evaporation. 
In 3 grams of the natural stuff and 1 gram of lactose used in the exper- 
iment there was contained 16.38^ of equivalent galactan on basis of dry 
matter. 
From the results, it can be inferred that in the determination of galactan 
in natural products containing galactan up to the above limit, the immediate 
filtration after evaporation will not cause any loss of mucic acid. 
The Proposed Method. 
On the basis of the above experiments the fbllowig modification in the 
procedure of the method is here proposed and recommended. 
Take a given quantity of the substance to be examined, extract with 
ether and place the residue in a beaker, together with nitric acid and evapo- 
rate the solution in a water bath, exactly in the same manner as recommend- 
ed in the “provisional method” already referrd to. Filter hot immediately 
after evaporation and wash well with hot water. The filtrate is again evapo- 
1) Cotyledon of soy-bean. 
