METHOD FOR TUE DETERMINATION' OF GAL ACT AN. 339 
Lactose alone (1 g) 0.3446 
Total 0.4660 
Natural stuff (3 g) and Lactose (1 g) together 0.2077 
Loss 0-2583 
Tt is thus seen that in the case of natural stuff and lactose in combination 
a considerable portion of the mueic acid was prevented from crystallization 
and lost in the filtrate. 
2) In extracting the mucic acid with ammonium carbonate solution to 
free it from the admixed impurities, the partially oxidixed organic material 
is dissolved, more or less, by the reagent used. The dissolved organic material 
is again precipitated together with the mucic acid, upon evaporation and 
subsequent addition of nitric acid. It is perhaps needless to remind those 
who have had the experience in this line of work that the final mucic acid 
obtained very often has a dirty appearance, clearly indicating the presence 
of some other organic matter admixed. 
Attempts have therefore been made by us to improve the method and 
avoid the inaccuracies already pointed out. 
By repeated trials with natural stuffs it has been found that the parti- 
ally oxidized organic material could be separated completely from the solution 
containing mucic acid not yet- crystallized, upon filtering immediately after 
evaporation with nitric acid to exactly one-third its volume. To determine 
whether or not the amount of mucic acid yielding substance affects the time 
required for crystallization of the acid under the given circumstances, the 
following experiments were undertaken with lactose 0 . 
Table II. 
Lactose. Time required for crystallization of mucic acid. 
S 
3.00 Immediately after evaporation. 
1.50 
1.00 
0.50 On the following day. 
1) The sugar used contained 5.035 % water. 
