67 
ii 
Sometimes a watery solution of Bauhinia gum is stained blue by 
| ferric salts on account of some tannic acid going over from the bar 
into the gum after heavy rains. 
The Bauhinia gum can be used like arabic gum, if soaked in 
water for some time. A little salicylate of soda must be added to 
Prevent decomposition by the action of microbes. 
_ The Bauhinia gum comes nearest to the gum of Acacia pen- 
ninervis, Sieb. 
ANALYsIs— : 
Arabin ie Hs 5 Se oe aoc aeU 
: Metarabin ... ae ie fe K ia 079 
Water = eo pet ee ee a 
100°0 
Acacia Cunninghamii, Hook., Fl. Austr. ii. 407. Black Wattle. 
The arabin present in this brownish gum amounts only to 10 per cent. 
Mmy samples. Its watery solution is not disturbed by lead acetate, 
and not gelatinised or coagulated by ferric chloride. Alcohol preeipi- 
es the arabin. HC in in i 
In cold water on addition of KOH. The solutions are not acted on 
by lead acetate or ferric chloride; but alcohol precipitates the arabin, 
fae precipitate is dissolved in the alcohol on addition of an excess 
ANaLysis— 
Water . eee ore 175 
Arabin os oe ad? aoe 
Metarabin ,,, 
ose oe eee ow woe 
100°0 
Theo takes oy in the watery solution by sugar of lead or Fe,Cl,. 
Sue nes of the gum is not dissolved by boiling bce unless 
Tedisgo iy € arabin; a few drops of HCl prevent this reaction, 
_¥e the precipitate alseady formed in the alcohol. , 
