296 
Indian Forest liecurds. 
[VoL. 1. 
On treatment of the dry alcoholic extract with strong nitric 
acid, it was observed that it swelled up to a very bulky sponge-like 
mass of a yellowish colour. On long continued heating of the 
extract with strong hydrochloric acid, it became jjorous and swelled 
up though not to the same extent as when treated with nitric acid. 
Besides, the swelled ii]) mass in this case finally assumed the appear- 
ance of caoutchouc. TJrushic acid extracted from Urushi behaves 
exactly in a like manner. H. Yoshida has shown that nitric acid 
gives nitro-substitution products, while the action of hydrochloric 
acid produces a polymeric variety of Urushic acid. 
On thoroughly mixing iron rust with Urushic acid, the latter 
was found to assume a very dull and browner appearance. This 
was due to the formation of a quantity of the Urushate of iron, as 
suggested Iw Yoshida. From this reaction it will be easily inferred 
that thitsi when brought in contact with iron, is liable to be con- 
taminated with iron impurities especially in the presence of moist 
air. It should be noted that if these impurities are present in thitsi, 
they woiiid interfere with the proper development of the required 
depth or shade of colour during preparation of the varioiislv col- 
oured and gilded v’arnishes, because of the very brown and dull 
appearance which they impart to thitsi. 
E, rami nation of the Aqueous Extract {B). 
The gummy constituent, which was insoluble in alcohol and 
ether, was a light-coloured friable substance devoid of any taste, 
flavour or odour, and in appearance strongly resembled the ordi- 
nary gum arabic. In structure it was neither crystalline nor 
organised but was quite amorphous. It dissolved entirely in cold 
water, forming a glutinous frothy solution. With a small quantity 
of water, it gave a strongly adhesive mucilage. 
In its composition and chemical reactions it hardly differed from 
gum arabic. Its solution, after treatment with nitric acid, gave 
with calcium chloride a white precipitate of calcium oxalate.’ A 
solution of mercuric chloride, to which some solution of this gum 
' When a gum. whether Arabinic, Cerasinic or Bassorinie, is oxidised with 
nitric acid, one of the products of oxidation is oxalic acid. Cerasinic and Bassorinie 
gums are insoluble in cold water, and with hot water assume only a gelatinous 
appearance. Arabinic gums, however, are almost completely soluble in water. 
The formation of oxalic acid by oxidising the substance proves the latter to be a 
gum. Its complete solubility in water distinguishes it as belonging to the Ara 
binic class. 
