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Indian Forest Records. 
[VoL, 1. 
of the varnish depended on the reduction, by the atmospheric 
air, of its organised structure to a state of complete homogeneous 
fluidity. Urushi, i.e., Japanese lacquer and its constituents have, 
however, been completely investigated. The first important con- 
tribution to the chemistry of TJrushi was that made by Mr. S. 
Ishimatsu of Tokyo in a paper communicated through Professor 
Roscoe to the Philosophical and Literary Society of Manchester 
(February 18th, 1879). He shewed that the constituents of TJrushi 
are a resin, a gum, water, and a small quantity of diastatic matter 
insoluble in water and alcohol. These constituents were afterwards 
made the subject of a complete investigation by H. Toshida [loc. 
cit.) and by the same author in association with 0. Korschelt 
{Transact. 4s. Soc. Japan, xii, pp. 182-220). It was shown by these 
authors that the most important and predominant ingredient of 
TJrushi is its resin which is extracted by pure alcohol. The name 
U rushic acid was given to this constituent. Its chemical composi- 
tion was ascertained, and is represented by the formula Ci 4 Hjg 02 . 
It does not dissolve in water, but is soluble in pure alcohol, benzene, 
ether, carbon disulphide and some other organic solvents. It is a 
very stable body of pasty consistence, and unlike the original TJrushi 
refuses to dry when exposed to moist air. 
The gum was shown to be a complex mixture of the metallic 
salts of arable acid, Cj2H220jj. It exists in TJrushi in the form of 
aqueous solution, and it was shown that it takes no part in the pro- 
cess of the drving up of lacquer, as its aqueous solution was found 
to produce absolutely no change in TJrushic acid, even when a mix- 
ture of these (in the proportion in which they exist in the natural 
juice) was exposed to the conditions most favourable for the drying 
of the original TJrushi. The aqueous solution of this gum, it was 
suggested, keeps the constituent particles of the lacquer in a state of 
intimate emulsion, and besides increases the adhering power of the 
lacquer. The third constituent was ascertained to consist mainly 
of a nitrogenous substance, and it was shown that it was the action 
of this diastatic matter on TJrushic acid that caused the drying of 
the lacquer. An investigation instituted to test the activity of this 
constituent on TJrushic acid under different conditions showed that 
moist oxygen or air at the temperature of 20°C. or thereabouts 
was a conditio sine qua non for this nitrogenous constituent to dis- 
play its fullest activity in causing the drying of the lacquer. It 
