Part IV.] Puran Sing : Nole on Btirtnese VarnhK. 
301 
matters such as sesame oil, with which the pure juice is known 
to be commonly adulterated. This view is supported by the result 
of a drying experiment performed with a mixture of the pure 
thitsi with sesame oil (see below p. 30')). The author believes 
that the presence of oily substances in natural varnishes paralyses 
to a more or less extent the catalytic action of the diastatic con- 
stituent in helping forAvard the drying process. The .Tapanese 
adulterate their varnish with linseed oil, which, if excess is avoided, 
does not, according to Yoshida, greatly impair the drying power of 
Urushi. For making lacquer of different colours, therefore, lin- 
seed oil (about 15 per cent.) would form a better substitute for 
sesame oil- Turpentine would still be better, but it imparts to the 
varnish a very brown colour. 
The Japanese varnish contains a small proportion of an unde- 
termined volatile substance of a poisonous character, which causes 
a A'ery violent and painful itching to the parts of the body exposed 
to it. It is eliminated from the lacquer by stirring the latter in 
open shallow vessels. In the course of the present investigation 
I have not, however, found any such material in the two specimens 
of Burmese varnish examined, but it has been affirmed that the 
Burmese wood-cutters object to fell the Melanorrhoea Usitafa trees, 
being afraid of some poisonous juice contained in the wood which 
produces a very disagreeable irritation and burning in the parts of 
the body exposed to it. 
Thiclening and Thinning of Thitsi. 
Professor J. J. Rein {loc. cif. pp. 347-348) mentions that when 
purified urushi is closely mixed up with water, it loses its fluidity, 
thickening to a jelly-like mass which dries very quickly. Further, 
the thickened urushi may be reduced to its liquid state by the 
application of a sIoav heat or, if heat is to be avoided, by thoroughly 
mixing with it finely pulverized camphor or camphor oil. Pre- 
cisely similar effects were produced when both liquid and thickened 
specimens of the Burmese varnish were treated as just described. 
?7o explanation of these peculiar effects has yet been given, but the 
suggestion may be offered that on the addition of water the large 
sparsely scattered globules of gum, which move about freely in the 
thin varnish, aggregate into larger masses ^partial dissolution of 
