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Proceedings of the Royal Society 
Specimens of lacquer juice for tliis research, have been received 
from different parts of the country. That on which I worked was 
kindly supplied by Mr Magaribuchi from Yoshino. As this juice 
was originally intended for chemical investigation, and as it was 
collected in the best place in the Empire, under strict official in- 
spection, it must have been in the purest form obtainable. 
The pure juice is a thick greyish fluid of dextrinous consistency, 
which, under the microscope, is found to consist of minute globules, 
of darker or lighter colour, mixed with small particles of opaque 
brownish matter, the whole being held mixed in the form of an 
intimate emulsion. It has a characteristic sweetish odour. The 
specific gravity is 1-0020 (20° C.) ; but some specimens, such as 
that obtained from Hachioji, contained bark, dust, and other im- 
purities, which raised the specific gravity to P038. If the juice be 
exposed to the air in a thin layer at 20° C., it rapidly darkens in 
colour, and dries up to a lustrous translucent varnish. 
Mr S. Isliimatsu (now S. Hiraga), in a paper on Ur us hi, which 
was written some years ago at Tokio University, and afterwards 
communicated to the Manchester Literary and Philosophical Society,* 
by Professor Eoscoe (Eeb. 18, 1879), has shown that the consti- 
tuents of the juice are a resin, a gum, water, and a small residue 
insoluble in water or in alcohol. The method of separation which 
I employed was the same as that adopted by Mr Hiraga. A 
resinous acid (urushic acid), together with a small quantity of the 
volatile matter, is separated from the other substances of the juice 
by treating it with absolute alcohol, evaporating the solution, and 
drying the acid at 105° to 110° C. The residue is boiled for some 
time with water, and the extract evaporated on a water-bath until it 
acquires a constant weight. This gives the quantity of gum. The 
residue, from the water extract, consisting of a coagulated diastatic 
matter, with small quantities of insoluble colouring substances, is 
dried at 100° C., and weighed. The difference of the sum of the 
percentages from 100 gives the amount of water and volatile matter. 
Thus pure Yoshino lacquer was found to have the following 
composition : — 
* Memoirs, Manchester Literary and Philosophical Society, 3rdser., vol. vii. 
p. 249. 
