of Edinburgh, Session 1884-85. 
177 
i. 
Part soluble in alcohol (urushic acid), 
85*15 
Gum arabic, ...... 
3-15 
Residue (nitrogenous matter), 
2-28 
Water and volatile matter, 
9-42 
100-00 
The other unadulterated samples of the j uice, some of which were 
analysed by Mr J. Takayama in our laboratory, had the following 
composition : — 
II. 
Hotta- 
mura 
Hitachi. 
III. 
Sagami 
(southern 
district). 
IV. 
Yechigo 
(northern 
district). 
V. 
Hachioji 
Sagami. 
VI. 
Origin 
unknown. 
Bought 
at Tokio. 
VII. | 
Origin 
unknown. 
Bought 
at Tokio. 
Urushic acid, 
64-62 
68-83 
66-92 
80-00 
64-07 
58-24 
Gum arabic, . 
5-56 
5-02 
4-75 
4-69 
6-05 
6-32 
Nitrogenous matter, 
2-10 
2-01 
1-72 
3-31 
3-43 
2-27 
Oil, .... 
0-09 
0-06 
0-06 
0-23 
? 
W ater and volatile 
matter, 
27-63 
24-08 
26-55 
12-00 
26-22 
33-17 
100-00 
100-00 
100-00 
100-00 
100-00 
100-00 
The juice which contains the largest amount of urushic acid is 
considered the best ; in this respect No. I. Yoshino sample is 
superior to the rest, whilst YI. and VII. represent the average 
quality of the juice found in commerce. 
I. Examination of the alcoholic extract , Urushic Acid . — 
This peculiar acid is the main constituent of the original juice, and 
also of the portion soluble in alcohol. The juice also contains a 
very small quantity of a volatile substance which passes into 
alcoholic solution, and is almost completely driven out during the 
drying of the acid at 105°~110° C. 
Urushic acid is a pasty substance of somewhat dark colour, 
having the characteristic smell of the juice, readily soluble in 
benzene, ether, carbon bisulphide, and chloroform, less easily soluble 
in fusel oil and petroleum of high boiling point. It is quite 
insoluble in water. Its specific gravity, taken at 23° C., is 0-9851. 
The acid is not affected by a temperature of 160° C., but above 
200° C. it decomposes slowly with carbonisation. When exposed to 
the air or in oxygen gas it neither dries up nor shows any sign of 
