CLOVES. 229 
with 5-per-cent. solution. 5 grams yielded 7°9 grams benzoyl- 
eugenol, equivalent to 96°6 per cent. eugenol : 
7°9 x 100 x 164 
5 x 268 = 96°67. 
4. A mixture of 8 parts eugenol (No. 1) with 2 parts sequi- 
terpene from clove-oil. 5 grams yielded 6°45 grams benzoyl- 
eugenol, equivalent to 78°94 per cent. eugenol :— 
6°45 x 100 x 164 
5 x 268 
=78°94. 
Oil of cloves is frequently adulterated with phenol. This may 
be recognized by the following test, recommended by Fliickiger*. 
The suspected oil is shaken up with fifty times its volume of hot 
water ; after cooling, it is decanted, and concentrated at a gentle 
heat to a small bulk. A drop of liquid ammonia and a pinch of 
chloride are then dropped on the surface. If phenol be present, 
the liquid will assume a green colour, changing to blue, which will 
remain for several days. If the oil be pure, no coloration will be 
produced. This process is based on Berthelot’s discovery that 
ammoniacal phenol becomes blue on the addition of hypochlorite 
of lime. 
The above test is certain in its action, but has since been modi- 
fied by Jacquemin, in a way to test very small samples :—One drop 
of the suspected oil is mixed with a small trace of solution of 
aniline by means of a glass rod and then shaken with 5 or 6 c.c. 
of distilled water. By the addition of a few drops of sodium 
hypochlorite to the mixture, the characteristic blue coloration due 
to phenol will be developed in a few minutes, whereas with the 
oil nothing but the purplish-violet colour of aniline will be 
perceived. Stirring or shaking must be avoided after the addition 
of the hypochlorite, the reaction will take place without it. This 
is a very delicate test. A drop of oil containing 1 per cent. of 
adulteration distinctly develops the blue colour. 
In 1863, Scheuch detected the presence of salicylic acid in oil of 
cloves, existing probably in the form of a compound ether. It can 
be isolated by agitating the oil with a solution of carbonate of 
ammonium. It is probably the presence of this acid in the oil 
* Schweizerig Woschenschrift fiir Pharmacie, 1870, p. 200. 
