PIPEKACE.E 111
Esters
Alcohols.None. Saponification number after acetylation 56-1
As a result of their observations on these essential oils they come to
the conclusion that certain of the abnormal oils of commerce have been
produced from mixtures of the genuine berries with either this hitherto
unidentified one which has been described, or possibly another variety.
It is perfectly clear that a mixture of one part of the normal cubebs
with one part of this variety would yield an oil having approximately
the characters which have been found in these abnormal oils, namely,
a rotation of - 15° or - 16° and a specific gravity of about 0910. It
must not be forgotten that, in taking a mixture in equal parts of the
two fruits, the yield of essential oil of the genuine is practically twice
as much as that of the substitution fruit.
A sample of false cubeb oil examined in the laboratory of Evans
Sons, Lescher & Webb, Ltd.,^1 had the following characters :—
Specific gravity. ......... 0916
Optical rotation - 9° 30'
Kefractive index...+ '4921
On fractionation it behaved as follows (sample a) compared with
two pure oils (b and c) :—
VACUUM-DISTILLED FRACTIONS OF CUBEB OILS.
Fraction. Optical Rotation. | Boiling-Point.(c) J5 per
cent.
5 per
cent.
20 per
cent.20 per
cent.
10 P^
cent.
40 per
cent,
(residual){
+ 27° 20'- 31° 5'
- 35° 47'
- 24° 30'
- 37°
- 29°
- 10°
- 32°
- 26° 30'
- 20° 20'
- 31° 40'
- 25° 40'
- 20° 5'
- 32° 30'
- 24° 45'
- 18°
30° 30'
26° 20'
52° to 59°
57° „ 69°
53° „ 109°
to 63°
„ 86°
„ 129°
!„ 89°
122°
133°
119°
127-5°
139-5°
126°
130°
140-5°
over 126°
„ 130°
„ 140-5°Refractive
Index.1-4675
1-465
1-4735
1-469
1-47
1-485
1-4753
1-49
1-496
1-4953
1-4957
1-498
1-5005
1-4965
1-4993
1-5041
1-498
1-5012Specific
Gravity.0-854
0-851
0-8680-855
0-9078
0-918
0-9198
0-9300-927
0-9438
The following investigation, which was carried out by Dr. J. Dek-
ker,2
Director of the Colonial Museum at Haarlem, throws considerable
light on the question of the abnormalities observed in certain oils of
cubeb.
In a quantity of 500 grms. of cubebs were principally found four
-different kinds of fruit, which have been sorted out and classified as
follows:—
Class 1.—Keal cubebs, i.e. those showing both macroscopically and
microscopically the features of piper-cubebs, producing, if brought into
.touch with concentrated sulphuric acid, the well-known red colouring.
1
Evans' Annual Report^2 P. (1913), and E.O.E. 29. (1913), 89.