0-955
- 44°
1-5065
0
1-5
to 0'980
»» *"
„ 1
„ 1
5„^8• 62°
-5130
LABIATE 253
a result he came to the conclusion that the best results are to be obtained
by c -tting the plants when they have five pairs of leaves, and to distil
only the leaves, as the leaf-stalks contain so little oil that they do not
pay to distil.
The table on opposite page shows the variation in oil distilled from
leaves which were either fresh, dried, or fermented before distillation.
The oil from fresh leaves appears to be practically valueless.
The above considerations indicate the difficulty in fixing standards
for an oil, which varies so much by alterations in the conditions of culti-
vation, preparation of the leaves, and distillation.
Oils distilled locally from the dried Singapore leaves (" imported
oils") will usually have characters falling within the following limits :—
Specific gravity at 15°.0-955t
Optiral rotation-44°„-62°
Refractive index at 20°
Acid value.0„1
Ester „
Soluble in 3 to 10 volumes of 90 per cent, alcohol.
The oil is sometimes less soluble than this, but any marked devia-
tion from these figures should be regarded with suspicion, and the oil
should be subjected to minute examination.
Oils distilled in Europe from imported Singapore leaves, which are of
much finer odour than most of the native distilled oil, have in general,
the following characters :—
Specific gravity at 15°....... 0-965 to 0 995
Optical rotation - 50° „ - 68°
Refractive index at 20° 1-5060 „ 1-5130
Acid value 1 „ 5
Ester ,„ 2 „ 12
Most samples are soluble in 1 to 2 volumes of 90 per cent, alcohol,
although some samples require 4 to 6 volumes for solution.
Dilem oil, or patchouli oil distilled irom Java leaves, has an odour
distinctly, recalling that of calamus oil, and has characters differing con-
siderably from those of the patchouli oil fi om Singapore leaves. This
oil usually has characters falling within the following limits:—
Specific gravity at 15° 0920 to 0940
Optical rotation + 4° „ - 38°
Refractive index at 20° 1-5000 „ 1-5060
Acid value ......... 1 „ 5
Ester , 6 „ 20
It is soluble, sometimes with turbidity, in 6 to 10 volumes of 90 per
cent, alcohol. Oils are, however, from time to time found with values
much outside these limits, but how far this is due to the addition of
other species of patchouli leaves to the distillation material is not known^
Schimmel & Co. have recorded an oil from Java leaves having a specific
gravity 09659 and an optical rotation - 51° 16'.
A sample of patchouli oil distilled from 1 aves from Perak has been
reported upon by the Imperial Institute, having the following char-
acters :—
Specific gravity at 15°. 0*9595
Optical rotation - 43° 51'
Refractive index 1-5063
Soluble in 7*4 volumes of 90 per cent, alcohol.