UMBELLIFEE.ZB 309
distilled from the herb, with or without the unripe fruits. It has a
specific gravity 0-905 to 0'935, optical rotation + 37° to + 60
°
and
refractive index 1-4910 to 1-4970. It does not contain more than 20
per cent, of carvone. Schimmel & Co. have found a large amount of
phellandrene in a sample of English, and also in Spanish oil. Apart
from this, the only known constituents are limonene and carvone, with
traces of a solid body, possibly a paraffin hydrocarbon, and, in Indian
oil, dill apiol C 12 Ht4O 4. Spanish oil contains phellandrene, carvone,
iimonene, dill apiol, and dill isoapiol. Pure dill oil is used to a con-
siderable extent in pharmacy as a carminative.
African dill oil has recently been examined by J. C. Umney.
1
The African fruits are slightly larger than the English fruits,^ and
a little paler in colour. Their odour closely resembles the English.
They are produced from plants grown from English imported seed,
whilst the Indian variety has been ascribed by some to a different
species, Anethum sowa, which is also the source of the Japanese dill.
The yield to ether of these fruits was 11'6 per cent., comparing
very closely therefore with English fruits, which yielded 10'9 per cent,
to ether.
The essential oil had the following characters, and contained no
fraction heavier than water :—
Specific gravity at 15° C 0-9117
Optical rotation at 20° C + 77° 3'
Solubility in 80 per cent, alcohol.... 1 in 6 to 1 in 6£
As a general rule it is found that the yield of essential oil from
umbelliferous fruits is higher in temperate climates, as for example
from fennel, the Galician and Eoumanian varieties of which yield as
much as 4 per cent, of oil against 0
- 75 per cent, from the East Indian
fruits, but in this case the difference is not so marked.
If the fruits can be produced in quantity in Cape Colony, they
should form a most useful source of supply.
OIL OF FENNEL.This oil is distilled from the fruit of several varieties of Foeniculum
vulgare, which is found all over Europe except in the north and north-
east, being especially common on the Mediterranean littoral, and is also
found in Asia Minor, Persia, India, and Japan. Two oils are recognised
in commerce, the "sweet" and <
;
bitter" oils, the former being more
esteemed. The sweet fennel is distilled from Foeniculum dulce, but
this is probably only a variety of the common wild fennel. The yield
of oil obtained is very variable, according to the fruit distilled. In
general it averages from 4 to 6 per cent. In the ordinary way, Galicia
and Roumania furnish some of the best fennel crops, and from their
fruit a large portion of the oil of commerce is distilled. The great
variability in the fruits of different districts makes it necessary to fix
some limits for the physical characters of the oil, which, however, may
be exceeded in individual cases.
Ordinary sweet fennel oil has the following characters :—
Specific gravity 0-964 to 0-976
Optical rotation + 6° to + 20° (rarely to + 26°)
Refractive index 1-5280 to 1-5380
Congealing-point + 3° ,, + 10°
1
P. and E.O.R. (1910), 290.