Chemistry of Essential Oils

CONIFEE^ 33

OIL OF JUNIPER.
The plant yielding this oil is Juniperus communis, a native of Greece,
and widely distributed over Europe. It is a small shrub or tree varying
from 2 to 6 ft. in height, but in parts of Norway it forms a forest tree
some 30 to 40 ft. in height. The Italian berries, however, are most
valued for oil. According to Pereira, the juniper of the Bible was a
leguminous plant, probably the broom or furze tree. Fraas considers
the Kt'8/)o« fuxpa of Dioscorides was our juniper. The plant is usually
dioecious, and the scales of the cones, when ripe, become succulent, and
cohere to form a kind of berry (galbulus). These berries are rich in
sugar, and by their fermentation and distillation the well-known beverage,
gin, is obtained, which owes its characteristic flavour to the oil of juniper.
It has been stated that the oil is distilled from the full-grown, but unripe,
fruit. But with reference to this point, Schimmel and Co.^1 states that
"this is an error, at least no such oil is distilled on a large scale. It is
an antiquated idea, originating with Zeller, that unripe fruits render a
larger yield in oil than ripe ones. In any case, the oil distilled from
unripe berries in all essential qualities is inferior to normal oil of ripe
fruits." The following are given by Schimmel as the average yields of
oil from plants grown in certain districts —•

Bavarian.. 1/2 per cent.

East Prussian

Thuringian

Swedish

Italian

Polish

Hungarian

•6

•7

•5

1 to 1-5
•9
•8 to l
The oil is distilled on a very small scale in England, but, according
to the Perfumery and Essential Oil Record* hitherto it has not been
possible to produce the oil competitively with southern Europe, because
of the relative cheapness of labour and the vast tracts of land over which
the trees grow wild. It also must be remembered that the foreign oil is.
produced under somewhat different conditions, and may be almost con-
sidered a by-product. There is a considerable demand on the Continent,
for an aqueous extract of the berries, called " Boob," or " Bob of Juniper,""
and the distilled oil is in this case a by-product, the berries being first
crushed and macerated with water and then distilled with water, and the
residue in the still evaporated to a soft consistence.
Much of the oil met with in commerce also is probably not normal in
composition, but is obtained as a by-product in the manufacture of gin
and similar spirits.
There can be no reason why it should not be possible for our northern
dependencies to produce all that is required.
The juniper plant is a small shrub 4 to 6 ft. high, or in sheltered
woods growing higher, widely distributed throughout the northern hemi-
sphere, in Europe from the Mediterranean to Scandinavia, in Asia
northwards from the Himalaya Mountains, in North America from the
southern states to Greenland. It requires a certain amount of moisture,
with some drainage, and apparently prefers some lime in the soil. It
occurs freely on the slopes of the chalk downs near London, and on
healthy, and therefore silicious, soil where a little lime occurs. On
mountains in the Arctic regions a small form of the plant occurs, viz.,
1
Report, October, 1898, 30.
2
P. and E.O.R., March, 1915, 63.
VOL. I. 3