_Oil of Cajuput_, _Kayu-puti Oil_; F. _Essence de Cajuput_; G.
_Cajeputöl_.
=Botanical Origin=—_Melaleuca Leucadendron_ L., a tree often attaining
a considerable size, with a thick spongy bark peeling off in layers,
and slender, often pendulous branches. It is widely spread, and
abundant in the Indian Archipelago and Malayan peninsula, and is also
found in Northern Australia, Queensland, and New South Wales.
[1054] Obligingly presented to me by our friend, Dr. Squibb, Brooklyn
(1879).—F. A. F.
[1055] _Proceedings of the Am. Pharm. Asso._ 1865. 160.
[1056] _Am. Journ. of Pharm._ 1874. 161.—In the same periodical (1876,
335) 300 lbs. are stated to have been collected at Dyersburg, Tenn.
[1057] _Hist. Plant._ iii. (1704), appendix p. 233.
[1058] Chap. 34. sec. 5. § 1. _Aromatic Trees._ For a modern fig., see
Hooker’s _Icones Plant._ 3rd series, i. tab. 1020.
[1059] _Pharm. of India_, 1868. 88.
The tree, according to Bentham,[1060] varies exceedingly in the size,
shape, and texture of the leaves, in the young shoots being silky,
and the spikes silky-villous or woolly, or the whole quite glabrous,
in the short and dense, or long and interrupted spikes, in the size
of the flower, and in the greenish yellow, whitish, pink, or purple
stamens, so that it is difficult to believe all can be forms of a
single species. Yet upon examination, none of these variations are
sufficiently constant or so combined, as to allow of the definition of
distinct races.
The variety growing in Bouro, where the oil of cajuput has been
distilled ever since the time of Rumphius, and known as _M. minor_
Smith, is described by Lesson, who visited the island in 1823, as a
tree resembling an aged olive, with flowers in little globose white
heads, and a trunk the stout bark of which is composed of numerous
satiny layers.
=History=—Rumphius, who passed nearly fifty years in the Dutch
possessions in the East Indies and died at Amboyna in 1702, is the
first to give an account of the oil under notice, and of the tree
from which it is obtained.[1061] From what he says, it appears that
the aromatic properties of the tree are well known to the Malays and
Javanese, who were in the habit of steeping its leaves in oil which
they then impregnated with the smoke of benzoin and other aromatics, so
obtaining an odorous liquid for anointing their heads. They likewise
used cushions stuffed with the leaves, and also laid the latter in
chests to keep away insects.
The fragrance of the foliage having thus attracted the attention of
the Dutch, probably suggested submitting the leaves to distillation.
Rumphius narrates how the oil was obtained in very small quantities,
and was regarded as a powerful sudorific.
In Europe it appears to have been first noticed by J. M. Lochner,[1062]
of Nürnberg, physician to the German Emperor. About the same time
(1717), a ship’s surgeon, returning from the east, sold a provision
of the oil to the distinguished apothecary Johann Heinrich Link at
Leipzig, who published a notice on it and sold it.[1063] It began
then to be quoted in the tariffs of other German apothecaries,[1064]
although it was still reputed a very rare article in 1726.[1065]
Somewhat larger quantities appear to have been soon imported by
Amsterdam druggists.[1066] In Germany the oil took the name of _Oleum
Wittnebianum_, from the recommendations bestowed on it by M. von
Wittneben, of Wolfenbüttel, who was much engaged in natural sciences
and long resident in Batavia.[1067] In France and England, it was
however scarcely known till the commencement of the present century,
though it had a place in the Edinburgh Pharmacopœia of 1788. In the
_London Price Current_, we do not find it quoted earlier than 1813,
when the price given is 3_s._ to 3_s._ 6_d._ per ounce, with a duty of
2_s._ 4½_d._ per ounce.
[1060] _Flora Australiensis_, iii. (1866) 142.
[1061] _Herb. Amboinense_, ii. (1741) cap. 26.
[1062] _Acad. Nat. Curios. Ephemerid. Cent._ v. vi. (Nürnberget, 1717)
157.
[1063] _Sammlung von Natur und Medicin ... Geschichten_, Leipzig, 1719.
257.
[1064] _Pharm. Journ._ vi. (1876) 1023.
[1065] Vater, _Catalog. varior. exoticor. rarissimor...._ Wittenbergæ,
1726.
[1066] Schendus van der Beck, _De Indiæ rarioribus, Act. Nat. Cur._ i.,
appendix (1725) 123.
[1067] Goetz, _Olei Caieput historia—Commercium Litterarium_, 1731. 3;
Martini, _De Oleo Wittnebiano dissertatio_, 1751.
=Manufacture=—In the island of Bouro, in the Molucca Sea, the leaves of
the _Kayu-puti_ or Aij-puti, _i.e._ _White-wood_ trees, are submitted
to distillation with water, the operation being conducted in the
most primitive manner, as already witnessed, about the year 1792, by
Labillardière in his celebrated voyage with Lapérouse. Bickmore,[1068]
an American traveller who passed three months in the island in 1865,
states that it produces about 8,000 bottles of the oil annually, and
that this is almost its only export. The Trade Returns of the Straight
Settlements published at Singapore, show that the largest quantity is
shipped from Celebes, the great island lying west of Bouro.
[1068] _Travels in the East Indian Archipelago_, Lond. 1868. 282.
=Description=—Oil of Cajuput is a transparent mobile fluid, of a
light bluish-green hue, a fragrant camphoraceous odour, and bitterish
aromatic taste. It has a sp. gr. of 0·926, and remains liquid even at
(8°·6 F.)-13° C. It deviates the ray of polarized light to the left. On
diluting it with bisulphide of carbon it becomes turbid.
=Chemical Composition=—The researches of Schmidl (1860) and of
Gladstone (1872) have shown that cajuput oil consists chiefly of
_Hydrate of Cajuputene_ or _Cajuputol_, C₁₀H₁₆, H₂O, which may be
obtained from the crude oil by fractional distillation at 174° C. If it
is repeatedly distilled from anhydrous phosphoric acid, _Cajuputene_,
C₁₀H₁₆, passes over at 160-165° C.; it has an agreeable odour of
hyacinths. After the cajuputene, _Isocajuputene_ distils at 177°,
and _Paracajuputene_ at 310-316°, both agreeing in composition with
cajuputene.
Like most essential oils having the formula C₁₀H₁₆, crude cajuput oil
is capable of forming the crystallized compound C₁₀H₁₆, 3OH₂. This
we have abundantly obtained by mixing 4 parts of the oil with 1 of
alcohol 0·830 sp. gr., and one part of nitric acid 1·20 sp. gr.; the
mixture should be allowed to stand in shallow dishes. By adding 1 vol.
of absolute alcohol to 3 vol. of cajuput oil, and saturating it with
anhydrous hydrochloric gas, crystals of the compound C₁₀H₁₆(HCl)₂ may
be obtained. By vapour of bromine the oil acquires a beautiful green
colour.
If 1 part of iodine be gradually dissolved in cajuput oil, the
temperature being maintained at 50° C., fine green crystals of
(C₁₀H₁₆HI)₂OH₂ are formed. They may be recrystallized from very little
glacial acetic acid, but will not keep for more than a few weeks.
The green tint of the oil is due to copper, a minute proportion of
which metal is usually present in all that is imported. It may be
made evident by agitating the oil with water acidulated by a little
hydrochloric acid. The compounds of copper with inorganic acids being
comparatively of a fainter colour than the cupric salts of organic
acids, the aqueous solution of chloride of copper now formed displays
no longer the fine green tint. To the solution, after it has been
put into a platinum capsule, a little zinc should be added, when the
copper will be immediately deposited on the platinum. The liquid may be
then poured off and the copper dissolved and tested. When the oil is
rectified, it is obtained colourless, but it readily becomes green if
in contact for a short time with metallic copper. The presence of the
metal in the oil may also be shown at once by a scrap of paper which
has been impregnated with fresh tincture of guaiacum wood and dried. If
it is then moistened with water containing 1 per cent. of sulphocyanate
of potassium, the paper turns intensely blue by the contact with the
oil provided the latter contains copper.
Guibourt[1069] has however proved by experiment that the volatile
oil obtained by the distillation of the leaves of several species of
_Melaleuca_, _Metrosideros_ and _Eucalyptus_, has naturally a fine
green hue. It is not improbable that this hue is transient, and that
the contamination with copper is intentional in order to obtain a
permanent green.
=Commerce=—The oil is imported from Singapore and Batavia, packed in
glass beer or wine bottles. From official statements[1070] it appears
that the imports into Singapore during 1871 were as under:—
From Java 445 gallons
” Manilla 200 ”
” Celebes 3,895 ”
” other places 350 ”
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Total 4,890 ”
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Of this large quantity, the greater portion was re-shipped to Bombay,
Calcutta, and Cochin China.
=Uses=—Cajuput oil is occasionally administered internally as a
stimulant, antispasmodic and diaphoretic: externally as a rubefacient
it is in frequent use.
=Substitutes=—The oil of _Eucalyptus oleosa_ F. Muell. has, we find,
the odour of cajuput; and according to Gladstone it agrees, as well
as the oils of _Melaleuca ericifolia_ Sm. and _M. linariifolia_ Sm.,
almost entirely with cajuput oil, except in optical properties. The
same is probably the case with the oil of _Eucalyptus globulus_ Labill,
which Cloez (1870) states to be dextrogyre. These oils are shipped to
some extent from Australia to Europe, probably as adulterants of other
essential oils.