MYETACE^E 387
of the highest importance that in the production of a high-class bay oil
there should be no admixture of leaves of the lemoncillo type."
It is suggested that the distillation of the oil should be carried out
at a central distillery under competent control, so that a uniform pro-
duct can be assured.
A sample of bay oil from Fiji, examined at the Imperial Institute in
1909, differed considerably from ordinary commercial bay oil. The oil
was pale brown, and had the characteristic odour of bay oil, with, in
addition, a distinct anise-like odour. On examination it furnished the
following constants : Specific gravity at 15° C., 0961; optical rotation in
100 mm. tube at 20° C., - 1° 58'. The oil was soluble in its own
volume or more of 90 per cent, alcohol, and contained only 23 per cent,
of phenols instead of the 60 per cent, found in good bay oil, and was
unusually rich in methyl ethers. In view of recent investigations
recorded in the Kew Bulletin,^1 it seems probable that the Fiji sample
consisted of oil derived from the leaves of the form of Pimento, acris
known as " Bois d'Inde Anise ".
Bay oil has the following characters (subject to the above remarks
on the irregularity of the distillation):—
Specific gravity 0-965 to 0-985
Optical rotation - 0° 30' to - 3°
Refractive index 1-5100 to 1-5200
Phenols......... 55 to 68 per cent.
Our knowledge of the chemistry of this oil is chiefly due to Mitt-
mann,
2
who first thoroughly investigated the oil, and to Power and
Kleber,^3 who cleared up several points left in an obscure state by the
first-named chemist. According to Mittmann, pinene and probably
dipentene are present, together with the principal constituent eugenol,
and its methyl ether. He also believed a diterpene to be present, but
this was probably formed by polymerisation during the distillations he
effected. Power and Kleber do not agree that teither pinene or dipen-
tene are present, but state that the only terpene( is laevo-phellandrene.
The oxygenated compounds which these chemists state they have
identified are eugenol, methyl-eugenol, chavicol, methyl-chavicol, and
citral. In addition to this they found a hydrocarbon of the formula.
Clojj1(; with the abnormally low specific gravity '802. This, and other
considerations exclude the probability of this hydrocarbon being an
ordinary terpene, and the chemists above named term it myrcene, and
it is now recognised as an olefenic terpene.
The oil is sometimes adulterated with oils of cloves and pimento,
which cause an increase in the specific gravity. Turpentine is also
added at times. This alters the optical rotation and specific gravity,
and if the oil be distilled in a small fractionating flask the bulk of the
turpentine is obtained in the early fractions. Assuming that pinene is
not present at all in oil of bay, turpentine may be detected by adding
to, say, the first 10 per cent, distilled, an equal volume of amyl nitrite
and two volumes of glacial acetic acid. The mixture is kept cold in ice
and salt, and a mixture of equal parts of glacial acetic acid and hydro-
caloric acid is added drop by drop so long as a blue colour is developed.
If pinene is present a white crystalline precipitate of pinene nitroso-
chloride C 10 H 16 NOC1 is formed. Ten per cent, of turpentine can be
1
P. and E.O.R., October, 1918, p. 278. Arch. Pharm., xxvii., 529.
3
Pharm. rendus, New York, 13 (1895), 60.