Chemistry of Essential Oils

464 THE CHEMISTRY OF ESSENTIAL OILS

Specific gravity .......... 0-875
Optical rotation + 13°
Refractive index 1*4693
Acid number .......... 6

• 1
  Ester value 28-2
  A sample examined by Schimmel & Co.
  1
  had the following characters :—
  Specific gravity 0-871
  Optical rotation + 32° 54'
  Refractive index 1'4887
  Acid value .......... O'J
  Ester „ 20-4
  The oil consisted almost entirely of terpenes, of which /?-pinener
  limonene, and dipentene were detected with certainty. No other con-
  stituent has been identified.

OIL OF HEERIA PANIC ULOSA.

The berries of Heeria Paniculosa, a plant indigenous to Zuzulandr
known to the natives as Isifeku, yield from 4*5 to 6 per cent, of essen-
tial oil, which has been examined by Juritz.^2 A sample examined in
the Imperial Institute Laboratories had the following characters :—

Specific gravity 0'852

Optical rotation + 3'75°

Ester value 4'2

Acid value 1-6

„ „ (after acetylatioii) 14*8

The oil consists mainly of terpenes.

BURSERACLVE.

OIL OF MYRRH.

Myrrh is an oleo-resinous substance obtained as a secretion in the
parenchyma of the bark of various species of Commiphora. The so-
called true myrrh, or Herabol myrrh, is collected principally in Arabia
and Somaliland, whilst Bisabol myrrh, or bdellium, occurs as an ad-
mixture of true myrrh, especially when collected in Somaliland, and is
identical or closely related to Indian bdellium.
Herabol Myrrh is chiefly derived from Commiphora myrrha, and
yields from 3 to 10 per cent, of a thick, yellow essential oil, having the
following characters :—

Specific gravity 0-985 to 1-045
Optical rotation - 30° „ - 90°
Refractive index 1-5180 „ 1-5280
Acid value 1 „ 8
Ester ,„15 „ 45
„ „ (after acetylation) 30 „ 70
It is soluble with, at most, slight turbidity, in 10 volumes of 90 per
cent, alcohol.
Lewinsohn
3
emphasises that the composition of myrr h oil differs
according to the origin of the resin, the method of production, and the
age. He believes that distillers add small quantities of alkali to tl^e

1

Report, April (1913), 86.

2

Chemical News, 1920,120, 277.

3

Arch, der Pharm., 244 (1906), 412.