Chemistry of Essential Oils

282 THE CHEMISTEY OF ESSENTIAL! OILS

probable that this ester is formed from the alcohol C 8 H 16 O and the acid
C 6 H 10 O 2 , and that it possesses the formula C 14 H 24 O 2 , which would require
G. 75 per cent., H. 1O7 per cent., whereas the carbon found varied
from 75'7 per cent, to 78

• 4 per cent, and the hydrogen from 8'88 per
  cent, to 1040 per cent. The excess of carbon and the deficiency - of
  hydrogen would result from the splitting-off of water.
  With regard to the small amount of volatile substance associated
  with the paraffin in birch oil, it may be said that independently of the
  aldehyde or ketone, which is also present, it appears to consist chiefly
  of the above-mentioned ester, and not to contain the body of alcoholic
  nature which is present in the oil of gaultheria. The presence, therefore,
  of this intensely odorous alcohol, C 8 H 16 O, in the latter oil, imparts to it
  a specific character, so that by the odour alone it is possible to distin-
  guish it from the oil of birch.
  A sesquiterpene alcohol, betulol, C 15 H 24 O, and its acetic ester have
  been found in the oil of Betula lenta.
  Many colour reactions have been suggested for differentiating be-
  tween the oils of gaultheria and sweet birch and artificial methyl
  salicylate. Most of these are unsatisfactory, the only one which yields
  useful results in the author's opinion being that of Umney,^1 which is as
  follows:—
  To five drops of the oil in a test tube add five drops of a 5 per cent,
  alcoholic solution of vanillin and 1 c.c. of alcohol. Shake well, and add
  2 c.c. of concentrated sulphuric acid and mix thoroughly. When this
  test is applied, pure gaultheria oil produces an intense crimson colour, and
  pure Betula oil a deep blood-red, while synthetic esters give a yellow colour.
  Methyl salicylate has been detected in the following amongst other
  plants:—
  BETULACEJE. Discoverer. Discovery.
  Betula lenta L. ..... Wm. Procter, jr.. 1844
  Betula lutea Mich, probably, but
  not yet determined.

Lindera Benzoin Meissner

ROSACES.

Spircea ulmaria L. ....

ERYTHBOXYLACE.E.

Erythroxylon coca Lam.

„ bolivianum (?).

Polygala senega L. ....

, , var. latif. Torr. and Gray

, baldwinii Nuttall.

, variab. H. B. K. albifl. D. C.

, javana DC..

, oleifera Heckel

, serpyllacea Weihe.

, (depressa Warden).

, calcarea F. Schultz

, vulgaris L.

PYBOLACE^E.

Hypopitys multiflora Scop.

(Monotropa Hypop. L.).

TERNSTBOSMIACE^:.

Thea chinensis .....

Schimmel & Co.

Schneegans & Gerock

Iv. Romburgh

Langbeek.

L. Reuter.

J. Maisch.

1

Iv. Romburgh.

J

VBourquelot

J

Bourquelot

Schimmel & Co.

1885

1892

1894

1881

1889

1890

1894

1894

1894

189T

1

P. and E.O.R., 5 (1914), 60. •