LABIAT^B 269
tion in the condensing worm, while from No. 2 it had been partly
extracted by freezing out.
OIL OF COLEUS AMBOINICUS.Weehuizen
l
has obtained 25 c.c. of essential oil by distilling 120 kilos
of this Labiate plant, using the fresh herb for the purpose. The prin-
cipal constituent was identified as carvacrol.
OLL OF MLCROMEBIA.Micromeria Chamissonis is a plant found wild on the Western
Coast of the United States, where it is known as Yerba Buena. The
oil has been examined by Power and Salway.
2
The air-dried herb yielded 0*16 per cent, of essential oil having the
following characters :—
Specific gravity 0*9244 at 20
°Optical rotation - 22° 48'
By extraction of the plant with hot alcohol, and steam distilling the
extract, an oil was obtained having the following characters :—
Specific gravity 0-9450 at 20°
Optical rotation - 26° 44'OIL OF AMARACUS DICTAMNUS.An oil resembling oil of pennyroyal, and probably derived from
Amaracus Dictamnus, has been examined by Schimmel & Co.^3 The oil
has the following characters:—
Specific gravity 0-933 to 0935
Optical rotation..+ 3° „ + 6°
Acid value 23
Ester „ 20-9
„ „ (after acetylation) 80
It contains from 66 to 85 per cent, of pulegone, and some menthol
and borneol.
OIL OF PYCNANTHEMUM.Pycnanthemum lanceolatum yields an essential oil resembling
American pennyroyal oil in odour. It has been examined by Correll 4
who found it to have the following characters:—
Specific gravity 0*918 to 0*936
Optical rotation- -05„ -11*1°
It has more recently been examined by E. E. Miller,
5
prior to whose- work Correll had identified carvacrol in the oil, and Alden 6 had shown
that pulegone was also present. The oil examined by Miller had a
specific gravity 09017 at 25°, optical rotation - 4'6°, and refractive
index 14881 at 16°. He showed that in addition to the two bodies above
lRec. Trav. Chim. 2 Pays-Bas., 37 (1918), 355.
Jour. Ainer. Ghem. Soc., 30 (1908), 251.
3
Bericht, October, 1906, 84.
*§ Pharm. Rev., 14 (1896), 32.
6 Circular 2, April, 1918, Pharm. Expt. Station, University of Wisconsin.
Pharm. Review, 16, 414 (1898).