LABIATE 197
flavour, which places it far behind lavender as an odoriferous plant,
very considerable quantities of lavandin are cut for distilling.
Lamothe estimates that the lavandin oil which is brought to market
•every year amounts to about 20 per cent, of the total output of lavender
*>il or, in weight, to about 12,000 kilos. He regards this as most re-
grettable and utters an emphatic warning against the distillation of
lavandin flowers, for although they yield a better return than true
lavender, and with less trouble, their oil is decidedly inferior and may
easily injure the present predominant position of French lavender oil.
Lamothe gives a very interesting comparison of the respective outputs,
which deserves to be quoted here. In the same time which is required
to collect about 55 kilos true lavender flowers, nearly 400 kilos of the
freer-flowering lavandin can be gathered without trouble. And where-
as for the production of 1 kilo lavender oil 145 kilos of flowers are needed,
from 77 to 80 kilos of flowers suffice to produce 1 kilo of lavandin oil.
With regard to the properties of lavandin oil, Lamothe states that
the samples distilled by him had an average ester-content of 24 per
cent.
Lavender oilds a pale yellow oil having the following characters :—Specific gravity ........ 0'879 to 0-900
Optical rotation - 3° „ - 10°
Kefractive index 1-4600 „ 1-4660With regard to any further tests to be applied to the oil, the place
of origin must be taken into consideration. An English oil will not
give an ester number outside the limits 7 to 10 per cent., calculated as
linalyl acetate, whilst foreign oils yield about 25 to 44 per cent., or even
higher values under certain conditions. This fact is exceedingly im-
portant in discriminating between English and mixed lavender oils.
The usual adulterants of lavender oil used to be spike oil and turpen-
tine. Neither of these oils contains appreciable quantities of ester, so
that the ester determination affords much information here. Spike oil
being usually dextro-rotatory causes a diminution in the rotatory power
of the oil. American turpentine has the same effect, whereas French
turpentine increases the laevo-rotation. Mixtures of spike oil and
French lavender oil can be made having the same ester content as
English oil, but the optical rotation is interfered with (the specific
gravity is slightly raised also, but not necessarily above the limits for
normal oil). To-day, however, the most dangerous adulterant one has
to guard against is spike oil, or a similar oil, enriched with artificial
esters.
The esters used are, in general, glyceryl acetate, terpinyl acetate,
ethyl phthalate, ethyl succinate or ethyl citrate, most of which yield a
saponification value indicating a much greater amount of linalyl ace-
tate. The specific gravity of the oil is raised by these additions, un-
less this is counterbalanced by the suitable addition of a low gravity
oil. Schimmel gives the following method of detecting ethyl succinate.
About 2 grms. of the oil are saponified and the insoluble oil washed
fcway with ether; the aqueous solution is neutralised with hydro-
chloric acid and diluted to 50 c.c. Ten c.c. of cold saturated solution
of barium chloride are added and the liquid warmed on the water-bath
for two hours and then cooled. The formation of any crystalline pre-
cipitate indicates adulteration, since the barium salts of acetic and