_Garden Thyme_; F. _Thym vulgaire_; G. _Thymiankraut_.
=Botanical Origin=—_Thymus vulgaris_ L., a small, erect, woody shrub
reaching 8 to 10 inches in height, gregarious on sterile uncultivated
ground in Portugal, Spain, Southern France and Italy, and in the
mountainous parts of Greece. On Mont Ventoux near Avignon, it reaches
an elevation above the sea of 3700 ft. (Martins). It is commonly
cultivated in English kitchens as a sweet herb,[1782] and succeeds as
an annual even in Iceland.
=History=—We are not aware that thyme had any reputation in the
antiquity, nor do we know at what period it was first introduced in
northern countries. Garden thyme was commonly cultivated in England in
the 16th century, and was well figured and described by Gerarde. It is
even said to have been formerly grown on a large scale for medicinal
use in the neighbourhood of Deal and Sandwich in Kent.[1783] _Camphor
of Thyme_ was noticed by Neumann, apothecary to the Court at Berlin in
1725;[1784] it was called _Thymol_, and carefully examined in 1853 by
Lallemand, and recommended instead of phenol (carbolic acid) in 1868 by
Bouilhon, apothecary, and Paquet, M. D. of Lille.
=Description=—The plant produces thin, woody, branching stems, bearing
sessile, linear-lanceolate, or ovate-lanceolate leaves. These are
about ¼ of an inch long, revolute at the margin, more or less hoary,
especially on the under side, and dotted with shining oil-glands. The
small purple flowers are borne on round terminal heads, with sometimes
a few lower whorls. The entire wild plant has a greyish tint by reason
of a short white pubescence, yet as seen in gardens the plant is more
luxuriant, greener and far less tomentose. It is extremely fragrant
when rubbed, and has a pungent aromatic taste.
=Production of Essential Oil=—Though cultivated in gardens for culinary
use, common thyme is not grown in England on a large scale. Its
essential oil (_Oleum Thymi_), for which alone it is of interest to the
druggist, is distilled in the south of France. In the neighbourhood
of Nîmes, where we have observed the process, the entire plant is
used, and the distillation is carried on at two periods of the year,
namely in May and June when the plant is in flower, and again late
in the autumn. The oil has a deep, reddish-brown colour, but becomes
colourless though rather less fragrant by re-distillation. The two
sorts of oil, termed respectively _Huile rouge de Thym_ and _Huile
blanche de Thym_, are found in commerce. The yield is about 1 per cent.
Oil of thyme is frequently termed in English shops _Oil of Origanum_,
which it in no respect resembles, and which was never, so far as we
know, found in commerce.[1785]
[1782] In many of the references to thyme, _Wild Thyme_ (_Thymus
Serpyllum_ L.) is to be understood, and not the present species.
[1783] Booth in _Treasury of Botany_, ii. (1866) 1149.
[1784] _Phil. Trans._ No. 389.
[1785] For a note on _True Oil of Origanum_, see Hanbury, _Pharm.
Journ._ x. (1851) 324, also _Science Papers_, 1876, p. 46.
=Chemical Composition=—The only constituent of the herb that has
attracted any attention is the above-named essential oil. This
liquid by fractional distillation is resolved into two portions: the
first, more volatile and boiling below 180° C., is a mixture of two
hydrocarbons, _Cymene_, C₁₀H₁₄ (see page 333), and _Thymene_, C₁₀H₁₆,
the latter boiling at 165° C.
The second, named _Thymol_, C₁₀H₁₄O, which may also be extracted from
the crude oil by means of caustic lye, has been described in our
article _Fructus Ajowan_, at page 303. Commercial oil of thyme is said
to be sometimes fraudulently deprived of thymol by that treatment.
=Uses=—Oil of thyme is an efficient external stimulant, and is
sometimes employed as a liniment. Its chief consumption is in
veterinary medicine. Thymol has been proposed as a disinfectant in the
place of carbolic acid, in cases in which the odour of the latter is
objectionable. The herb is not used in modern English medicine, but is
often employed on the Continent.