_Radix Liquiritiæ_; _Liquorice Root_; F. _Réglisse_; G. _Süssholz_,
_Lakritzwurzel_.
=Botanical Origin=—_Glycyrrhiza glabra_ L., a plant which under several
well marked varieties[716] is found over an immense extent of the
warmer regions of Europe, spreading thence eastward into Central Asia.
The root used in medicine is derived from two principal Varieties,
namely:—
α. _typica_—Nearly glabrous, leaves glutinous beneath, divisions of
the calyx linear-lanceolate often a little longer than the tube,
corolla purplish blue, legume glabrous, 3-6 seeded. It is indigenous to
Portugal, Spain, Southern Italy, Sicily, Greece, Crimea, the Caucasian
Provinces and Northern Persia; and is cultivated in England, France and
Germany.
γ. _glandulifera_ (_G. glandulifera_ W.K.)—Stems more or less pubescent
or roughly glandular, leaves often glandular beneath, legume sparsely
or densely echinate-glandular, many-seeded, or short and 2-3 seeded. It
occurs in Hungary, Galicia, Central and Southern Russia, Crimea, Asia
Minor, Armenia, Siberia, Persia, Turkestan and Afghanistan.
_G. glabra_ L. has long, stout, perennial roots, and erect, herbaceous
annual stems. In var. α., the plant throws out long stolons which run
horizontally at some distance below the surface of the ground.
=History=—Theophrastus[717] in commenting on the taste of different
roots (3rd cent. B.C.) instances the sweet Scythian root which grows
in the neighbourhood of the lake Mæotis (Sea of Azov), and is good for
asthma, dry cough and all pectoral diseases,—an allusion unquestionably
to liquorice. Dioscorides,[718] who calls the plant γλυκιῤρίζη, notices
its glutinous leaves and purplish flowers, but as he describes the
pods to be in balls resembling those of the plane, and the roots to be
sub-austere (ὑπόστρυϕνοι) as well as sweet, it is possible he had in
view _Glycyrrhiza echinata_ L. as well as _G. glabra_.
Roman writers, as Celsus and Scribonius Largus, mention liquorice as
_Radix dulcis_. Pliny, who describes it as a native of Cilicia and
Pontus, makes no allusion to it growing in Italy.
The cultivation of liquorice in Europe does not date from a very remote
period, as we conclude from the absence of the name in early mediæval
lists of plants. It is, for instance, not enumerated among the plants
which Charlemagne ordered (A.D. 812) to be introduced from Italy into
Central Europe;[719] nor among the herbs of the convent gardens as
described by Walafridus Strabus,[720] abbot of Reichenau, lake of
Constance, in the 9th century; nor yet in the copious list of herbs
contained in the vocabulary of Alfric, archbishop of Canterbury in the
10th century.[721]
[716] We accept those adopted by Boissier in his _Flora Orientalis_,
ii. (1872) 202.
[717] _Hist. Plant._ lib. ix. c. 13.
[718] Lib. iii. c. 5.
[719] Pertz, _Monumenta Germaniæ historica, Legum_, i. (1835) 186.
[720] Migne, _Patrologiæ Cursus_, cxiv. 1122.
[721] Wright, _Volume of Vocabularies_, 1857. 30. This work contains
several other early lists of plants.
On the other hand, liquorice is described as being cultivated in Italy
by Piero de’ Crescenzi[722] of Bologna, who lived in the 13th century.
The cultivation of the plant in the north of England existed at the
close of the 16th century, but how much earlier we have not been able
to trace.
As a medicine the drug was well known in Germany in the 11th century,
and an extensive cultivation of the plant was carried on near Bamberg,
Bavaria, in the 16th century, so that in many of the numerous
pharmaceutical tariffs of those times in Germany not only Glycyrrhizæ
succus creticus, seu candiacus, seu venetus is quoted, but also
expressly that of Bamberg.[723]
The word _Liquiritia_, whence is derived the English name _Liquorice_
(_Lycorys_ in the 13th century), is a corruption of _Glycyrrhiza_, as
shown in the transitional mediæval form _Gliquiricia_. The Italian
_Regolizia_, the German _Lacrisse_ or _Lakriz_, the Welsh _Lacris_[724]
and the French _Réglisse_ (anciently _Requelice_ or _Recolice_) have
the same origin.
=Cultivation, and habit of growth=—The liquorice plant is cultivated in
England at Mitcham and in Yorkshire, but not on a very extensive scale.
The plants, which require a good deep soil, well enriched by manure,
are set in rows, attain a height of 4 to 5 feet and produce flowers
but not seeds. The root is dug up at the beginning of winter, when
the plant is at least 3 or 4 years old. The latter has then a crown
dividing into several aerial stems. Below the crown is a principal root
about 6 inches in length, which divides into several (3 to 5) rather
straight roots, running without much branching, though beset with
slender wiry rootlets, to a depth of 3, 4 or more feet.[725] Besides
these downward-running roots, the principal roots emit horizontal
runners or stolons, which grow at some distance below the surface and
attain a length of many feet. These runners are furnished with leaf
buds and throw up stems in their second year.
Every portion of the subterraneous part of the plant is carefully
saved; the roots proper are washed, trimmed, and assorted, and either
sold fresh in their entire state, or cut into short lengths and dried,
the cortical layer being sometimes first scraped off. The older
runners distinguished at Mitcham as “_hard_,” are sorted out and sold
separately; the young, called “_soft_,” are reserved for propagation.
In Calabria, the singular practice prevails of growing the liquorice
among the wheat in the cornfields.
=Description=—Fresh liquorice (English) when washed is externally of a
bright yellowish-brown. It is very flexible, easily cut with a knife,
exhibiting a light yellow, juicy, internal substance which consists
of a thick bark surrounding a woody column. Both bark and wood are
extremely tough, readily tearing into long, fibrous strips. The root
has a peculiar earthy odour, and a strong and characteristic sweet
taste.
[722] _Libro della Agricoltura_, Venet. 1511. lib. vi. c. 62.
[723] Gesner, _Valerii Cordi Hist. stirp._ Argentorati, 1561.
164.—Flückiger, _Documente zur Geschichte der Pharmacie_, Halle, 1876.
39. 46.
[724] In the “Meddygon Myddvai” of the 13th century, Llandovery, 1861,
p. 159. 355 (it is written there Licras).
[725] This form of root, which reminds one of a whip with three or
four lashes and a very short handle, is probably due to the method of
propagating adopted at Mitcham, where a short stick or _runner_ is
planted upright in the ground.
Dried liquorice root is supplied in commerce either with or without
the thin brown coat In the latter state it is known as _peeled_ or
_decorticated_. The English root, of which the supply is very limited,
is usually offered cut into pieces 3 or 4 inches long, and of the
thickness of the little finger.
_Spanish Liquorice Root_, also known as _Tortosa_ or _Alicante
Liquorice_, is imported in bundles several feet in length, consisting
of straight unpeeled roots and runners, varying in thickness from ¼ to
1 inch. The root is tolerably smooth or somewhat transversely cracked
and longitudinally wrinkled; that from Tortosa is usually of a good
external appearance, that from Alicante sometimes untrimmed, dirty, of
very unequal size, showing frequently the knobby crowns of the root.
Alicante liquorice root is sometimes shipped in bags or loose.
_Russian Liquorice Root_, which is much used in England, is we presume
derived from _G. glabra_ var. _glandulifera_. It is imported from
Hamburg in large bales, and is met with both peeled and unpeeled. The
pieces are 12 to 18 inches long, with a diameter of ¼ of an inch to 1
or even 2 inches. Sometimes very old roots, split down the centre and
forming channelled pieces as much as 3½ inches wide at the crown end,
are to be met with. This liquorice in addition to being sweet has a
certain amount of bitterness.
=Microscopic Structure=—The root exhibits well-marked structural
peculiarities. The corky layer is made up of the usual tabular cells;
the primary cortical tissue of a few rows of cells. The chief portion
of the bark consists of liber or endophlœum, and is built up for the
most part of parenchymatous tissue accompanied by elongated fibres of
two kinds, partly united into true liber-bundles and partly forming a
kind of network, the smaller threads of which deviate considerably from
the straight line. Solution of iodine imparts an orange hue to both
kinds of bast-bundles, and well displays the structural features of the
bark.
The woody column of the root exhibits three distinct forms of cell,
namely ligneous cells (libriform) with oblique ends; parenchymatous,
almost cubic cells; and large pitted vessels. In the Russian root, the
size of all the cells is much more considerable than in the Spanish.
=Chemical Composition=—The root of liquorice contains, in addition
to sugar and albuminous matter, a peculiar sweet substance named
_Glycyrrhizin_, which is precipitated from a strong decoction upon
addition of an acid or solution of cream of tartar, or neutral or basic
acetate of lead. When washed with dilute alcohol and dried, it is an
amorphous yellow powder, having a strong bitter-sweet taste and an
acid reaction. It forms with hot water a solution which gelatinizes
on cooling, does not reduce alkaline tartrate of copper, is not
fermentable, and does not rotate the plane of polarization. From the
analysis and experiments of Rösch, performed in the laboratory of
Gorup-Besanez at Erlangen, in 1876, the formula C₁₆H₂₄O₆ was derived
for glycyrrhizin. By boiling it with dilute hydrochloric or sulphuric
acid it is resolved into a resinous amorphous bitter substance named
_Glycyrretin_, and an uncrystallizable sugar having the characters of
glucose. The formula of glycyrretin has not yet been settled. Weselsky
and Benedikt, in 1876, showed that 65 per cent. of it may be obtained
from glycyrrhizin. By melting glycyrretin with about 5 parts of caustic
potash paraoxy-benzoïc acid is produced.
Alkalis easily dissolve glycyrrhizin with a brown colour and emission
of a peculiar odour. In the root it perhaps exists combined with
ammonia, inasmuch as the aqueous extract evolves that alkali when
warmed with potash (Roussin, 1875). According to Sestini (1878)
glycyrrhizin is present in the root combined with calcium; he obtained
6·3 per cent. of glycyrrhizin from the root previously dried at 110°.
By exhausting glycyrrhizin with glacial acetic acid Habermann in 1876
succeeded in isolating almost _colourless_ crystals having the sweet
taste of the root. They yield, by boiling them with dilute acids, a
yellow substance which would appear to agree with glycyrretin. The deep
yellow walls of the vessels and prosenchymatous cells appear to be the
chief seat of the glycyrrhizin.
The sugar of liquorice root has not yet been isolated; the aqueous
infusion of the _dried_ root separates protoxide of copper from an
alkaline solution of cupric tartrate. Yet the sugar as extracted from
the _fresh_ root by cold water does not precipitate alkaline cupric
tartrate at all in the cold, and not abundantly even on prolonged
boiling.
_Asparagin_ was obtained from the root by Robiquet (1809) and by
Plisson (1827). Sestini (1878) isolated 2-4 parts of asparagin from
100 parts of the root dried at 110° C. Robiquet also found the root to
contain malic acid. The presence of starch in abundance is shown by the
microscope as well as by testing a decoction of the root with iodine.
The outer bark of the root contains a small quantity of tannin.
=Commerce=—Liquorice root is imported into Great Britain from Germany,
Russia and Spain, but there are no data for showing to what extent.
France imported in 1872 no less than 4,348,789 kilogrammes (4282 tons),
which was more than double the quantity imported the previous year.[726]
Liquorice root is much used in China, and is largely produced in some
of the northern provinces. In 1870, 1,304 peculs were shipped from
Ningpo,[727] and 7,147 pepuls in 1877 from Cheefu (one pecul = 133·33
lb. avdp.).
=Uses=—Liquorice root is employed for making extract of liquorice and
in some other pharmaceutical preparations. The powdered root is used to
impart stiffness to pill-masses and to prevent the adhesion of pills.
Liquorice has a remarkable power of covering the flavour of nauseous
medicines. As a domestic medicine, liquorice root is far more largely
used on the Continent than in Great Britain.
[726] _Documents statistiques réunis par l’administration des Douanes
sur le commerce de la France_, année 1872, Paris, 1873.
[727] _Reports on Trade at the Treaty Ports in China for_ 1870,
Shanghai, 1871. 13. 62.