_Cacumina vel Summitates Scoparii_; _Broom Tops_; F. _Genêt à balais_;
G. _Besenginster_, _Pfriemenkraut_.
=Botanical Origin=—_Cytisus Scoparius_ Link (_Spartium Scoparium_ L.,
_Sarothamnus vulgaris_ Wimmer), the Common Broom, a woody shrub, 3 to 6
feet high, grows gregariously in sandy thickets and uncultivated places
throughout Great Britain, and Western and temperate Northern Europe. In
continental Europe it is plentiful in the valley of the Rhine up to the
Swiss frontier, in Southern Germany and in Silesia, but does not ascend
the Alps, and is absent from many parts of Central and Eastern Europe,
Polonia for instance. According to Ledebour, it is found in Central
and Southern Russia and on the eastern side of the Ural Mountains. In
Southern Europe its place is supplied by other species.
=History=—From the fact that this plant is chiefly a native of Western,
Northern and Central Europe, it is improbable that the classical
authors were acquainted with it; and for the same reason the remarks
of the early Italian writers may not always apply to the species under
notice. With this reservation, we may state that broom under the name
_Genista_, _Genesta_, or _Genestra_ is mentioned in the earliest
printed herbals, as that of Passau,[695] 1485, the _Hortus Sanitatis_,
1491, the _Great Herbal_ printed at Southwark in 1526, and others.
It is likewise the Genista as figured and described by the German
botanists and pharmacologists of the 16th century, like Brunfels,
Fuchs, Tragus, Valerius Cordus (“Genista angulosa”) and others. Broom
was used in ancient Anglo-Saxon medicine[696] as well as in the Welsh
“Meddygon Myddvai.” It had a place in the London Pharmacopœia of 1618,
and has been included in nearly every subsequent edition. Hieronymus
Brunschwyg gives[697] directions for distilling a water from the
flowers, “_flores genestæ_”—a medicine which Gerarde relates was used
by King Henry VIII. “against surfets and diseases thereof arising.”
Broom was the emblem of those of the Norman sovereigns of England
descended from Geoffrey the “Handsome,” or “_Plantagenet_” count of
Anjou (_obiit_ A.D. 1150), who was in the habit of wearing the common
broom of his country, the “_planta genista_,” in his helmet.
=Description=—The Common Broom has numerous straight ascending wiry
branches, sharply 5-angled and devoid of spines. The leaves, of which
the largest are barely an inch long, consist of 3 obovate leaflets on
a petiole of their own length. Towards the extremities of the twigs,
the leaves are much scattered and generally reduced to a single ovate
leaflet, nearly sessile. The leaves when young are clothed on both
sides with long reddish hairs; these under the microscope are seen each
to consist of a simple cylindrical thin-walled cell, the surface of
which is beset with numerous extremely small protuberances.
[695] _Herbarius, Patavie_ 1485.
[696] Cockayne _Leechdoms_, &c., iii. (1866) 316.
[697] _De arte distillandi_, first edition 1500, Argentorati, cap. xv.
The large, bright yellow, odorous flowers, which become brown in
drying, are mostly solitary in the axils of the leaves; they have a
persistent campanulate calyx divided into two lips minutely toothed,
and a long subulate style, curved round on itself. The legume is oblong
compressed, 1½ to 2 inches long by about ½ an inch wide, fringed with
hairs along the edge. It contains 10 to 12 olive-coloured albuminous
seeds, the funicle of which is expanded into a large fleshy strophiole.
They have a bitterish taste, and are devoid of starch.
The portion of the plant used in pharmacy is the younger herbaceous
branches, which are required both fresh and dried. In the former state
they emit when bruised a peculiar odour which is lost in drying. They
have a nauseous bitter taste.
=Chemical Composition=—Stenhouse[698] discovered in broom tops two
interesting principles, _Scoparin_, C₂₁H₂₂O₁₀, an indifferent or
somewhat acid body, and the alkaloid _Sparteine_, C₁₅H₂₆N₂, the first
soluble in water or spirit and crystallizing in yellowish tufts, the
second a colourless oily liquid heavier than water and sparingly
soluble in it, boiling at 288° C.
To obtain scoparin, a watery decoction of the plant is concentrated so
as to form a jelly after standing for a day or two. This is then washed
with a small quantity of cold water, dissolved in hot water and again
allowed to repose. By repeating this treatment with the addition of a
little hydrochloric acid, the chlorophyll may at length be separated
and the scoparin obtained as a gelatinous mass, which dries as an
amorphous, brittle, pale yellow, neutral substance, devoid of taste and
smell. Its solution in hot alcohol deposits it partly in crystals and
partly as jelly, which after drying are alike in composition. Hlasiwetz
showed (1866) that scoparin when melted with potash is resolved, like
kino or quercetin, into _Phloroglucin_, C₆H₆O₃, and _Protocatechuic
Acid_, 2 C₇H₆O₄.
The acid mother-liquors from which scoparin has been obtained when
concentrated and distilled with soda, yield besides ammonia a very
bitter oily liquid, _Sparteine_. To obtain it pure, it requires to be
repeatedly rectified, dried by chloride of calcium, and distilled in a
current of dry carbonic acid. It is colourless, but becomes brown by
exposure to light; it has at first an odour of aniline, but this is
altered by rectification. Sparteine has a decidedly alkaline reaction
and readily neutralises acids, forming crystallizable salts which are
extremely bitter. Conine, nicotine, and sparteine are the only volatile
alkaloids devoid of oxygen hitherto known to exist in the vegetable
kingdom.
Mills[699] extracted sparteine simply by acidulated water which he
concentrated and then distilled with soda. The distillate was then
saturated with hydrochloric acid, evaporated to dryness, and submitted
to distillation with potash. The oily sparteine thus obtained was dried
by prolonged heating with sodium in a current of hydrogen, and finally
rectified _per se_. Mills succeeded in replacing one or two equivalents
of the hydrogen of sparteine by one or two of C₂H₅ (ethyl). From 150
lb. the (dried?) plant, he obtained 22 cubic centimetres of sparteine,
which we may estimate as equivalent to about ½ per mille.
[698] _Phil. Trans._ 1851. 422-431.
[699] _Journ. of Chem. Soc._ xv. (1862) l.; Gmelin’s _Chem._ xvi.
(1864) 282.
Stenhouse ascertained that the amount of sparteine and scoparin depends
much on external conditions, broom grown in the shade yielding less
than that produced in open sunny places. He states that shepherds are
well aware of the shrub possessing narcotic properties, from having
observed their sheep to become stupified and excited when occasionally
compelled to eat it.
The experiments of Reinsch (1846) tend to show that broom contains
a bitter crystallizible principle in addition to the foregoing. The
seeds of the allied _Cytisus Laburnum L._ afford two highly poisonous
alkaloids, _Cytisine_ and _Laburnine_, discovered by A. Husemann and
Marmé in 1865.
=Uses=—A decoction of broom tops, made from the dried herb, is used as
a diuretic and purgative. The juice of the fresh plant, preserved by
the addition of alcohol, is also administered and is regarded as a very
efficient preparation.