QUALITIES. A transparent, and colourless liquid of the specific gravity
·815; it has not hitherto been rendered solid by any diminution of
temperature; it boils at 176°, and if water be added, its boiling point
is proportionably raised; hence, says Dr. Henry, the temperature at
which it boils is not a bad test of its strength; it is combustible, and
burns with a blue flame, leaving no residue. CHEMICAL COMPOSITION.
Alcohol, in a state of complete purity, consists of carbon, hydrogen,
and oxygen, in proportions not hitherto determined with accuracy; this
preparation however contains 7 per cent. of water; Lovitz and Saussure
succeeded in obtaining it at a specific gravity of ·791, which may be
considered as nearly pure. Alcohol unites chemically with water; and
caloric is evolved during this union; the quantity of alcohol and water
in mixtures of different specific gravities, may be learned from Mr.
Gilpin’s tables, _Philosophical Transactions_, 1794, or _Nicholson’s
Journal_, _4to. vol._ 1. The Edinburgh Pharmacopœia has no process for
the preparation of alcohol, but it most incorrectly assigns the title to
that which is the “Rectified Spirit” of the other Colleges. SOLVENT
POWERS. Alcohol dissolves soap; vegetable extract; sugar; oxalic,
camphoric, tartaric, gallic, and benzoic acids; volatile oils; resins,
and balsams; it combines also with sulphur, and the pure fixed alkalies,
but not with their carbonates: for its other habitudes, and
applications, see _Spiritus Rectificatus_.
ALLII RADIX. L.E.D. Allium Sativum.
_Garlic._[360]
QUALITIES. This bulbous root has when recent a fœtid smell, and acrid
taste, which are extracted by watery infusion; by decoction they are
nearly lost; by expression, the root furnishes almost one-fourth of its
weight of a limpid juice, and by distillation, an odorous, acrid,
essential oil is procured, in which the existence of sulphur may be
detected. Garlic has a considerable analogy to squill and onion, and
like them, exerts a diuretic, diaphoretic, expectorant, and stimulant
operation; (see p. 103). It is a very common domestic remedy for the
expulsion of tænia, and it is undoubtedly of advantage in such cases; it
is usually administered in the form of a decoction, with milk, on an
empty stomach; it is however but rarely used in modern practice, as it
possesses no superiority over remedies less nauseous and objectionable;
the bruised root, externally applied, is highly stimulant, and
rubefacient. Sydenham speaks highly of the application of garlic to the
soles of the feet, as a powerful means of producing revulsion from the
head. OFFICINAL PREPARATION. _Syrupus Allii._ D.[361]