ALCOHOL.[359] L.D. _Alcohol. Ardent Spirit._ 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] ALOES EXTRACTUM. _Aloes._ There are three species met with in the shops, viz.