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.
| 1. | Alöe Spicata, L. Socotorina, D. Perfoliata. E. | Socrotrine Aloes. Cape Aloes. |
| 2. | Alöe Vulgaris.[[362]] L. Hepatica, E. D. | Common or Barbadoes Aloes. |
| 3. | Alöe Cabalina. Fetid, Cabaline, or Horse Aloes. | Employed only by Farriers. |
Qualities. The above varieties of aloe differ in their purity, and likewise in their sensible qualities; the Socotrine is the purest, it is in small pieces of a reddish brown colour; the Barbadoes is in large masses, of a lighter colour, and having an odour much stronger and less pleasant; the Cabaline is still more impure and less powerful. All the kinds are characterized by an intensely bitter taste, which, in the Socotrine, is accompanied by an aromatic flavour. Chemical Composition. In this there appears to be some obscurity; M. Braconnot (Ann. Chim. tom. 68.) conceives it to be a substance, sui generis, which he terms “bitter resin,” while others regard it as composed of resin, gum, and extractive, the proportions of which are supposed to vary in the different species, but that their peculiar virtues reside in the extractive part. Solubility. It is to the slowness with which aloe undergoes solution in the primæ viæ, that it is indebted for the medicinal properties which distinguish this substance; by boiling water it is dissolved, but on cooling a precipitation ensues, and by long decoction it becomes quite inert; weak acids dissolve it more abundantly than water, but proof spirit is the most perfect solvent: its solubility is increased by the addition of alkaline salts and soaps, but by such a combination it undergoes a material change in its medicinal properties; the bitterness is diminished, its purgative effects impaired, and it ceases to operate specifically upon the large intestines, a fact so far valuable, as it enables us in certain cases to obviate its irritating action upon the rectum. Medicinal Use. Aloe is a bitter stimulating purgative, emptying the large intestines, without making the stools thin; it likewise warms the habit, quickens the circulation, and promotes the uterine and hemorrhoidal fluxes. Dose, gr. v.–xv. No greater effect is produced by a large dose than from one comparatively moderate; its tendency, however, to irritate the rectum renders it, in many cases, an objectionable remedy;[[363]] and its sympathetic action on the uterus may occasionally produce mischief, in irritable habits, while in other states it may, for reasons equally obvious, prove beneficial. Forms of Exhibition. The form of pill should be preferred on account of its extreme bitterness, as well as being, for the reasons above mentioned, the one most likely to fulfil the intention of its exhibition; for in addition to what has been stated in a preceding part of this work, on the important influence of solubility, it may be here observed that since the aloe does not undergo solution in the stomach, it is admirably adapted for the basis of remedies intended to obviate constitutional costiveness, for in our endeavours to supply the deficiencies of nature by the resources of art, we should at least attempt to imitate the modes of her operation; the natural stimulus of the intestines, the bile, is poured into them below the stomach, and whenever it regurgitates into that organ it produces disease; so it happens with our cathartic medicines, and unless we so modify their solubility that their operation cannot commence until after their passage through the stomach, we shall find that we only increase the evil we are endeavouring to obviate, and that, in addition to the torpor of the intestinal canal, we shall induce the stomach to participate in the disease, or excite a morbid fretfulness of that organ which will be attended with the most distressing symptoms.[[364]] See Formulæ 12, 13, 79, 80, 81. Aloes in combination with assafœtida furnishes an eligible purgative in the dyspepsia of old persons; it is also well calculated to obviate the costiveness so generally produced by Opium, (Form: 11, 12, 13.) See also p. 162. Officinal Preparations. Pulv: Aloes comp: L. Pil: Alöes cum Myrrha. L.E.D. Pil: Aloes comp: Pil: Alöes cum Assafœtida. E. Pil: Aloes cum Colocynthide. E. Pil: Cambogiæ comp: (B.M.) L. Pil: Rhei. comp: (F) E. Pil. Scammon, cum Aloe. D. Decoctum Aloes comp: L. Extractum Aloes purificatum. L.D. Extractum Colocynthidis comp: L.D. (F) Tinct: Alöes L.E.D. Tinct: Alöes comp: L.E.D. Tinct: Alöes Ætherea, E. Tinct: Benzoin: comp: (G) L.E.D. Tinct: Rhei et Aloes E. Vinum Alöes. L.E.D. Adulterations. It is frequently adulterated with common resin, but the fraud more generally committed is that of mixing with, or substituting the inferior species for the Socotrine, but the Barbadoes Aloes may, independent of its want of aromatic flavour, be distinguished from the Socotrine by a simple test, for the latter dissolves entirely in boiling water and alcohol, whereas the former, when treated in a similar manner, leaves a considerable residue; sometimes the Horse Aloes is made to appear so bright and pure, as not to be easily distinguished by the eye even from the Socotrine, but its rank odour, of which no art can divest it, will readily betray the fraud.
ALUMEN. (Super-sulphas Aluminæ et Potassæ.) Sulphas Aluminæ. E.