A dispensatory, or commentary on the pharmacopoeias of Great Britain (and the United States) comprising the natural history, description, chemistry, pharmacy, actions, uses, and doses of the articles of the materia medica / [Sir Robert Christison].
- Robert Christison
- Date:
- 1848
Licence: Public Domain Mark
Credit: A dispensatory, or commentary on the pharmacopoeias of Great Britain (and the United States) comprising the natural history, description, chemistry, pharmacy, actions, uses, and doses of the articles of the materia medica / [Sir Robert Christison]. Source: Wellcome Collection.
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![held, as to the influence of various circumstances in vegetation on the activity of medicinal plants, are often erroneous, and generally subject to important exceptions; that the practical rules founded on those doctrines are sometimes faulty; and that the pharmaceutic art stands much in need of a new and thorough investigation of this imperfectly trodden field. Most works on pharmacy contain under the present head a Druggist’s Kalendar, showing the several periods at which vegetable simples ought to be collected. But for the reason just adverted to, none of these kalendars can be relied on, and it therefore seems unnecessary to reproduce them here.. Some observations, however, will be found on the subject under the head of the special articles of the vegetable Materia Medica. The preparing of vegetable substances for preservation is now tolerably well understood in most particulars. Itis unnecessary, therefore, to say much here on the methods usually practised. Seeds ought to be exposed to a mo- derate heat, and then sifted and winnowed, to remove insects and their ova, with other impurities. Leaves and flowers should be promptly dried in a current of heated air, and out of reach of bright light; and the Dublin Col- lege properly directs that leaves, which are used in the state of powder, should be reduced to that form as soon as they are dry, and immediately stored in well-stopped, opaque bottles.. This is the most effectual way to preserve them against both damp and insects, and likewise in small space. Even those leaves whose properties are fugacious, such as. hemlock leaves, may be thus preserved for years without alteration. Barks are best preserved in drawers or boxes in a dry, well-aired apartment, woods and dry roots in the same manner, but fresh roots in sand in a cellar. Dried fruits are usually preserved in boxes or drawers, sometimes in bottles; but fresh pulpy fruits can be pre- served with difficulty in any way. The only important medicinal fruit of this kind, the lemon, is better preserved in fresh carefully slaked lime, within stone-ware jars or bottles, than in any other method I have'tried. Vinegar or salt, recommended for the purpose in some pharmaceutic works, may pre- serve their colour, but not their flavour, nor their own proper acid—as might be inferred from the principles of endosmosis and exosmosis, established by Datrochet.—The directions given by the London College for the purification of opium and gum-resins are unnecessary or even injurious. Opium may now be obtained at any time so free of mechanical impurities as not to re- quire the operation of cleaning; and no other quality should be recognised by the Colleges or admitted into the shop of the druggist. The same remark may be applied to the gum-resins. Such impurities as may be removed by the College process are easily detected on examination, and occur only in the inferior qualities of these drugs, now gradually becoming less abundant in the market, and manifestly such as no sensible druggist will admit into his esta- blishment. Besides, the College process cannot be applied without detriment, because a portion of the volatile oil, the most important ingredient of many gum-resins, must be driven off by the heat, more especially in that modifica- tion of the process in which the gum is dissolved in boiling water and after- wards recovered by evaporation. It has been lately stated, however, that if the gum-resin be softened by the aid of heat with three-eighths of its weight of proof-spirit, instead of water, it may be dried after expression without loss of volatile oil [Gobley]. : VINEGARS. There are few preparations of this kind in the Pharmacopeias. Never- theless, the state of solution in distilled vinegar is probably one of the best officinal forms for many vegetable drugs, so far at least as energy is concerned. The reason is that acetic acid, even much diluted, is a powerful solvent of](https://iiif.wellcomecollection.org/image/b33284313_0036.jp2/full/800%2C/0/default.jpg)
