Thomson's Conspectus of the British pharmacopoeias.

  • Anthony Todd Thomson
Date:
1852
Catalogue details

Licence: Public Domain Mark

Credit: Thomson's Conspectus of the British pharmacopoeias. Source: Wellcome Collection.

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    Many of the metallic salts effloresce, and attract oxygen from the atmosphere; others are altered in their properties by moisture, and some of them are decomposed by the action of light; hence, perhaps, it ought to be a general rule to keep all of them in well-stopped bottles made of green glass, or otherwise rendered opaque. In forming those which are soluble into lotions, distilled water should be used; and in mixtures, attention should be paid not to unite them with incompatible substances. PREPARATIONS OF SULPHUR. The combinations of sulphur with the alkalies and the earths are named sulphurets, and require to be carefully preserved from the atmosphere, as they attract moisture from it, deliquesce and are decomposed. When they are prepared with water, the oxygen of the water acidifies part of the sulphur, and forms sulphates; while one part of the hydrogen, uniting with a portion of the sulphur, volatilizes it in the form of sulphuretted hydrogen gas, and another assists in producing hydroguretted sulphurets of the alkaline base. One test of the goodness of concrete sulphurets is their want of odour; for whenever the foetid gas is evident, decomposition has already commenced. PREPARATIONS OF IODINE, BROMINE, AND CHLORINE. All of these substances combine with metals forming iodides, bromides, and chlorides. When the compound consists of one equivalent of each of the components, the addition ofpi'otorproto is used, as protoidide, protochloride, &c.; when it contains two equivalents of the base, the syllable bin or bi is added; thus, biniodide, bichloride. The iodide of iron should never be kept in the solid form : the syrup is the best mode of preserving it. VEGETABLES. Vegetable substances ought to be collected in a dry season, when moistened neither by showers nor dew. They should be gathered annually and not kept beyond a year. Roots and rhizomes ought to be dug up when the leaves and old stem have fallen off, and before the new ones are put forth. Barks ought to be collected in the season when they can be most easily separated from the wood. Herbs and leaves ought to be gathered after the flowers have blown, and before the seeds have ripened. Flowers must be gathered when freshly blown. Fruits and seeds must be collected when ripe. But as the collection of vegetable substances cannot be at- tended to by the medical practitioner, the directions usually
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