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
Catalogue details

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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    where heat is used in such way as to exclude the risk of empyreuma. If it does not require to be finely divided, as in the case of fresh leaves and flowers, it may be put conveniently into a net-bag; which is suspended in the middle of the still, and may be withdrawn with facility when its contents are ex- hausted. Some manufacturers use, not water, but steam for obtaining distilled- waters: That is, the material to be distilled is spread over a fine gauze par- tition or a plate perforated with numerous small holes, and steam is driven through the mass. When the vegetable substance to be exhausted is a bark, wood, or other ~ solid matter, it must be reduced to a state of moderately fine division. But this is not generally necessary in the case of leaves or flowers, because boil- ing water breaks down the cells in which the volatile oil is contained. When leaves, however, are thick and leathery, as in the instance of the cherry-laurel, the process is facilitated by chopping them down; and in most cases, where leaves are large, it is difficult to get a sufficient quantity into the still without cutting them into pieecs.——In preparing the finer kinds of distilled waters, it is necessary to clean the materials carefully, to remove all decayed leaves or flowers, or those infested by insects, and sometimes also to separate the leaf-stalks, or the green claw of the petals. Distilled waters, however carefully they may be kept, are apt to lose their aroma sooner or later; and some of them even become mouldy and acquire thereby an unpleasant odour. ‘They have been thought to keep better with the addition of about a fortieth part of rectified spirit; which may be either put into the still with the water, or added afterwards to the distilled fluid. But the advantages of this addition, although sanctioned by the authority of the Dublin Pharmacopeia, are doubted by practical men. And it is believed that the most effectual precaution for preserving them is to prepare them with extremely pure natural waters, such as snow, rain, or very fine spring water | Muller], free especially of any unusual proportion of carbonic acid; and to keep them in black, orange, or red bottles, not in bottles of clear glass [ Hanle }. ENEMAS. A consideration often neglected by practitioners in extempore prescriptions for administering drugs in the form of injection, is, that the volume of it must vary with the object. If it be intended to evacuate the gut, the quantity of the fluid should not be less than sixteen fluidounces or a pint. But if the medicine be intended to exert its own peculiar action through absorption, or through the nervous system, it ought to be administered in a quantity of fluid nof exceeding four fluidounces; otherwise it may be speedily ejected, owing to the mere mechanical stimulus of distension. EXTRACTS. Lond. In preparing extracts, unless other- wise directed, let the liquor be evaporated Genrerat Directions, Edin. Extracts are usually prepared by evaporating the ex- pressed juices of plants, or their infusions or decoctions, in water, proof spirit, or recti- fied spirit, ata temperature not exceeding 212° by means of a vapour-bath. Most of them, however, may be obtained of greatly superior quality by the process of evapora- tion in vacuo. And the extracts of expressed juices cannot perhaps be better prepared _ than by spontaneous evaporation in shallow vessels, exposed to a current of air. Ex- tracts should be evaporated to such a con- sistence as to form a firm pill-mass when cold. in a basin as quickly as possible over a vapour-bath, stirring it assiduously towards the close, till a consistence be attained fit for making pills. | To all the softer extracts a little rectified spirit ought to be added, for the prevention of mouldiness. Dub, All the simpler extracts, unless ordered otherwise, are to be prepared in the follow- ing manner. Let the vegetable materials be boiled with eight times their weight of water, till half the liquid remain; then ex- press the liquor and strain it when the im-