Elements of pharmacy, materia medica, and therapeutics / by William Whitla.

  • Whitla William, Sir, 1851-1933.
Date:
1898
Catalogue details

Licence: Public Domain Mark

Credit: Elements of pharmacy, materia medica, and therapeutics / by William Whitla. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    59/656 (page 55)
    OINTMENTS. required. Rarely, if ever, will the extemporaneous ointments ordered by the physician require any melting. If two ointments, or an ointment and a liquid or oil, are ordered to be mixed, the simplest method of procedure is to weigh and measure the ingredients out on a porcelain slab, and thoroughly blend them with a long spatula. This will answer in many instances, but the disjienser is cautioned against making extracts, powders, or gritty substances into an ointment in this way. . In such rases the substance to fie incorporated with the fatty or oily basis is put into a mortar and ground with some minute quantity of excipient to the finest conceivable state of sul* division, and by far the best excipient ever devised is a little of the old-fashioned “ elbow-grease. The pe<tle should be worked as shown in Fig. 5, and the mortar should be capable of holding very many times more of the ointment than is about to f>e made. When the powder, or extract, or crystal i^ put into it, it is subjected to firm powdering or rubbing A very little of the fatty bads is added, and trituration continued till a smooth, impalpable paste is obtained ; then the remainder of the basis is added gradually, sweeping the sides of the mortar and pestle from time to time with a spatula, so that all is thoroughly mixed. Often, however, it will be necessary to add something to facilitate the grinding before adding the ointment : thus, if camphor is ordered, it must l>e rubfred very fine by the aid of a little spirit which evaporates during the mixing. If an extract is to be added to an ointment it is fust put into the mortar and rubbed to absolute smoothness with a little spirit, water, or glycerin, before adding the unctuous fiasis. If the extract is hard, or even of pilular consistence, the best plan is to previously warm the mortar by pouting hot water into it, and drying quickly with a cloth, when the extract ran be rubbed to smoothness before a little of the basis is added. Soluble crystals, like iodide of jiotassium or carbonate of potassium or sodium, are triturated with a little water before adding the remaining ingredients. Iodine should 1* rubbed to powder, a few drops of spirit added, and the trituration continued. Iodide of sulphur should be most perseveringly rublred down with a little olive oil, borax with a little glycerin, and red precipitate with distilled water. Volatile liquids should be added after the other ingredients ate well mixed, so that evaporation is reduced to a minimum, as in the case of Prussic acid and chloroform. Steel knives should not f>e used in the preparation of ointments with the alkaloids, or with acids, or especially with the acid nitrate of mercury, red precipitate, or yellow oxide of mercury ointments, which are ruined by the touch of iron. Many fine and jiearly compounds made with cold cream are well prepared