Royle's manual of materia medica and therapeutics : including the preparations of the British pharmacopoeia and other approved medicines / by John Harley.
- Harley, John, 1833-1921.
- Date:
- 1876
Licence: Public Domain Mark
Credit: Royle's manual of materia medica and therapeutics : including the preparations of the British pharmacopoeia and other approved medicines / by John Harley. Source: Wellcome Collection.
Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.
41/856 (page 29)
![PRESCEIBING. coloured glass, in order to exclude the chemical rays of the spectrum, and put away in a dark closet. The exclusion of air is, generally speaking, of even more import- ance than that of light, for it implies the exclusion of oxygen, car- bonic acid, and water. Thus hydrocyanic acid, and sether rapidly decomposes on exposure to the air fixim absorption of oxygen. The caustic alkalies, lime and magnesia, are converted into carbonates or oxycarbonates from absorption of carbonic anhydride ; the caustic alkalies, the chlorides of sodium, potassium, calcium, zinc,_ carbonate of ]3otash, sulphuric acid, glycerine, and alcohol, greedily absorb water, even from a moderately dry air. Substances, on the other hand, require to be secured in aii-tight vessels, in order to prevent the evaporation of volatile matters, and the deterioration caused by frequent atmospheric changes. Very volatile liquids, such as aether, chloroform, benzol, hydrosulphate of ammonia, are scarcely to be retained by the most accurately fitting stoppers, and the bottles con- taining them should, therefore, be provided with caps, which not only afford a further security against evaporation, but if properly fitted, prevent jumping of the stopper, which is apt to occur with increase of temperature. Volrunetric solutions, for an obvious reason, shoidd be preserved in such botfles. Even certain salts become altered in strength by loss of water of crystallisation from exjjosure to the air; this is the case with most of the salts of soda, notably the sulj)hate and phosphate, sulphate of zinc, and acetate of lead, which effloresce in moderately dry air. All vegetable substances suffer from exposure to a moist air, they should therefore always be preserved, after careful drying, in well- covered tin vessels. The more perishable, such as the leaves of henbane, hemlock, digitalis, and the flowers of the rose and chamo- mile, require the greatest care both m collecting, drying, and keep- ing; they should be preserved in a dry, but not a warm place, and be renewed annually. Prescribing and Dispensing. A few words on these topics and on the relative duties of the prescriber and dispenser will form an appropriate conclusion to this section. Prescribing.—Experience dictates and science requires attention to the following rules :—1. The prescriber should refuse conversation with his patient when he is writing the prescription, and he should read it carefully through before giving it to the patient. 2. He should affix his initials and full address, and the date to every pre- scription ; for the latter is useful for reference to all the parties con- cerned, and the former is necessary to allow the dispenser to com- municate with file prescriber, in case of obscurity or obvious error in the prescription. 3. The directions should be written in English, the rest of the prescription in unabbreviated Latin. The utility of the present Pharmacopceia is marred by the use of the Englisli anguage, instead of the more widely-known Latin. A free and'](https://iiif.wellcomecollection.org/image/b21302911_0041.jp2/full/800%2C/0/default.jpg)
