Of course it is not intended that the carbonate of magnesia can be rubbed to powder, the water boiled, the bottles washed and fitted with strings and corks in the time above mentioned. My plan is to have the bottles prepared with their corks, strings, and syrup in advance, and to keep the carbonate of magnesia in a state of powder for this purpose.
[Continued from the March number.] PRACTICAL HINTS. BY A WHOLESALE DRUGGIST.
BALSAM PERU. For many years past a factitious balsam Peru has been manufactured in a neighboring city in very considerable quantities, and has entered largely into consumption; it is made by dissolving balsam tolu in alcohol. It closely resembles the true balsam, and is calculated to deceive unless subjected to a close examination. If one’s attention is particularly called to it, a smell of alcohol is perceptible. It is, however, easily tested by burning in a spoon or small cup. The factitious balsam readily ignites on the application of flame and burns, as may be supposed, with a blue flame. The true balsam ignites with much more difficulty and emits a dense black smoke, and on the application of considerable heat, the air becomes filled with small feathery flakes of lamp black. This test, together with the sensible properties of appearance, taste and smell, will enable one to determine without doubt as to its genuineness.
LAC SULPHURIS. SULPHUR PRECIPITATUM. MILK OF SULPHUR. This preparation of sulphur is made by boiling sulphur and lime in water, and after filtering, precipitating the sulphur with muriatic acid. It differs from the ordinary sulphur in being in a state of more minute division and being softer and less brittle after having been melted. {134}
When sulphuric acid is used to precipitate the sulphur, sulphate of lime is formed and cannot be separated from the precipitated sulphur by the ordinary process of washing, that salt being insoluble in water; for this reason muriatic acid should be used, as the salt thus formed, the muriate of lime or chloride of calcium is perfectly soluble and can be readily separated from the sulphur by washing.
The ordinary lac sulphuris of commerce, is prepared by the use of sulphuric acid, and in consequence is found to contain a very large proportion of sulphate of lime, or plaster of Paris.—Several specimens examined were found to consist of nearly equal parts of sulphate of lime and sulphur.
The test for the above impurity is by burning in a small cup or spoon. The sulphur burns out entirely, leaving the impurity unaltered. The exact amount of impurity may be determined by weighing the substance before and after burning, and deducting the one weight from the other.
PRECIPITATED CHALK OR CARB. LIME. It is very important that physicians should be able to obtain this preparation of a reliable quality. A preparation purporting to be the above, but in fact nothing more nor less than sulph. lime or plaster of Paris, has, in very considerable quantities entered into consumption within a year or two past. It is difficult to determine between the two from their appearance. The test, however, is very simple and consists in treating the suspected article with muriatic acid. It should dissolve perfectly with brisk effervescence, if it be in reality pure carbonate of lime. If it consists, wholly or in part, of sulphate of lime, the whole or such part remains unaffected by the acid.
Pure muriatic acid should be used, as the commercial acid frequently contains sulphuric acid, in which case a portion of sulphate of lime is formed and remains undissolved.