An experimental examination of the last edition of the Pharmacopoeia Londinensis : with remarks on Dr. Powell's translation and annotations.

  • Richard Phillips
Date:
1811
Catalogue details

Licence: Public Domain Mark

Credit: An experimental examination of the last edition of the Pharmacopoeia Londinensis : with remarks on Dr. Powell's translation and annotations. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

    34/160 (page 26)
    2(5 the mixture, the exact point of neutralization should he determined more precisely than by the-cessation of efferves- cence, as directed by the London College. In the Dublin Pharmcopoeia it is ordered to be determined by litmus; but as excess of alcali is to be avoided, even more than excess of acid, the saturation should be ascertained by the alternate use of papers stained with turmeric and litmus. There is one circumstance incident to this solution, which has caused some practitioners to suspect that the acid used in its preparation must have been adulterated by sulphuric acid. It is frequently employed externally with superacetate of lead, and in consequence of the action of these solutions upon each other, considerable precipita- tion ensues. It may be also suspected that this effect is produced by excess of alcali, but this is not the case, for I have found even whe'n the solution contained acid un- » saturated, that the addition of lime water occasioned pre- cipitation of carbonate of lime when more was employed than was sufficient to saturate the acetic acid ; and from this experiment it is also evident, that the acetate of lead is decomposed by the carbonic acid evolved from the subcarbonate of ammonia, which remains diffused through, the solution. 4 LIQUOR AMMONIA CARBONATIS. Dr. Powell has stated in his remarks upon the carbo- nate of ammonia, that one part of this salt is soluble in two parts of water; now even supposing this statement exact, which however it is not, fl.oz. 16 of water, being equal to about only 15 oz. by weight, would be insuffi- cient to dissolve 8 oz. of the salt, as now directed. It has been very correctly remarked by Mr. Stocker, [Pharm. Officinal. Brit. p. 122], that waiter is incapable of