Observations on a neiv variety of Peruvian Bark, &fc. 55 



in mint water. This, he continues, is obviously injudicious, since 

 tartaric acid decomposes the sulphate and occasions an insoluble tar- 

 trate, which is precipitated. With deference to Dr. Paris, I would 

 beg leave to differ, on the following grounds. The cream of tartar 

 is objectionable, merely from the circumstance that the active part 

 of the compound may be obtained in a more direct and speedy pro- 

 cess by the tartaric acid. The combination of cream of tartar and 

 sulphate of quinine, in the above prescription, does produce decom- 

 position, as Dr. Paris has observed, but the virtue of the medicine 

 is not in the least affected by it, and the precipitate, instead of being 

 an insoluble tartrate of quinine, as he observes, is sulphate of po- 

 tassa ; tartrate of quinine is a very soluble salt and is held in solu- 

 tion, while the water becomes slightly turbid, by the precipitation of 

 sulphate of potassa, which however, from its extremely minute di- 

 vision, is speedily taken up by the water, when you have a transpa- 

 rent solution of tartrate of quinine and sulphate of potassa, and as 

 the latter answers neither a good nor a bad purpose, it of course can 

 very conveniently be dispensed with, and therefore, as before stated, 

 the tartaric acid should be preferred, as having a more direct and 

 speedy action. ■''^■•' 



- The high price which the sulphate of quinine has always com- 

 manded, and the increasing demand which its reputation has con- 

 stantly kept up, has been an inducement to fraud ; and it is much to 

 be regretted that this valuable article of our materia medica, like 

 others of an expensive kind, has been mixed with foreign substances 

 of inert character, for the base consideration of reducing the cost 

 and enhancing the profit on its sale, and all this at the expense of the 

 health of the suffering patient, to the disappointment of the practi- 

 tioner, and not unfrequently to the injury of the reputation of the 

 genuine medicine. It is of high importance therefore to be acquaint- 

 ed with the most efficient means of testing its character, where we 

 have any doubt of its purity. The following are the distinctive char- 

 acters and properties of the sulphate of quinine, and the most simple 

 and effectual method of discovering fraud or adulteration in its com- 

 position.^ 



1. The sulphate of quinine must be soluble, at a moderate heat, in 

 rectified alcohol ; if it contains sulphate of lime, soda, potassa, or any 



* See observations, communicated by Dr. Faust, on the adulteration of quinine, 

 bark, &c. Vol. XVIII, pp. 81, 84, of this ioM\nz\.—Ed. 



