212 OH VARIOUS SVECIF.S OF CINCHONA. 



8. But one or the other of these suppositions must neces- 

 sarily be true, since the infusions of these two sorts of cin- 

 chona mutually precipitate each other. 

 Principle that 9. The principle, which in some species of cinchona pre- 

 Sntine."* "^ c *P* tates isinglass, has a bitter and astringent taste : it is more 

 soluble in water than thatj' which in other species precipitates 

 infusion of tan: it is likewise soluble in alcohol: and it does 

 not precipitate tartarised antimony. 



10. It appears, that the substance which precipitates infu- 

 sion of tan is the same, as that which decomposes antimoniated 

 tartrite of potash. 

 Knowlcge of We see from all these doubts, that much remains yet to be 

 principle a*de- ^ ofl *» before we shall attain an accurate knowledge of the. 

 sideratum. principle or principles in cinchona, from which it derives its 

 efficacy in the cure of fevers. It is to be hoped, that time 

 and assiduity will accomplish the solution of this important 

 question. 



Analysis of the salt of cinchona. 



Salt of cinch*. Mr. Deschamps, jun., a druggist at Lyons, is the first to 

 my knowledge, who announced the presence of a peculiar salt 

 in cinchona, which must not be confounded with the essential 

 sflll of la Garaye, for this contains at the same time both resin 

 and mucilage: but as Mr. Deschamps has described only 

 some of the physical properties of this salt, I thought it neces- 

 sary to analyse it, in order to discover the nature and pro- 

 portions of its principles. I have already said how this salt 

 may be obtained and purified : here therefore I shall confine 

 myself to an account of its properties. 



Its characters. 1. This salt is white; crystallizes in square laminae, which 

 are sometimes rhomboidal, or truncated at their solid angles; 

 and these lamina? frequently unite in clusters. 



2. It has scarcely any taste, and is flexible between the 

 teeth. 



3. It requires about five parts of water at 10° [50° F.] for 

 its solution. 



4. On burning coals it swells up like tartar, and emits a 

 - imilar smell ; and leaves a grayish substance, which dissolves 



