286 
CINCHONA. 
or caustic alkalies, or lime, precipitate the ej^tractive matter ; when 
the caustic alkali is used, the precipitate may be re-dissolved hj an 
addition of the alkali.* From the experiments of Dr. Irving, pub- 
lished in 1783, the comparative power of different menstrua upon 
Peruvian bark, is in the following order, viz. dulcified spirit of vitriol, 
caustic ley, French brandy, Rhenish wine, soft water, vinegar and 
water, dulcified spirij; of nitre, mild volatile alkali, rectified spirit of 
wine, mild vegetable alkali, and lime water. Vauquelin ascertained 
that there were three, if not four, classes of Cinchona bark, differ- 
ing essentially in chemical constitution : the first class precipitate 
astringents, but not gelatine ; the second precipitate gelatine, but not 
astringents ; the third precipitate both astringents and gelatine ; and 
lastly, some barks which precipitate neither gelatine nor astringents, 
but these he did not consider as properly belonging to the genus 
Cinchona. Each of the three first classes was thought capable of 
curing intermittents. But the more recent discoveries of the French 
chemists, MM. Pelletier and Caventou, supersede all the previous 
researches, so far as medicine is concerned, into the nature of the 
Cinchonas. It had long been a desideratum among pharmaceutical 
chemists, to discover in the barks the particular substance to which 
the febrifuge property might be ascribed ; and in pursuit of this 
object, MM. Laubert of Paris, Strenss of Moscow, and Gomez of 
Lisbon, published, about the same time, the result of their observa- 
tions ; unfortunately however they did not agree in their conclusions. 
The French chemists were more successful ; they obtained a sub- 
stance, which they recognised as that to which M. Gomez had given 
the name of Cinchonine, and they further discovered that it was 
alkaline. 
The Cinchonine was obtained, by operating on the Cinchona 
Condaminea, or grey bark of the French botanists ; the Cinchona 
Cordijolia, (the Oliicinalis of our colleges, the yellow bark of the 
French,) was next subjected to analysis, and from this was obtained an 
alkali, in many points resembling the Cinchonine^ but still differing in 
many important ones, sufficiently to prevent their being confounded ; 
this new alkali they called Quinine. The examination of the red 
bark (Cinchona Oblongifolia) followed, and " it was an interesting 
question," says M. Magendie, " to determine whether this species, 
considered by many medical men as eminently febrifuge, contained 
* Lime water and the alkalies, as precipitating the extracted matter, appear asi im- 
proper menstrua for the oxhibition of bark. 
