38 JlLxperiments upon the 



as well as for commercial people who deal in the article by 

 wholesale. 



It' we had an accurate and simple method of ascertaining 

 the best species of cinchona^ or of distinguishing them from 

 the false, or from such as had betn any way adulterated, it 

 would be wise in government, in my opinion, to institute 

 a commission, forn)ed of physicians and apothecaries, in 

 even,- sea- port town, in order to examine all the cinchonas 

 which arrive there, and to prevent from being circulated in 

 commerce such as do not undergo the tests prcscril)ed. But, 

 unfortimatelv, the judgment hitherto formed upon the good 

 or bad quality of this medicine has been made to depend 

 upon some physical properties, often deceitful ; such as the 

 coloucj smtll, taste, fracture, compactness, Sec. ; qualities 

 which are too arbitrary, because the senses and custom are 

 the tests here employed. 



M. Seguin has lately endeavoured, by experiments, to 

 throw a light upon this subject more certain than what vve 

 have hitherto had. According to him, the aqueous infusion 

 of the best sorts of cinchona possesses exclusively the pro- 

 perty of precipitating an infusion of tan ; while, on the 

 contrary, the bad species precipitate a solution of animal 

 gelatine: thus he not only judges of the absolute qualities 

 of these substances, but he can also give the measure of the 

 respective qualities of the different species of cinciiona, by the 

 greater or less abundance of the precipitates he obta*ns. 



If the observation of M. Scguin held true in all the good 

 cinchonas, and if the phaenonienon which occasioned it was 

 owing to the principle, which in this substance is a febri- 

 fuge, they would iurnish a strong argument w by govern- 

 ment should adopt the measure above recommended. 



But I shall have occasion, hereafter, to make some re- 

 marks upon the assertions of M. Scguin, in showing that 

 there are several species of true cinchona which do not pre- 

 cipitate a solution of tan, bu^ which, however, are capable 

 of curing fevers. 



§ III. 



