32 Observations and Experiments on Peruvian Bark. 



The importance therefore of adopting terms more definite 

 to distinguish the several species of Peruvian bark must be 

 obvious, and that the botanical nomenclature of these spe- 

 cies is imperfect and inadequate, is equally so. The qual- 

 tity of Peruvian bark appears to be modified and influenced 

 by locality, produced by difference in soil, altitude of situa- 

 tion, exposure, or some other circumstances peculiar to the 

 location, hence the diflferent provinces of Peru afford bark 

 differing very materially in their physical characters and par- 

 ticularly in the activity of their medical qualities, from which 

 circumstances it would appear that a nomenclature derived 

 from the names of the provinces in which the different spe- 

 cies grow, would be a systematic arrangement. 



The following are some of the most important species 

 which now occur in commerce which I have submitted to 

 experiments, and have given to each the comparative pro- 

 portion of quinine and cinchonine which they respectively 

 contain. The names which are given to distinguish these 

 several species, are derived from the provinces in which 

 they grow, which at present, (in consequence of the confu- 

 sion in the botanical history and arrangement of cinchona,) 

 is the most direct and certain mode of distinguishing those 

 species of bark which now are found in our shops. 



Calisaya Bark — Two Varieties. 



Of this very important species there are two varieties in 

 commerce. 



1st. Calisaya arrollenda, (Quill Calisaya.) This variety is 

 in quills from three quarters of an inch to an inch and a half 

 in diameter, and from eight inches to a foot and a half in 

 length. The epidermis is thick and may be readily remov- 

 ed from the bark ; and hence you find in the seroons or cases 

 a great proportion deprived of this inert part. It is generally 

 imported in seroons weighing about one hundred and fifty 

 pounds, and very seldom comes in .cases ; it has many deep 

 transversal fissures running parallel, the fracture is woody 

 and shining, the interior layer is fibrous and of a yellow col- 

 or, and the taste is slightly astringent and very bitter. 



This species of bark will yield a much larger proportion 

 of the active principle, (quinine,) than any other bark in com- 

 merce, and consequently may be justly esteemed the best. 



