34 



and this indentity might exist, without our con- 

 cluding thence, that the medical virtues were 

 analogous. We see, that the different species 

 of sugar and tannin, when they are extracted 

 from plants not of the same family, display 

 numerous differences: while the comparative 

 analysis of sugar, gum, and starch ; the disco- 

 very of the radical of the prussic acid, the 

 effects of which are so powerful on the organi- 

 zation ; and so many other phenomena of ve_ 

 getable chemistry ; clearly prove, that " sub- 

 stances composed of a small number of identical 

 elements, and in the same proportion, exhibit 

 the most heterogeneous properties," on account 

 of that particular mode of combination, which 

 corpuscular chemistry calls the arrangement of 

 the particles *. 



On coming out of the ravine which descends 

 from the Impossible, we entered a thick forest 

 traversed by a great number of small rivers *f", 



Grindel, Russisches Jahrb. der Pharm. 1808, p. 183). Not- 

 withstanding the extreme imperfection of vegetable chemis- 

 try, the experiments already made on cinchonas sufficiently 

 show, that to judge of the febrifuge virtues of a bark, we 

 must not attach too much importance either to the principle 

 that turns to green the oxides of iron, or to the tannin, or to 

 the matter that precipitates infusions of tan. 



* Gay-Lussac, Exp. on Jodine, page 149, note 1, (Humb. 

 Vers, ueber gereizte Muskelfaser, B. 1, p. 128.) 



f The Manzanares j the Cedeno, with a plantation of cacao 

 trees, and an hydraulic wheel j the Vichoroco j the Lucas" 



