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and this identity might exist, without our concluding 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
discovery of the radical of the prussic acid, the effects of which are so powerful on the organization; and
so many other phenomena of vegetable chemistry; clearly prove, that "substances 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†,
Grindel, Russisches Jahrb, der Pharm. 1808, p. 183. Notwithstanding the extreme imperfection of
vegetable chemistry, 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.)
† The Manzanares; the Cedeno, with a plantation of cacao trees, and an hydraulic wheel; the
Vichoroco; the Lucasperez,