30 Dr. Grateloup on the utility of Botany in Medicine. 



moss, obtained in the trade, is only a mixture of many species of 

 marine Conferva? and Ceramias. M. De Candolle found 18 dif- 

 ferent species, and the Fucus helminthocorton did not constitute 

 one third part of the parcel he examined. 



The same analogy has led to a knowledge of the anthelmintic 

 properties of the roots of the large species of Ferns, of the 

 tonic and nutritive properties of the foliaceous Lichens, of the 

 physica and cladoiiia, of the poisonous effects of the greater 

 number of mushrooms, &c. 



Medical experience has sanctioned all these discoveries of the 

 properties of plants. It is the triumph of that great analogic 

 principle : Quod plant ee, qua genere conveniebant, qua vires 

 etiam coinciderent. (Linn, amaen. acad. vires, plant, t. I, p. 420.) 

 But medical experience ought to anticipate the rights of 

 chemical analysis and botanical analogy. The union of the 

 insight furnished by these three powerful sources is absolutely 

 necessary. When researches are being made on properties un- 

 known amongst vegetables, medical experience is an essentially 

 empiric mode. It could not proceed alone without being fre- 

 quently exposed to eminent danger. Eulightened by the assist- 

 ance of botany and chemistry, this mode is of the greatest 

 importance, as it establishes the real properties of plants or of 

 vegetable medicines. 



Is it not true that a root, a bark, or a flower, endowed with a 

 bitter juice, will be immediately considered as bearing tonic or 

 febrifuge qualities ; but if it is bitter and caustic will it not be said 

 that it is irritating ? Then, if it causes irritation, principally in 

 the digestive orgaus, it may give rise to evacuations, either 

 as a purgative or vomitive ; it will be an emeto-cathartic or 

 drastic, according to the power of its irritating and evacuating 

 property. But this same substance may also be a strong and ac- 

 tive poison. We have similar examples in the Euphorbia, the 

 Elaterium, the Colocynth, the Croton. To this we should 

 be exposed by recurring to medical experience only. But 

 if chemical analysis is employed to operate on the substance of 

 uliirli I bave spoken, and it is demonstrated that it possesses a 



