Of the root named * Parcira Brava. 



OEEING, in the Pliilolbpliical Tranfat^tions of the Royal Society 

 of London, the Root named Pareira Brava, very much extolled, on 

 account of the medicinal virtues it is faid to poflefs, I was induced to 

 publifli tiie obfcrvations I had made on that root. 



A gentleman of fome confequence in this country, produced to 

 me a piece of tliis root, adding-, tliat it was difficult to be met with, 

 and was very highly valued, for that a fev/ grains of the poN\der, 

 adminiftered to a fick perfon, would be found of fingular benefit. 



In order to examine this wood by the microfcope, I obtained from 

 this gentleman a fmall piece, from which I cut off' about the quan- 

 tity of a grain, and this again, I divided into frill fmaller flices, 

 fome by a longitudinal, and I'ojne by a tranfverfe fe6lio!T. I thens 

 by the help of the microfcope, difcovercd, that the wood contained 

 many very large pores, in fome places dilpofed fnigly, in others, two 

 or three placed adjoining to each other. I next, put thefe very thin 

 flices into a pcrfeilly dean glafs, and j)oured water on them, in 

 order to feparate from them, tlie falts they might contain, which 

 I was very defirous to examine. Then, upon applying the micro- 

 fcope, I obierved great numbers of exceflively minute, glittering 

 particles difpofed throughout the water. Thefe particles \\ere of 

 various and peculiar fliapes, very like thofe falts which I have oftea 



* This is the root of an American convolvulus, {ths cijfampelos Parcira oi lAnnxus) 

 brought to us from Brczil. The read-rr v/ill find it defcribcd in the New Edinburgh DiC— 

 pen(;Uorj', being an improvement of Dr. J^ewis's, 



