Researches of Pitaya Bark. 
333 
its external physical characters — to the latter, that of ex- 
amining it chemically. 
Folchi commences the description of the Pitaya bark by a 
brief historical account of that substance. He relates that 
professor Brera, in his desideratum, calls it Pitaya china ; 
that it was brought to Liverpool, in 1817, from Guagaquil, 
under the name of Cinchona Peruviana, was sent from there 
to Hamburg, and thence to every part of Germany, where it 
w r ent by the appellation of Cinchona nuova. He adds that 
some pharmacologists have mistaken it for the Techames and 
Bicolor barks ; but the physico-chemical differences existing 
between these barks is so great that this supposition is entirely 
given up. Mr. Batka, of Prague, in an interesting memoir 
presented to the Royal Academy of Medicine of Paris, states 
that in England, the name of Pitaya is given only to the 
Cinchona bicolor — this also is erroneous. Mr. Guibourt, in 
the second edition of his history of drugs, has dwelt more 
than any other author upon the subject of this bark ; but 
Folchi doubts whether the bark mentioned by him, and in 
which Henry, jr. found both quinine and cinchonine, is the 
same as the bark under consideration, because the physical 
characters are altogether different, and it contains none of the 
vegetable alkalies that are fonnd in the cinchonas. 
Among the samples entrusted to Mr. Folchi, the largest 
pieces were half rolled upon themselves ; the thinnest had the 
edges closely rolled as the common bark. The former were 
more than a foot long, one inch in diameter, and of one and 
a half thick. The external surface, formed of the epidermis 
and the cellular tissue, varied in different pieces ; in some and 
especially in the largest pieces, it was furnished with a white 
epidermis, partially rubbed off by friction, and resembling the 
pearly cuticle of the Carthagena bark. In others, the surface 
was sometimes fungous, tubercular, rough, with slight fissures, 
and divided in some parts in small scales. The colour was 
ash-gray, apparently soiled ; internally of a fawn colour ; the 
liber composed of thin fibres of a fawn orange colour, of a 
deeper tint towards the internal surface. 
