ARISTOLOCHIA SERPENTARIA. 
243 
tartar, are likewise officinal articles produced from the grape. The 
first of these salts is gradually deposited on the sides of the casks in 
which the wine is made, and from which it is scraped off. When 
taken from the cask, it is found mixed with an earthy, oily, and 
colouring matter ; that obtained from red wine is of a deep brown 
colour, and commonly called red ; when it is of a paler colour, it is 
called white tartar. It is purified by dissolving it in boiHng water, 
and filtrating the boiling solution. This solution on cooling deposits 
irregular crystals, containing the colouring matter, which is separated 
by boiHng the mass with white clay : thus purified it is called cream 
of tartar, and proves in some cases an useful laxative and diuretic. 
If this be exposed to a red heat, its acid flies off, and what remains 
is the vegetable alkali, or salt of tartar. This salt is frequently 
-employed in medicine, in conjunction with other articles, particularly 
in making saline neutral draughts and mixtures; it is also used by 
itself, in doses of from gr. iii to 3ss, and in this way very frequently 
operates as a powerful diuretic. It should be given in a liquid 
form, and well diluted. 
ARISTOLOCHIA SERPENTARIA. 
Virginia Snake-root, Birth-wort * 
Class Gynandria. — Order Hexandria. 
Nat. Ord. Sarmentacete, Linn. Aristolochije, Juss. 
'Gen. Char. — Calyx none. Corolla of one petal, strap-shaped, 
ventricose at the base. Capsule six-celled, inferior, contain- 
ing many seeds. Stem twining, frutescent. 
Spec. Char. Leaves heart-shaped, oblong. Stems winding, 
columnar. Flowers solitary. 
* Fig. a represents a flower cut open. 
