THE SARSA OF THE RIO NEGRO. 
325 
ART. XL VII. — SARS AP ARILL A, THE SARSA OF THE RIO 
NEGRO, AND THE VARIOUS PREPARATIONS OF SARSA- 
PARILLA. By John Hancock, M. D. 
The xarave del rey, or Rio Negro compound, has 
become known and highly appreciated by many emi- 
nent physicians in North America, as an efficacious re- 
medy in chronical disorders. It is this species which, 
as Humboldt justly remarks, is the most active of all 
that are known, and much preferred to the zarza of the pro- 
vince of Caraccas, or of the mountains of Merida. That it 
has not come into more general use in this country, may be 
accounted for from the difficulty there exists in procuring the 
necessary ingredients which enter its composition, and which 
are indigenous and peculiar to the American Continent. 
In the "United States Dispensatory, of 1836, edited by 
Drs. Wood and Bache, this subject has been treated at some 
length, and those gentlemen unite with me in opinion, that 
the present manipulations of sarsa are extremely imperfect, 
and calculated to spoil a most useful and important remedy; 
repeated experiments having proved that the long boiling dis- 
sipates the volatile principles, and destroys other properties, 
and that water alone is a very imperfect menstruum for hold- 
ing its alkaloid in solution. 
According to experiments made by several eminent conti- 
nental chemists, three or four alkaloids have been named as 
being the active principles of sarsaparilla; but more recently 
M. Paggiale reduces these principles to one only, stating that 
they are decomposed by heat, and that the pith as well as the 
bark contains salsaparine. The active principle, he says, is 
very imperfectly taken up by water ; but is readily soluble 
in alcohol, acids, and ether, forming a solution which is very 
nauseous and bitter. These differences of opinion may rea- 
sonably be accounted for, when we consider the variety of 
roots there are passing under the common denomination of 
sarsaparilla. 
VOL. IV. — NO. IV. 42 
