THE SARSA OF THE RIO NEGRO. 
327 
afford the only correct criterion. It is to be regretted, as 
highly detrimental to the advance of knowledge, that authors 
should thus proceed copying each other, adopting every opi- 
nion and every dogma, true or false, and giving the sanction 
of their names to numberless errors, without reflection and 
without investigation. The gentlemen above named, are 
enrolled among the high authorities, and, as a matter of 
course, their opinions regulate the inferior writers; it was, 
therefore, a duty incumbent upon them to consider well, and 
duly investigate, such matters, ere they gave their opinions to 
the world. 
Before my paper on this subject appeared on record no one 
seemed to be aware that the genuine sarsaparilla, when 
chewed, impressed a nauseous acrimony on the mouth, and 
especially on the throat and fauces. 
My remarks upon this subject, addressed to the Medico- 
Botanical Society, have been reprinted entire in the " Journal 
of the Philadelphia College of Pharmacy," vol 1., and trans- 
lated into the Italian, French, German, and most other Euro- 
pean languages; and my deductions as to the proper solvents 
of the active principles of sarsaparilla have been confirmed by 
some of the ablest experimental chemists of France and Ger- 
many.* From the notice taken of the subject, (in France 
and North America particularly,) we find it has obtained a 
much higher consideration abroad than in this country; this 
I think is to be attributed to its unbounded extent of com- 
mercial speculation, and the consequent substitution of other 
plants which are brought to this market from every quarter 
of the globe,t as likewise to the defective methods of distin- 
guishing the comparatively small quantity of the genuine 
from the abundance of non-medicinal roots sold under the 
* In proof of this see "Journal de Pharmacie," vols. 15, 16, and some 
subsequent numbers. 
| Professor Marsius, in his learned and elaborate work, the " Pharma- 
cognosia," has enumerated no less than thirteen different kinds belonging 
to other genera which are sold as the genuine sarsaparilla, but which in 
fact have no alliance with it, except in the basis of the roots. 
