(Rhus Toxicodendron.)
_Sumach Leaves_, or _Poison Oak_.
QUALITIES. Its leaves are inodorous, but have a sub-acrid taste.
CHEMICAL COMPOSITION. Gallic acid, tannin, and a certain acrimonious
matter, upon which the virtues of the plant depend, and which, according
to Van Mons, is disengaged from the leaves in the state of gas during
the night, or while they do not receive the direct rays of the sun. MED.
USES. Dr. Alderson of Hull introduced the leaves of this plant to
notice, in whose hands they proved successful in several cases of
Paralysis; the same results however have not been obtained by other
physicians; the plant has therefore fallen into disuse, and might, in
deference to public opinion, be removed from the materia medica. When
applied externally it has been known to produce an erysipelatous
affection of the skin; a remarkable instance of which lately occurred at
the Botanic garden at Chelsea, where a person merely rubbed his eye
after having casually touched the plant in question.