_Red Oxyd of Mercury._
The _Precipitate per se_ of the older Chemists.
QUALITIES. _Form_, minute crystalline scales, of a deep red colour,
inodorous, but acrid and caustic; it is soluble in several of the acids
without decomposition; it is also slightly soluble in water; from which
solution it is precipitated by ammonia. USES. It is very active as a
mercurial, and has been a favourite remedy with John Hunter (_Form.
141_) and other celebrated practitioners; it is however apt to affect
the bowels, and is therefore now rarely employed except as an external
application. DOSE, gr. j. combined with opium gss. ADULTERATIONS. It is
seldom adulterated, as it would be difficult to find a substance suited
to that purpose. If well prepared it may be totally volatilized by heat.