lead. This is a test of extreme delicacy; and it acts in whatever state
of combination the lead exists, whether fluid or solid.
It is preferable to the hydrosulphate of ammonia as a medico-legal test;
for, as Fourcroy observed, the hydrosulphate of ammonia acts on many
sound wines as if they contained lead,[1223] while hydrosulphuric acid
never causes with them a black precipitate, unless they contain either
lead or some other metallic impregnation. It must be remembered that
many other metallic solutions, such as those of mercury, copper, silver
and bismuth, yield a black precipitate with this test.