We are not aware of any instance of death having, from accident or
design, taken place in consequence of the administration of this
substance; indeed its red colour, insolubility in water, and comparative
rarity, will protect mankind sufficiently against mistake, and at the
same time render its secret administration extremely difficult. It is,
moreover, mild in its effects, unless in large doses, or, under
particular circumstances of constitution. It may be identified by its
form, which is that of minute crystalline scales, of a deep red colour,
and by exposing it to heat in a glass tube, by which it undergoes
decomposition, giving out metallic mercury, adhering to the sides of the
tube, and oxygen gas, which is disengaged.
RED PRECIPITATE, or _Nitric Oxide of Mercury_.
This is, strictly speaking, a _sub-nitrate_ of mercury, and is much more
poisonous than the preceding substance. _Plouquet_[293] relates the case
of a man, who swallowed by accident some red precipitate, when he
immediately experienced violent colics, copious vomitings, a trembling
of his limbs, and cold sweats. Its external characters will at once
enable the chemist to identify it.