The verdegris of commerce is a compound mass, consisting of the acetate,
and sub-acetate of copper, carbonate of copper, and copper partly
metallic, and partly oxidized; it, moreover, contains the stalks of
grapes and other extraneous matter. Boiling water dissolves it in part,
and, at the same time, occasions in it a chemical change, by
transforming one portion of the _sub_-acetate into the soluble acetate,
and another, into an oxide of copper, which is precipitated. With cold
water, verdegris demeans itself very differently; the acetate is
dissolved by it, whilst that portion which is in the state of _sub_-salt
remains suspended in the form of a fine green powder. Vinegar converts
all the _ærugo_ into a soluble acetate. Sulphuric acid poured on its
powder decomposes it with effervescence, and vapours of acetic acid are
disengaged; a character by which this substance may be easily
identified.
BLUE VITRIOL. _Sulphate of Copper._
_Blue Copperas—Roman Vitriol._
This salt occurs in crystals of a deep rich blue colour, and whose form
is that of a rhomboidal prism; their taste is harsh, acrid, and styptic;
on exposure to air they slightly effloresce, and assume a greenish hue.
When treated with sulphuric acid, no effervescence occurs, a
circumstance which at once distinguishes this salt from _ærugo_.
_Symptoms of Poisoning by the Salts of Copper._
The operation of these bodies, upon the human system, is betrayed by an
acrid, styptic, coppery taste, in the mouth; nausea; head-ache; a dry
and parched tongue; vomiting; coppery eructations; a cutaneous eruption;
violent pains in the bowels; very frequent alvine evacuations, sometimes
green, and often bloody and blackish; great and painful distention of
the abdomen; small and irregular pulse; heat of skin; ardent thirst;
difficult and laborious respiration; hiccup; syncope; cold sweats;
convulsions—death. It does not, however, kill so speedily as arsenic, or
corrosive sublimate.
_Organic Lesions discovered on Dissection._
Where death has been speedily produced by a cupreous poison, dissection
will generally discover inflammation, and even gangrene in the mucous
membrane of the alimentary canal. Like other poisons of the corrosive
class it will also be found to have occasionally extended its
inflammatory action to all the coats of the canal, producing sloughs,
easily detached, and leaving perforations. _Dr. Male_ has also remarked
that inflammation will sometimes be observed in the brain; but that this
is not an universal effect of copper poison. It has been stated, that
the fluids contained in the _primæ viæ_ are, upon these occasions, very
frequently tinged with a green colour.
_Chemical Tests by which the presence of the preparations of Copper may
be detected._
1. _The suspected body is in a solid form._—We have already pointed out
the characters by which the principal preparations of copper may be
identified. Our judgment, however, upon these occasions will require
that confirmation from experiment, which the following processes are
calculated to afford.
A. _By its reduction to a metallic state._ If the copper presents itself
in the form of an oxide, it may be easily reduced by heating it, in the
usual manner, in contact with some carbonaceous matter; an earthen
crucible will furnish the most convenient vessel for the occasion. If
the substance has been scraped from a surface of copper, it is probably
in the state of carbonate, (_natural verdegris_,) and may be calcined
with charcoal in order to procure the metal. Should the substance in
question be true _ærugo_, we may at once heat it to redness in an
earthen crucible, when, without the aid of any carbonaceous matter, we
shall obtain metallic copper.