Mercury is obtained from cinnabar by roasting and distilling with lime. It is a silver-white metal, liquid, and giving off vapor at ordinary temperatures, and capable of being entirely volatilized by heat. All the different preparations are derived directly or indirectly from the metal itself.

Physiological Actions

In the metallic form mercury is inert, large amounts of the pure metal having been swallowed and discharged from the intestines without poisoning or injury; but in the form of vapor, or any of its preparations, it is very readily absorbed by the pulmonary and other mucous membranes, by the alimentary canal, and by the skin and tissues, either whole or broken. The constitutional effects may be reached in any one or all of these ways.

All mercurials are antiseptic and disinfectant.

The local action of mercury in moderate strength, either externally or internally, is astringent, antiphlogistic, and stimulant. In large or concentrated doses it is irritant to the stomach and intestines, and in some forms is a locally acting purgative.

In various pathological conditions of the system mercury exerts an influence as an alterative, through some power over nutrition which is not perfectly understood. It is considered a specific in some forms of syphilis.

Mercury is excreted by the saliva, perspiration, milk, urine, and bile.

Symptoms Of Poisoning

The mildest evidences of over-doses of mercury are: slight fetor of the breath and soreness if the teeth are knocked together or struck; a metallic taste next appears. After this comes salivation, an abnormal amount of fluid being poured out from the salivary glands, and small ulcers appear on the lips, gums, and tongue. A feeling of constriction of the throat, which is found among the symptoms of acute poisoning, has been caused in some susceptible persons by a single medicinal dose of mercury.

When its use is continued beyond this point saliva 6 tion increases. The gums become swollen and spongy, and bleed easily. The tongue swells, sometimes protruding from the mouth. The teeth are loosened, and a dark line is seen at their upper margin. In some cases ulceration of the soft parts and necrosis of the jaw-bones result. In pronounced chronic poisoning, in addition to these symptoms, there are abdominal pains, nausea, vomiting and diarrhoea, anaemia, emaciation and general weakness; aching pains in the bones and joints; loss of hair; a trembling or shaking palsy; and paralysis, with a brown tint of the skin. In some cases there is wrist-drop. Chronic poisoning may be caused indirectly by exposure to the metal or its fumes, as in various occupations, and it may come on very suddenly.

When chronic poisoning by mercury is evident, the drug should be stopped immediately, the throat and mouth gargled regularly with a solution of potassium chlorate, and atropine may be given to lessen the excessive secretion of saliva, while potassium iodide is used to eliminate the mercury from the tissues.

Acute poisoning will be described under corrosive sublimate.