Mercurial poisoning may result either from the administration of medicines or from accident. Cases of the former kind follow the internal use of sublimate or calomel. Doses of 2 to 2½ drams of calomel, if repeated for a certain time, may prove toxic in the ox. Accidental poisoning results from the use of mercurial ointment as a parasiticide over large surfaces. Poisoning, however, rarely occurs unless the animal is able to lick the parts. Some authors have tested this point by freely applying mercurial ointment over parts likely to absorb it readily, without having seen any bad effect.
Symptoms. Free salivation, the saliva gradually becoming fœtid and blood-stained. The slight irritation of the buccal membrane first seen is soon replaced by congestion of the gums, then by gingivitis and periostitis, with local ulceration and hæmorrhage. The portion of the gums surrounding the teeth becomes violet, and suppurative alveolitis may follow.
As a consequence of disturbance in the digestive secretions digestion ceases, defæcation becomes irregular, the fæces are often hard and coated, and can only be passed with difficulty, though sometimes there is profuse fœtid diarrhœa.
Respiration is difficult, jerky, or even dyspnœic, and is accompanied by discharge from the nose and by expectoration. The gait is irregular, and paralysis may follow. Finally the skin shows an eruption resembling that of impetiginous eczema; vesico-pustules, covered with yellowish crusts, appear over the entire surface of the body.
Lesions. The lesions of hæmorrhagic gastro-enteritis are sometimes accompanied by catarrhal tracheo-bronchitis, and even intra-pulmonary hæmorrhage. The muscles are discoloured, appear as though boiled, and are covered with ecchymoses. Blood effusions occur beneath the eczematous crusts, but the rest of the skin is anæmic.
Treatment includes administration of raw eggs, or, better still, of white of egg beaten up in water; the albumen in coagulating imprisons the mercury. Failing these, other bodies, like flowers of sulphur and iodide of potassium, which with mercurial salts form soluble and harmless compounds, may be given. Chlorate of potash has also been recommended.
Complications like stomatitis and gastro-enteritis are treated by the usual methods.
LEAD POISONING: SATURNISM.
Lead poisoning is very rare, and seldom occurs except near camps or factories. It then results from swallowing lead “spray” mixed with the grass or from inhalation of lead vapour.
The symptoms comprise salivation, nausea, colic, obstinate constipation, tympanites, and arrest of milk secretion. A peculiar form of trembling affects the head; epileptiform convulsions, amaurosis, and paralysis may also occur. General sensibility diminishes, and death follows.