Lead poisoning in animals is usually the result of feeding on tainted pastures, or inhaling the fumes of chemical works, and manifests itself in impaired digestion, capricious appetite, colicky pains in the bowels, followed by constipation. After a variable lapse of time, the diagnostic symptom appears, a greyish or blue discoloration along the margin of the gums. It is deposited lead, which becomes more or less blackened by hydrogen sulphide in the mouth, or by the administration of sulphur in the food. Cramp and paralysis of the muscles, followed by wasting, choreic movements, and convulsions, ending in blindness (amaurosis), commonly precede death.
If lead poisoning or plumbism is diagnosed before any very serious wasting has occurred, an effectual antidote will be found in dilute sulphuric acid, and sulphate of magnesia, given in repeated small doses, as these have the effect of converting the lead into harmless insoluble sulphate. The sulphate of magnesia assists also in regulating the bowels, which, as we have seen, are disposed to constipation and to cramps; sulphur and potassium iodide are also employed as eliminants, given separately and at short intervals. An occasional laxative dose of oil is advised when the sulphate of magnesia is not being administered, as this hastens the removal of lead salts excreted into the bowels.