XXIV Lead and its Preparations
Acetate of Lead (Sugar of Lead).—A glistening white powder or crystalline mass. Soluble in water, with a sweetish taste. It is practically the only lead salt which gives rise to acute symptoms, and only when taken in large doses.
Symptoms.—Metallic taste, dryness in throat, intense thirst, vomiting, colicky pains, cramps, cold sweat, constipation and scanty urine, severe headache, convulsions.
Chronic lead-poisoning is liable to occur in those who handle lead in any form—white-lead workers, paint manufacturers, plumbers, pottery workers, etc.
In chronic lead-poisoning the most prominent symptoms are a blue line on the gums, anæmia, emaciation, pallor, quick pulse, persistent constipation, colic, cramps in limbs, and paralysis of the extensor muscles, causing ‘dropped hand.’ May get saturnine encephalopathies, of which intense headache, optic neuritis, and epileptiform convulsions, are the most common. Albumin in urine, tendency to gout, and in women to abortion.
Post-Mortem Appearances.—Inflamed mucous membrane of stomach and intestines, with layers of white or whitish-yellow mucus, impregnated with the salt of lead.
Treatment.—Sulphate of sodium or magnesium, or a mixture of dilute sulphuric acid, spirits of chloroform, and peppermint-water. Milk, or milk and eggs. As a prophylactic among workers in lead, a drink containing sulphuric acid flavoured with treacle should be given. Lavatory accommodation should be provided, and scrupulous cleanliness should also be enjoined in the workshops. The dry grinding of lead salts should be prohibited. The ionization method of Sir Thomas Oliver is most useful both as regards cure and also prevention of chronic poisoning by lead.
Fatal Dose and Fatal Period.—Uncertain.
Method of Extraction from the Stomach.—Dry the contents of the stomach or portions of the liver, etc., and incinerate in a porcelain crucible. Treat the ash with nitric acid, dry, and dissolve in water. The solution of nitrate of lead may now have the proper tests applied.
Tests.—Sulphuretted hydrogen gives a black precipitate; liquor potassæ, white precipitate; sulphuric acid, white precipitate, insoluble in nitric acid; iodide of potassium, a bright yellow precipitate. A delicate test for lead in water is to stir the water, concentrated or not, with a glass rod dipped in ammonium sulphide: a brown coloration is produced. One-tenth of a grain of lead in a gallon of water may be detected.
Chronic lead-poisoning is an ‘industrial disease,’ and, being an occupation risk, its victims are entitled to compensation at the hands of their employers. In case of death, compensation has been awarded even when at the autopsy the patient has been found to have suffered from acute tuberculosis of the lungs. The responsibility of apportioning the monetary value of disablement resulting from the action of the lead rests with a judge or jury, who are guided by the expert medical evidence available.
Diachylon, or lead-plaster, is largely used as an abortifacient.