Lead (Pb = 205.35) is an element occurring largely in ores in the form of the sulphide. Found chiefly in the upper Mississippi valley.

Pharmacodynamics.

Central Nervous System. - Lead is irritant to the brain-cells, to the nerves, and to the cells of the cord, especially those of the anterior column. Cell degeneration frequently ensues.

Muscular System. - Obscure alterations in unstriped muscle.

Respiration not affected.

Heart is slowed reflexly in intoxications.

Blood-pressure may be raised at times by vasoconstrictor irritation.

Eye. - Lead is irritant to the retinal cells and to the optic nerve, tending to produce degenerative changes.

Alimentary Tract. - Lead is irritant to mucosa, and to the vasomotor terminals.

Secretory Glands. - Lead is decidedly irritant to the kidney cells, tending to induce parenchymatous and interstitial degenerations.

Metabolism. - Lead induces a debilitated condition of the red blood-corpuscles, and brings on in an obscure way a pronounced disturbance of the trophic system.

Temperature. - No effect.

Absorption. - Lead is absorbed rapidly, and remains lodged in the tissues for a long time.

Excretion. - Urine chiefly; also in milk and saliva, and in epithelial glands.

Local Effect. - Protective through formation of pellicle of lead albuminate.

Symptoms.

Therapeutic Dose.

Sweetish, metallic taste. Astringent after-taste. Constipation.

Acute Poisoning. Nausea and vomiting. Abdominal pain. Bloody purging. Great thirst, weakness. Acute gastro-enteritis. May lapse into chronic type. May cause death from exhaustion.

Chronic Poisoning.

Anorexia, constant metallic taste.

Fetid breath. Bluish-black gums.

Nausea. Obstinate constipation.

Anaemia from erythrolysis.

Acute, intermittent colic.

Paralysis of forearm extensors.

Contractures of flexors, caused by peripheral neuritis.

Local, intermittent anaesthesias.

Amblyopia from retinitis.

Cerebral irritations, choreas, tremors, depressions, manias.

Nephritis, gout.

Arteriosclerosis.

Therapeutics.

Lead is administered for its astringent effect in diarrheas, but could well be discarded entirely as a medicinal agent.

Dosage..

Plumbi Acetas, 0.05 to 0.3 Cm.