This section is from the book "Materia Medica: Pharmacology: Therapeutics Prescription Writing For Students and Practitioners", by Walter A. Bastedo. Also available from Amazon: Materia Medica: Pharmacology: Therapeutics: Prescription Writing for Students and Practitioners.
The heavy metals, though differing markedly in some of their details of action and in their therapeutic uses, have certain pharmacologic actions in common. Their salts tend to precipitate proteins, forming metallic albuminates of variable composition. The salts which are most readily dissociable into ions act most rapidly and tend to be irritant. They may even be caustic, causing death of tissue. The soluble salts, through precipitation of the proteins of the cells, tend to be astringent. The organic preparations and double salts tend to dissociate less easily and have less local action. The salts of inorganic acids tend to be especially astringent from the setting free of the acid.
The absorption of most of the salts is slow, and their excretion also very slow, and chronic poisoning by some of the metals may follow the repeated ingestion for many days of very minute quantities. They are mostly excreted by the kidneys and the gastro-intestinal tract; and in the poisoning these organs tend to be inflamed.
The nervous system is also sensitive to the metals, peripheral neuritis, excitability, and scleroses in the brain or cord being sometimes manifestations of metallic poisoning.