Advertising leaflet for a work entitled 'Cases of successful practice with Perkin's Patent Metallic Tractors', published by George Cooke, London, England, 1801 (see note).

Elisha Perkins was an American doctor who in 1795 claimed he could draw out disease by removing excess electricity. He did this by

passing two tapered brass and silver rods known as tractors over the body. Critics and supporters emerged on both sides of the Atlantic. Illnesses apparently cured by the 'tractors' included rheumatism, gout, sprains and contusions, burns, scalds, inflammation, epilepsy, bites and stings. Despite claims his invention cured more than 5,000 people in England of various complaints, the treatment was later discredited.