Caption:
Bezoar stones are found in the stomachs and intestines of animals and humans. They are made from things that cannot be digested in the body, such as hair, and fibres from fruit and vegetables. This forms a hard, solid stone. The stones were placed in drinks to counteract poisons from would-be assassins. (It was believed that bezoar stones could counteract any poison.) The stone on the right is 45 mm in diameter. It is shown here with a bezoar stone from a camel. Supplied by Science Museum, London, courtesy of Wellcome Images.