" When the English introduced the new Enfield rifle in 1857, the cartridges for the rifle came from the factory liberally coated with grease. It was necessary to bite the cartridges to release the powder. Among the sepoy regiments there was a rumor that the grease was made from pigs and cows, and thus these cartridges were a trick to defile the sepoys and make them break caste. "

― Michael Crichton , The Great Train Robbery