Witch Cake or Witch's Cake

It was believed that a witch's cake had the power to reveal the names of witches who were afflicting someone. In Salem Village, Massachusetts, in 1692, when two girls began behaving erratically at the beginning of the events leading up to the trials, a neighbor of the Parris family recommended that a slave in the Parris household make a witch's cake to identify the witches afflicting the girls. The witch's cake was made of rye mixed with the urine of the girls and fed to a dog. The expectation was that the witch's cake would injure whoever had hurt the person whose urine was used, and that would reveal their identity.