Page "Salem witch trials" Paragraph 88

According to English folk understanding of how witches accomplished affliction, when the dog ate the cake, the witch herself would be hurt because invisible particles she had sent to afflict the girls remained in the girls ' urine, and her cries of pain when the dog ate the cake would identify her as the witch.

This superstition was based on the Cartesian " Doctrine of Effluvia ", which posited that witches afflicted by the use of " venomous and malignant particles, that were ejected from the eye ", according to the October 8, 1692 letter of Thomas Brattle, a contemporary critic of the trials.