"If you look in a looking glass too long you are sure to see the devil," warns a nineteenth-century English saying. A more visceral rendition of the same moral admonishment appears in a book of folklore published in 1883:
When a boy, one of my aunts who lived in Newcastle-on-Tyne used to tell me of a certain girl that she knew who was very vain and fond of standing before the looking glass admiring herself. One night as she stood gazing, lo! all of her ringlets were covered with dripping sulphur, and the devil appeared peeping over her shoulder.
A superstition that lingered from the eighteenth century well into the twentieth held that mirrors must be covered or turned to face the wall in the presence of a dead person. Some said this was to signify "an end to all vanity." Others took it to be a demonstration of respect for the dead. Still others believed an uncovered mirror was an open invitation for ghostly apparitions to appear.
"It is not good for a corpse to be reflected in a glass or mirror . . . because the dead will not rest," wrote Marie Trevalyan in Folklore and Folk-Stories of Wales (1909). The possible consequences of failing to act accordingly are made plain in this excerpt from a 1924 issue of Notes & Queries:
Nearly seventy years since, in Durham, I remember seeing my grandmother when laid out. Mirror and pictures were covered with white sheets. I was told then, or later, that this was done lest persons seeing themselves reflected, the corpse should also be seen looking over their shoulders, and give them a fright.What connects this quaint superstition to the Bloody Mary ritual is the motif of "the apparition in the looking-glass" the critical difference being that in the former the ghost appears because someone forgot to cover a mirror; in the latter, the ghost is purposely summoned.
Make no mistake, when a gaggle of adolescents stand in front of a mirror chanting "Bloody Mary, Bloody Mary, Bloody Mary," or "I believe in Mary Worth, I believe in Mary Worth," they're uttering what they believe to be or hope to be, or fear to be a magic spell to conjure up a ghost or demon spirit. The notion that ritual incantations can be used to achieve supernatural ends derives not only from folklore and fairly tales, wherein remnants of so many age-old myths and superstitions are retained, but also from the childhood mindset itself, which is subject to a variety of forms of magical thinking. Among those is a phenomenon identified by developmental psychologist Jean Piaget as "nominal realism," which, simply put, is the tendency to confuse objects with their names, resulting in the belief that words and thoughts can influence real-world events.
Of the many ways "Bloody Mary" can be interpreted, the most obvious and literal is as a cautionary tale demonstrating the perils of playing with magic. But it's also a ghost story.