On Independence Day, 1850, President Zachary Taylor consumed a large amount of food at a celebration of the holiday, including milk, cherries, and a wide variety of other dishes presented to him by well-meaning citizens.  Almost immediately the chief executive would fall ill, and five days later he'd be dead - largely believed to have succumbed either to gastroenteritis or cholera.

In the late 1980's, conspiracy theorists surmised that Taylor was, in fact, murdered by means of poisoning.  After some cajoling of Taylor's descendants, an exhumation of his body was authorized, and on June 17, 1991, the remains of the twelfth President of the United States were exhumed, with hair, fingernail and tissue samples taken.  Assassination by poisoning was subsequently ruled out, but the exact means of Taylor's death to this day remain shrouded in mystery.

One mystery, or at least a controversy, was laid to rest along with Taylor however:  upon his death, Vice President Millard Fillmore was almost immediately sworn into office as the nation's thirteenth President - with none of the hue and cry that surrounded John Tyler's ascent to the presidency nine years earlier.  Fillmore's inauguration confirmed the Tyler Precedent and, in effect, made it de facto law.