In the 19th century, before the development of vaccines by Louis Pasteur in 1885 (according to the CDC), people desperately turned to various other remedies to treat diseases like rabies. For some, a mad stone – if you could find one – seemed like an appropriate treatment. As a medicine, the “stone” would be applied to the site of infection of a rabies victim, where it was believed that over time the stone would draw out the “poison” and cure the affected person.
According to Ozarks Public Radio, when the madstone was needed, it was first boiled in milk until it got quite hot; then it would be applied to the wound site – normally a rabies infected bite, but the crazy stones could also be used for snake or spider bites – and if the stone stuck to the wound it was proof that there was indeed infection or poison in it.
The stone remained stuck to the wound until it fell off, which could often take up to a day or two, at which point it was again placed in warm milk. If the stone worked properly, the milk would turn green with the “poison”, after which the stone would be reapplied to the wound. This process would be repeated until the stone stopped sticking, which was a sure sign that the infection was gone.
Despite the high demand and subsequent value of madstones as medicine, it was strictly forbidden to buy or sell it, or even to charge for its use. As a result, these stones were usually passed down from generation to generation.