serpent around a staff:
In ancient times infection by parasitic worms
was common. The filarial worm Dracunculus
medinensis, aka "the fiery serpent", aka "the
dragon of Medina" aka "the guinea worm"
crawled around the victim's body, just under
the skin. Physicians treated this infection by
cutting a slit in the patient's skin, just in front
of the worm's path. As the worm crawled out
of the cut, the physician carefully wound the
pest around a stick until the entire animal
had been removed.
It is believed that because this type of
infection was so common, physicians
advertised their services by displaying a
sign with the worm on a stick.
