Didn't they used to use toxic heavy metals to treat syphilis?

Was the cadeuceus associated with Hermes or Mercury?

Honestly, I don't know what the connection is between medicine and any Roman or Greek god, but I have heard it suggested that the serpent on the staff might derive from the act of removing a guinea worm (Dracunculus medinensis) from a body by means of a stick. This might have been one of the common procedures carried out by early physicians. The worm is also called the "serpent worm," and the connection to the serpent on the cadeuceus seems obvious.


LINKS:

http://mywebpage.netscape.com/teodorcapraru/images/dractreatlube.jpg


http://drblayney.com/Asclepius.html#hermes Very interesting history of Hermes/Mercury and the cadeuceus vs the Staff of Asclepius. e.g.:
In reply to:

The probable medical origin of the single serpent around a rod: 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 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.

http://ucdnema.ucdavis.edu/imagemap/nemmap/ent156html/nemas/dracunculusmedinensis

http://www.biosci.ohio-state.edu/~parasite/pictures/dracunculus_3.gif (not for the squeamish)