“Many “medical” organisations use a symbol of a short rod entwined by two snakes and topped by a pair of wings, which is actually the caduceus or magic wand of the Greek god Hermes (Roman Mercury), messenger of the gods, inventor of (magical) incantations, conductor of the dead and protector of merchants and thieves. It is derived from the Greek karykeion = “herald’s staff”, itself based on the word “eruko” meaning restrain, control. It is interesting to see that most of organisations using this symbol are generally either commercial or military (or American).”

http://drblayney.com/Asclepius.html

http://www.youtube.com/watch?v=LwkDbgRmA5w&feature=player_embedded