<P> The caduceus (☤; / kəˈduːʃəs / or / kəˈdjuːsiːəs /; Latin cādūceus, from Greek κηρύκειον kērū́keion "herald's wand, or staff") is the staff carried by Hermes in Greek mythology and consequently by Hermes Trismegistus in Greco - Egyptian mythology . The same staff was also borne by heralds in general, for example by Iris, the messenger of Hera . It is a short staff entwined by two serpents, sometimes surmounted by wings . In Roman iconography, it was often depicted being carried in the left hand of Mercury, the messenger of the gods, guide of the dead and protector of merchants, shepherds, gamblers, liars, and thieves . </P> <P> Some accounts suggest that the oldest known imagery of the caduceus have their roots in a Mesopotamian origin with the Sumerian god Ningishzida whose symbol, a staff with two snakes intertwined around it, dates back to 4000 B.C. to 3000 B.C. </P> <P> As a symbolic object, it represents Hermes (or the Roman Mercury), and by extension trades, occupations, or undertakings associated with the god . In later Antiquity, the caduceus provided the basis for the astrological symbol representing the planet Mercury . Thus, through its use in astrology, alchemy, and astronomy it has come to denote the planet and elemental metal of the same name . It is said the wand would wake the sleeping and send the awake to sleep . If applied to the dying, their death was gentle; if applied to the dead, they returned to life . </P>

Why is there snakes in the medical symbol