The sake and staff are known as the "Rod of Ascepius".
Asclepius is the Greek god of Medicine and Healing, hence the symbolism. Snakes then symbolized rejuvenation. 
Many mistakenly think that the Caduceus (a short staff with two snakes and a winged top) is the symbol of medicine, or call the Asclepius staff a caduceus. The Caduceus is the symbol or Hermes (Roman = Mercury) the messenger and symbolizes travel, commerce, etc. While this may not be all of it, some of the confusion traces back to around 1920 when the US Army mistakenly used the Caduceus for their medical personnel.
