G'day DB,


The symbol was later adopted and acquired by
Hermes and became winged and as this
is the caduceus, the symbol of medicine!

Seems it depends on which country one resides in,

The Tale of Two Rods
The rod of AESCULAPIUS, with one snake entwined,
is the symbol of the British and Australian Medical Profession.
It should not be confused with the CADUCEUS of Mercury
and symbol of the American Medical Profession, it has two snakes
http://cjoint.com/data/gwqFQNaUIv.htm