The
serpentine staff here (not shown) is called a caduceus. It has Greek
origins—Hermes, the messenger of the gods, carried it as a symbol of peace.
Ancient Romans and Greeks
created the caduceus
as a badge of honor; ambassadors and noblemen carried a long staff entwined with
garlands or ribbons to announce their presence. The garlands were later
interpreted as snakes, and a pair of wings was added to denote Hermes, the
winged messenger.
Here's where it gets tricky.
The U.S. Army medical corps adopted the caduceus as their insignia because of
its similarity to the staff carried by Asclepius,
the god of medicine. The staff of Asclepius is considered the "true symbol
of medicine"—it features only one snake, and no wings. It's the emblem of
the American Medical Association.
The two symbols are quite
similar in appearance, and both are derived from Greek
mythology.
The caduceus generally stands for peace, although it may also serve as a symbol
of trade and communication, while the staff of Asclepius
stands for healing.