Medical serpents in symbol and practice

Have you ever considered why the medical arts are represented by snakes? Serpents, then, just to be polite. Having worked in the field of alternative medicine (in a concurrent career) the question hadn't really come up. But as the president-elect is expected to deliver on his promise to eradicate Obamacare, that a rod encircled by snakes symbolizes medicine is worth a look. It's true that the medical arts have made amazing advances over the centuries, yet the caduceus appears to be relatively new on the scene. For those unfamiliar with the term 'caduceus' it refers to the oft-used insignia of a staff wrapped by two snakes sporting a set of wings. Whereas the chiropractic (which art was discovered in 1896) caduceus is a ribbon flowing around the human form that evokes the medical standard, it is meant to elevate the concept of innate health.