Rod of Asclepius

The rod of Asclepius (also known as the rod of Asklepios, rod of Aesculapius or asklepian ) is an ancient Greek symbol associated with astrology and with healing the sick through medicine. It consists of a serpent entwined around a staff. Asclepius, the son of Apollo, was practitioner of medicine in ancient Greek mythology.

Symbolism
The rod of Asclepius symbolizes the healing arts by combining the serpent, which in shedding its skin is a symbol of rebirth and fertility, with the staff, a symbol of authority befitting the god of Medicine. The snake wrapped around the staff is widely claimed to be a species of rat snake, Elaphe longissima, also known as the Aesculapian or Asclepian snake. It is native to southeastern Europe, Asia Minor, and some central European spa regions, apparently brought there by Romans for their healing properties.

Origin
There are several different theories as to the origin and development of the rod of Asclepius, any or all of which may have contributed to its development. The symbol is named for an ancient Greek legend, although the legend could be older.

Greek mythology
According to Greek mythology, Asclepius was said to have learned the art of healing from Chiron. He is customarily represented as a surgeon on the ship Argo, Asclepius was so skilled in the medical arts that he was reputed to have brought patients back from the dead. For this he was punished and placed in the heavens as the constellation Ophiuchus (meaning "serpent-bearer"). This constellation lies between Sagittarius and Libra. In early Christianity, the constellation Ophiuchus was associated with Saint Paul holding the Maltese Viper.

'Worm' theory
Some scholars have suggested that the symbol once represented a worm wrapped around a rod; parasitic worms such as the "guinea worm" (Dracunculus medinensis) were common in ancient times, and were extracted from beneath the skin by winding them slowly around a stick. Physicians may have advertised this common service by posting a sign depicting a worm on a rod.

Biblical
A similar symbol, Nehushtan, is mentioned in the Bible in Numbers 21:4–9. Attacked by a plague of snakes in the wilderness, Moses holds up a serpent coiled around a staff, both made from bronze, so that the Israelites might recover from the bites.

Usage
A number of organisations use the rod of Asceplius as their logo, or part of their logo. These include:
 * The World Health Organization
 * The American Osteopathic Association
 * The Canadian Medical Association
 * The American Veterinary Medical Association
 * The British Royal Army Medical Corps
 * The Australian Medical Association
 * The Star of Life - symbol of the National Registry of Emergency Medical Technicians
 * The American Medical Association

Confusion with the caduceus
The caduceus is often incorrectly used as a symbol for medicine or doctors, in place of the rod of Asclepius which is the usual symbol of the medical profession. A 1992 survey of American health organisations found that 62% of professional associations used the rod of Asclepius, whereas in commercial organisations, 76% used the caduceus.

Early confusion between the symbols almost certainly arose due to the links between alchemy and Hermes, whose symbol is the caduceus. The alchemists adopted the caduceus because Hermes, the God of Messengers, was also the patron lord of gamblers, thieves, tricksters and alchemists. By the end of the 16th century, alchemy became widely associated with medicine in some areas, leading to some use of the caduceus as a medical symbol.

The main reason for the modern confusion over the symbols occurred when the caduceus was adopted by the Medical Department of the United States Army in 1902. This was brought about by one Captain Reynolds, who after having the idea rejected several times by the Surgeon General, persuaded the new incumbent (WH Forwood) to adopt it. The mistake was noticed several years later by the librarian to the surgeon general, but was not changed.

There was further confusion caused by the use of the caduceus as a printer's mark (as Hermes was the god of eloquence and messengers), which appeared in many medical textbooks as a printing mark, although subsequently mistaken for a medical symbol.

Standard representation
The rod of Asclepius has a representation on the Miscellaneous Symbols table of the Unicode Standard at U+2695.