Hello Dear Reader(s)

There are two images that most the world knows as medical symbols, but as with things taken from antiquity, there are some very different meanings to them.

The above image is Hermes Staff, also known as the cādūceus. (It was also carried by Iris, but that is another subject)
This symbol represents the God Hermes (Mercury in the Roman Mythos) and the attributes associated with him.
The wand of the staff was supposed to wake the sleeping and send the awake to sleep. (Possible use of needing rest when sick or in pain for the medical aspect here) If the staff was applied to the dying, their death would be a gentle one, but if applied to the dead, they would return to life.
And since Hermes is considered to be the messenger of the Gods and protector of travelers, the caduceus also represents commerce and negotiation.
Now before we continue let’s look at the other symbol used by medicine:

The rod of Asclepius is traditionally depicted in the Emergency Medical Services’ Star of Life (Pictured below)

The God Asclepius is associated with healing and medicinal arts. Asclepius’ attributes, the snake and the staff, sometimes depicted separately in antiquity, are combined in this symbol.

It has been claimed that the snake wrapped around the staff was a species of rat snake, Elaphe longissima, the Aesculapian snake.

There were many healing temples of Asclepius that ranged from north-eastern Peloponnese to  Pergamum in Asia.

In honour of Asclepius, a particular type of non-venomous snake (Aesculapian snakes) was often used in healing rituals in these temples, the snakes crawled around freely on the floor in dormitories where the sick and injured slept. From about 300 BCE onwards, the cult of Asclepius grew very popular and pilgrims flocked to his healing temples (Asclepieia) to be cured of their ills. Ritual purification would be followed by offerings or sacrifices to the god (according to means), and the supplicant would then spend the night in the holiest part of the sanctuary – the abaton. Any dreams or visions would be reported to a priest who would prescribe the appropriate therapy by a process of interpretation.

The original Hippocratic Oath began with the invocation “I swear by Apollo the Healer and by Asclepius and by Hygieia and Panacea and by all the gods …”

The serpent and the staff appear to have been separate symbols that were combined at some point in the development of the Asclepian cult. 

Serpents could be a healing symbol because sometimes the shedding of skin and renewal is emphasized as symbolizing rejuvenation. The ambiguity of the serpent as a symbol, and the contradictions it is thought to represent, reflect the ambiguity of the use of drugs, which can help or harm, as reflected in the meaning of the term pharmakon, which meant “drug”, “medicine”, and “poison” in ancient Greek. However the word may become less ambiguous when “medicine” is understood as something that heals the one taking it because it poisons that which afflicts it, meaning medicine is designed to kill or drive away something and any healing happens as a result of that thing being gone, not as a direct effect of “medicine”. Also take into consideration that several products deriving from the bodies of snakes were known to have medicinal properties in ancient times, and in ancient Greece. Snake venom was also ‘prescribed’ in some cases as a form of therapy.

The staff has also been variously interpreted. One view is that it, like the serpent, “conveyed notions of resurrection and healing”, while another is that the staff was a walking stick associated with itinerant physicians. 

Asclepius derived his name from healing soothingly and from deferring the withering that comes with death. For this reason, therefore, they give him a serpent as an attribute, indicating that those who avail themselves of medical science undergo a process similar to the serpent in that they, as it were, grow young again after illnesses and slough off old age; also because the serpent is a sign of attention, which is required in medical treatments, as well as the staff. For by means of this it is set before our minds that unless we are supported by such inventions as these, in so far as falling continually into sickness is concerned, stumbling along we would fall even sooner than necessary.

So onto the medical symbol confusion:
The Rod of Asclepius is the dominant symbol for professional healthcare associations in the United States. One survey found that 62% of professional healthcare associations used the rod of Asclepius as their symbol. The same survey found that 76% of commercial healthcare organizations used the Caduceus. The author of that study suggests that professional associations are more likely to have a historical understanding of the two symbols, whereas commercial organizations are more likely to be concerned with the visual impact a symbol will have on sales.
So we now see that Asclepius’ Rod has the correct meaning for the medial industry, athough it is common, especially in the United States, to find the caduceus as the symbol of medicine.
This usage was popularized by the adoption of the caduceus as its insignia by the U.S. Army Medical Corps in 1902 at the insistence of a single officer.

It remains a contention in the medical community as this quote shows:
“As god of the high-road and the market-place Hermes was perhaps above all else the patron of commerce and the fat purse: as a corollary, he was the special protector of the traveling salesman. As spokesman for the gods, he not only brought peace on earth (occasionally even the peace of death), but his silver-tongued eloquence could always make the worse appear the better cause. From this latter point of view, would not his symbol be suitable for certain Congressmen, all medical quacks, book agents and purveyors of vacuum cleaners, rather than for the straight-thinking, straight-speaking therapeutist? As conductor of the dead to their subterranean abode, his emblem would seem more appropriate on a hearse than on a physician’s car.” — Stuart L. Tyson, “The Caduceus”, in the Scientific Monthly, 1932

In arguement for the Caduceus for use in the medical industry, it may be linked to the alchemical “universal solvent”, Azoth, of which the symbol of which was the caduceus.

The Guildhall Museum in London holds a 3rd-century oculist’s seal with Caduceus symbols both top and bottom. The seal was used to mark preparations of eye medicine. The Greek poet Homer who described the Caduceus as “possessing the ability to charm the eyes of men”, which relates to the business of an oculist, so that seal may be in reference to that instead of use as a healing aid.

“there are very definite connections between medicine and (Hermes)-Thoth, who later became known as Hermes Trismegistus. […] although these various factors may link Hermes/Mercury, along with his Caduceus, with alchemical medicine, they may just as well link all the other non-medical aspects of alchemy with Hermes/Mercury and the Caduceus”. – Walter Friedlander

The role of Hermes in the afterlife was limited to guiding souls of the deceased, whereas the powerful Egyptian god Thoth was truly lord of the underworld and master of death. Thoth was at times depicted with two staves encircled by one cobra each, which might well have influenced the iconography of Hermes’ caduceus. However, in ancient Egypt the snake staff represented the attribute of a powerful sorcerer, not a merchant or messenger. Compared to Hermes, Thoth was associated much more with magic and with potent actions preserving balance in the divine world, than with the unpredictable whims of a trickster deity.

The Caduceus became a symbol of alchemy and pharmacy in medieval Europe. Its first appearance as a medical symbol can be traced back to 1st−4th century CE in oculists’ stamps that were found mostly in Celtic areas, such as Gaul, Germany and Britain, which had an engraving of the name of the physician, the name of the special medicine or medical formula and the disease for which the medicine was to be used.

Medieval alchemy used the Caduceus to represent preparations containing quicksilver, later known as mercury. It was believed to be the basis of all substances and this element has been represented by the caduceus for many centuries.

It was also used to signify pharmacy, Sir William Butts, physician to Henry VIII, was the first physician to adopt it as his emblem.