Caduceus

Before it was the staff of a god, the caduceus was the staff of an office. In Homer's world, the herald, the keryx, was a sacred figure: he summoned assemblies, mixed the wine of truce, carried challenges between kings and messages between enemies, and from Troy to Ithaca no hand could be raised against him without offending Zeus himself, for heralds stood under the protection of the herald-god. The mark of that protection was the staff he carried, the kerykeion, and when the Greeks imagined the herald of heaven they gave him the same equipment a mortal herald used on the roads of Greece: a wide-brimmed traveller's hat, the petasos; winged sandals, the talaria, for speed; and the herald's wand, which in Homer's hands becomes a golden rod with a specific and uncanny power. Twice the poet describes it in the same words: the wand with which Hermes charms the eyes of men, whomever he wills, and wakes again those who are sleeping. Sleep and waking, death and life: the caduceus commands the border between them, which is exactly the territory of its bearer.

The story of how Hermes won the staff begins on the day he was born, which was also the day he committed his first theft. The infant god, son of Zeus and the nymph Maia, climbed from his cradle in a cave on Mount Cyllene before his first sunset, invented the lyre from a tortoise shell, then slipped away to steal fifty cattle from the herds of his elder brother Apollo. He drove them backwards so their tracks pointed the wrong way, invented fire-sticks to roast two of them, and was back in his swaddling clothes by dawn, playing innocent when Apollo arrived in a rage. Dragged before Zeus on Olympus, the baby lied with such artistry that the father of gods laughed aloud, and then ordered the truth. What followed was not punishment but one of mythology's great reconciliations. Hermes gave Apollo the lyre, and Apollo, enchanted by music he had never imagined, gave Hermes in return the golden wand of the herald, the lordship of herds and pastures, and the office of guide and messenger. The Homeric Hymn to Hermes tells it as the founding bargain of two brothers: the lyre for the staff, music for the road, and between them the whole territory of song, speech, travel and trade divided up like an inheritance.

The serpents came later, and they came with a story of their own. In the older Greek images the herald's staff is a plain rod, sometimes forked at the top; the two snakes wind around it only as the classical age ripens. The mythographers explained the change with a tale. Hermes, walking the road, once came upon two serpents locked in combat, each trying to swallow the other. The god threw his staff between them, and instead of striking the rod the two snakes wound themselves about it, and in winding, forgot their quarrel, and came to rest face to face in perfect symmetry. Hermes kept them there as a memorial, and so the staff of the herald became a picture of the herald's work: two enemies brought to a standstill, neither devouring, neither devoured, held in balance by the power of the word between them. The Greeks, who read serpents as creatures of the earth, of healing and of the dead, could hardly have missed the meaning. The caduceus binds opposites: the two snakes of the upper and lower worlds, and above them, in later art, a pair of small wings for the swiftness of the god who carries thought itself from mind to mind.

The powers of the wand run through the oldest stories of Hermes. When Zeus's affair with the nymph Io was discovered by Hera, the queen of heaven transformed the girl into a white cow and set over her a herdsman no bribe could pass: Argus of the hundred eyes, who slept with fifty eyes open and watched with the rest. Zeus sent Hermes to free her, and the god came down disguised as a shepherd, sat with the giant through the long afternoon, played his pipes and told him the story of the syrinx until one by one, under the lullaby of the caduceus's master, all hundred eyes drifted shut. Then Hermes drew his sword and struck, earning the title he carries through Homer: Argeiphontes, the Slayer of Argus. The wand's other great office appears in the last book of the Odyssey, where Hermes summons the souls of the dead suitors from the palace floor. He holds out the beautiful golden wand, and the dead rise and follow him down the dark road to the meadows of asphodel, squeaking and clustering like bats disturbed in the corner of a cave. To charm, to wake, to summon and to guide: that is the full register of the caduceus, and no other tool of Olympus touches both the bedroom and the grave.

Rome took the staff with the god and made it the emblem of the marketplace. Mercury, the Roman Hermes, gave his name and his nature to everything mercurial: merchants, merchandise, commerce itself, all from merx, the goods that move from hand to hand. The caduceus went with him onto coins, milestones and the standards of ambassadors, the sign that this traveller carries words, not weapons, and must pass free. Virgil gives the wand its grandest Roman moment when Mercury descends to Carthage, leaning on the staff with which he calls pale souls up from the underworld and sends others down, puts men to sleep and opens their eyes in death. Later ages multiplied its meanings. The alchemists read its twin serpents as the union of opposing principles, sulphur and quicksilver, fixed and volatile. Printers and journalists adopted it as the sign of the swift and eloquent word. And in 1902 the United States Army Medical Corps fixed it to their collars in a famous confusion, mistaking it for the Rod of Asclepius, the true emblem of medicine, which bears a single snake and no wings. The error spread across American hospitals and endures to this day, though the old distinction is simple enough: one serpent heals the sick, two serpents carry the message. From the cradle-theft on Mount Cyllene to the banks of the Styx, from Roman coinage to a modern hospital gate, the caduceus remains what Apollo made it on the first evening of Hermes' life: the golden guarantee that the word will arrive, and the messenger will come home.