Arteries normally carry pneuma or air rather than blood.

The name artery comes from a world in which an empty vessel in a corpse could look like an air tube.

In Hellenistic Alexandria, Erasistratus developed an influential cardiovascular physiology in which veins carried blood while arteries carried pneuma, a vital air-like substance. The model was linked to a broader theory of respiration, pulse, and vital function.

Post-mortem anatomy offered some intuitive support: arteries can be relatively empty after death, while veins often contain obvious blood. The arterial pulse also made arteries seem functionally distinct.

Galen rejected the air-only artery. In the second century CE he used vivisection and ligature experiments and argued at length that arteries in living animals are filled with blood. This was a genuine experimental correction, although it was still far from the modern concept of circulation. Galen still described separate arterial and venous systems, liver-produced blood, pneuma, invisible cardiac pores, and an open-ended distribution of blood to tissues.

So the historical sequence is unusually instructive: one ancient physiological claim was experimentally overturned by another ancient physician, while the replacement theory itself remained deeply wrong in other ways for more than a millennium.

Because the pneuma-only artery belonged to particular Hellenistic schools rather than universal ancient medicine, it is excluded from lifespan rankings.