Harvey and the circulation of blood
Quantity settles an argument: the heart pumps far too much for blood to be consumed.
- When
- Known to
- ± 1 year
- Era
- Early Modern, Holocene
William Harvey publishes in 1628 the demonstration that blood circulates in a closed loop. His decisive argument is arithmetic — measuring the volume the heart expels per beat shows it moves more than the body's weight in blood every hour, which cannot be continuously manufactured and consumed as Galen held. He could not see the capillaries; they were found with a microscope decades later, confirming him.