> The fact that the heart by itself is incapable of sustaining the circulation of the blood was known to physicians of antiquity. "The ancients knew" is always

> The fact that the heart by itself is incapable of sustaining the circulation of the blood was known to physicians of antiquity. "The ancients knew" is always a good start. > The heart, an organ weighing about three hundred grams, is supposed to 'pump' some eight thousand liters of blood per day at rest Or 92 mL/second. Or 46-92 mL per beat. > through millions of capillaries I read 10 billion capillaries elsewhere, but let's go with '5 million' capillaries. This would mean the heart pushes 18.2 nanolitres through each capillary per second.