Galen (129-216) was a Greek physician that built upon Hippocratic medicine by incorporating theology. Galen was limited to studies on animals, but once in a while was fortunate enough to earn access to human bodies. He placed dominion in the Hippocratic concept that human health was a balance of four bodily fluids called humors, which were blood, phlegm, black bile, and yellow bile. In addition, each humor embodied a specific quality; hot, cold, dry, or wet. However, Galen rejected the notion that anatomy founded the basis of medicine and instead adopted the theological belief that “nature does nothing in vain” to explain the structure and function of the body. Galen and his successors taught that the liver produced venous blood from food that was ingested. It was subsequently distributed to the rest of the blood through an ebb and flow. The ebb and flow proposed that the body constantly consumed the blood as nutrient. In short, blood was constantly being wasted and replenished by the food ingested. In the right ventricle, impurities in the blood were expelled into the pulmonary artery and then exhaled from the lungs. While purified blood went to the left ventricle through invisible pores in the interventricular septum and combined with pneuma that came from the pulmonary veins to cool down the body. Subsequently, the mixture of pnuema and the small amount of blood traveled to the pulmonary arteries. The left ventricle …show more content…
He coordinated an experiment to determine the amount of blood that courses throughout the heart each day. He began by draining blood from animals and then measuring the volume of the left ventricles. He found that each left ventricle contained up to 2 ounces of blood. He estimated that each heart expelled about half an ounce of blood. Afterwards, he multiplied this amount by the number of heartbeats in a half hour and found that it exceeded the quantity that could be supplied from the food ingested. Harvey concluded that more blood passed through the heart than ingested by food, thus, proving Galen wrong. Harvey proposed that blood revolved in a circuit, hence, a closed-ended system. Blood was a fixed amount that routinely traveled in a