The Description of the Human Body He believed the heat of the heart somehow caused all movement of the body. Blood vessels he realized were pipes, he saw that veins carried digested food to the heart. (This was brought further by William Harvey. Harvey developed the idea of the circulation of the blood.) Descartes felt that an energetic part of blood went to the brain and there gave the brain a special type of air imbued with vital force that enabled the brain to experience, think and imagine. This special air then went through the nerves to the muscles enabling them to move. The Description of
Medicine in the medieval Islamic world blood is pumped to the rest of the body. According to Galen in the 2nd century, blood reached the left ventricle through invisible passages in the septum. By some means, Ibn al-Nafis, a 13th-century Syrian physician, found the previous statement on blood flow from the right ventricle to the left to be false. Ibn al-Nafis discovered that the ventricular septum was impenetrable, lacking any type of invisible passages, showing Galen's assumptions to be false. Ibn al-Nafis discovered that the blood in the right ventricle of the heart is instead carried to the left by way of the lungs. This discovery