Page 40 - 新思维科学学生用书6 样章

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Ibn al-Nafis was an Arab physician who lived 800 years ago. In about the year 1240

he discovered that blood moves from the right side of the heart to the lungs and
back to the left side of the heart. He was the first person to challenge Galen’s idea

that blood could pass directly from the right side of the heart to the left side of the

heart.
William Harvey was an English doctor who lived 400 years ago. At that time doctors

and scientists thought that the lungs moved the blood around the body. They also

thought the heart’s function was to control our feelings. Harvey observed water
pumps in London which gave him the idea that the heart pumped blood around the

body. He studied the heart and blood vessels and carried out experiments. He was
very thorough in his work and spent many hours repeating experiments and going

over every detail. He also read the work of early doctors to help him build up his

own ideas.
Harvey’s results showed him that the heart works by muscle contraction to pump

blood to body organs and that blood is carried away from heart by arteries and
returns to heart through veins. He observed that in one hour the heart pumps more

than the body’s weight in blood. This showed him that the body did not use up the

blood that flowed to body organs. In 1628 Harvey explained how blood flows in one
direction throughout the body and that gases enter and leave the blood in the lungs.

Just over 30 years later, in 1661, an Italian scientist called Marcello Malpighi used

a microscope to observe capillaries for the first time. He suggested that capillaries
connected the arteries and veins which allowed the blood to flow back through the

body in a continuous pathway. We now know that he was correct.

Questions

1 a What incorrect ideas did doctors and scientists have about circulation up to
400 years ago?

b What correct ideas did doctors and scientists have about circulation before

William Harvey’s discoveries?
2 Compare the ideas from the ancient Chinese medical book with Malpighi’s findings

two thousand years later. How are they the same? How are they different?

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