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The English physician William Harvey showed in 1628 that the heart pumps the same blood round the body in a circuit. In his book De Motu Cordis (On the Motion of the Heart), he used dissections, the valves in the veins and simple arithmetic: the heart moves far more blood than food could ever replace.

William Harvey, De Motu Cordis (1628)

HealthHistoryScience

The story behind the card

Harvey's key argument was a calculation. Taking deliberately low figures for how much blood each heartbeat pushes out, he showed that within half an hour the heart moves more blood than the whole body contains, so the same blood must keep coming back. The one-way valves in the veins, described by his teacher Fabricius in Padua, let blood flow only towards the heart. Harvey was physician to King James I and then to Charles I, and stayed loyal to the Crown in the Civil War. He could not see the tiny vessels linking arteries to veins; Marcello Malpighi found these capillaries under a microscope in 1661, four years after Harvey's death.

Türkçe oku
İngiliz hekim William Harvey 1628'de, kalbin aynı kanı vücutta durmadan dolaştırdığını gösterdi. De Motu Cordis (Kalbin Hareketi Üzerine) adlı kitabında yaptığı diseksiyonlara, toplardamarlardaki kapakçıklara ve basit bir hesaba dayandı: Kalp, yiyeceklerle yerine konabilecek olandan çok daha fazla kan pompalıyordu.

Harvey'nin en güçlü kanıtı bir hesaptı. Kalbin her atışta pompaladığı kan için bilerek düşük rakamlar aldı ve kalbin yarım saatte bütün vücuttaki kandan daha fazlasını pompaladığını gösterdi; demek ki aynı kan dönüp geliyordu. Hocası Fabricius'un Padova'da tanımladığı toplardamar kapakçıkları, kanın yalnızca kalbe doğru akmasına izin veriyordu. Harvey önce Kral I. James'in, sonra I. Charles'ın hekimliğini yaptı ve İç Savaş boyunca krala bağlı kaldı. Atardamarlarla toplardamarları birleştiren incecik damarları göremiyordu; bu kılcal damarları Marcello Malpighi 1661'de, Harvey'nin ölümünden dört yıl sonra, mikroskopla buldu.

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Background reading: William Harvey
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