Today, a peculiar fable about blood and martyrdom.
The University of Houston's College of Engineering
presents this series about the machines that make
our civilization run, and the people whose
ingenuity created them.
The early Christian writer
Tertullian once said, "The blood of martyrs is the
seed of the Church." That takes on a strange irony
in the case of Michael Servitus.
By the mid-1500s the question of how blood flows
through the body was becoming a real puzzle. For
1400 years we'd believed what the Roman doctor
Galen told us.
Galen thought the liver converted food into blood.
The veins carry the blood to the heart. There it
leaks through the septum into the arteries. The
arteries carry it to our extremities, where the
body consumes it. It was a once-through theory.
William Harvey straightened all that out in 1628.
He told us blood gets from the arteries to the
veins through invisible capillaries. He realized
that blood isn't made in the liver at all. It
recycles after the lungs refresh it.
Harvey's idea wasn't original. But he worked it out
in clear-headed, modern terms. He supported the
theory with ingenious experiments.
Before Harvey, blood flow was a philosophical --
even a theological -- issue. For example, the way
the alchemist Paracelsus attacked Galen was to
compare blood flow to the cyclic action of rain and
This is where the theologian Michael Servitus comes
in. In 1546 he wrote a book on spiritual
regeneration. He attacked the doctrine of the
Trinity. He thought the Nicene Creed dishonored the
idea of redemption. That was dangerous thinking
during the Protestant Reformation.
Servitus -- almost incidentally -- described the
regeneration of blood in the lungs. It was part of
his theology of regeneration. But it was quite
accurate. Servitus told us just what Harvey did, 85
Servitus sent a copy of his book to Calvin. Calvin
took it very badly. He ordered Servitus's arrest
and trial as a heretic. A tribunal sentenced
Servitus to burn in a fire fueled by slow-burning
green wood and his own books.
Harvey surely heard of Servitus's theories. It's
unlikely he ever read Servitus's ponderous text.
But others had plagiarized the parts on blood flow.
And what about Calvin? Well, Servitus's ghastly
death discredited him. Servitus's martyrdom led to
Church reform. In that sense, his blood really was
the seed of the Church. And his blood-flow theory!
Well, that was a major seed of modern medicine.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
Clendening, L., Behind the Doctor. New
York: Alfred A. Knopf, 1933, Chapter VI.
Boorstin, D.J., The Discoverers. New
York: Random House, 1983, Chapter 47.
Debus, A.G., The English Paracelsians.
New York: Franklin Watts, Inc., 1966.
The Engines of Our Ingenuity is
Copyright © 1988-1997 by John H.
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