Today, we cast a new light on disease. 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.
Mary Shelley spent the
summer of 1816 in Switzerland. First she read
Erasmus Darwin's ideas about the spontaneous
generation of life in rotting food. Then she wrote
her own story about generating life. She wrote the
Sixty years later, another English visitor summered
over in the Swiss Alps. He was the physicist John
Tyndall. Like Shelley, he'd also thought about the
spontaneous generation of life. In spring, a nearby
lake was clean and lifeless. By summer's end it
teemed with life. If you weren't careful, he said,
you could think that life arose spontaneously in
the sterile melted snow.
Today, we know Tyndall for his work with heat,
light, and sound. We forget his work on
micro-organisms and airborne disease. Yet it stands
right along with Pasteur's and Lister's.
He'd begun in the 1860s when he was studying light.
He wanted to make air dust-free. So he created the
Tyndall Box. He coated the walls inside a sealed
box with glycerin.
After 3 days, all the particulates in the air stuck
to the walls and left the air in the box clean as a
whistle. Tyndall had made the air optically pure.
He showed that beams of light are invisible when
they enter a window and pass through clean air.
By now doctors knew that dirt and dust caused
disease. They also suspected that germs might be
major agents of disease. Tyndall put those ideas
together. He saw that by cleaning the air he'd
removed the vehicle that carries micro-organisms.
To make his point, he exposed test tubes of urine
to the clean air in a Tyndall box. Bacterial life
grew in the test tubes under normal air. They
stayed sterile in the box. So he repeated the
experiment with meat, fish, and vegetables. Same
story. None of them putrefied in clean air, either.
He made his work public in 1870. Then the fun
began. Biologists attacked him. One of them, a
believer in spontaneous generation, scalded him for
"quitting his own metier." He told Tyndall that the
germ theory of disease was the business only of
biologists and physicians.
We hear a lot of that today. Don't talk about
poetry if you're a historian. You can't understand
medicine unless you're an M.D. Tyndall shot back:
If that were true, then the chemist Pasteur
shouldn't be allowed to study germs.
Tyndall began by studying light. When he was done,
he'd pinned down the origin of disease. He brought
alien knowledge to biology. He changed biology when
he took it into that clever box -- and cast the
clean invisible light of his physics upon it.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds