Engines of Our Ingenuity

No. 848:
BAD AIR

by John H. Lienhard

Click here for audio of Episode 848.

Today, we try not to breathe the evil vapors of the night air. 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.

Here're two words for you: Malaria literally means "bad air." Miasma was a word we once used for air that carries diseases like malaria. A miasma was air, usually night air, tainted with poison. That's why a Shakespearean suitor said of his love,

O, when mine eyes did see Olivia first,
Methought she purged the air of pestilence.
All through the 19th century we still believed that bad air, actually smelly air, caused disease. Microscopes had shown us germs swimming in water, but we didn't connect them with disease.

Then, in 1853, an English doctor, John Snow, struggled with a cholera epidemic in London. The stink of death and sickness was all around. People thought that stink carried the disease. But Snow studied statistics. He finally pin-pointed a well whose water was fed by sewage from a public toilet up the hill.

After that, Lister, Koch, and Pasteur identified disease-carrying germs. They learned to kill them. But the concept of miasma didn't go away. In 1870 the English physicist Tyndall proved that particles in air can carry germs -- the aerosol droplets we cough up, or dust. The air itself carries nothing at all.

But we still believed in miasma. Tropical diseases like malaria and yellow fever seemed to be carried by miasma. You caught them without touching the sick. Africans had correctly told the English explorer Richard Burton that mosquitoes carried yellow fever. He laughed at natives who didn't understand that bad air simply arrived during mosquito season.

It was 1897 before two doctors, Ronald Ross working in India, then Walter Reed working in Havana, began looking at mosquitoes. In 1897 Ross cut mosquitoes open. He found evidence of the bacterium that caused malaria in their stomachs. He was so excited that he sat down and wrote bad poetry about it:

Henceforth I will resound,
But praises unto Thee;
Tho' I was beat and bound,
Thou gavest me victory.

By now typhoid and yellow fever were taking a terrible toll among our soldiers in Cuba. Walter Reed went looking for the cause. At first he suspected the miasma. However, by 1900 his team had proved that water carried typhoid. Two years later they showed that mosquitoes, not bad air, were carrying yellow fever.

So we had, at last, "purged the night air of pestilence." Now we embraced fresh air as never before. We began building our houses with outdoor sleeping porches. Fresh air was still the great cure-all when I was a child.

And maybe rightly so. For a new miasma of airborne carcinogens and pollutants is afflicting us. Today, we might well need fresh air, purged of pestilence, more than we ever did.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


Tyndall, J., Essays on the Floating-Matter of the Air (Reprinted from the New York Edition of 1882, R.N. Doetsch, ed.). New York: Johnson Reprint Corp., 1966. (See also Episode 642 on this work by Tyndall.)

See articles on Ross and Reed in the Dictionary of Scientific Biography. (C.C. Gilespie, ed.) Chas. Scribner's Sons, 1970-1980, and entries for miasm and miasma in The Oxford English Dictionary.

Root-Bernstein, R.S., "Ends & Means," The Sciences, March/April, 1991, pp. 10-12.

The Shakespeare lines are spoken by Orsino in the opening scene of Twelfth Night:

O, when mine eyes did see Olivia first,
Methought she purged the air of pestilence!
That instant was I turn'd into a hart;
And my desires, like fell and cruel hounds,
E'er since pursue me.
The connection between Ross's work on mosquito-borne malaria and sleeping porches is part of research in progress by Margaret Culbertson, UH Art and Architecture Library. Martha Steele, UH Library, points out that in the late 19th century Henry James calls the miasma down on one of his literary characters. His Daisy Miller foolishly dares to venture out one night in Rome to visit the Coliseum. She contracts a disease that James vaguely calls "Roman Fever" from the night vapors and dies of it.

Image of a mosquito from the 1897 Encyclopaedia Britannica



The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.

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