Engines of Our Ingenuity

No. 1179:
HOW ASPIRIN FINDS THE HEADACHE

by John H. Lienhard

Click here for audio of Episode 1179.

Today, aspirin looks for your headache. 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.

How Does Aspirin Find a Headache? That's the title of yet another book by David Feldman. He's done many books filled with questions like that, along with their answers. Feldman's questions serve as a kind of smelling salts for my mind.

Try that aspirin question: I always thought aspirin just entered the blood and reduced pain wherever the blood went. Aspirin does enter the blood, but then it acts selectively on pain and inflammation. Not 'til the 1970s did pharmacologists figure out how it did that. Aspirin attacks a certain fatty acid that serves as an early warning system by increasing the sensitivity of pain receptors. Aspirin turns those painful warning bells off.

Feldman's "How" and "Why" books remind us to keep raising questions we'd otherwise forget to ask. The world is neither simple nor obvious, and its secrets will be kept from us as long as we fail to ask. So let's try four more questions:

First, should I drain that water off top of my yogurt? Well now: That isn't water at all. It's whey, as in "Little Miss Muffet sat on a tuffet eating her curds and whey." Whey contains sugar, minerals, protein, and nutrients. It's part of what you pay for when you buy yogurt. So you definitely want to mix it back in.

Next, why are the Muppets all left-handed? (I hadn't realized they were. But they are!) Puppeteers, it seems, reach upward to carry a puppet, like a glove, on their right hand. They use their left hand to operate wires that control the arms. It's a lot easier to give the dominant action to the puppet's left hand.

Why did a rabbit once have to die to indicate pregnancy? The old test involved injecting a rabbit with the woman's urine. Then, after a day or so, the rabbit was killed so its ovaries could be inspected. It turns out the rabbit died either way. The test was later improved to give results without killing the rabbit at all.

Finally, where did the dollar sign come from? We've been told it's the combined initials for United States -- a U on top of an S with the bottom of the U dropped off. The problem with that is, dollar signs were used long before there was a United States.

The first European coins on this continent were Spanish pesos. They circulated and were widely used in the Colonies during the 18th century. The abbreviation for pesos was an S superposed on a P and that devolved into the dollar sign. Our dollar sign turns out to be a borrowed sign for pesos.

Things are seldom what they seem. Ask a question -- I mean really ask in the hope of being surprised -- and you will be surprised. So many of our questions really aim only to confirm what we already believe. But the real fun is the down-and-dirty business of rooting out our own ignorance.

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

(Theme music)


Feldman, D., How Does Aspirin Find a Headache? New York: Harper Collins Publishers, 1993.


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

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