Hey there, Freakinomics Radio listeners. We are taking advantage of August to replay you a special

three-part series we did last year called Bad Medicine. Today, part one, the story of 98.6,

and it starts right now. We begin with the story of 98.6. You know the number, right?

It is one of the most famous numbers there is because the body temperature of a healthy human being

is 98.6 degrees Fahrenheit, isn't it? So now I'm going to take your temperature if you don't mind,

just open your mouth and I'll insert the thermometer. Perfect. The story of 98.6 dates back to a

physician by the name of Carl Wunderlich. This was in the mid 1800s. Wunderlich was medical director

of the hospital at Leipzig University. In that capacity, he oversaw the care and the taking of

vital signs on some 25,000 patients. Pretty big data set, yes? 25,000 patients. And what did

Wunderlich determine? He determined that the average temperature of the normal human being

was 98.6 degrees Fahrenheit or 37 degrees centigrade. This is Philip McCovic, a professor of medicine

and a medical historian at the University of Maryland. Well, I am an internist by trade and

an infectious disease specialist by subspecialty. So my bread and butter is fever.

There's one more thing McCovic is. I am by nature skeptic and it occurred to me very early in my

career that this idea that 98.6 was normal and that if you didn't have a temperature of 98.6,

you were somehow abnormal, just didn't sit right. Philip McCovic, I have to understand, cares a lot

about what is called clinical thermometry. And if you care a lot about clinical thermometry,

you care a lot about the thermometer that Carl Wunderlich used to establish 98.6. His thermometer

is an amazing key to this story of 98.6. So you can imagine how excited McCovic was when

on a tour of the weird and wonderful Mooter Museum in Philadelphia, the curator told him

they had one of Wunderlich's original thermometers. I said, good heavens, may I see it? And she said,

sure, would you like to borrow it? And I said, of course. And so I was able to take this thermometer

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