Black Box

February 27, 2026

AI Summary

5 min read

Black Box

On October 16, 1846, in the Ether Dome at Massachusetts General Hospital, a dentist named William T. G. Morton walked into an operating room where a surgeon was about to cut into a patient's neck. Morton claimed he could erase the man's pain. He put an inhaler to the patient's face, manually operated the valves for every breath, and after three or four minutes the patient went unconscious. The surgeon cut. For the first time in that room, you could hear the scalpel. "The silence was far more deafening than all the screams that had ever been heard in that operating theater," says historian Julie Fenster. News of the operation traveled around the world faster than war or peace.

But nearly 170 years later, we still don't fully understand how anesthesia works. Dr. Patrick Purden, a professor of anesthesia at Harvard Medical School, calls it a "black box" — you can see what goes in, you can see what comes out, but the middle remains a mystery. This matters practically because patients can sometimes wake up during surgery, paralyzed by neuromuscular blocking agents but fully conscious, unable to move or signal. Estimates range from 1 in 10,000 to 1 in 1,000 cases.

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What you'll learn

1 (02:04) **Introducing the Black Box** - Hosts frame the episode around the concept of a "black box": a system where you can see input and output but not the internal mechanism.
2 (02:29) **The Black Box of Anesthesia: The Ether Dome** - Producer Tim Howard visits the historic Ether Dome at Mass General Hospital with anesthesiologist Patrick Purdon.
3 (07:54) **The Personal Experience of the Gap** - Science writer Carl Zimmer recounts his own appendectomy, describing the jarring experience of losing time under anesthesia.
4 (10:57) **The Black Box of Anesthesia: The Mystery** - Despite 170 years of use, how anesthesia works remains a "philosophical kind of mystery."
5 (14:30) **The Brain's "Switch" and the Slow Wave** - At the moment of unconsciousness, the brain produces a slow, sweeping wave (about 1 cycle/sec) and a frontal alpha wave.
6 (17:36) **The Fenway Park Analogy** - Purdon compares the slow wave to "the wave" at a baseball stadium, which disrupts normal conversation.
7 (21:10) **Cracking the Code in the OR** - Purdon and colleague Emery Brown demonstrate the technology on a real patient, Doris.

+ Full timestamped outline available in the app

Guests on this episode

Carl Zimmer

Show Notes

In this episode, first aired in 2014, we examine three very different kinds of black boxes—spaces where we know what’s going in, we know what’s coming out, but can’t see what happens in-between.

From the darkest parts of metamorphosis to a sixty-year-old secret among magicians, and the nature of consciousness itself, we shine some light on three questions. But for each, we contend with an answerless space, leaving just enough room for the mystery and magic, always wondering what’s inside the Black Box.

EPISODE CREDITS:
Reported by Tim Howard and Molly Webster
Produced by Tim Howard and Molly Webster

EPISODE CITATIONS:
Radio Show: ABC's Keep Them Guessing (https://tinyurl.com/9r9zmftr)

LATERAL CUTS:
Last year we shared a story on our feed about butterfly researcher Dr. Martha Weiss, and how she befriended a little boy on the other side of the world who wanted to do his own caterpillar memory study.

Martha’s daughter Annie Rosenthal captured the whole adventure on tape and produced a gorgeous audio feature, “Caterpillar Roadshow,” which was first published in the audio magazine Signal Hill.

You can find it on our feed (https://zpr.io/xPdAYXFUMr4s)
–or on Signal Hill’s website. (https://zpr.io/a4bjPKeXJQWK)

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