Transcript

MICHAEL MOSLEY (VOICEOVER)

It was actually a gunshot wound that revolutionised our understanding of human digestion.

Our story starts in June 1822, when a young man is accidentally shot in the chest.

[GUNSHOT SOUND] MICHAEL MOSLEY (VOICEOVER)

The victim was Canadian boatman Alexis St. Martin, working on the shores of Lake Michigan. The blast ripped through his ribs, his lungs, and the front wall of his stomach.

First on the scene was young army Doctor, William Beaumont. He dressed the wound, but really didn’t expect his patient to live.

But survive he did. Now I’ve come to meet medical historian Lindsey Fitzharris, to find out how this unfortunate accident went on to lay the foundations of modern gastroenterology.

LINDSEY FITZHARRIS

So this is an actual diagram of the original wound, and you can see the outline of it. It was really big. When St. Martin was shot, it was about the size of a man’s palm essentially.

MICHAEL MOSLEY

Wow, that big.

LINDSEY FITZHARRIS

Very big, yes. It was on the left side of the chest, right about there. We tend to think of the stomach being low, but it’s actually much higher up, right below the diaphragm. When he was shot, parts of his undigested breakfast began pouring out, along with bits and pieces of his torn stomach. But Beaumont’s called to the scene, and over a course of a year, he’s able to nurse Alexis back to health. And what happens to this giant hole is that it shrinks, and it forms this two and 1/2 centimetre diameter fistula.

MICHAEL MOSLEY

Right. So you’ve got the original hole, the size of my palm, and it shrunk right down.

LINDSEY FITZHARRIS

Yes.

MICHAEL MOSLEY

But it’s still open.

LINDSEY FITZHARRIS

It’s still open. And through that fistula, he can see directly into the stomach. It was an incredible opportunity for Beaumont to study the living digestive system, in a way that no other surgeon or physician had been able to do, until that point.

MICHAEL MOSLEY (VOICEOVER)

Beaumont certainly made the most of this opportunity.

Once his patient had recovered, he employed him as a handyman, and studied his stomach for the next 10 years.

LINDSEY FITZHARRIS

He subjects St. Martin to a series of experiments. And he takes little bags like this, and he wraps pieces of food in these bags. Cabbage, meat, all kinds of things. And he sticks it directly into that fistula.

MICHAEL MOSLEY

Right.

Very nicely he just pops it into the--

LINDSEY FITZHARRIS

Pops it into the stomach, yes.

MICHAEL MOSLEY

Leaves it there to brew for awhile. Put like a cup of tea and then bring it out, inspect it.

LINDSEY FITZHARRIS

He was very interested in how different conditions affected the digestive system. For instance, if it was cloudy, if it was sunny, if it was cold.

MICHAEL MOSLEY (VOICEOVER)

As well as putting things into St. Martin’s stomach, Beaumont also sucked out the juices that were produced there.

And it was these, previously inaccessible bodily fluids, that were to turn popular beliefs about digestion on their head.

MICHAEL MOSLEY

Did he know what that juice was?

LINDSEY FITZHARRIS

He didn’t at first, but he had it analysed. And they discovered that, of course, what we know today, that a lot of it is hydrochloric acid, which is highly corrosive.

MICHAEL MOSLEY (VOICEOVER)

As well as acid, the juices contained digestive enzymes. And Beaumont discovered he could break down food outside the body, simply by mixing it with this juice. Until then, it was widely believed that digestion was purely mechanical, but Beaumont showed that the gastric juices also had a vital role to play.

MICHAEL MOSLEY

And this was a big revelation, I’m presuming.

LINDSEY FITZHARRIS

Oh, it was a huge paradigm shift. I mean, you’re going from the mechanical view to the chemical view. And he was criticised for it back home in America. He really achieves his fame afterwards and today, of course, he’s known as the father gastric physiology .

MICHAEL MOSLEY

This is a wonderful, wonderful story, isn’t it? I mean, just an extraordinary story.

LINDSEY FITZHARRIS

It is an extraordinary story, and one that really changed the way we understand the body today.