From Medical Maggots To Stench Soup, 'Grunt' Explores The Science Of Warfare : Shots - Health News When it comes to curiosity, science writer Mary Roach describes herself as someone who is "very out there." Her new book, Grunt, looks at some scientific developments that help keep soldiers safe.
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From Medical Maggots To Stench Soup, 'Grunt' Explores The Science Of Warfare

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From Medical Maggots To Stench Soup, 'Grunt' Explores The Science Of Warfare

From Medical Maggots To Stench Soup, 'Grunt' Explores The Science Of Warfare

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TERRY GROSS, HOST:

This is FRESH AIR. I'm Terry Gross. My guest, Mary Roach, has written a new book about military science. Not the science behind weapons, but the science that helps keep our soldiers alive and helps them endure the heat of the desert, survive explosions and prevent wounds from becoming infected. Actually, there is a weapon she writes about, a weaponized form of stink.

Roach is known for her witty science books about the human body including "Stiff: The Curious Lives Of Human Cadavers," "Bonk: The Curious Coupling Of Science And Sex" and "Gulp: Adventures On The Alimentary Canal." Her new book is called "Grunt: The Curious Science Of Humans At War."

Mary Roach, welcome back to FRESH AIR. So your previous book was about the digestive system. And the book was like an adventure following...

(LAUGHTER)

GROSS: ...food from the mouth until excretion at the end. And it was just a fascinating look about how our body works when it comes to ingesting and digesting food. And there's a chapter of your new book that's kind of related to that. And this gets to a very serious problem in the military, and that is diarrhea.

And it's not a subject people like to talk about for obvious reasons. But because of eating, like, food that's been contaminated or drinking water that has been contaminated, because of the problem with flies in certain areas and also because of stress, this is a very serious issue. It's a serious medical issue.

MARY ROACH: Well, it is. And it's particularly serious among special operations service members - Army Rangers, Navy SEALs, people who are operating off the bay in bases in quite remote, rural areas, in villages where there isn't a safe water supply. They may be eating food that's been contaminated by flies, not refrigerated. So they're getting diarrhea at a rate that's twice what the average enlisted person is getting.

And the average enlisted person - there was a study done, I think it was 2003 to 4. And they asked people, you know, how often did you come down with diarrhea or what kind? Seventy-some percent had had diarrhea, 40 percent bad enough that they sought medical treatment. And 32 percent were in a situation where they couldn't get to a toilet in time.

And you could imagine, if you were a special operations team, like three or four people going to do some, you know, highly classified critical mission where you can't really stop and say, hold on. Hold on, I got to go behind that rock. I mean, it's not - and it sounds silly. And I actually - I was in Camp Lemonnier, which is in Djibouti.

And there's a lot of counterinsurgency work that leaves from there. And so special operations people are coming in and out from, you know, Somalia or Yemen or neighboring nations. And I made it my task to talk to one of these somewhat intimidating individuals about a topic that sounds kind of silly. And I, you know - I approached this guy. And they're all off in their own - the special zone, the restricted zone.

They only come out to go to the dining facility. So my one opportunity to talk to this special operations fighter - and I'd chosen this one guy that I wanted to talk to. My one chance to talk about diarrhea was over dinner. So that added an element of awkwardness. So I approached this guy.

And I kind of stumble and, you know, hello, I'm writing a book. I've come here - first of all, he didn't believe - he's like, who are you? What is the objective here? I kept saying, no, no, no, really, I've traveled all the way to Djibouti to talk to you about diarrhea. But then I - you know, I said, this is - it sounds like a silly topic, I know.

And he stopped me and he said, it's not. You're welcome to sit down.

GROSS: No, it's not. People die of this. If it's not treated and if you can't take care of it, I mean, you can die. So...

ROACH: Oh, yeah.

GROSS: ...It's very serious.

ROACH: Yeah...

GROSS: And what soldier wants to live in soiled clothes? I mean, it's really - I think it's, like, really terribly serious. So what is the military working on to, like, address the seriousness of the issue and how widespread it is and how difficult it is to avoid this problem in the conditions that soldiers have to work and live in?

ROACH: The researcher that I accompanied at Camp Lemonnier is Captain Mark Riddle, who's with the Navy. And he's looking at a better treatment regimen for traveler's diarrhea, which can really put you out of commission for a while. And so he's looking at a one-dose regimen, rather than three or four days.

It was something that you could take and within the day, start to be feeling better and be over it - Rifaximin, I believe it was, and combined with Imodium, I believe. He's looking at different protocols. But anyway, a faster, more efficient way to knock it out. And also if it's faster, if it does its work faster, there's less time for a resistant strain of bacteria to develop.

So that was also an advantage there. There also - the Navy is working with I think the Gates Foundation to - Bill and Melinda Gates Foundation - to come up with a vaccine for something called enterotoxigenic E. coli, which causes a lot of - you know, when people say traveler's diarrhea, a large percentage of it is that.

So a vaccine for that would be great, not just for military personnel but because there's around half a million people, many of them children, worldwide die of ETEC - that's enterotoxigenic E. coli - every year. So it would have tremendous benefits for civilian world as well.

GROSS: So flies are a real issue that you write about in your book in two ways, that flies who have been on something contaminated, including human waste, flies that then land on food can spread disease. But on the bright side, maggots - and this is going to sound creepy - but maggots are being used in a very interesting medical way.

And this dates back to World War I. You want to tell the story?

ROACH: Sure, sure, yes. This was a battlefield in World War I. And there was a medical man, William Baer, with the French expeditionary forces, and he noticed that a couple of his patients had come in with these wounds on the legs and on the genitals. And, you know, they'd been out in the field for seven days, they'd been lying there. They were brought in, and the wounds were infested with maggots. And initially, there was that, you know, revulsion - oh my God, we've got to clean them out. And they did clean them out.

And then what he saw was this beautiful, pink, new, fresh tissue that had grown in. The maggots had been impressively effective at debriding the wound - that is, eating the dead tissue, which is important in wound healing. You want to have - let - give the fresh tissue a chance to grow and, you know, the old - the dead tissue doesn't get blood. It doesn't heal. It stands in the way of healing.

The maggots also seemed to prevent infection. Something that they were doing was causing - was preventing infection. So it was this kind of miraculous feat that the maggots had achieved. And William Baer, some years later, back in civilian life, he kept thinking about this. And he thought, I'm going to try this.

There were some children with bone infections - it was a TB infection of the bone, and he tried the maggots and it worked. And you can imagine that was a fairly brave thing to do, to put - you know, to place maggots in these children's wounds. But they were wounds that had not responded to treatment - other treatment or surgery, and it actually worked. So that's - and that's - there's work going on still today with maggot therapy, as it's called. Actually, the FDA has approved maggots as a medical device.

GROSS: So who is using maggot therapy now?

ROACH: It is mostly used for foot ulcers in diabetics. Like, they get these wounds that are very difficult to heal, and maggots are - seem to be the only thing that really works there. And that buys you time before you would have to actually amputate the limb.

GROSS: So I'm surprised to hear that maggots prevent infection as opposed to spread infection because I think of maggots as being dirty and spreading disease. So I think if there was maggots in an open wound, even if they were eating the dead tissue they could still spread infection. How come they're not spreading infection in these instances?

ROACH: They seem to be excreting something that is countering infection. They seem to have some antibacterial capacity that isn't exactly known. But they - yeah, you would think - exactly. They're coming from the ground, the ground is full of bacteria, they themselves would be covered with bacteria. It makes no sense intuitively. But they're very effective. There was actually an effort to genetically modify them to create specific antibiotics that depending on, you know, what you wanted - and it's underway. It hasn't - it's not - they haven't succeeded with that yet, but that's something that the Walter Reed - an entomologist named George Peck at Walter Reed's military entomology branch was working on.

GROSS: You know, I interviewed a surgeon who had worked a lot in war zones - this was years ago - and he told me that when there are no antibiotics, he has used maggots.

ROACH: Yes. Yes. No, there was a survey done not that long ago of military medical care providers asking, you know, have you heard of maggot therapy, would you be open to it, and have you used it? Most of the MDs had heard of it, thought of it as a positive thing, would like add it to their repertoire, but were actually just unsure - well, where do I I procure the maggots? And how do I apply them? And what's the dosage? And what's the insurance number?

I mean, all of that information is not as widely known as might be. It is all out there. I can actually tell you the Medicare reimbursement number for maggots. But they didn't - you know, there's a - there is this - not only is there a revulsion factor that you have to overcome with the staff - say, the nurses - or we're going to have to go in - you're going to have to clean the maggots out after a couple of days.

You don't want them to pupate, to become flies, because even flies flying around a hospital, which is the last thing you would ever want because a fly can spread disease from landing on material in the bathroom and then landing on a wound, it's the last thing you would want in a hospital. So you have to be careful using maggots. But there is that - so there's that - those factors that are at work as well.

GROSS: Yeah, so it might sound like oh, that's really so cheap and easy. You just, like, put some maggots in a wound. But you really have to be trained and know what you're doing. And also, are these, like, laboratory maggots that doctors are using? Or, you know, are they just, like, any old maggots?

ROACH: No, they're not any old maggots. It's - they're a particular kind of bottle fly. They're from a company called Medical Maggots, which has - there's a - you know, they come with a dosage card. It's something like five to eight maggots per such and such square centimeter. So, you know, there's a dosage card. And they come in a vial, kind of like drugs. It's - yeah, you don't want to just sort of attract any kind of fly to come and lay eggs in a wound. That would be a little dicey. But yes, there are medical maggots for you to - you need a prescription now.

GROSS: It's just so interesting how modern medicine would be turning to something that sounds so, like - so much like an ancient, outdated, horrible practice (laughter). But...

ROACH: ...Yeah, yeah. But it's also - there are - yeah. So yeah, there are - the same company, I believe, sells leeches. And now they've added to their product line fecal bacteria for fecal transplants, for bacteria therapy. So this is an unusual, niche business.

GROSS: If you're just joining us, my guest is Mary Roach. And we're talking about her new book, which is about military science - what the military is doing to help design better, more efficient clothing and food and medicine for soldiers. And there's all kinds of interesting stuff in here about just, like, smell and health and so on. So the book is called "Grunt." We're going to take a short break here, and we'll be right back. This is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: This is FRESH AIR. And if you're just joining us, my guest is Mary Roach. And her new book is called "Grunt: The Curious Science Of Humans At War." And it's about military research into things that will help soldiers be more comfortable and be safer while they're at war, including ways of, like, healing wounds, dealing with amputated limbs, dealing with having food that's light weight that you can carry with you, that will last a long time, having clothes that won't burst out into flame if they're near an IED.

So let's move on to something that really surprised me. There are so many things that surprised me in your book. And this is stink bombs - how, like, during World War II, our predecessor of the CIA, the OSS, thought that a kind of stink bomb could really help us in the war, especially against the Japanese. So the whole idea of a stink bomb actually dates back to World War II?

ROACH: Yes. Yes, there was a - and I use the term stink bomb sort of casually in the title. This was more specifically a think either spray, squirtable spray or a smearable paste. And the idea was to get this very simple cheap weapon into the hands of resistance organizations, people in occupied countries - France, China - give it to them, and they would surreptitiously approach officers - German or Japanese officers - and squirt this little 2-inch tube of this very heavily-researched and tested very foul-smelling odor which was nicknamed Who Me, as in who dealt it. So it was yeah, a - kind of a surreal and bizarre chapter in the history of World War II.

GROSS: OK, when I think of something like that, I think, like, you definitely want to leave the room - not be in the room with the smell. But, you know, how does that lead to the end of a war or the end of a battle?

ROACH: Well, it doesn't lead to the end of the war or the battle. It's just - the thought was to give motivated citizens things that they could easily and cheaply use to undermine morale, to isolate, humiliate these officers. You know, it's a very small - a small gesture. It wasn't - you know, it wasn't going to turn the tide of war.

And in fact, Who Me, this smell paste, was never deployed. It - the project went on for two years, and a lot of testing went on because there was a tremendous amount of difficulty with the delivery system. The tubes tended to leak and dribble up, and then the operator himself or herself would have this stench on their hand. There was problems with - in hot weather, the tubes weren't (laughter) the tubes were leaking. So it was a bit of a fiasco. But they did in the end develop a couple of hundred of these tubes. And then the final report came out about a week before the bomb was dropped on Hiroshima. So the Who Me tubes were never used.

GROSS: Yeah, that's an interesting contrast, you know, a smelly substance and a nuclear weapon.

ROACH: Yeah, and the NRDC - the Nuclear - no, National Defense Research Committee had had a hand in both of those. I mean, they were - it was the OSS working with the NDRC. And they were - they had worked on the Who Me stink bomb as well as the actual bomb. So yeah, it was a - would the - you know, would the - wars could be won with tubes of smelly substances.

GROSS: Was anything like that ever used by the U.S. or any other country in combat?

ROACH: Well, there are - they're called malodorants, nonlethal weapons that are stinks. They're not - and they are used to clear terrain - in other words to go into a room that you want to clear of insurgents, or during Vietnam they were used to clean out tunnels or to protect a weapons cache to make a place unappealing to go to. So it's - you know, these substances have been developed. And there's still work that goes on. Monell Chemical Senses in Philadelphia has done work over the years on malodorants. They created one called Stench Soup. This was a joint nonlethal weapons directorate back in the '90s commissioned them to come up with a universally-loathed scent because there's some cultural differences.

They actually looked into different cultural reactions to the scent of vomit, of burned hair of dirty feet, all of these different odors to see can we find one that is universally loathed? And then we could use that in any military setting, in any country, in any culture. And it's very hard to do. It's very hard because if you don't know what you're smelling, some, for example, butyric acid depending on the context may smell like smelly feet or it may smell like parmesan cheese. It completely depends on the context whether you think it's smells good or bad.

GROSS: How close did you get close to the stink soup?

ROACH: Oh, I have - (laughter) - I actually have in a box in my closet a sample of Stench Soup. It's in a bottle that is double-bagged and sealed with paraffin and packed in a box. And I haven't had the courage to open it up because the last time I opened up something that came from the Monell Chemical Senses Center, which was an old, archival sample of Who Me, my - and I opened it up out on the deck. It was quite some time before anybody could go out on the deck. I was - I actually gagged. And as you can imagine, it's not - I'm not easily repulsed or revulsed (ph). I'm not easily disgusted. So I'm a little hesitant. I have got this box with me, and I plan to bring it along on tour but probably never open it.

GROSS: My guest is Mary Roach, author of the new book "Grunt." We'll talk more about military science after a break. Also, jazz critic Kevin Whitehead will review a new album that features guitarist Pat Metheny as a guest on an album by one of his former sidemen. And we'll listen back to a soundbite excavated from deep in the FRESH AIR archive. This is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: This is FRESH AIR. I'm Terry Gross, back with Mary Roach. Her new book "Grunt" is about military science, what military researchers are learning about how to keep our soldiers alive and help them endure the heat of the desert, survive explosions and prevent wounds from becoming infected.

So any doctor practicing in a combat zone, they need to know what it's like to medicine with people who have just been hit by an IED and to maybe be surrounded by guns going off or more bombs going off. It's hard to practice that at home and then get experience. And so there are some interesting ways that doctors can learn to treat patients under those circumstances. And I'd like you to tell us about Stu Segall and his company.

ROACH: Yes. Stu Segall owns Strategic Operations, which is a - it's a big former movie studio. They used to - Stu Segall Siegel used to produce action films on this very large collection of sets. And around 9/11, when the appetite for action and violent movies waned, he repurposed his talents for gore and battle scenes and created this company Strategic Operations, where Navy corpsman, who are medics who serve the Marine Corps, and Army medics can come and be in a sense inoculated against the stress that they're going to deal with in the real world. In other words, they these - hyperrealistic is the term that they use - have actually trademarked - hyperrealistic battle scenarios.

And when I say hyperrealistic, I mean they have amputee actors come in and they outfit the amputee's stump with silicon sleeve that is very, very realistic that looks like it has just been blown off. They have a backpack with a pump that will make that stump bleed. And they have sound effects, and they have the sounds of war. They play in the background the soundtrack to "Saving Private Ryan," the beach scene. They have the sounds of RPGs where the dust hits you see dust coming up as though there's actually the rifle fire's hitting the ground.

It is really intense. It is something that I - even though I knew it was - what it was and what to expect, my heart rate was definitely higher. So into this chaos, they introduce these trainee Navy corpsman or medics, and they have to go in and apply a tourniquet or go through the motions. Obviously, they're not cutting a new airway on someone. But they can cut an airway on one of the simulated combat victims - is wearing something called a cut suit, which is kind of like Resusci Anne.

You know, it's a patient simulator, but it's wearable. So it's this big torso with guts, and you can strap on kind of an external airway that the trainee would have to - if you're having trouble breathing, you have to cut an airway. And they can practice needle decompression, which is if you have a hole in your lung and the lung has collapsed and you need to relieve pressure that's building up outside the lung, they can practice that on this cut suit, actually put the needle through and go through the motions, all the while with people yelling and screaming and gunfire and blood flowing copiously.

The idea is - I think the term is stress inoculation. You would give them a little dose here, and hopefully that will make them a little better equipped to cope when the real deal happens overseas.

GROSS: Did you talk to any of the medics who were undergoing this kind of training?

ROACH: Yes. I spoke to some young people who had been through the course who had trained. There are a number of ways to do this. There's also practicing on anesthetized livestock. It's called live-tissue training. It's very controversial. They've done that; they've done this simulation, and they also train in inner city emergency rooms.

All of these things are done with the aim of getting them prepared. And I said well, what works best? And they said well, each thing has its advantage. I mean, the live-tissue training it was a chance to actually grasp an artery in your fingers and close it off and stanch the bleeding. And that is something, you know, that they couldn't really do on a cut suit in the same way. But then again, they said that's not a screaming chaotic realistic battle environment so that - you know, there was - that element was helpful for the strategic operations training.

So all of it put together they felt was helpful. But, you know, in the end, I don't think anyone can prepare you for doing all of that medical work with people shooting guns around you and trying to kill you.

GROSS: In your acknowledgments, you write about how you expected the military to brush you off and to think of you as somewhere between an intruder and a nuisance. But instead, everybody was very, you know, welcoming and shared their research with you. They were interested in telling you about the work that they were doing. That made me happy to read that, that (laughter) - so...

ROACH: Yeah.

GROSS: ...Talk a little bit about what it was like to approach people who are doing - in some instances kind of secretive research and approaching them and asking them to allow you to observe, especially if they knew your work because on the one hand, you're a serious science writer. At the same time, you usually adopt a kind of comic tone, and you enjoy having a certain gross-out element in what you're writing about because you're fascinated with the human body and all of its beauty, ugliness and absurdity.

ROACH: Yeah, it came as a surprise to me as well. I kind of imagined a certain amount of emails going unanswered or no, we can't help you with that or just unexplained nos. But in fact, it was very straightforward. If something was classified, the answer was no. But unless it was classified, people were - and the other thing is I would send them a copy of my previous books. I didn't want anyone to think I was writing something more straightforward. And technically, I wanted them to know that I'm kind of this scattershot goober who comes around with her notepad and does - just - I'm an outsider. I'm very curious, but, you know, I'm not terribly careful in what I say and how respectful I sound.

And I wanted them to know all of this, and they took the book and they said yeah, we'll do what we can. The most difficult part was often finding who's the person who can say yes. No one was saying no. People all along the way were saying yes, but I'm not the person who has to say yes. So dozens of emails would be zipping back and forth, like is it Is it Is it the Pentagon? Who can sign off on this?

It was more like a - kind of a weird bureaucratic jungle that I was - not just me but the specific public affairs person would be trying to figure out well, no one's asked to do this. I don't even know who has to sign off. But they were never the kind of wary, obfuscating squirrely type of public affairs person that is sort of the stereotype that - they were never like that.

They were - I think there was a sense that this is a story that doesn't get told. This is good work, and we're proud of it. And if you want to write about it in whatever your style is, you know, however you want to do it, go and do it. So that was surprising and heartening.

GROSS: So how high did the permission have to go? Do you think the commander-in-chief, President Obama, had signed off on this?

ROACH: (Laughter) I - at one point I asked - because I - in the course of my research, I went out on a Trident-missile submarine. Part of that submarine is classified, and I never knew where I was. That took a year and a half to get that to happen.

When I came back, I asked the guy who was dropping me off at the airport, I said how many levels of permission did this take? He said well, let's see, there was the commanding officer for the submarine. There was the fleet forces commander, the group commander, the chief of naval operations and I believe the secretary of defense all had to sign off at some point, and I - which was stunning to me that all of that had taken place. And it was really just the - I just kept sending out emails - hi, it's me. Just checking in - any progress? Is there someone else we might talk to? Could I send someone a book? Could I call someone?

I think at a certain point - I think when I was trying to get myself to Camp Lemonnier, where a lot of counterinsurgency work goes on, there was a tremendous amount of back-and-forth email. And in the end, it was the guy - the public affairs guy, young guy on the base who said yes. And I said that Seamus (ph) - this was for the diarrhea chapter - I said how did you make this happen? He goes, you know, I saw these emails going back and forth all over the place, and a certain point I said, you know, this is not diarrhea. You can't just hydrate and wait for it to go away. We're going to have to deal with this woman.

And so he walked into the base commander's office, and he said you mind if this chick comes here and talks to people about diarrhea (laughter)? He said yeah, whatever, sure. So that was the most challenging part of it, not people saying go way Mary Roach. We don't want your type poking around.

GROSS: If you're just joining us, my guest is Mary Roach. And we're talking about her new book, which is about military science, what the military is doing to help design better, more efficient clothing and food and medicine for soldiers. And there's all kinds of interesting stuff in here about smell and health and so on. So the book is called "Grunt."

We're going to take a short break here, and we'll be right back. This is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: If you're just joining us, my guest is Mary Roach, and her new book is called "Grunt: The Curious Science Of Humans At War."

So you're interested in aspects of the human body that a lot of people would find kind of gross and not want to confront or talk about or see images of. Why do you think you're interested in that?

ROACH: I think that the things I write about, ultimately, everyone is interested in. And I'm just someone who's OK with being very out there with my curiosity, perhaps. I don't know - I mean, I think cadavers and sex and digestion and war and - all of these things are - you know, the human body, we all have one. And so we have this inherent fascination, I think.

So I think I'm maybe just tapping into something that's fairly universal. I'm just not embarrassed to go out there and seem like I'm obsessed with it. I'm kind of the bottom feeder...

GROSS: (Laughter).

ROACH: ...Of science writing. And I'm used to that reputation, and it doesn't - so it kind of frees me up to appear to be kind of a weird person.

GROSS: Were you exposed to anything unusual about the human body when you were young?

ROACH: Well, my parents were a lot older. My dad was 65 when I was born. My mother was 44. So I was around human bodies that had started to sag and fade and have problems. I remember our - in the bathroom medicine cabinet, my dad had put little hooks. And there was this arsenal of senior toenail clipping devices that, you know - that looked like, you know, wire cutters.

And, I mean, it was just a nail clipper. It was - you know, I remember seeing that thinking, wow, it's really different trimming your toenails when you're old. So there were things like - you know, my mom had witch hazel. I don't know what that was. What is witch hazel? So there were these mysterious kind of older person potions and things.

So maybe because my parents were bodies in decay, in a sense, as I was growing up, as I was a teenager, it felt normal or natural in some way. I don't know. I don't know what's wrong with me.

GROSS: What happens to toenails when people get older that make them harder to cut?

ROACH: They get very thick and hard, and they get harder to - they just get - I don't know why. That should be my next book...

GROSS: There you go.

ROACH: ...Geezer, geezer.

GROSS: You're welcome.

(LAUGHTER)

GROSS: Can I ask how old you are?

ROACH: Sure, I'm 57.

GROSS: So do you feel like your body is starting to change in a way that you find both unfortunate and really interesting?

ROACH: Unfortunate, yes, mildly interesting. More unfortunate - oh, yeah. Oh, yeah, you know, I just - you look down and suddenly there's these little - your thighs are kind of piling up over your knees and...

(LAUGHTER)

ROACH: And there's little red blebs on your chest that you used to have one or two. They're now skin tags. What are those? Why? Everywhere under - yeah, it's everywhere, Terry. I actually started keeping a list a few years ago sort of documenting my decline over the years. And it's - yeah. It's, well, interesting, yeah (laughter).

GROSS: So I think you should write a book about that. I really do.

ROACH: Yeah, there are a lot of books that are written about staying young and fighting old age. But I think old age and what happens to the body is just as a science topic is kind of interesting.

GROSS: And when you see things on your own body like a skin tag, which is, you know, benign, so it's not something you have to worry about. It's not a sign of major decline. But do you have any distance from that? Like, do you find it, like, really discouraging or can you maintain a certain, like, wow, that's really fascinating?

ROACH: (Laughter) I definitely want to learn about it. What is it? Why is it? Not with the idea that I can get some remedy to it or that I'm going to cut them off or - but just what are they and why are they? And I'm the kind of person, I go to, you know, the doctor and I have way more questions than they had time for. Not out of a concern for my health but just what are they? Why are they? How many more am I going to get? How many people get them? Is there any evolutionary purpose to a skin tag? They're just disgusting? Could I just cut it off? What would happen? Do animals have skin tags? You know, so I'm that kind of annoying patient.

GROSS: (Laughter) I want to thank you so much for joining us. And good luck with your new book.

ROACH: Oh, thank you so much for having me, Terry.

GROSS: Mary Roach's new book about military science is called "Grunt."

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