Science Friday - Sleep and the Immune System, Measuring Carbon, Specimens of Hair. Feb 1, 2019, Part 2

Episode Date: February 1, 2019

Some citizen scientists collect minerals or plants. But 19th-century lawyer Peter A. Browne collected hair—lots and lots of hair. His collection started innocently enough. Browne decided to make a scientific study of wool with the hope of jumpstarting American agriculture, but his collector’s impulse took over. By the time of his death, Browne’s hair collection had grown to include elephant chin hair, raccoon whiskers, hair from mummies, hair from humans from all around the world, hair from 13 of the first 14 U.S. presidents, and more. Bob Peck of Drexel University’s Academy of Natural Sciences explains what Browne hoped to learn from all these tufts. See more images from Browne's collection. Whether you’re a night owl or an early riser, we all sleep. But for something so universal, we don’t understand much about what makes us sleep. Researchers looking into this question recently found a gene called neumri that triggered sleep in Drosophila flies. That gene produced a protein that is linked to antimicrobial activity, and the results were published in the journal Science. Neuroscientist Amita Seghal, who is an author on the study, talks about the role sleep might play in sickness and keeping us healthy.  It’s one of the first things you learn in elementary school science class: Trees take in carbon dioxide and breathe out oxygen. That may have satisfied our childhood questions about how trees work, but as adults, we understand the picture to be a lot more complex. Christopher Woodall, project leader with the USDA Forest Service joins guest host John Dankosky to crunch the numbers on carbon sequestration. And Christa Anderson, research fellow at the World Wildlife Fund, talks about how forests may be our best weapon for fighting carbon emissions. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm John Dankoski. I'm sitting in for the next few weeks while Ira Flato is away on vacation in Southeast Asia. But he is still keeping an eye out for science, and he sent us this audio postcard from Ho Chi Minh City, Vietnam. I'm standing in downtown Saigon or Ho Chi Minh City in front of the old post office building, and really unusually, the post office is ringed with the names of famous scientists. I'm looking at Galvani, Faraday, even Franklin, Davy. I could walk around the building and find all these scientists at the last place I would have expected at the government post office that was constructed by the French in 1886 and now is owned by the Vietnamese government. And to see all of these scientists around the building with their plaques up is totally unexpected. Well, there's a fun travel tip. Thank you, Ira, and have a lot of fun in your trip. Up next,

we're going to talk about sleep. You might be a night owl or a morning lark. Wherever you fall on the scale, everyone sleeps. It's universal. You've probably had that sleepy feeling when you get sick. All you want to do is take a long nap. Well, researchers were able to find a gene linked to our immune system that causes sleepiness. Their results were published this week in the journal Science. Let me introduce my next guest, Amita Sigel, is an author on that study. She's also professor of neuroscience at the University of Pennsylvania. Welcome to Science Friday. Thank you.

Let's start by just talking about sleep, and we all do it. I don't know that most people know exactly what sleep is. Maybe you can define what sleep is in your mind. Yes, so the definition of sleep is something, believe it or not, that has been debated over the years. To my mind, it is a behavioral state of relative immobility that, occurs with a circadian, a 24-hour rhythm, and during which animals have what we called an increased arousal threshold, which means that they are less sensitive to sensory stimulation. And it is a process that is essential, and so it's what we call homeostatically controlled.

And what that means is that when you deprive an animal or a human of sleep, they have to make up for the sleep lost. So if a person is up all night, they'll be sleepy in the morning because there's something that sleep is needed for that hasn't been accomplished. And maybe we'll get back in a moment to some of the other reasons why it's important for us to sleep. I'm wondering if you can give us another definition. The difference between sleep and circadian rhythms, how these things are connected. Right. So that question comes up a lot. So a circadian rhythm is any process that has a 24-hour rhythm to it that's driven by the day-night cycle. So, for instance, body temperature is different at different times of day, blood pressure is different at different times

of day, glucose, cholesterol, insulin. It's actually hard to find a physiological process in our bodies that doesn't on some level show a 24-hour pattern. And, you know, when I say these things are driven by the day-night cycle. I mean that the day-night cycle synchronizes them, but they're really controlled by clocks within us. Now, sleep is just one example of a circadian rhythm. And it happens to be the best-known circadian rhythm, but it's not the only one. And when we're studying sleep, we're studying also aspects of it independent of its 24-hour rhythm. We're studying why we sleep, what makes us sleepy, and so forth. In this study, you looked for genes that induce sleepiness, so maybe you can tell us how

you did that. How did you look? Yeah, so we use fruit flies in our studies, and because they're a great model to do genetics in. And so what we did in this particular study was we expressed a random, increased expression of random genes across the fly genome. And we asked which ones, when turned on, would increase sleep. And we did this in like, you know, 12,000 different fly lines, fly line basically being like, you know, a fly family.

And what did you find? This led to some genetic discoveries, including this so-called nemuri gene. Maybe you can explain it to us. Right. So what was a big surprise to us was that of the 12,000 lines, we looked at only one showed an increase in sleep. So, you know, we looked at thousands of genes and only one when turned on would increase sleep. And that was the gene that we called Nimori, which is the Japanese word for sleep.

And then what we did was to try to figure out what this Nimori gene is, what kind of protein it makes, and so on. And what did you find? What did you learn about it? And we learned that it is actually an immune molecule. So it's what's called an antimicrobial peptide, which means it kills bacteria. And so we think that this is a molecule that has these two functions, one of which is to kill bacteria, and the other is to make the animal sleep. and both of those functions help the animal recover from the stress or the infection. So then what might that tell us about the relationship of sleep and sickness, that maybe the body needs to shut down whenever it's got an illness coming or what?

Right. So there's data out there indicating that sleep enhances recovery from illness. So, you know, when you feel sleepy at a time when you're sick, don't fight it. You should sleep because it's going to help with your recovery. And those data have been demonstrated in different animal models, and they're also true in humans. What we're finding is that the same molecule is actually turning both those things on, as in it's involved in the immune system, which is directly fighting the infection, but then it's also turning on sleep. This numericine also controls the type of sleep that the flies have? So in flies, we don't really have different stages of sleep that we know of yet. We don't have defined them yet as humans do, right?

So humans have rapid eye movement sleep and then they have the, which is REM sleep, and then they have non-REM sleep. In flies, so far we only know of one type of sleep. And it's a state in which they are quite immobile. that occurs mostly at night. How similar or different are fruit flies from us? I mean, what can we learn about the ways that fruit flies sleep, which seemingly is not as complicated as human sleep,

and how can we think about what that might mean for us? Yes, so flies have been a great model for figuring out lots of processes, for determining how the nervous system develops, how muscles develop, even pathways that are involved in cancer. So for instance, flies don't get cancer, but some of the signaling pathways that lead to cancer actually serve other functions in flies. So you can study like the biochemistry

and the genetics on the molecular biology. When it comes to circadian rhythms and sleep, flies are actually more similar than they might be, let's say, for studies of cancer, because flies do have very robust circadian rhythm, so they have this very robust 24-hour patterns of sleep and wake. And the molecules that generate the internal clock, the 24-hour clock, were first discovered in the fly, and they turn out to be conserved in mammals, and they're even mutated in human sleep disorders.

So, and that is the work for which the Nobel Prize was awarded a year ago, in the 2017 Nobel Prize went to three people who worked with flies and figured out the basis of the endogenous clock. One of those people actually was my postdoc mentor. And for sleep, sleep is a relatively new area in the fly. Circadian rhythms has been studied much longer. But so far, genes that we have found that affect sleep and flies are turning out to have conserved roles in sleep in humans.

This numeri gene we're talking about, do humans possess this? No. So humans do not possess nemori, but humans do have other antimicrobial peptides. So other peptides, you know, small proteins that fight bacteria. And so the hypothesis is that there will be genes that are like nemori but don't look exactly like it that may do the same thing in humans. But we still need to figure that one out. There have been some other studies and other animals in the past that have linked sleep to the immune system.

Can you tell us about that? Yeah. So the most work and the best work on this subject has been done by Jim Kruger and Mark Op, and they found that cytokines build up with sleep loss. So when an animal is kept awake for a long period of time, you get increases in interleukin-1 and in TNF alpha, which are cytokines, their immune molecules. And those do promote, seem to promote sleep. But it's not really known where those cytokines come from under conditions of sleep loss

and exactly how they're promoting sleep. Before we run out of time, I should ask, why is it so important for us to get sleep? What protective qualities have you learned about sleep in humans? So I think that sleep is, so let me start. by saying that the function of sleep is still really unknown. What we do know is that when people don't sleep, then they are impaired in many different ways. So their cognitive function declines and their metabolic function declines. So we know that they are severely affected by it. But what is it that happens during sleep to facilitate those functions is unclear?

And some of the work that we're doing in flies is to actually get down to the cellular level, to see what happens during sleep that would help with all these processes. You know, maintain, for instance, homeostasis in the brain. And we actually published recently that one of the things that happens during sleep is clearance of molecules through the blood brain barrier. So, yeah, go ahead. I was going to say which seems important for us for a number of reasons. Unfortunately, we've run out of time.

I want to thank our guest. Amita Segal is a professor of neuroscience at the University of Pennsylvania. Thank you so much for sharing this research with us. I really appreciate it. Thank you. Happy to be here. Now, when we come back, why our best weapon for offsetting carbon emissions could be found right in our forests? This is Science Friday.

I'm John Dankowski. It's one of the first things you learn in elementary school science class. Trees take in carbon dioxide and breathe out oxygen. They may have satisfied our childhood questions about how trees work, but as adults, we understand this picture could be a lot more complex. Carbon dioxide is a potent greenhouse gas, which means our forests are some of our biggest natural weapons to fight rising global temperatures. But how much carbon do our forests truly capture?

That's a question for my next guest. Christopher Woodall's research project leader with the USDA Forest Service. Welcome to Science Friday. Thanks for being here. Hi there. Good afternoon. And if you want to join our conversation, 844-8255 or 844-Sai Talk. Christopher, you said that the future of our carbon trajectory hinges on the future of forests. So forests play that bigger role in this equation, huh? Yeah, yes, indeed.

Our forests annually sequester about 15% of what our fossil fuel emissions give off. So when we look at the mass balance as far as CO2 in the atmosphere, we're looking at emissions. as far as burning fossil fuels, concrete production, but also we're looking at what goes into our forests, you know, forest taking in carbon dioxide and sequestering it in wood and dead wood and soils, etc. And so annually that's about 15% reduction. So they play this huge role,

but it's important to remember that trees also emit carbon when they die. Tell us what happens there. Yeah, it's kind of like a checkbook balance. You have some emissions from burning of trees, decomposition, largely in the U.S., our growth and expansion of forests still outweigh those losses to the atmosphere. So over time over the millennia, as far as forest sequestering carbon, that's really tallied up to quite a store of carbon U.S.

force that is equivalent to almost like 70 years of emissions, of fossil fuel emissions at our annual rates. So not only is there annual sequestration of carbon being taken out of the atmosphere by U.S. forest, but there's tremendous amount of carbon currently stored in forests across the United States. So there's all this carbon being stored in the forest. Just so we understand, though, how much does a tree release when it decays and how much does it put into the soil and keep there? Well, a large portion of it, probably the majority is going to be emitted through heterotrophic respiration or what you call decomposition. Areas out west where it might be even drier, you might have immediate combustion through wildfires and immediate release. But always a portion of it is going to be fragmented and decomposed into the soil for long-term storage.

Like I said, at higher latitudes where it's colder, that can be millennia of carbon stored deep into the soils. This is in some ways difficult to measure because we're not exactly sure how much carbon is in any given tree. Reporter Patrick Scahill from member station Connecticut Public Radio talked with forest pathologist Bob Mara about this. What's going on inside of these trees, it's kind of hidden to us for the most part. trees that otherwise look to be perfectly fine and you would have no reason to think otherwise can have internal decay taking place. If we're going to look to forests as a way to sequester carbon, we should develop much more accurate estimates of how much carbon is actually sequestered. So, Christopher, how do we measure how much carbon is being sequestered right now in any given tree?

Yeah, so I'll talk about the population of trees we're typically talking about. and the U.S. Forest Service for about 20 years has conducted an annual inventory of forests across the United States, hundreds of foresters a year going out there measuring millions of trees, going back and re-measuring them, not only measuring live trees, but standing dead trees, dead wood, soils, and from that we apply models to estimate a carbon. At time one, time two, hopefully that produces a fairly certain estimate of changes in forest carbon. Now, it is correct. A lot of the models we apply to the carbon.

these measurements like measuring the diameter of a tree are still just models. And there's current work ongoing and has been for decades to refine our modeling approaches. And emerging signs like lasers scanning, tomography, which was just reported in that story, can really augment our ability to refine our estimates of carbon and force and trees. So the different techniques that are used go from just observation of a tree to actually scanning through the middle of it. Do you feel fairly certain that we know how much carbon any given tree stores, or are there new technological advances coming that might be able to give us even more information than we have currently?

Yeah, yeah. So at the large scale, I'd say we're fairly certain. In preparation of our annual submissions to the United Nations as far as U.S. forest carbon, it's been a sink as far as storing net carbon since 1990. We're very certain on that on that. When you scale down to an individual tree, indeed, you need. to start using a lot more science to bear on that. So the emerging technologies I mentioned, such as lasers scanning from, you know, satellites,

other information like Lansat, change detection, and just refine modeling. A lot of the, you know, machine learning algorithms, et cetera. There's a lot more statistical advances we can use these days with our big data sets to refine our estimation of forced carbon. And are there different types of forests or different types of trees that are better at storing carbon than others? Well, certainly we can see it in our greenhouse gas reports that the western U.S., just due to droughts and struggles they've had out west, is probably not sequestering as much carbon as we are in the east right now.

It's been a little bit wetter the past decades in the eastern U.S., coupled with land use change, where agriculture has reverted to forest in many areas, so we're gaining forest, forest or growing rapidly in parts of the U.S. So certain forest types, indeed, are currently able to sequester more carbon than other forest types, But all forests are valuable and part of the equation. We can't lose forests because if we do, that's carbon emissions. So in the viewpoint of increasing carbon sequestration, it's about having more forests and healthier growing forests. Denser forests, old growth forests, are they different than newer forests or places where there are just some trees planted amongst others, say, agricultural fields? You know, I like to kind of talk about a portfolio approach to looking at carbon sequestration.

Certainly across wilderness areas, we have old growth, where old trees are putting on tremendous increments, still storing a lot of carbon. But also younger forests, coupled with forest industry, producing long-lived wood products, you know, building condos out of wood instead of concrete, etc., really present a lot of opportunities to have a lot of carbon-friendly approaches of increasing forest across our diversity of forest conditions, whether old growth, young forest, plantations, etc., across the United States. I want to bring in another guest now. Krista Anderson is a research fellow at the World Wildlife Fund. She studied California's Forest Carbon Offset Program. Krista, welcome to Science Friday. Thanks for joining us. Thanks, John.

These carbon measurements are being used in a forest carbon offset program in California. So maybe you can explain how exactly that works. Once we figure out how much carbon is in a forest, how exactly is it used in this program in this market? Oh, sure. Well, I've been researching the California. California Forest Offset Program for several years, and most of the work that I've done occurred prior to joining the World Life Wildlife Fund. So the science and views I present are my own. And what I've looked at is in this research is really this premier example, as you said in California, of how

the state is working to store carbon in forests. The main idea and how it works is that a forest owner can opt to join the offset program, and thereby they would change their forest management practices so that they're going to store additional carbon in their forest. They measure that carbon using some of the techniques that Chris already mentioned. And then once they've measured it and it's been verified, they get what's called a carbon credit. And that's for each additional ton of carbon that they can measure that they've stored in their forest land. Those credits they can sell to greenhouse gas emitters here in California like power plants or refineries. In California, we have a cap and trade program. So those greenhouse gas emitters are required to reduce their emissions. And

And they can do that. One of the ways they can do that is by buying these forest offset credits. So they buy these credits and the credits have to come from forests that are actually doing something in their management plan to create more carbon storage. Can you explain that a little bit more? That it's not just any piece of property with some trees on it that you can get into this California market. You know, they have a number of options for ways that they can change the management of their forest. But I think the easiest one to think about is that if you're a forest owner who's harvesting wood from your forest, at a regular rotation cycle. In order to, on average, store more carbon, you might say, hey, instead of doing a harvest

every, say, 20 years, I'll stretch it out and harvest every 30 years. That way, on average, I'm storing more carbon. That's sort of the easiest way to think about the options that they have for storing more carbon. And the forest owners can be anywhere, not just in California. Who exactly are there? The big companies, are they conservation groups that have large parts of forest that they want to preserve? Yeah, that's right. Actually, it's a California program, but the forests can be located anywhere in the U.S. And one of the really interesting features of the program is that a lot of different landowners have been participating.

There are private companies, there are nonprofit forest owners, there are individuals, there are investment firms, and there are a number of tribes who are also participating as forest owners. Christopher, I'm wondering if I can bring you back in and talk a bit about what you think a marketplace like this does for the ability for America to think about preserving forests, to sequester carbon in this way? What do you make of this California marketplace? Yeah, I think it's important. Having marketplace for anything we're interested in, whether it's stocks or forest carbon, really draws attention to the science and the objective information for trading and for investment.

So if we're seeing investments in forest carbon where there's high risk, whether from wildfire, it can really be impetus to refine our mansion. adopt kind of carbon-centric management techniques to increase the carbon and or like mitigate the risk from wildfire, insect disease, the other threats that our forest face. So I think it's a very valuable tool to, you know, drawing attention to this and increasing the science as far as refining our estimates of forest carbon with new technologies. Christopher, what else can you tell us, though, about the management techniques used to increase carbon sequestration to actually apply for these credits and get them for us,

have to be better than average at carbon sequestration. So how do you get to that point in the forest? Sure, sure. That's a good question because professional foresters for over 100 years have been really focused on whether, you know, increasing timber production, wildlife habitat production, you know, yield of water. Now carbon is another thing. So, you know, adjusting the structure of trees, adjusting species composition over time,

adjusting the density of trees that is pertinent to the forest type and the climate you're in can really kind of increase the growth of trees and hence increase the carbon yield, as it were. Christo, what are some of the limitations of this program? It seems like it's something that could really work to preserve forest, to make sure we're growing and preserving more trees and also create a marketplace for this. But what are some of the limitations or the problems down the road you see? Yeah, you know, one thing is that it's really hard to figure out how do you know that the thing that's happening in the forest to store more carbon wouldn't have happened without the program.

So how do we know that we're really storing additional carbon? And the California Offset Program has taken a few steps to safeguard and make sure that that is the case. But it's definitely one of the ongoing questions that we're working on and we'll continue to need refinement as forest offset programs grow and expand. And the bigger picture, a Forest Offset Program is one of the tools and a good approach to incorporate forests and forest management. into our overall picture of climate change mitigation. And forest carbon can really do good, especially when you think about the co-benefits of forests as well.

And we can do more with forests than we have been doing. But it's certainly not the whole climate solution. We need forest carbon and we need to be decreasing all of our energy and industrial emissions. So it's an important piece of the puzzle, but one of the pieces. We're talking with Christopher Woodall, and that was just Krista Anderson. She's a research fellow at the World Wildlife Fund.

Christopher Wadall is a research project leader with the USDA Forest Service, and we're talking about carbon sequestration, how to store carbon in forest. We're going to get to some of your phone calls in just a moment. I'm John Dankowski. This is Science Friday from WNYC Studios. I want to go to Scott. Scott is calling from Lake Sisku in California. Hi there, Scott. Go ahead. Yeah, I was just wondering about the clear cutting that's been going on in our area. My 90-year-old father used to be a timber faller back in the early days. And he's noticed just an incredible amount of clear-cutting, especially Mount Shasta, which is just northwest here. On the east side of Mount Shasta, there's virtually no trees around there.

And it's just really astounding how much clear-cutting has happened. I thank you for bringing us this issue, Scott. And I'm wondering, Christopher, you can talk about that, about the impact. on carbon with clear-cutting? Yeah, sure. I mean, I can't speak to a Western example as I'm located in the east, but generally, clear-cutting is to use as regeneration technique,

very valuable in some forest situations where you need a lot of light to come in to reduce competition and allow trees to regenerate in other areas. It's more used as a industrial technique as far as plantation forestry. The key thing is is about regeneration, whether you're using clear cutting or something with just patches or selection treatments where you're just taking out a few trees in a forest. The key is regeneration.

So that's the question as far as if you're clear cutting, are you clear cutting it and paving it over? Land use change to agriculture or urbanization. That's a real, real risk to forest. As far as clear cutting to regenerate another stand of trees, That can have carbon benefits over the long run, but it has to be, you know, professionally applied. You know, Krista raised something before I'd really like to hear you talk about, Christopher. It's this idea that there are questions in some people's minds about whether or not the carbon that is stored in forest through a program like this California program that's incentivizing people to do different forest management techniques, whether or not that carbon would have been stored anyway. How do you respond to that?

Yeah, that's, that's always been a trying thing with the market. as far as trying to demonstrate the additionality that Christa talked about. So that continues to be an issue, but we've got to keep trying as far as having a marketplace, find out what works and what doesn't work. We're looking at adaptation as far as managing our forests in the future. So if we're changing climate so much in the future projections as far as climate change, we've got insects and disease that are coming into our borders. We have deer brows, et cetera.

We have a lot of threats to our forests. So adaptive management as far as maybe changing the species composition, looking at alternative stand structures in the future. That might be a way to kind of like really kind of get to forest management on a step into the future where we can have productive force despite the changes that we see coming down the pike as far as climate change. I should ask you quickly, if you could, about a recently published study that suggested something unusual.

Land that was 50 to 60 percent forested could take up as much in as much, carbon as land that was 100% forced. Can you explain how that works briefly if you would? Yeah, sure, sure. I was the author of that study. So a lot of landscapes, we shouldn't forget about where it's not 100% forested as far as carbon sequestration. These might be areas where very productive forest was clear cut, but transferred to an agricultural land use, urbanization, suburbanization. So a lot of those soils are very productive. And so the forester remain, even though it's only 60% forested in a landscape, they're very productive, growing a lot of trees at a fast rates. So those shouldn't be overlooked.

In addition to our national forest and wilderness areas that are 100% forested, we need to also consider private forest lands in areas where we have mixed agriculture in with them due to the productivity of the soils. Christopher Woodall, a research project leader with the USDA Forest Service. Thank you so much for joining us. I appreciate it. Thank you. Thanks also to Krista Anderson, Research Fellow at the World. Wildlife Fund. Thank you, Krista. You betcha, thanks.

We're going to be right back after the short break with a curious collection of something very interesting. If you found a box with George Washington's hair in it, would you throw it out? We'll find out a little bit more right after this. This is Science Friday. I'm John Dankowski sitting in for Ira Flato. 43 years ago, Bob Peck started a new job at the Academy of Natural Sciences in Philly, the oldest natural history institution in the U.S. Just under a month into the job, he spotted some cool-looking metal boxes sitting in the Academy's hallway destined for the trash. Thinking these boxes might make a cool end table for his apartment, Bob, of course, snagged them, only to find they weren't empty boxes.

Inside was a strange kind of collection, a collection of hair. Inside these boxes were human hair, animal hair, hair from mummies, and hair from, get ready, from 13 U.S. presidents. Bob had stumbled on the collection of Peter Brown, a citizen scientist whose collection of hair, Hair says as much about 19th century science as it does about the diversity of the stuff topping our heads. Today, Bob is the curator of art and artifacts at the Academy, and he's written a book about Brown's idiosyncratic collection. It's called Specimens of Hair, and he joins me now to talk about it.

Bob, welcome to Science Friday. Thank you. Glad to be with you. Maybe you can describe what you saw when you opened these metal boxes some 43 years ago. Well, of course, at first I thought they were just empty boxes since they were in the trash. But there, to my surprise, were some albums, dozens and dozens. of albums, actually, beautifully leather-bound, and in each page were little tufts of hair. First few albums were sheep, wool, and then we got into animal hair, and then finally, human hair.

Some of which was perfectly anonymous, but I began recognizing names on some of the other sheets that caught my attention. I can imagine, and we'll get to some of those names in a moment. Given what you found in there, why was the Academy throwing the stuff away? Well, we were in a process of moving from one place to another. There were lots of things that were being reviewed. And I think the curators at the time felt that this was not something that really deserved scientific attention. They were mostly looking at the wool and some of the animal fur.

And they thought, well, we've got full skins of animals elsewhere. Why would we keep these scrapbooks? They're just taking up a lot of space. And they were probably wondering, what exactly can we do? What does this have to do with our collection? Well, exactly. And remember, this was all in a sort of a pre-DNA era. DNA was only isolated in the 19th century, but identified in the 1950s.

And then the complete human genome wasn't sequenced until 2003. So all of this back in the 1970s was not recognized, really, for the value that it is today. So this is the collection of Peter Brown. And this is a big part of the story. Who was Peter Brown? Peter Brown was a lawyer in Philadelphia, but a very patriotic and philanthropic man. And he was trying at first to help advance the agricultural world in America. He was collecting sheep wool from all over the world so that he could instruct the growers of sheep here,

which breeds would be best suited to which purposes. So this one might work well for a blanket or a sweater. This one might be good for a felt hat. And people hadn't really paid much attention to that until he began to do so. Go ahead, please continue, yeah. Quite sort of from one step to another. He thought, well, if we can do all this with sheep wool, and he was examining the wool very carefully. He had invented a little mechanism to test his strength and its size called a trachometer.

He was looking at it with microscope. He said, if I can study this much about sheep wool, maybe there are things in other animal wool and hair that could be used. to us. So, he sent out letters asking. I have to ask you, though, but that's what's so interesting about this, because it makes sense that you would find sheep wool interesting because you can make things out of it, but elephant tail hair or raccoon whiskers, what possible use could this have to human industry? Well, that's what we might say now in retrospect.

But at the time at all, anything was possible. And in fact, some of the things he found did prove to have commercial value. And we still use Kashmir, which is from goats. We use alpaca and llama fir and various other things. In the 19th century, actually quite a bit more of it was being used, not necessarily for blankets, but for putting in cushions and insulation. Sometimes even animal hair was used in wall plaster. Now, when he collected all this animal hair, part of what he was trying to study was

what he could learn about these different animals and how they might be related to one another. And, you know, this was all pre-Darwin. What was he learning about animals or at least thinking he was learning about animals through studying and collecting their hair? Well, I think, as you say, pre-Darwinian era, trying to figure out just what might be related to what, these great charts that we're now used to in our science books that tell us how things are related didn't exist then. And he was thinking that perhaps by looking under a microscope, he could tell if this kind of shrew was related to that one or a mouse or a rabbit, whether a giraffe was any relation to a wildebeest and so on.

And I think at that point, he was just throwing the net as widely as he could to figure out what might come up out of it. So then why does he start to collect human hair? What was he trying to learn there? And human hair, the same kind of thing. And remember, this was an era when first. Phrenology was kind of a pseudoscience, but people were thinking that the bumps in one's skull might help tell something about their personality. He thought, well, maybe hair could tell us something, too. So he wanted the whole range of humanity, everything from criminals to

presidents of the United States, from writers, musicians, politicians, to the average person. He wanted young people, old people, and all sorts of ethnic groups. And he put these very carefully into the albums. Each page was devoted to a single donor, a little Greek key motif around the edge, sometimes a portrait if the person was well enough known to have an engraving, and all the information that he could get about them, written out carefully as a sort of a label. He asked people to help him all over the world, Indian agents on the frontier, explorers who were traveling in the South Pacific and around the world. as well as his own friends and correspondence domestically.

So this is the part of the story where it turns maybe a little bit dark because, as you say, of the pseudoscience of phrenology and where science was at the time, some of the conclusions he was drawing seemed to suggest that different type of people had different type of hair, maybe even that there were different species of human, or you could learn something about someone's intelligence or capacity through their hair.

Maybe you can talk about how he got this so very wrong at the time. Yes. Well, it was a general area of discussion at the time is were people, if they appeared to be different, were they actually different? And the same was going on in other fields of science, so people would look at different birds and different colored feathers or mammals with different fur

and thinking, well, if this one is this different from this, perhaps it's a different species. When he looked at human hair, he divided it all into three different groups. They were either cylindrical, that is round, which he found related to people from Asia, Central America, South America, proving that American Indians, for example, had in fact come across the Bering Straits and were related to those from Asia. Second category was oval, and he found that was mostly people from Europe and England, and therefore most of the white population in North America,

and then eccentricly elliptical, which is the way he described, African hair that he found. So once he had broken these into the different classifications, then others took that information and tried to use it as proof that in fact there were different species of humans. We now know, of course, that that's not true,

but at the time it was part of the general discussion. And it really does tell us something about the state of science at the time. It's not just this eccentric hair collector who is making these findings and trying to figure out about the human species through his discoveries. But, you know, this is the type of science that was going on at the time that he was alive. Yes, absolutely. And in every field, as I say, people were looking at insects and fish and plants and trying to classify and organize them. and Brown was just simply part of that process. We're fortunate that he made the collections he did,

not so much for his conclusions, but for the very fact that he preserved these things, because many of the people whose hair he arranged to be collected are now much more difficult to isolate genetically and from a DNA point of view. But at the time he was collecting them, There were tribal groups and people living on islands in the South Pacific and so on who had not yet had contact with the Western world. And therefore, their hair samples are about as pure as one can get in this field.

Well, let's get to the way in which he collected this human hair because this sounds so incredibly unusual to us here. I was talking to our producer, Annie, about this. hair kind of grosses me out. The idea of a big box of hair is not the most appealing thing in the world. And the idea that you would, I don't know, send a letter to someone and say, hello, may I have a lock of your hair? Today sounds so strange. But that's actually something that was done back in the day. Yes, it was quite common. Both 18th and 19th century, people, families almost universally exchanged hair with one another, kept them in, kept hair in lockets and brooches and rings and cufflinks and so on. in the American Civil War, almost every soldier in the field would have had a locket of his wife or his girlfriend, his mother, and at home, likewise, they would have been retaining lockets from him as he went off to war. It was a very intimate way to exchange a close relationship with someone else. Interestingly, some celebrities were also considered fair game. And even George Washington, right in the midst of the

American Revolution received a letter at Valley Forge from a stranger saying, Dear General Washington, can I have some of your hair? And he very nicely obliged with a letter and a little snippet. Right in the middle of Valley Forge. Things aren't going all that well for him, but someone asks for a lock of his hair and he sends it along. He was quite flattered by it. And his wife, Martha, was actually sending out hair to all kinds of people, whether they asked for it or not. It's like sending out a headshot today. So I have to ask you, how did he know that he actually had George Washington's hair? I mean, he had the hair of 13 presidents all the way up to, but not including Lincoln.

How did he know that the hair he was collecting was actually the hair from those men? Well, with all of the living presidents of his time, he was able to write to them directly. And we have in these albums, their replies, the handwritten notes that they'd send back saying, oh, I'm so sorry, I just had my hair cut, but if you wait for a month, I'll send it. And then others, if the president was no longer living, he would write to their immediate family, daughter, granddaughter, whatnot, and say, could we have some of the hair? And those families had all universally retained the locks of their ancestors for their own use, and also with the intention of sharing them. When George Washington died, his secretary was asked to cut as much hair as he could from him before he was buried because he knew that Martha would be. be besieged with requests from people who had known him during his lifetime.

I'm John Dankosky, and this is Science Friday from WNYC Studios. And we're talking with Bob Peck about the fascinating book, Specimens of Hair, the Curious Collection of Peter A. Brown. You've kind of picked up this as you've been a collector yourself, and you've asked former presidents for samples of their hair. What kind of responses did you get? Well, as you might guess, not much response from most of them. In fact, I'm probably in some file somewhere as someone to be avoided.

A no fly list, yes, please. But I did get a very nice letter back from Jimmy Carter. I had invited him to come to Philadelphia in 2016 at the time of the Democratic Convention to see an exhibit of the hair that we had on view. But I said, if you would like to donate some of your hair, we'd be happy to add it to the collection. And he wrote a very nice letter back saying he wasn't coming. coming to Philadelphia and wouldn't be able to see the show, but he'd be happy to donate if we really were interested. And so he did. And so he is the most recent president since Franklin Pierce to join the collection.

That's amazing. Can we learn anything about the hair donors from their hair? I mean, as you say, obviously technology has come quite some way. Can we do DNA testing on George Washington's hair and find out a little bit more about the environment where George, Washington lived or how he physically looked or was? We can very much so. And I think as technology advances in the years to come, we'll be able to tell even more and more about this from these samples. But we can tell something about his diet and the atmosphere and so on. Some of the studies that were made of Thomas Jefferson and Sally Hemming and their relationship

have been derived from hair samples from Jefferson and his descendants. And recently in Europe, there was a study of Napoleon Bonaparte's hair because there had been concern that he might have been poisoned during his final months at St. Helena. And in fact, they did find almost 100% more arsenic in the hair samples than his contemporaries. So literally through studying the collected hair of Napoleon, you're able to find something about the end of his life that you just would. have known otherwise that may have just been a story or a rumor? You can, indeed. And I think as time goes on, we'll be asking more and more questions that DNA will be able to tell us that we never could have dreamed of even a few years ago. I have to ask you about the mummy hair. We've been talking a lot about people and some about

animals, but where did Brown get it and why did he want mummy hair? Well, there was a very interesting guy named George Glidden, who was traveling around the U.S. at the time. He had been are representative in Egypt. And he came to America with mummies and went on kind of a lecture tour with a huge diorama behind him that showed the Nile and the pyramids and so on. And he drew huge crowds. So 500 people or 800 people would come to hear him in a single night. And tens of thousands of people heard him over the course of a few years. He inevitably was introduced to Peter Brown. And Peter Brown said, well, if you're doing all this work on Egyptian mummies, could you save a little bit of the hair for me?

I'm getting it from all over the world, but I also would like to have a kind of a time track on this. And we know how old some of these mummies are. Perhaps that will shed some light. Does hair change over time? Do ethnic profiles alter and morph through the centuries? And so Glidden very happily cooperated. Now, Glidden himself was a little bit of an unsavory. fellow, and he was sometimes stealing these things from graves and without permission taking them.

But Brown, as long as he kept a certain distance from Glidden himself, was happy to receive the specimens. We just have a few seconds left. Do people ask you for samples of this hair collection to test it in any way all the time? Well, we haven't had the request yet. This hair collection has been pretty much in storage and out of sight for a while. But I think with the publication of specimens of hair, this new book, we're going to be getting a lot more requests. Well, it's a fascinating book. Bob Peck is curator of art and artifacts at Drexel University's Academy of Natural Sciences.

His book about Peter Brown's hair collection is Specimens of Hair. Thank you so much, Bob. I appreciate it. Thanks for the invitation. And if you're curious about what all this looks like, you can go to ScienceFriiday.com slash hair book. B.J. Leatherman composed our theme music. If you missed any part of this program or you'd like to hear it again, subscribe to our podcasts. And if you have a smart speaker, you can ask it to play Science Friday. It doesn't even have to be Friday.

Every day is Science Friday. Say hi to us on Facebook, Twitter, Instagram, or email us. The address is SciFri at ScienceFri.com. Send feedback and tell us what you'd like to cover too. In New York, I'm John Dankoski.