William Firth Wells and Mildred Weeks Wells

00:00:01
Speaker 1: Welcome to Stuff You Missed in History Class, a production of iHeartRadio. Hello, and welcome to the podcast. I'm Tracey V. Wilson and I'm Holly Freight.

00:00:16
Speaker 2: Before we start our episode today, a couple of folks have asked us where they can buy shirts and things because we used to have a T shirt store.

00:00:25
Speaker 1: Yeah, and then it went away.

00:00:27
Speaker 2: Uh and the reason for that is just that iHeartRadio moved that they didn't. They were already with a different T shirt vendor than we had been with when iHeart acquired us, and so eventually we needed to all be on the same thing. Uh. So our T shirt store now is at Cottonbureau dot com. You can either go to cottonbureau dot com and search for stuff you missed in history class, or you can go to Cottonbureau dot com slash people slash stuff you miss in history class, with each of those words separated by a dash. Personally, it seems easier to me to just go to Cottonbureau dot com and use the search function, but you do you Right now, we have coffee mugs, tope bags, cell phone cases, stickers, and T shirts. Our prior T shirt vendor was the creator of a lot of our previous T shirt designs. So right now what we've got is stuff with our logo on it, but in the future we may have some other designs also kind of working on that behind the scenes. Just wanted to let everybody know in case you either have looked for a shirt recently or have just wondered, do they have T shirts and stuff? Now we do again Cottonbureau dot com, and now we can start the episode. A couple of weeks ago, I was listening to an episode of the podcast ninety nine Percent Invisible, and this episode was called Airborne. It was an interview with Carl Zimmer, who wrote Airborne, The Hidden History of the Life We Breathe. I have not read this book. I did use it to confirm some details biographically about the people that we were talking about today, but I cannot comment on the book as a whole. What I can comment on is that over the course of this episode I got progressively more frustrated because they were talking about some research that sounded like that least in theory that could have really lessened the impact of the COVID nineteen pandemic. But this was not like new research from after the pandemic started. It was from the nineteen thirties and forties, So as I was listening to this, I jotted down a couple of potential podcast topics for our show as I was listening and getting mad about it. One was nineteenth century chemist Max von pet and Kulfer, who I knew sounded familiar but had forgotten that we already did an episode on We will have that episode as our next Saturday Classic. And the other thing I wrote down was today's topic, which is husband and wife team William Firth Wells and Mildred Weeks Wells. Their research had the potential to make a really big difference in the safety of the indoor air, but that research did not really have that kind of impact on public health. And just to note, this research did involve some experiments on animals.

00:03:30
Speaker 1: Mildred Weeks was born in eighteen ninety one to William F. Weeks and Mary Alice Denton Weeks. She was born in what's now Oklahoma, then it was called Indian Territory, and she had an older sister named Marian. We don't really know a whole lot about Mildred's early life, but it seems like things may have been difficult for her and her sister, even though they were from a prominent family, so.

00:03:54
Speaker 2: That explanation goes back to before her parents, William and Mary Alice, were mayor married. The girl's great grandfather, John B. Denton, was the namesake of the city and County of Denton, Texas, and then his son, Their grandfather, Ashley Newton Denton, was an actor who was appointed superintendent of the Texas State Lunatic Asylum. The asylum bookkeeper was the girl's future father, William Weeks. Denton and Weeks were both accused of mismanaging the asylum's funds, and Weeks was eventually charged with embezzling somewhere between one thousand and fifteen hundred dollars.

00:04:35
Speaker 1: Both men maintained that they had not done anything wrong. One newspaper write up of Weeks's arrest said that quote his numerous friends here assert that while he was careless in business matters, he will explain out of it. These allegations don't seem to have affected Denton's opinion of Weeks, though, since he presumably gave his permission for his daughter Mary Alice to marry him in eighteen eighty, which was right In the middle of all of this.

00:05:03
Speaker 2: William was exonerated in eighteen ninety and the family went to Indian Territory, which, as we said, is where Mildred was born. But rumors continued to follow William, and eventually he seems to have kind of disappeared. Mary Alice died when Mildred was only ten, and Mildred and her sister Marian were raised primarily by their grandmother, who lived in Austin, Texas. Mildred earned a bachelor's degree from the University of Texas Medical Branch in nineteen eleven. She earned her MD from the University of Texas at Austin in nineteen fifteen, where she was one of only three women in a class of thirty four. She moved to Washington, d C.

00:05:45
Speaker 1: And got a job studying bacteria at the Public Health Service Hygienic Laboratory. While working at the lab, she met William Firth Wells.

00:05:54
Speaker 2: William Firth Wells was born in Boston, Massachusetts, on August twenty fifth of either a teen eighty six or eighteen eighty seven. I found both those years. His parents were Obadiah F. Wells and Helen Davis Wells, and he was one of their four children. We don't have a lot of detail about his early life either, but he studied bacteriology at the Massachusetts Institute of Technology.

00:06:19
Speaker 1: He graduated from there in nineteen o nine. After graduating, he eventually made his way to Washington, d c. To become a sanitary bacteriologist for the Public Health Service, a few years before Mildred also started working there. Mildred Weeks and William Firth Wells got married in nineteen sixteen, and a year later they had a son, William Junior. They called him Bud. We also don't have a whole lot of detail about Bud, but it seems as though he was disabled or he had some kind of mental illness. He always lived with family until being institutionalized, which happened after Mildred's death, and at that point he was in his forty.

00:07:01
Speaker 2: During World War One, William Senior was drafted and joined the Sanitary Corps, serving both stateside and in Europe and attaining the rank of captain. His work before, during, and after the war was largely focused on water contamination and water borne illnesses. He studied how diseases could be spread through the water and how salmonella typhi, which causes typhoid fever, could grow in oysters. He developed filtering techniques to purify river water so that it would be drinkable, and chlorination methods to clear bacteria out of oyster beds. After the end of World War One, the Weekses moved to New York, where william had gotten a job with the state's Conservation commission. He continued working with oysters, including developing methods to artificially propagate them and repopulate depleted oyster beds. Inspired by machines that separated cream from milk, he developed a centrifuge that could separate oyster larvae from the water so that they could be raised in tanks and then returned to the Long Island Sound. This combined with his earlier sanitation and water quality work to ensure that these oysters would be safe to eat once they were harvested. By nineteen twenty five, Williams's work with oysters was being hailed as almost miraculous. The Association of Fisheries Commissioners and the National Association of Oyster Growers and Dealers held a celebratory dinner on October first of that year with artificially propagated oysters on the menu, and this whole thing was praised in newspapers.

00:08:43
Speaker 1: Two years later, an Associated Press write up on William's work described the oysters that he was growing as super oysters. He moved from the New York State Conservation Commission to a higher paying job with an oyster company, but then in October of nineteen twenty, the stock market, of course crashed, which is marked as the start of the Great Depression. The oyster company was sold and William lost his job.

00:09:10
Speaker 2: William tried to make ends meet by writing and consulting, and Mildred got a job working with the International Committee for the Study of Infantile Paralysis, also known as polio. Polio had been on the rise in parts of the world since the late nineteenth century, and it was widely feared and not completely understood. Karl Landsteiner and Irwin Popper had confirmed that polio was infectious, and they had concluded that it was caused by a virus in nineteen oh eight. Doctors also had a sense that polio could be spread asymptomatically, but once they were able to isolate the actual virus, they didn't usually find evidence of it in people. Who were not experiencing symptoms, so they didn't really understand exactly how the virus was spreading. Outbreaks often happened in large waves, usually in the summer, but the patterns of cases within those outbreaks could seem almost random. Mildred Wells was part of a project to systematically evaluate all of the research that had been done on polio and to produce a comprehensive work on the subject. That work was published in October of nineteen thirty two as Poliomyelitis a Survey made possible by a grant from the International Committee for the Study of Infantile Paralysis. This was primarily funded by philanthropists Jeremiah Millbank. Other than Millbank's forward and a preface by doctor William H. Park, this book was written entirely by women. The first chapter, historical summary, was by Elizabeth F. Hutchin, and the remaining chapters were all by women. Mds Helen Harrington, Josephine B. Neil, and Mildred Weeks Wells. Well wrote the chapter on epidemiology. Several modes of transmission had been proposed for polio, including direct transmission through respiratory droplets, milk water, insect bites and fomites. When she started working on this project, insect transmission had been generally rejected, and the most widely accepted theory was droplets. Droplets were believed to be able to travel only a short distance, meaning that people had to be in close contact to spread droplet born diseases. This idea grew from the work of German microbiologist Carl Fluga, who had done research primarily focused on tuberculosis in the late nineteenth and early twentieth centuries. He was building on earlier work which had already demonstrated that coughs and sneezes could carry infectious particles that could settle on things like clothing, bedding, and handkerchiefs. Fluga did things like placing microscopes at varying distances from tuberculosis patients, finding that the slides closest to the patients collected the largest respiratory droplets with the most basilli, while the ones farther away had much smaller droplets with very few beecsillai. So through this findings were way more complex than this, and a lot of them were specific to tuberculosis. He hadn't test studied other diseases. In whether they worked the same way at all. But a lot of doctors took away from this that diseases were spread through droplets, and droplets didn't travel very far and settled out of the air quickly, so close contact was required for most disease spread, and airborne spread at a much greater distance was not really a big concern. One such doctor was Charles Chapin, Health Officer of Providence, Rhode Island, and author of the nineteen sixteen public Health manual The Sources and Modes of Infection that was regarded as a landmark text in the field. This work stressed the role of droplets while minimizing the idea that there was much danger from airborne pathogens that could travel longer distances. Under the heading actual Danger of Infection by air, Chapin wrote, quote, pathogenic bacteria may withstand drying and the pulverization of the dried material, and they may actually be found floating in the air. Yet they may not, after all, be dangerous, either because they have holly or partially lost their virulence, or because there are too few in number, or for some other unknown reason. Mildred weeks Wells's research into the epidemiology of polio didn't line up with what was known about droplets. She described polio's seasonal recurrence as difficult to reconcile with droplet transmission. At one point, she wrote, quote, certainly, poliomyelitis as we ordinarily encounter it in the United States does not behave epidemiologically in accordance with the concepts that have become crystallized as to how a contagious disease should behave.

00:14:14
Speaker 1: She then quoted from a nineteen thirty one paper by M. Greenwood titled on the Statistical Measure of infectiousness quote, an illness is held to be catching when it has usually been possible to explain the existence of a case of it by close association with an immediately pre existing case. The notion of more or less infectiousness depends on some appraisement of the proportion of persons attacked to persons exposed to the risk of attack.

00:14:43
Speaker 2: So polio was weird. It seemed to be catching, and yet it did not fit that description of catching because people who caught it often didn't have a history of close contact with another polio patient. Wells wound up concluding that polio was similar to other airborne or droplet infections, but that people seemed to have a higher innate resistance to it than to diseases like smallpox or measles, possibly because people became immune to polio after being infected but without developing clinical symptoms. Today, polio is known to be transmitted through droplets and aerosols and through fecal contamination, which the research Mildred was working with really did not think was the case, so she wasn't completely on the right track for thoroughly explaining the epidemiology of polio, but this did lead her to thinking about ways that disease might travel through the air. Mildred's and William's work came together after this, which we will get to after a sponsor break. William birth Wells's work with oysters led him to the use of centrifuges to separate oyster larvae from fluid. Mildred Weeks Wells's work on polio led her to think about airborne disease spread. Those two things came together in nineteen thirty when William found another full time job working at Harvard doing research and teaching sanitary science. This job paid a lot less than he had been making working for the Oyster Company, but the Great Depression was still going on and the Wellss really needed the money. At Harvard, William Wells developed a machine, the Wells Air Centrifuge, that could separate bacteria, dust, and other contaminants from the air the way that he'd separated oyster larvae from seawater. He also developed a nutrient medium to use in the centrifugees collection tubes so that any bacteria from the air would be able to grow so that he could then analyze it. At a request of the Commonwealth of Massachusetts, he used this centrifuge to study the safety of the air in textile mills in Townslake Fall River, Lawrence, Lowell, and New Bedford, where the air was full of textile dust and also artificially humidified. Wells eventually brought on assistance for this and other work, and those were brothers Richard and Edward Riley. In nineteen thirty four, William Wells intentionally introduced bacteria into one of the air conditioning systems at Harvard and then used his centrifuge to collect air samples and track where all the bacteria went. That same year, he did an experiment during one of his lectures. He used the centrifuge to sample the air at the beginning of class, and then he introduced some sneezing powder into the machine's exhaust. As it spread, the student started sneezing, and he collected another sample of the air. He collected another sample after some more time had passed, and then a final sample after class was over and the students had left the room. He compared each of these samples, finding the largest number of normally occurring respiratory bacteria and the samples that had been taken sometime after the students had started sneezing, but there were also still bacteria in the sample that he took after the class was over. Mildred was also part of this research, although she was not officially hired at Harvard until nineteen thirty five, and even then she wasn't paid a salary. A lot of their work was collaborative, with both of them deeply involved, but Mildred was the one who wrote most of.

00:18:40
Speaker 1: The papers and lectures. Much of their published work was published under both of their names.

00:18:47
Speaker 2: Their research strongly suggested that some bacteria could travel more than just a short distance, like in a droplet and could stay in the air and stay viable for a long time, building up in the air of a room the longer people were in their breathing it. But when they took the center views outdoors, their samples yielded few, if any viable bacteria.

00:19:11
Speaker 1: These findings were summed up in a patent application a few years later. Quote Ordinarily, the droplet and nuclei are so rapidly dispersed in the outside air that there is but little danger of infection thereby. In crowded or poorly ventilated spaces, however, they constitute a real menace. Even well ventilated buildings are not free from this danger, particularly where the same air after conditioning is recirculated so as to be used over and over again for breathing. For such recirculation merely adds to the bacterial concentration of the recirculated air.

00:19:49
Speaker 2: While a lot of their colleagues were really skeptical of their work, William and Mildred became convinced that diseases could be spread through the air beyond just most close contact from droplets, and they started experimenting with ultraviolet light as a way to stop it.

00:20:07
Speaker 1: As with William's work with oysters. This got some media attention. On July thirtieth, nineteen thirty six, the Decatur Daily Review ran a photo of Wells with his research equipment at the Harvard School of Public Health, and it ran under the headline scientists fight flew germs with violet ray. He was working on an experiment that involved funneling influenza infected air to a ferret enclosure. The vents carrying the air to some of the ferrets were treated with UV light while the other vents were not, and the ferrets getting the UV treated air stayed healthy while the others got sick. In November of nineteen thirty six, Mildred and Richard published two articles in the Journal of the American Medical Association. One was titled Airborne Infection and the other was Airborne Infection Sanitary Control. Airborne Infection detailed the Wells's conclusion that there were two types of airborne disease transmission. There were droplets, as previously described by Carl Fluge. These were larger than zero point one millimeters in diameter. These quickly fell from the air due to gravity, But droplets smaller than zero point one millimeters in diameter could stay aloft, and as they were aloft, they evaporated, leaving behind only the droplets infectious nucleus, which could stay in the air even longer and travel much farther than droplets could. A graph of the relationship among gravity, evaporation and how long infectious material can stay in the air is known as the Wells curve. They also concluded that the number of bacteria in the air quote correspond to the degree of contamination by the occupants, and they can compaired this to waterborne intestinal illnesses. People were being exposed to diseases carried through the air, including influenza, pneumonia, bronchitis, colds, and measles, over and over in a cycle that would continue until the whole population was finally immune to whatever the illness was. But if people were experiencing the same number of intestinal infections by repeated exposure to waterborne illnesses, quote, that would condemn a water supply as being highly dangerous. They went on to say, quote, it might be concluded on epidemiologic grounds that the atmospheres of our common habitations are even more highly infective airborne infection. Sanitary Control reported on experiments conducted in the tunnels under Harvard Business School, which tested the susceptibility of airborne pathogens to ultraviolet light. The most dramatic reductions of bacteria in the air were within five feet of UV light source, but there was still a measurable difference as far as fifty five feet away. They concluded, quote air purification methods that depend on filtration or sedimentation may be more effective against dust an ultraviolet rays may be more effective against nuclei, the two being complementary and therefore effectively combined. In nineteen thirty seven, the Washington d c. Evening Star noted the Wells's work, although without mentioning Mildred. This write upset in part, quote doctor William Firth Wells is the trapshooter of the scientific world. For five years he has been gunning for the flu bug, dropping it with an ultraviolet ray. This write up went on to call the project a quote scientific cleansing of workaday breathing air, which will vastly lessen casualties from nose and throat diseases.

00:23:58
Speaker 2: That same year, William Firth Wells and Mildred Weeks Wells were fired from Harvard. William had been hired even though he didn't have an advanced degree, and on top of that, he is not described as a very good teacher, giving ponderously boring lectures and caring only about his research, not his classes.

00:24:19
Speaker 1: But a bigger.

00:24:20
Speaker 2: Issue seems to have been that he and Mildred both developed a reputation for being really hard to work with, including being crabby and argumentative. Some frustration is understandable here, given that a lot of their colleagues just seemed really dismissive of their work, but the Wells is also apparently argued with people who were on their side and with people whose opinion of them really mattered, like their boss, Gordon Fair, professor of sanitary engineering. Fair apparently thought he should be credited on the Wells' publications as well as named on the patent application that came from their work. That was US Patent two one nine eight eight sixty seven Method and Apparatus for Preventing Infection, which we read from earlier. That patent was awarded in nineteen forty not only with Fair's name on it, but with Fair listed first. William and Mildred both seemed to have fought with Fair over this credit issue, and according to some accounts, Mildred was more aggressive about it, but it's also really hard to take that at face value since people's perceptions of her would have been influenced by social expectations for women to be polite and unassertive. Yeah, was she really being aggressive or did people just think she was aggressive because she wasn't being meek? Also, she was doing work and not getting paid for it right and handing over the credit to men. Uh. It took some effort for them to find a new employer, which we will get to you after a sponsor break. After being fired from Harvard, the Wells's next move was to Philadelphia, where the University of Pennsylvania had established an airborne infection laboratory. This included paid positions for both William and Mildred. While Mildred was being paid about a third of what William made even though she had an MD and he had a bachelor's degree, their combined salaries were more than William had been making at Harvard. In nineteen thirty eight, William and Mildred published Measurement of Sanitary Ventilation in the American Journal of Public Health that began quote ability to modify man's environment is not confined to enhancement of comfort, convenience, or even safety, but extends to the prevention of disease and the promotion of health. By supplying pure water and pure food, the sanitary engineer has in many communities almost eliminated intestinal infection. Is it unreasonable to hope that when airborne infection is better understood, diseases conveyed through the respiratory tract may likewise be reduced through the provision of pure air supplies. This paper presented multiple possible configurations for using UV light to reduce the number of pathogens in the air. One was using UV light to treat the air within a ventilation system before circulating that air back into a room. That could be the most useful and small crowded spaces like train cars. In large rooms, there was a lot more space and a lot more air, making that kind of ventilation treatment inefficient. The UV lights at the time had the potential to cause eye damage, so treating the whole room was most easily done in scenarios like operating rooms where there was a high need for infection control, and also all the people in the or could reasonably be expected to wear eye protection. Other possibilities included things like light barriers, like a curtain of UV light that would separate hospital wards from each other. There were equations for the bacterial reduction that could be expected with each of these different setups. From there, the paper expressed a hope that this kind of research could be correlated with epidemiological data quote this may lead to a realization of our present hope that if the sanitary quality of air is controlled, reduction of respiratory disease will be accomplished. William had invented what he called an infection machine, which could be used to expose animals to air that was laden with viruses or bacteria. By nineteen forty one, William had used this machine to demonstrate that tuberculosis, influenza, and strep could all be transmitted to animals through the air, and that treating that air with UV light could prevent those infections. Meanwhile, Mildred was working on a practical experiment that had started at Germantown Friends School in nineteen thirty seven. UV lamps installed in some of the classrooms seemed to reduce the number of measles cases during an outbreak at the school. There were about ten times fewer measles cases in the classrooms with the lights than the ones without them. Mildred published Ventilation in the Spread of Chicken Pox and Measles within school Rooms in nineteen forty five, which detailed these findings. Not all of their experiments were that effective, though. In nineteen forty two, UV lights installed in the town of Swarthmore seemed to stop one outbreak of mumps, but it didn't have much of an effect on another one. The weeks As speculated that there might be a seasonal factor to this. The lights seemed to work in the winter when the air was dry, but not in the summer, when it was humid. They speculated that this humidity might affect how well the lights worked, and that that might also be connected to the seasonality of some illnesses. During World War Two, William advised the War Department on protections for soldiers living in crowded camps and barracks. He and Mildred were both concerned about something like the nineteen eighteen flu pandemic happening again. But while there was some limited use of UV lights at military facilities, the military's attention just seemed to be focused elsewhere, and this really frustrated William, especially when he later learned that the army had been focused on airborne disease transmission when it came to the idea of germ warfare, just not when it came to protecting soldiers from ordinary illnesses. William and Mildred's marriage also seems to have fallen apart, at least partially during this period. Their maid left her job, and it's likely that the maid had been doing some of the caregiving work for Bud. Mildred resigned from the Airborne Diseases Lab in nineteen forty four. Each of them did projects on their own or with other collaborators rather than together.

00:31:19
Speaker 1: After this.

00:31:20
Speaker 2: That includes Mildred's nineteen forty five paper that we mentioned earlier, which was published with only her name.

00:31:27
Speaker 1: William worked with Herbert Ratcliffe on a tuberculosis study which concluded that only very small particles could get deep enough into the lungs to cause that disease. He also worked with his former assistant, Richard Reiley, now a researcher in his own right, and a new assistant, Kretel C. Mills, on an experiment at the Baltimore Veterans Administration. This involved three hundred guinea pigs which were exposed to air from the rooms of tuberculosis patients. Half of the guinea pigs got air that was treated with UV light, and the other half got air that was not. All of the guinea pigs getting UV treated air stayed healthy, while about three a month in the other group developed tuberculosis.

00:32:12
Speaker 2: Mildred worked with the New York State Department of Health trying to replicate the results of their earlier research with UV lights. They started with an experiment in central schools that were located in rural areas, based on the idea that these students mostly saw each other only at school, without a lot of crowd exposure from outside of school, like a student would probably get if they lived in a city.

00:32:38
Speaker 1: This experiment had mixed results. The classrooms that had UV lights did seem to have a different pattern of disease spread During a measle's outbreak. A few students at a time got sick over many weeks in the UV treated classrooms, while lots of children all got sick almost simultaneously in the untreated classrooms, But the total number of students who got measles was not that different. One possible complicating factor in this experiment was that the children rode buses to school, and those buses did not have UV lights. Mildred also worked with William Halla to install UV lights in as many places as possible in Pleasantville, New York, so that it could be compared to nearby Mount Kisko, which did not have the lights. They published a paper on this in nineteen fifty titled Ventilation in the Flow of Measles and Chicken Pox through a Community. Beyond installing these lights weeks in Halla figured out all of the children's susceptibility to measles and chicken pox based on their past history so that they could factor that in to their disease risk calculations, and they did contact tracing for each new case in each of the towns. The results of this study were also mixed. Pleasantville had a measles out break, but it hit during a rainy spring, and the Wellses had already published that their UV lights were not as effective in high humidity. And it also seemed like even though there were no UV lights installed in Mount Kisco, its whole population was partially protected by the irradiation program that was going on in Pleasantville. It basically cut off one of the possible sources for an illness to be introduced into Mount Kisco. Meanwhile, William was writing a book called Airborne Contagion and Air Hygiene, An Ecological Study of droplet infections. It was published in nineteen fifty five after many years of work. It was more than four hundred and fifty pages long, and while he had really hoped that it would serve as the definitive work on airborne infections and air sanitation, this book was really not a success. As we have said, Mildred was the better writer. She had written a lot of her stuff before this. She did not work on this book with him. Mildred Weeks Wells died on February twenty third, nineteen fifty seven, at the age of sixty five. William Firth Wells died on September nineteenth, nineteen sixty three, at the age of seventy six. Both of them had experienced serious health issues in the last years of their lives. Mildred's sister Marian, tried to take over Bud's care after Mildred's death, but she was also in her late sixties by them, and as we mentioned earlier, ultimately Bud was institutionalized.

00:35:36
Speaker 2: William Firth Wells's guinea pig study in Baltimore was still going on when he became too sick to work. After his death, Mills and Riley finished the work and published it. Mills also contracted TB, but she recovered with treatment. This research definitively demonstrated that tuberculosis could be airborne and led to the development of the Wells Riley equation, also called the Wells Riley model, which is a way to calculate the probability of being infected by an airborne pathogen. William Wells's name was not included on the final publication of this work, though Riley later wrote an article about this in which he described that omission as his eternal shame. So Mildred Weeks Wells, and William Firthwells studied airborne disease transmission for more than twenty years. They showed that a lot of diseases could be spread through aerosolized particles rather than just large droplets, and that some larger droplets had the potential to evaporate into much smaller particles. They also demonstrated that UV light could potentially reduce the number of pathogens in the air and thus the number of illnesses at least in some scenarios. But while there were some other researchers who did experiments to replicate their work in the nineteen forties and earth nineteen fifties, this didn't lead to a huge rethinking of airborne disease transmission and its prevention, especially in public settings. The Wells's work had more influence on studies of the physics of particles spread through the air than on public health. To be clear, the widespread adoption of the kinds of UV lights that the Wellses were using probably would have caused other issues, including skin cancer, especially if those lights were shining on people rather than being used within air circulation systems. But it seems like if their work had gotten more favorable attention, we might today be living in a world where illnesses that are spread through the respiratory system are less frequent and less widespread than they are today. Like we might not be living in a world where it's just sort of taken for granted as inevitable that there is a cold and flu season, and this of course also applies to COVID.

00:38:03
Speaker 1: There's some speculation around why their work didn't get that kind of attention. One possibility is just William and Mildred's reputation for being hard to work with, which made people just not want to. Another is that when they first started their research, the world of medicine was still trying to distance itself from the idea of miasmas as agents of disease. William and Mildred absolutely were not describing things as miasma's. They were talking about actual pathogens being spread through the air. But it's possible that there was just some innate resistance to the idea of revisiting the air as a source of contagion. During and after their lifetime, some of the diseases they studied became preventable through vaccines or treatable with antibiotics, which also may have made large scale projects to clear pathogens from indoor air just kind of seem less urgent.

00:38:56
Speaker 2: Simultaneously, it seems like a conflation or oversimplification of ideas in the Wells work may have contributed to standards that did eventually emerge in the field of infectious disease and public health, but standards that have some real limitations. One is an idea that diseases can be spread as droplets or as aerosols, and that there's a five micron threshold forming a dividing line between these two things, with most illnesses on the droplet side of that line. That played a huge part in the public health messaging about COVID in twenty nineteen and twenty twenty, when organizations like the World Health Organization and the Centers for Disease Control really emphasize the idea that COVID was droplet based, not aerosol or airborne.

00:39:51
Speaker 1: That droplet guidance led.

00:39:53
Speaker 2: To things like the social distancing guideline of six feet apart or one or two meters depending on where you live, and a very big focus on hand washing and surface sanitizing. It was not until more than a year into the pandemic that both of those organizations acknowledged that COVID could be airborne, meaning aerosolized particles could travel a lot farther and stay in the air longer than droplets could. Washing your hands and cleaning things is still very important. It leads to reducing the spread of other diseases we've talked about on the show, like neurovirus, but with COVID, a really big thing is just not breathing in virus laden air.

00:40:39
Speaker 1: A paper titled how did we get here? What are droplets and aerosols? And how far do they go? A Historical Perspective on the Transmission of Respiratory infectious Diseases was published in twenty twenty one. It looked at gaps in the understanding of airborne disease transmission and how those gaps affected public health policies during the early pandemic in a way that was confusing and ineffective. This paper traces the idea of the five micron threshold to multiple concepts from Wells's work that all got kind of mashed together. The idea that droplet and airborne transmission both existed depending on the size of the particle, and that particles measuring between one and five nanometers could penetrate deep enough into the lungs to cause tuberculosis. Conflating those ideas led to a different idea entirely, which has some parallels to what happened with the work of Carl Fluga, which we mentioned earlier. Meanwhile, in the context of COVID nineteen, specifically, far UVC lights started making headlines as a kind of new and novel way to possibly fight the pandemic in early twenty twenty one, and this has continued to be reported on in more recent months. Some articles on this acknowledged that uv light has been known to kill mike organisms for roughly a century, but far UVC has not really been framed as like a refinement of something that the Wells is we're using sometimes with really promising results back in the first half of the twentieth century, that is William Firth Wells and Mildred Weeks Wells. Do you also have a little bit of listener mail? I do?

00:42:26
Speaker 2: This is from Aaron and Aaron's email is titled Chronologue Yes with four s's and two exclamation points, community science advocacy listener mail, which I love the excitement of that title. Aaron wrote, are you allowed to write listener mail about another listener mail? I squealed when I heard the listener mail at the end of the July Unearthed Part two. I work for a land conservancy in northern Lower Michigan and we use Chronologue to track restoration sites that our nature preserves. It's an invaluable tool for us and a really easy way to contribute to community science data aggregation. We have a relatively small team for the area. We serve thirty eight people for a service area the size of Delaware, and only ten of them are land stewards. I cannot stress enough the importance of community science. Data from I Naturalist, E Bird Journey, North Nature's Notebook and Chronologue are used in our stewardship plans, restoration, site management, invasive species tracking, communications, storytelling, and fundraising. Community science is the quickest, easiest, cheapest, and in my opinion, most fun way to get involved with your local land trust organization. Thanks to you both for the amazing podcast. I love your obvious passion for telling everyone's history from a fair and neutral stance. The infinite fun facts I use to annoy my husband are just a bonus and now some pet adjacent tax for your time at work. We employ two herds of miss and or retired dairy goats to help us battle an ongoing problem with the invasive shrub autumn olive. We also own and manage a farm where we manage a herd of belted galloway cattle as a demonstration tool for regenerative agriculture methods. I have attached a few photos of each stay weird erin man Aaron I love this email. I love these pictures of these cows so cute goats, also cute using goats for invasive plant management.

00:44:30
Speaker 1: Also love that.

00:44:33
Speaker 2: By coincidence, this weekend, I was on a hike in one of my local green spaces, and I am not sure if they were using Chronologue or another service, because I forgot my phone at home, and I was fine hiking without my phone because my watch can also make a phone.

00:44:56
Speaker 1: Call in the event of an emergency.

00:44:59
Speaker 2: But that meant that when I got to a thing I had never seen before, which was about helping them track the spread of an invasive plant, which was a similar like put your phone on this stand and take a picture, I could not see whether they were using Chronologue or some other some other service to do that, so I will have to go back by there at some point and find out. Thank you again, Aaron for this great email and these adorable pictures of delicious, delicious vegetation being munched up by goats. If you would like to send us a note about this or any other podcast, we are at History Podcasts at iHeartRadio dot com, and you can subscribe to our show on the iHeartRadio app or wherever I like to get your podcasts. Stuff you missed in History Class is a production of iHeartRadio. For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.