Stuff You Missed in History Class

Episode: William Firth Wells and Mildred Weeks Wells
Hosts: Tracy V. Wilson and Holly Fry
Date: September 10, 2025

Episode Overview

This episode explores the groundbreaking but underrecognized work of William Firth Wells and Mildred Weeks Wells, a husband-and-wife scientific team who conducted pioneering research on airborne disease transmission and indoor air safety in the early to mid-20th century. Their studies—spanning inventions, experiments, and practical interventions—laid foundational concepts for understanding how illnesses like tuberculosis, influenza, measles, and more spread through the air. The hosts examine both the couple’s scientific contributions and the social and institutional factors that hindered the adoption of their ideas—limitations with major implications during pandemics such as COVID-19.

Key Discussion Points & Insights

1. Setting the Scene: Frustration and Missed Opportunities

• Tracy describes being frustrated while listening to a modern podcast about the history of airborne research, discovering that key ideas dated back to Wells and Weeks in the 1930s/40s (05:14).
• She notes: their research "could have really lessened the impact of the COVID-19 pandemic" had it been more widely accepted early on.

2. Mildred Weeks Wells: Early Life and Education

• Born 1891 in Indian Territory, into a prominent but troubled family dogged by rumor and scandal (06:06).
• Earned her MD in 1915, one of only three women in her class of 34; started career at the U.S. Public Health Service Hygienic Laboratory (08:04).

3. William Firth Wells: Early Life and Career

• Born 1886 or 1887 in Boston, bachelor’s from MIT (08:30).
• Started as a sanitary bacteriologist, focusing on water contamination and safety, with significant contributions to oyster farming and purification (09:37–11:20).

4. The Marriage: Professional and Personal Partnership

• Married in 1916; had a son, Bud, whose later institutionalization is discussed (09:11).

5. Polio Research and Transmission Theories

• Mildred contributed vital work on the epidemiology of polio, questioning the droplet theory of transmission and highlighting the inconsistencies in how polio spread (13:35–17:19).
  • 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." – Tracy V. Wilson, reading Wells (16:16)

• Descriptions of the "droplet" model as dominant, yet lacking explanatory power for certain epidemics (14:01–17:57).

6. Collaboration at Harvard: Innovations and Experiments

• William invents the Wells Air Centrifuge to analyze airborne pathogens, paralleling his previous work with oyster sorting (21:38–23:02).
• Legendary experiment with sneezing powder during a lecture to demonstrate airborne spread and bacteria persistence (23:02–24:02).

7. Key Discoveries on Airborne Disease

• Their research describes droplets vs. "droplet nuclei"—smaller particles that can remain airborne and infectious much longer (24:26–28:21).
  • The “Wells curve” describes the dynamics of particle gravity, evaporation, and airborne longevity.
• Demonstrated, in animal models and real-world school experiments, that UV light could reduce the incidence of disease transmission in some settings (25:45, 37:06).

8. Institutional Pushback and Professional Setbacks

• Harvard colleagues were skeptical; both Welles were dismissed as "crabby and argumentative," possibly compounded by sexism and disputes about intellectual credit (29:37–31:30).
  • Notable moment:

    "Was she really being aggressive, or did people just think she was aggressive because she wasn't being meek?" – Tracy V. Wilson (31:15)

  • Mildred worked at Harvard without pay, while William did not have an advanced degree (24:02, 29:37).

9. Moving to University of Pennsylvania and Expanded Experiments

• Both secure positions at Penn, though Mildred’s salary is far less than William’s despite her higher qualifications (34:47).
• Publish influential papers on UV light applications for air purification and ventilation systems (35:17–37:06).
• Notable school experiments reducing measles transmission with classroom UV (37:49–38:22).

10. Mixed Outcomes, Frustration, and WWII Context

• Not all UV experiments were successful—often results were mixed or dependent on environmental conditions like humidity (38:22–42:36).
• Military slow to adopt their findings except in germ warfare, frustrating William:

  "The military's attention just seemed to be focused elsewhere... especially when he later learned that the army had been focused on airborne disease transmission when it came to the idea of germ warfare." – Tracy V. Wilson (38:57)

• The couple’s professional and personal partnership deteriorated during this period (39:35).

11. Major Later Scientific Contributions

• William and collaborators definitively demonstrated, via guinea pig experiments, that tuberculosis is airborne—a result foundational for the “Wells-Riley Equation,” used to calculate infection risk (40:08–44:18).
• Mildred continued research with community-wide interventions and comparative studies, with nuanced results (41:54–42:36).

12. Legacy, Oversimplification, and Modern Implications

• Their findings on airborne transmission and mitigation were largely ignored or misunderstood by the broader public health field—with adverse consequences for later pandemics, especially COVID-19.
  • Quote:

    "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." – Tracy V. Wilson (45:58)

• Ideas got boiled down into over-simplistic dichotomies (e.g., droplet vs. aerosol, 5-micron threshold), hampering pandemic policy (47:37–49:20).
  • Quote:

    "That droplet guidance led to things like the social distancing guideline of 6ft apart... and a very big focus on handwashing and surface sanitizing. It was not until more than a year into the pandemic that [WHO and CDC] acknowledged that COVID could be airborne." – Tracy V. Wilson (47:37–48:49)

• Recent interest in far-UVC technology as a “new” idea, when in reality the Wellses were using similar methods nearly a century ago (50:18).

Notable Quotes & Memorable Moments

• "People were being exposed to diseases carried through the air... over and over in a cycle that would continue until the whole population was finally immune to whatever the illness was." – Holly Fry (27:30)
• "The atmospheres of our common habitations are even more highly infective." – Quoted from William and Mildred’s publication (28:21)
• Reference to the “trap shooter of the scientific world” moniker for William in the press: “dropping [the flu bug] with an ultraviolet ray.” (29:04)
• On Mildred’s role and recognition: “She was doing work and not getting paid for it. Right, and handing over the credit to men.” – Holly Fry (31:22)

Timestamps for Important Segments

• Ep. Motivation, COVID Frustration & Research Origins: [05:14–06:06]
• Mildred’s Early Life and Family Troubles: [06:06–08:04]
• William’s Background & Waterborne Disease Work: [08:30–11:46]
• Polio Research and Epidemiology Contradictions: [12:48–17:57]
• Wells Air Centrifuge & Airborne Bacteria Studies: [21:38–23:02]
• Collaboration, Skepticism, and Gender Dynamics: [24:02–31:30]
• Transition to Penn & Detailed UV Light Findings: [34:47–38:22]
• World War II, Military Frustrations, and Marital Rift: [38:57–40:08]
• Guinea Pig Experiments & Wells-Riley Equation: [40:08–44:18]
• Influence on COVID-19 Response & Public Health: [45:58–50:18]

Episode Conclusion

Holly and Tracy close by reflecting on how William and Mildred Wells’s pioneering work—spanning airborne disease mechanics, experimental interventions, and epidemiological consequences—was largely sidelined due to professional conflicts, sexism, the dominance of older medical paradigms, and eventual over-reliance on vaccines and antibiotics. This oversight had serious ramifications for pandemic response in the 21st century, especially during COVID-19, as vital concepts of airborne spread and environmental control remained misunderstood or ignored.

Their legacy persists through terminology, equations, and a foundational understanding of disease ecology—though recognition came too late to influence the public health practices of their own era.