The Women Who Changed Medicine With Mason Jars
In 1948, two women—working 150 miles apart and connected only by the U.S. Postal Service—quietly changed the course of modern medicine.
Elizabeth Lee Hazen worked in New York City. Rachel Fuller Brown worked in Albany. They never shared a laboratory. They didn’t attend meetings together. There were no phone conferences or modern technology to help them collaborate. Their partnership depended on handwritten letters and mason jars sealed with wax, traveling back and forth through the mail.
Elizabeth Hazen was a microbiologist with a simple but demanding task: collect soil and look for life within it. She gathered dirt from gardens, forests, fields, and farms—anywhere microorganisms might be locked in microscopic battles for survival. From these soil samples, she cultured bacteria and tested them against dangerous fungi. When she found something that showed even a hint of promise, she packed it carefully into a mason jar and mailed it to Rachel.
Rachel Fuller Brown was a chemist. Her job was to analyze whatever Elizabeth sent—extracting compounds and testing whether they could kill fungi without harming the patient. Most of the time, the results were disappointing. Many samples did nothing at all. Others were effective against fungi but far too toxic to be used safely.
Still, they continued.
Jar after jar. Sample after sample. Hundreds of failures.
At the time, antibiotics like penicillin were transforming medicine by saving lives from bacterial infections. But they created an unexpected and dangerous problem. By wiping out helpful bacteria, antibiotics allowed fungi to grow unchecked. Patients suffered from severe fungal infections—painful thrush that made swallowing impossible, infections that invaded lungs and brains, and illnesses that were often fatal. There was no safe antifungal drug available.
Doctors could treat bacteria. They could not treat fungi.
Then everything changed with a single soil sample from a dairy farm in Virginia. Elizabeth collected dirt from the pasture of a friend, farmer William Nourse. Inside that soil lived a bacterium unlike any they had seen before.
They named it Streptomyces noursei, honoring the farmer who unknowingly helped change history.
From that bacterium, Rachel isolated a compound that was both powerful against fungi and safe for humans. In 1950, Hazen and Brown announced their discovery to the National Academy of Sciences. They called it Nystatin, named after New York State.
It was the first antifungal antibiotic safe for human use.
Nystatin treated life-threatening systemic fungal infections. It cured thrush in infants. It treated yeast infections, athlete’s foot, and countless other conditions—both deadly and merely miserable. When it entered the market in 1954, it became one of the most important medical breakthroughs since penicillin.
But its impact went far beyond medicine.
In 1966, the Arno River flooded Florence, Italy, submerging priceless Renaissance artworks in water and mud. As conservators raced to save centuries of cultural heritage, they made a remarkable discovery: Nystatin could stop mold from destroying the paintings. It killed fungi without damaging pigments. Masterpieces were preserved using a medicine originally designed to treat stomach infections.
Nystatin was also used to fight Dutch elm disease, helping protect American forests from fungal destruction.
A drug born from soil saved human lives, preserved irreplaceable art, and protected trees.
The patent for Nystatin earned more than $13 million in royalties by the time it expired in 1974.
Elizabeth Hazen and Rachel Brown kept none of it.
Instead, they donated every dollar to create the Brown–Hazen Fund, administered by the Research Corporation. For decades, the fund supported young scientists and emerging researchers—especially women—who struggled to secure funding. Between 1957 and 1978, it became the largest single non-federal source of funding for medical mycology research in the United States.
Rachel Brown’s generosity was deeply personal. She even repaid Henrietta Dexter, the woman who had helped fund her own education decades earlier. She believed knowledge was a gift meant to be passed forward.
Neither woman sought fame. They continued working quietly until retirement. When they received the Squibb Award in 1955, each accepted a $5,000 honorarium—the only money they ever personally took from their discovery. In 1975, they became the first women to receive the Chemical Pioneer Award from the American Institute of Chemists.
Elizabeth Lee Hazen died in 1975.
Rachel Fuller Brown died in 1980.
In 1994, both were posthumously inducted into the National Inventors Hall of Fame.
Their legacy is not only Nystatin—though the drug is still used worldwide today. Their legacy lives in every scientist supported by the Brown–Hazen Fund, every patient cured, every artwork saved, and every young woman who learned that collaboration, persistence, and integrity can change the world.
They didn’t need headlines.
They needed mason jars, trust, and patience.
And that was enough to save millions of lives.
