Did you know, on this day (June 25) in 1957, the U.S. Patent Office awarded Patent No. 2,797,183 to Elizabeth Lee Hazen and Rachel Fuller Brown for nystatin, the first antifungal antibiotic safe enough for human use.

The discovery had already been announced in 1950 and the drug had been on the market for three years before the patent was granted.

Their collaboration began in 1948 and was conducted almost entirely through the mail, with Hazen culturing organisms from soil samples and Brown isolating their active compounds 150 miles away.

After countless failures, a soil sample from a Virginia dairy farm yielded a bacterium that was harmless to mammals but deadly to dangerous fungal infections.

Nystatin entered the market in 1954 and became the world's first safe antifungal antibiotic.

Over the life of the patent, it generated more than $13 million in royalties.

Hazen and Brown took none of the money.

Instead, the royalties funded scientific research and programs designed to help more women enter scientific careers.

In 1994, Hazen and Brown became only the second and third women ever inducted into the National Inventors Hall of Fame.