The first antifungal to be discovered was nystatin; this medicine was discovered in 1950 by Rachel Fuller Brown and Elizabeth Lee Hazen, two researchers in the USA. These two researchers had a long distance partnership which relied heavily on the postal service to mail samples between each other. Hazen cultured bacteria from soil samples collected all over the US. She then tested to see if any of the compounds the bacteria produced were effective at killing fungi. When she saw something promising, she sent it in the post to Brown, who isolated and purified the compounds. Brown then posted the compounds back to Hazen who tested them on the fungi again and then if effective, tested them on animals. This went on until they found an active non-toxic compound. The compound they discovered was nystatin, which remains an effective treatment for skin, mouth, vaginal and intestinal tract fungal infections.