Surfactant prevents this collapse by reducing the surface tension of the fluids that line the lungs and helping to equalize the pressures between large and small air spaces. Surface tension is a measure of the attraction molecules of a fluid have for each other.
Buffalo Bill Cody, who later became famous for his Wild West Show, was a rider for the Pony Express and wrote of his experiences. We join Bill's story as he is hired - at the age of 15 - to ride a section of the trail that lies in modern-day Wyoming:
Born near LeClaire in Scott County, Iowa, in 1846, Buffalo Bill Cody rode on the Pony Express at the age of 14, fought in the American Civil War, served as a scout for the Army, and was already an Old West legend before mounting his famous Wild West show, which traveled the United States and Europe.