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:
Today in History. 1860 - Around midnight, the First Pony Express rider arrived in San Francisco with mail that originated in St. Joseph, Missouri. The first rider left St Joseph at the sound of cannon fire at 7:15 p.m., on Apr. 3 with a pouch that contained 49 letters, five telegrams and miscellaneous papers. 1865 - John Wilkes Booth shot President Abraham Lincoln at a play at Fordâs Theater in Washington, DC.