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:
The San Francisco AltaApril 4, 1860 The first Pony Express started yesterday afternoon, from the office of the Alta telegraph company, on Montgomery street. The saddle bags were duly lettered Overland Pony Express, and the horse, (a wiry little animal,) was dressed with miniature flags.he idea behind the Pony Express a horseback relay mail service goes back at least as far as thirteenth-century China, where Marco Polo saw post stations twenty-five miles apart.