A lot as changed in running the the past 100 years - especially the speed. The 1908 World record for the marathon stood at a relatively modest 2:55:18. Heck, with a few more miles I think I would have a chance to make the 1908 US Olympic team. I'm just not sure I could handle the ferry to London.
The marathon was first run in the 1886 Olympics, sprouting running interest and new races in the U.S. Here are some fantastic photos from the 1907 Illinois Athletic Association Marathon and other "ultra" events, via the Chicago Daily News archive:
Marathoner Albert Corey and an unidentified runner race towards the finish line of a 100-mile race from Milwaukee to Chicago. Notice the outfits they're wearing. How would you like to go 100 miles in those shoes?
Marathon runners stand abreast on a field before the start of the 1907 Illinois Athletic Club Marathon. I wonder if those men on the left are planning to run?
Albert Corey, marathoner, taking a fuel break.
A spectator looks like he wants to join in.
Athletes running along an unpaved road, beside automobiles. The athletes were reportedly very bothered by the automobile exhaust.