Two young medical students were standing on a street corner observing people as they passed by, discussing any abnormalities they noticed in the passers-by.
They saw this old fellow sort of duck waddling down the street at a slow pace.
The two students introduced themselves to the gentleman and told him that they didn't agree with each other's diagnosis of the old man's problem.
One says, "My friend thinks you have a bad case of hemorrhoids, and I think you have a hernia."
The old man said, "I thought it was a fart, but from the feel of it, looks like we were all wrong!"