An old lady goes to the doctor.

"Doctor," she says, "I keep farting, but my farts are silent and odorless. In fact I have farted 20 times since I was in your office but since my farts are noiseless and do not smell you have not noticed."

The doctor gives the lady some pills and instructs her to return after one week.

One week later, the lady is back at the doctor's office. "I do not know what was in those pills you gave me, Doctor," said the lady, "But my farts, though still silent, now stink like hell."

The doctor smiles in satisfaction. "Excellent! Now that we have cleared up your sinuses, let's work on your hearing."