An old lady goes to the doctor.
“I don’t know what’s wrong with me,” she says. “I keep farting but my farts are silent and odourless. In fact, I’ve farted 20 times since walking in here without you noticing.”
The doctor gives the lady some medication and instructs her to return in a week’s time.
At her next appointment, the lady has noticed a change.
“I don’t know what was in those pills you gave me, but my farts now stink like hell. They’re still silent, though.”
The doctor smiles. “Well, now that we’ve cleared up your sinuses we can work on your hearing.”