Assisting in provoking?

A patent medicine salesman at the fair was shouting his claims for his Rejuvenation Elixir.

"If you don't believe the label, just look at me," he shouted. "I take it and I am 300 years old."

"Is he really that old?" asked a farmer of the salesman's young assistant.

"I really don't know," said the assistant. "You see, I have only been with him for 180
years."

NB: You don't need to know who the assistant is!