Carbolic Smoke Ball advertised that any person taking their smoke ball as directed and catching flu could claim £100 from them. Mrs Carlill took the ball as directed and still caught flu. She claimed her £100 and Carbolic Smoke refused. Held: She could sue and claimed £100. It was an offer to the whole world that she had accepted. Her compliance with the terms had turned it from an offer to the whole world to contract with her personally.