£100 reward will be paid by the Carbolic Smoke Ball Company to any person who contracts the influenza after having used the ball three times daily for two weeks according to the printed directions supplied with each ball...£1000 is deposited with the Alliance Bank, shewing our sincerity in the matter.
”
Mrs Carlill bought and used some smoke balls, following the directions provided. She subsequently became ill with the flu and attempted to claim the £100 reward.
Held
The advert constituted an offer of a unilateral contract. Mrs Carlill had accepted the offer by performing the attached conditions. The defence arguments were dismissed as follows:
The £1,000 deposit showed an intention to enter legal relations and was not a mere sales puff.
An offer can be made to the entire world.
In unilateral contracts the offeree does not have to communicate an intention to accept, because acceptance is shown by full performance.
Despite possible ambiguity in the wording, it is possible to apply a reasonable time limit or confining it to those who began ill with flu after using the balls.
The use of the balls gave consideration to the defendants even if the balls had not been bought directly from them.
Notes
Wikisource has original text related to this resource:
Simpson, A.W.B. (1985). "Quackery and Contract Law: The Case of the Carbolic Smoke Ball". Journal of Legal Studies14 (2): 345–389. doi:10.1086/467776. For a legal historian's discussion on the case.
Collins, H. (2003). The Law of Contract: Law in Context (4th ed.). London: LexisNexis Butterworths. ISBN 0-406-94673-6. For a critical and social analysis of the case and its place within 19th century free-market philosophy.
Poole, J. (2003). Casebook on Contract Law (6th ed.). New York: Oxford University Press. ISBN 0-19-926059-1. For a basic discussion and analysis of the judgment.