154 Mass. 272, 28 N.E. 266 (Mass. 1891)
O\'Brien v. Cunard is a foundational torts case on the defense of consent to intentional torts, particularly battery.
Whether a passenger's conduct—standing in line for vaccination, approaching the surgeon, and exposing her arm without objection—constitutes consent to the procedure sufficient to defeat a battery claim, notwithstanding her unexpressed reluctance or belief that vaccination was required to land.
Battery is an intentional and unpermitted contact that is harmful or offensive. Consent is a complete defense to battery and may be manifested expressly or impliedly through conduct and the surrounding circumstances. The existence of consent is judged objectively from the perspective of a reasonable person in the actor's position; undisclosed, subjective reservations do not vitiate consent reasonably inferred from a person's words, acts, and silence in context.
Yes. The plaintiff's conduct objectively indicated consent to the vaccination, and the surgeon was justified in proceeding on that basis. Because the contact was consented to, no battery occurred. The directed verdict for the defendant was affirmed.
O\'Brien is a cornerstone case for the defense of consent in intentional torts and for the objective theory of consent. It teaches that consent may be implied from overt acts, silence, and situational context, and that uncommunicated reservations are legally irrelevant where conduct signals assent. For students examining personhood and property themes, O\'Brien highlights how tort law protects bodily integrity yet pragmatically relies on objective manifestations to guide social and institutional interactions (e.g., public health processes). The case is frequently paired with later informed consent cases to contrast battery-based theories (focused on permission to touch) with negligence-based informed consent (focused on disclosure and decision-making quality).