This case brief covers a seminal torts case holding that consent to bodily contact may be implied from a person’s conduct and surrounding circumstances, defeating a battery claim.
O\'Brien v. Cunard is a foundational torts case on the defense of consent to intentional torts, particularly battery. Decided by the Supreme Judicial Court of Massachusetts in 1891, it frames consent as an objective inquiry: what matters is not a plaintiff’s unexpressed reservations, but the reasonable meaning conveyed by her words and actions in context. By holding that a passenger’s conduct—queuing for vaccination, presenting her arm, and remaining silent—manifested assent, the court made clear that consent may be implied from overt behavior rather than explicit verbal agreement.
For law students, the case is an essential pivot between the interests of bodily integrity (a core aspect of personhood) and the social realities of public health, immigration control, and institutional processes. It underscores how the law protects personal autonomy through the doctrine of consent while relying on objective manifestations of will to guide and justify others’ actions. In courses that explore personhood and property, O\'Brien helps illuminate how tort law treats control over one’s body as a protected interest, yet subjects it to principled limits through doctrines like implied consent and the objective theory of intent.
154 Mass. 272, 28 N.E. 266 (Mass. 1891)
The plaintiff, an Irish immigrant traveling in steerage from Queenstown to Boston aboard a Cunard steamship, alleged that the defendant’s ship surgeon committed a battery by vaccinating her without consent. At the time, immigration authorities commonly required arriving passengers to present proof of vaccination or to be vaccinated before landing. On board, the ship’s surgeon announced that those without satisfactory proof should be vaccinated. The plaintiff joined a line of female passengers, approached the surgeon when called, and, after the customary inquiries, raised or held out her arm. The surgeon performed the vaccination without hearing any objection from her, and she did not withdraw or resist. After disembarkation, she sued the steamship company (as the surgeon’s employer) for assault and battery, claiming she had been previously vaccinated and did not truly consent, but felt compelled because she was told vaccination was required for landing. The trial court directed a verdict for the defendant. The plaintiff sought appellate review.
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.
The court emphasized that consent need not be verbal and may be inferred from behavior and context. Here, the plaintiff joined other passengers in a vaccination line after the surgeon announced the procedure for those lacking proof. She approached when called, made no protest, and presented her arm for the inoculation. Those actions communicated assent to a reasonable person in the surgeon’s position. The court rejected the argument that the plaintiff’s private unwillingness or her belief that vaccination was required to land converted the procedure into a nonconsensual touching. The relevant question is what her conduct reasonably conveyed, not what she silently wished. The court also noted that the surgeon acted within the scope of the apparent permission—performing only the vaccination described—and did not exceed any consent given. Under these circumstances, the contact was not offensive or unpermitted. Accordingly, there was no battery and, thus, no tort liability for the shipowner based on the surgeon’s act.
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).
It establishes that consent can be inferred from a person’s conduct and the circumstances. If a reasonable person in the actor’s position would interpret the plaintiff’s behavior as permission, that implied consent defeats a battery claim. Standing in line, approaching when called, and exposing an arm for vaccination objectively communicated assent.
No. Consent is judged objectively. Unexpressed, subjective reluctance does not negate the permission reasonably conveyed by the plaintiff’s words, actions, and silence. Secret reservations are immaterial if the actor reasonably understands the conduct as assent.
Not for purposes of battery in this case. The court treated the requirement as a condition of entry imposed by authorities, not as wrongful compulsion by the defendant. The plaintiff remained free to refuse the procedure, even if refusal entailed consequences for landing. Thus, her compliance, manifested through conduct, constituted consent.
O\'Brien addresses battery (unpermitted touching) and focuses on whether the touching was consented to, expressly or impliedly. Modern informed consent, typically sounding in negligence, concerns whether a medical professional adequately disclosed material risks and alternatives so the patient could make an informed decision. A touching can be consensual under O\'Brien yet still raise informed consent issues under negligence principles.
Likely yes. An explicit objection or clear withdrawal would negate consent. Proceeding with the vaccination after such a refusal could constitute a battery, because the contact would be unpermitted and offensive in the legal sense.
The case affirms the centrality of bodily autonomy (a key aspect of personhood) while showing that the law operationalizes autonomy through an objective standard. Although tort law treats control over one’s body as a protected interest, it uses outward manifestations—rather than internal states—to structure interactions, particularly in institutional and public health settings.
O\'Brien v. Cunard teaches that the law of battery turns on permission, and permission can be communicated without words. By analyzing consent through an objective lens, the court balanced personal sovereignty over the body with the practical need for others to rely on observable signals in dynamic settings like public health screening.
For law students, the case is a touchstone for understanding consent as a defense to intentional torts and a stepping stone to deeper inquiries into bodily integrity, personhood, and the evolution from simple permission-based analyses to the richer, disclosure-focused frameworks of modern informed consent. It remains regularly cited to illustrate how context and conduct can authorize contact and defeat liability.