Mohr v. Williams
Minnesota Supreme Court
104 N.W. 12 (Minn. 1905)
Mohr (plaintiff) consulted Dr. Williams (defendant) about problems with her right ear and consented to surgery on it after Williams found it partially diseased, though he was unable to examine her left ear beforehand. Once Mohr was under anesthesia, Williams discovered her left ear was actually significantly worse than her right, decided operating on the left ear would benefit her more, and performed that surgery instead — skillfully and successfully — without ever obtaining Mohr's consent to operate on the left ear. Mohr later alleged the unauthorized operation impaired her hearing and injured her, and sued for assault and battery; a jury awarded her over $14,000, but the trial judge found the verdict excessive and ordered a new trial, and both sides appealed.
Whether the absence of evil intent or negligence on a defendant's part serves as a defense to the civil tort of assault and battery.