George Brown (plaintiff) and George Kendall (defendant) both owned dogs. One day their dogs began to fight each other. Kendall took a long stick and began hitting the dogs to separate them. Brown watched from what he thought was a safe distance. But the dogs moved in his direction, causing Brown to move away from them, toward Kendall’s back. Kendall did not see Brown move. Kendall raised his stick again, and on his backswing, inadvertently hit Brown in the eye. Kendall severely injured Brown. Brown sued Kendall for assault and battery. The trial court judge instructed the jury that if Kendall had a duty to act and was acting in a proper manner, Kendall was not liable for Brown’s injuries. But if Kendall did not have a duty to act, then he was liable for Brown’s injuries unless he had exercised extraordinary care. After hearing these instructions, the jury returned a verdict for Brown. Kendall appealed to the Supreme Court of Massachusetts.