Mulcahy (P) alleged that Duggan (D) violently, wantonly, and maliciously assaulted P. D answered and admitted that he struck P but also counterclaimed for libel and that the assault was a direct result of the published libel. P demurred to the counterclaim, and that demurrer was overruled. During trial the court then ruled that the matter set out in the counterclaim was not properly before the court, but it might be proper in mitigation of damages and that D could show that a reasonable man was so provoked by the publication that he assaulted P without malice. D was allowed to amend his complaint and filed the facts as an affirmative defense. The trial court rejected this argument and P got the verdict. D appealed.