A person who voluntarily engages in the interchange of opprobrious epithets and mutual vituperation and abuse has been held to license his antagonist to reply in like manner. "The right to answer a libel by libel is analogous to the right to defend one's self against an assault upon his person. The resistance may be carried to a successful termination, but the means used must be reasonable." Common carriers, news-vendors, proprietors of circulating libraries and others who are merely unconscious vehicles for carrying defamation generally escape liability for its publication.
If the publication of a libel is the result of the joint efforts of several persons, each is responsible for the wrong done to the plaintiff. If A writes a libel, and B prints it and C publishes it, the person wronged may sue all jointly, or either one of them separately. The publication of the same slander by different persons is not a joint tort, it is a distinct wrong done by each slanderer.
There are distinctions between libel and slander that must be now stated. Slander is applied to oral speech or its equivalent, libel to matters expressed in writing or print, pictures, effigies or other visible and permanent forms. Libel is a criminal offense as well as a tort, while the slander of private persons is not a common law crime; but some forms of slander are crimes by statute. Falsely and maliciously to charge one with committing a felony or other indictable offense involving moral turpitude is in some states a crime. Scandalous matter is not necessary to make a libel. "It is enough if the defendant induces an ill opinion to be held of the plaintiff, or to make him contemptible or ridiculous." Says Burdick: "Any censorious or ridiculing writing, picture or sign made intentionally and without just cause and excuse is a libel upon its victim. The degree of censure or ridicule is not material. If the language is such that others, knowing the circumstances, would reasonably think it defamatory of the person complaining of and injured by it, then it is actionable."
In many cases of libels which affect the victim chiefly or solely in his office or vocation their tendency to cause injury is so clear that proof may be unnecessary. Thus, to import insanity or incompetency to a professional man, or that a public official is dishonest and corrupt is actionable. And when a libelous publication is directed against a class or body of persons, for example, the medical staff of a public hospital, any member of the body may maintain an action for the wrong.