Section 304 — Criminal Code: Selling book containing defamatory libel

No person shall be deemed to publish a defamatory libel by reason only that he sells a book, magazine, pamphlet or other thing, other than a newspaper that contains defamatory matter, if, at the time of the sale, he does not know that it contains the defamatory matter. Where a servant, in the course of his employment, sells a book, magazine, pamphlet or other thing, other than a newspaper, the employer shall be deemed not to publish any defamatory matter contained therein unless it is proved that the employer authorized the sale knowing that defamatory matter was contained therein; or defamatory matter was habitually contained therein, in the case of a periodical.