Every person shall be at liberty to speak, write or publish his opinion on any subject, being liable for the abuse of that privilege; and no law shall ever be passed curtailing the liberty of speech or of the press. In prosecutions for the publication of papers investigating the conduct of officers or men in public capacity, or when the matter published is proper for public information, the truth thereof may be given in evidence. In all indictments for libels, the jury shall have the right to determine the law and the facts, under the direction of the court, as in other cases.