Section 25. Whoever shall carry a weapon or weapons, concealed on or about his person, such as a pistol, bowie-knife, dirk, or any other dangerous weapon, on conviction of the first offense shall be fined not exceeding one hundred dollars, or imprisoned in the county jail not more than thirty days, and for for the second offense not exceeding one hundred dollars or imprisoned in the county jail not more than three months, or both, at the discretion of the court; Provided, however, If it shall be proved from the testimony on the trial of any such case that the accused was, at the time of carrying any weapon or weapons as aforesaid, engaged in the pursuit of any lawful business, calling, or employment, and the circumstances in which he was placed at the time aforesaid were such as to when justify a prudent man in carrying the weapon or weapons aforesaid, for the defense of his person, property, or family, the accused shall be acquitted.