Section 305. Whoever, with intent to defraud or injure, in baling or in packing in any container any commodity sold by weight, including wool, leather, cotton, waste, rags and paper, places therein any substance foreign to the contents thereof shall be punished for the first offence by a fine of not more than one hundred dollars, for the second offence by a fine of not more than two hundred dollars, and for a subsequent offence by a fine of fifty dollars and imprisonment for not less than one nor more than three months.