[Ordinances of the City of Portland,] § 41. Be it further ordained, That if any person shall fire or discharge any gun or pistol from the top or window of any house or other building, or in or upon any of the streets, wharves, lanes, alleys, or public squares, or in any yard or garden within the city, the same being loaded with ball or shot or with powder only , every person so offending, shall, for each offence, forfeit and pay one dollar. Provided, nevertheless, and it is hereby ordered, That nothing herein contained, shall be construed to prohibit any person or persons form the exercise of their lawful right of self defense, defense of property, aiding officers, or obeying the orders of their proper commanders on muster days, nor to prevent the destruction of mad dogs.