Sec. 3. _Be it further ordained, etc._, That every restaurant kitchen, hotel kitchen, cabaret kitchen, dairy, dairy depot, dock, wharf, pier, elevator, store, manufactory, and every other building, outhouse, or superstructure wherein or whereon foodstuffs are stored, kept, handled, sold, held, or offered for sale, manufactured, prepared for market or for sale, except stables, shall be rat proofed in the manner provided for hereinabove as class A: _Provided_, That such part of any structure hereinabove defined as of class A that shall be entirely over a body of water may be rat proofed as of class B, as hereinafter provided for. "Foodstuffs," as used in this ordinance, is hereby defined to be flour and flour products, animals and animal products, produce, groceries, cereals, grain, and the products of cereals and grain, poultry and its products, game, birds, fish, vegetables, fruit, milk, cream, and products from milk or cream, ice cream, hides, and tallow, or any combination of any one or more of the foregoing. All other buildings, outhouses, and superstructures, except stables, not hereinbefore specified as class A, and all buildings used exclusively for residential purposes, shall be rat proofed in the manner provided for hereinabove as class B: _Provided_, That the owner of any building, residence, outhouse, or other superstructure in class B may, if he so elects, rat proof same in the manner provided for in class A. _Provided_, That in any case where, under the foregoing provisions, any building, outhouse, or superstructure is required to be rat proofed as of class A and the said building or outhouse or superstructure is used in part for residential purposes, and the part used as a residence is effectively separated from the part falling within class A, by permanently and effectively closing all openings above and below the ground floor, or by constructing a new wall, and in either case the whole in such manner as to make such wall whole and continuous in its entirety, without doorways, windows, or other openings between the part used as a residence and that used for such purposes as makes it fall within class A, then in such case and for rat-proofing purposes only, the said building will, after such separation and closure of the openings, or by the construction of such new wall, be deemed to be two buildings; and that part used exclusively for residential purposes may be rat proofed in the manner provided for as a class B building, and the remaining part of said building shall be rat proofed in the manner provided for a class A building. _Stables._--Stables and all buildings hereafter to be constructed and used for stabling horses, mules, cows, and other animals shall be constructed as follows: