Nothing in this title shall apply to or prevent the sale, purchase or consumption

(1) of any pharmaceutical preparation containing liquor which is prepared by a druggist according to a formula of the pharmacopoeia of the United States, or the dispensatory of the United States; or

(2) of any proprietary or patent medicine; or

(3) of wood alcohol or denatured alcohol, except in the case of the sale, purchase, or consumption of wood alcohol or denatured alcohol for beverage purposes, either alone or combined with any other liquid or substance.