Section 37. “Drug business”, as used in the two following sections, shall mean the sale, or the keeping or exposing for sale of drugs, medicines, chemicals or poisons, except as otherwise provided in section thirty-five, also the sale or the keeping or exposing for sale of opium, morphine, heroin, codeine or other narcotics, or any salt or compound thereof, or any preparation containing the same, or cocaine, alpha or beta eucaine, or any synthetic substitute therefor, or any salt or compound thereof, or any preparation containing the same, and the said term shall also mean the compounding and dispensing of physicians’ prescriptions.