The purpose of antinarcotic laws represents an adjustment between common law and common welfare. In accordance with the provisions of the Hague convention of 1912, Congress made laws for controlling and regulating the production of and the traffic in the drugs mentioned by the convention. Now domestic production and traffic in these dangerous drugs is limited by federal law, first becoming effective, March 1, 1915, and subsequently amended by certain sections of the revenue laws. The penalties and restrictions imposed by the laws of Jan. 17, 1914, made prohibitive the legalized manufacture of smoking opium. The international traffic in narcotic drugs was first regulated by law, Feb. 9, 1909, and by subsequent legislation in 1914, 1922, 1924 and 1930. The importation of opium and coca leaves into the United States is restricted to the quantities considered necessary for medical and scientific uses only. In-transit shipments of smoking opium are forbidden.