Opinion, Convention signed at The Hague, Jan. 23, 1912, by plenipotentiaries of Germany, United States, China, France, Great Britain, Italy, Japan, Netherlands, Persia, Portugal, Russia, and Slam, for progressive suppression of abuse of opium, morphine, cocaine, and derivative drugs [and final protocol of 2d International Opium Conference siped The Hague, July 9, 1913].