§ 904.
([May 20, 1936, ch. 432], title I, § 4, [49 Stat. 1365]; [Sept. 21, 1944, ch. 412], title V, §§ 502(a), 503, [58 Stat. 739], 740; [Dec. 23, 1944, ch. 725], [58 Stat. 925]; [June 29, 1948, ch. 703], [62 Stat. 1070]; [Oct. 28, 1949, ch. 776], §§ 2, 4(e),