ACTS JUNE 30, 1947, CH. 163, 61 STAT. 193; MAR. 30, 1948, CH. 161, 62 STAT. 93; MAR. 30, 1949, CH. 42, 63 STAT. 18; JUNE 23, 1950, CH. 354, 64 STAT. 255— (§§ 1881_to_1884—1