6 U.S. 921, S.Ct. 700, 2 LEd.2d 716, rehearing denied, 1958, 366 U.S. 964, 78 S.Ct. 991, 2 L.Ed.2d 1072. J United States, 896, 897, we [14] In McCroskey 8 Cir., 1965, 339 F. stated: "Thirty-f' years I in Johnson United States, 32 F2d 127, 130 (8 ir. 1929), listed five re- quirements generally r