In N.L.R.B. v. Gulf Public Service Co., 5 Cir., 116 F.2d 852, 854, the controversy, arising over the efforts of the Board to extend the actual, to the limits of the theoretical, jurisdiction, then being in its early stage, we pointed out the absence from the act of any "standard of degree by the use of which it can be said, as a matter of power rather than of wise policy, that a particular amount of probable direct interference with interstate commerce is too little to come within its cognizance".