The decree entered by the District Court composed of three judges under 28 U. S. C. 380 is vacated upon the ground that the cause, so far as relief by injunction is sought, has become moot (Mills v. Green, 159 U. S. 651, 653; Jones v. Montague, 194 U. S. 147, 151, 152; Richardson v. McChesney, 218 U. S. 487, 492; Mahan v. Hume, 287 U. S. 575), but without prejudice to action by the District Court in relation to any matter which may remain' in the cause.