The Secretary of the Interior is authorized to accept, on behalf of and without expense to the United States, from the Izaak Walton League of America, or its authorized trustees, a gift of certain lands in Teton County, Wyoming, described as the south half of section 4; the east half of the southeast quarter of section 5; the southwest quarter of the southeast quarter of section 5; the south half of the southwest quarter of section 5; the southeast quarter of the northeast quarter of section 7; the east half of the southeast quarter of section 7; the southwest quarter of the southeast quarter of section 7, and lot 4 of section 7; all of section 8; the north half of the northeast quarter of section 9; the north half of the northwest quarter of section 9; and the southwest quarter of the northwest quarter of section 9; the north half of the northeast quarter of section 17; lot 1 of section 18; and the east half of the northwest quarter of section 18; all in township 41 north, range 115 west, of the sixth principal meridian, including all the buildings and improvements thereon, and all rights, easements, and appurtenances thereunto appertaining, subject to the conditions that they be used and administered by the United States, under the supervision and control of the Secretary of the Interior, for the grazing of, and as a refuge for, American elk and other big game animals, and that they be known as the Izaak Walton League addition to the winter elk refuge: Provided, That upon the conveyance of said lands to the United States, as herein provided, they shall become a part of the winter elk refuge established under section 673 of this title, and shall be subject to any laws governing the administration and protection of said refuge.