The boards of chosen freeholders respectively in any two or more contiguous and adjoining counties may resolve that:
provision be made for the permanent relief of the poor in such counties in a welfare-house to be jointly owned by such counties, or so many thereof as adopt the plan, or as the resolutions may provide, which shall constitute a district and be conducted by a welfare board constituted as provided in section 44:1-43 of this title, for the permanent relief of the poor of such counties. In such case permanent relief shall be provided for the poor of such counties, except those municipalities which maintain their own permanent poor and which have elected not to participate for such purpose in the jointly maintained district welfare-house.
N.J.S. § 44:1-38