The persons so appointed when duly qualified, constituting the board of park commissioners, and their successors, shall be a body politic, with power to sue and be sued, use a common seal and make by-laws. The members of the commission shall serve without compensation but their necessary expenses shall be allowed and paid. No person employed by the commission shall be a member thereof.

Before entering upon the duties of his office, each commissioner shall take and subscribe an oath that he will faithfully and impartially perform the duties of his office. Their oaths shall be filed in the office of the county clerk.