The board of park commissioners may contract for a term not exceeding three years, upon such terms as the board deems expedient, with any private corporation or association not for profit maintaining a museum of natural history in any county within which the park district is located in whole or in part, or which has for its object the promotion of interest in or the conservation and preservation of the flora or fauna in any portion or all of the territory comprising the district for the purpose of obtaining for such district such services and assistance as can be rendered by such corporation or association.