Section 62H. A contract for the care and treatment of children coming within the provisions of section sixty-two A, entered into by the commission on children's health camps of a city or town which accepts or has accepted sections sixty-two A to sixty-two G, inclusive, or by a commission on union children's health camps established or to be established under section sixty-two F, with the persons having control of any institution approved by the department in or near said city or town, shall, while such contract remains in force and effective, be deemed satisfactory compliance on the part of such city or town or union with the provisions of said sections sixty-two A to sixty-two G, inclusive, relative to the establishment and maintenance of children's health camps. No such contract shall become effective until it has been approved by the department.