It shall be unlawful for any teacher of a school supported in whole or in part from the public school funds of this State or any trustee of any such school or any other school officer to become an active or silent agent of any schoolbook publisher or be in anywise pecuniarily interested in the introduction of any schoolbook into any school in this State. Any person violating any of the provisions hereof shall be guilty of a misdemeanor, and, upon conviction thereof, shall be subject to a fine of not less than one hundred dollars or imprisonment in the county jail for a period of not less than thirty days, or both, at the discretion of the circuit judge.