One form of license shall be issued which shall be designated “License to Practice Chiropractic” and which shall authorize the holder thereof to practice chiropractic as defined in § 442-1 and also to use all necessary mechanical, hygienic, and sanitary measures incident to the care of the body, but shall not authorize the administration of drugs or medicine now or hereafter included in materia medica, or the performance of any surgical operation or the practice of osteopathy, dentistry, or optometry; provided that a holder of a license which has been limited, restricted, or placed under probation may practice chiropractic only within the limitation, restriction, or terms of probation.