Section 72A. Whoever, not being lawfully authorized to practice optometry, practices optometry, or holds himself out as a practitioner of, or as being able to practice, optometry, or whoever personates another practitioner, or violates any other provision of sections sixty-six to seventy-three, inclusive, or any rule or regulation made under authority thereof, shall, except as provided in section sixty-five, be punished for the first offence by a fine of not less than fifty nor more than two hundred dollars, or by imprisonment for not more than three months, or both; and for a subsequent offence, by a fine of not less than two hundred nor more than five hundred dollars, or by imprisonment for not less than three nor more than six months, or both.