The board may refuse to grant a certificate to any person who has been convicted of a felony involving moral turpitude, who has been guilty of unprofessional conduct, or who is addicted to any vice to such a degree as to render him, in the opinion of the board, unfit to practice chiropractic, and may, for any of said causes, after due notice and hearing, revoke a certificate already issued.
Mass. Gen. Laws ch. 112, § 93