Section 37. At any boxing or sparring match or exhibition there shall be in attendance a duly licensed physician, whose duty it shall be to observe the physical condition of the boxers and advise the referee or judges with regard thereto. Any competent physician who has had not less than three years’ experience as a medical practitioner may be licensed. No boxer shall be permitted to enter the ring unless, not more than three hours before, a physician licensed under the provisions of sections thirty-two to forty-seven, inclusive, shall certify in writing that the boxer is physically fit to engage in the proposed contest. The physician’s fee, as fixed by the commission, shall be paid by the licensee conducting the match or exhibition.