1. Any chiropractor who holds a license stating that the holder is not authorized to use X-ray in his practice shall on each registration, continue to obtain a license so marked. Any chiropractor holding such a license may obtain a license permitting the use of X-ray provided he first passes an examination in the use and effect of X-ray satisfactory to the board and the department.

2. An applicant who graduated from a school of chiropractic prior to January first, nineteen hundred sixty-eight need not meet the two-year preprofessional college study requirement provided for in subdivision two of section sixty-five hundred fifty-four.