In connection with the consideration of any application for disability pension or review of the pension granted under this part, any county pension board may refer any applicant or person receiving the pension to any physician receiving a regular monthly salary or fee from the State or any of its political subdivisions for physical examination and report to the board thereon as to the existence or continuance of disability. Any physician to whom the application is referred shall make the necessary physical examination and report the physician’s findings and recommendations to the board, but shall neither charge nor receive any fee for the particular examination and report.