All applicants for examination shall undergo a physical examination, which shall be conducted under the supervision of a doctor of medicine appointed by the sheriff of the county. No person shall be eligible to take an examination until said doctor certifies to the commission that the applicant is free from any bodily or mental defects, deformity or disease that might incapacitate him from the discharge of the duties of a deputy sheriff.
16 P.S. § 4221.9