(Amended by Ordinance No. 134934, effective July 20, 1972.) Whenever the Chief of Police is in doubt concerning the physical or mental ability of a member of the Bureau of Police to perform full police duties, the Chief shall require that member, upon written notice, to submit to a medical examination. The examination shall be conducted without expense to the member. Unexcused failure to take an examination required by this Section, after reasonable notice, shall be cause for the member’s dismissal.