If any member of said fire department or police department shall become or be found to be totally disabled for the discharge of his duties as a member of said fire department or police department, mentally or physically, by reason of sickness or injury caused or sustained by reason of service or discharge of his duty in said department, after such city shall have come within the terms of this article, said disability and relief board shall order the payment and there shall be paid from said fund to said fireman or policeman each month thereafter an amount equal to fifty percent (50%) of said fireman’s or policeman’s monthly salary, to be paid throughout such total disability for service. In passing upon the question of disability, said board shall require an examination of the applicant by the city physician or other physician or physicians as it may deem proper, and may require like examinations from time to time throughout the period of disability claimed by said fireman or policeman. If said city pays a salary to its firemen or policemen while disabled in an amount equal to the disability relief allowed under this section, said fireman or policeman shall not be entitled to any disability relief under this section.