The civil service board, in an emergency, or in cases where it deems proper, may authorize the chief of police to appoint for temporary service such number of police officers as in the opinion of the board of commissioners of the city the existing conditions demand. All officers so appointed shall be furnished with badges, the badge to be different in size and design from the regulation badges used by the regular members of the police and detective force, and shall have the words special officer across the face of them in large letters. The chief of police shall furnish the board with the names and addresses of all persons to whom he or she has issued special badges, and at the expiration of their appointment shall cause all such badges to be taken up. It shall be unlawful for any person to have in his or her possession any commission or any badge of a police officer of the city unless same has been issued to him or her by the civil service board.