§ 90. Police station houses for the detention of women; how designated. The mayor of every city containing a population of twenty-five thousand shall and the mayor of every other city when authorized by a resolution of the common council may designate one or more station houses within his city for the detention and confinement of all women under arrest in such city. Such mayor or board of commissioners of police may at any time designate for such purpose any additional station house or houses, or may revoke the designation of any station house or houses theretofore designated, provided that at least one such station house shall at all times be so designated for such purpose in each city.