By the term “courthouse door” of a county is meant either of the principal entrances to the house provided by the proper authority for the holding of the district court. If from any cause there is no such house, the door of the house where the district court was last held in that county shall be deemed to be the courthouse door. Where the courthouse, or house used by the court, has been destroyed by fire or other cause, and another has not been designated by the proper authority, the place where such house stood shall be deemed to be the courthouse door.