The county commissioners shall furnish at least one room in each court house where jury trials are held with twelve substantial and comfortable seats, and convenient desks, for the use of jurors when deliberating. The court may, in its discretion and subject to such rules as it may prescribe, permit women jurors to use a designated rest room or lavatory situated in any part of the court house; and the temporary separation of women jurors from the remainder of the jury for such purposes shall not work a mistrial in any civil or criminal case, provided that women jurors shall be accompanied by a sheriff or his deputy in case of necessity to use such room or lavatory after a case has been finally committed to the jury for deliberation thereon.