Whenever, in the opinion of the court, it is proper for the jury to have a view of real property which is the subject of litigation, or of the place in which any material fact occurred, it may order them to be conducted in a body, under the charge of an officer, to the place, which shall be shown to them by some person appointed by the court for that purpose. While the jury is thus absent, no person other than the person so appointed shall speak to them on any subject connected with the trial.