No constable, except as provided by this Code, shall be authorized to levy on any real estate unless there is no personal property to be found sufficient to satisfy the debt or unless the real estate, being in the possession of the defendant, was pointed out by the defendant. In such event the constable is authorized to levy on such real estate, if in his county, and to deliver over the execution to the sheriff of the county a return of the property levied upon; and the sheriff shall proceed to advertise and sell the same as in case of levies made by himself.