§ 651. Appointment of person to act as sheriff in certain cases. When a vacancy shall occur in the office of sheriff, and there be no undersheriff to perform the duties, the county judge shall designate and appoint some suitable and proper resident of the county to perform the duties of sheriff until a new sheriff is elected or appointed and has qualified. The designation shall be in writing and filed and recorded in the office of the county clerk. The county clerk shall notify the person so designated of such designation, and within ten days thereafter, an official undertaking shall be furnished in the same amount and approved in the same manner as that of the sheriff. If such undertaking be not furnished, the county judge shall designate another person in the same manner.