Professional office use-a professional office for the personal use of a physician, lawyer, dentist, or professional practitioner of a character similar to any of the foregoing, but specifically excluding funeral homes, realty offices, insurance offices, and similar practitioners which are provided for in the E-Business District, provided that the office is located within the residence of the professional person, and provided that the office is located within the residence of the professional person, and, provided further, that no goods are displayed nor professional identified other than by the display of a sign not to exceed 216 square inches in area with the name and profession of the person using the office, which sign shall be placed in a location approved and permitted by the Code Enforcement Officer, and, further provided, that no space is rented out or devoted to the use of other than the owner or tenant of said premises and not more than three assistants are therein employed and the essential character of the building as a residence is maintained.