§ 14. Previous disability. The fact that a volunteer ambulance worker has suffered previous disability or received benefits therefor as provided in the workers' compensation law, or this chapter shall not preclude him from benefits for a later injury nor preclude death benefits for death resulting therefrom; provided, however, that a volunteer ambulance worker who is suffering from a previous disability shall not receive benefits for a later injury in excess of the benefits allowed for such injury when considered by itself and not in conjunction with the previous disability. Notwithstanding the foregoing provisions of this section, if a volunteer ambulance worker has previously incurred permanent partial disability through the loss or loss of use of one hand, one arm, one foot, one leg, or one eye, and suffers the loss or loss of use of another such major member or eye, he may be adjudged permanently totally disabled and receive benefits for permanent total disability as provided in section eight of this article.