In addition to those persons, including the dependents of naval and Marine Corps personnel, now authorized to receive hospitalization at naval hospitals, hospitalization and dispensary service may be provided at naval hospitals and dispensaries outside of the continental limits of the United States and in Alaska, to the officers and employees of any department or agency of the Federal Government, to employees of a contractor with the United States or his subcontractor, to the dependents of such persons, and in emergencies to such other persons as the Secretary of the Navy may prescribe: Provided, That such hospitalization and dispensary service to other than the dependents of naval and Marine Corps personnel shall be permitted only where facilities are not otherwise available in reasonably accessible and appropriate non-Federal hospitals. The charge for hospitalization or dispensary service for persons other than dependents of naval and Marine Corps personnel as specified in this section shall be at such rates as the President shall from time to time prescribe, and shall be deposited as provided in section 32 1