((a)) When appropriate naval hospital facilities are unavailable, the Secretary of the Navy may provide for the care and treatment of members of the naval service, entitled to treatment in naval hospitals, in other United States hospitals, if the agencies controlling the other hospitals consent. Expenses incident to such care and treatment are chargeable to the same appropriation as would be chargeable for care and treatment in a naval hospital.

((b)) The deduction authorized by section 4812 of the Revised Statutes () shall be made from accounts of members hospitalized under this section.