(a) When the Public Health Service requires the services of consultants who cannot be obtained when needed through regular Civil Service appointment or under the compensation provisions of the Classification Act of 1949, special consultants to assist and advise in the operations of the Service may be appointed, subject to the provisions of the following paragraphs and in accordance with such instructions as may be issued from time to time by the Secretary of Health and Human Services.

(b) Appointments, pursuant to the provisions of this section, may be made by those officials of the Service to whom authority has been delegated by the Secretary or his designee.

(c) The per diem or other rates of compensation shall be fixed by the appointing officer in accordance with criteria established by the Surgeon General.