Neither the United States nor the District of Columbia, nor any officer, agent, or servant thereof, shall be at any expense by reason of the delivery of any body or bodies aforesaid, except such as may be properly chargeable on account of bodies delivered to the medical schools of the Army, Air Force, and Navy, the medical examining boards of the Army, the Air Force, the Navy, and the Public Health Service, and the Commission on Licensure to the Practice of the Healing Art; but all expenses of such delivery and distribution, except as hereinbefore specified, and of said Anatomical Board, shall be paid by the schools receiving such bodies, in such manner as may be specified by said board and by such school in proportion to the number of bodies which it has received; and no school which has failed or refused to pay its just proportion of such expense as determined by said board shall be allowed to receive any body or bodies, or parts thereof, while the amount so due remains unpaid.