The personnel of Voluntary Aid Societies employed in the medical units and establishments is, according to article 10, privileged to the same extent as the official personnel, provided that the Voluntary Aid Society concerned is duly recognised and authorised by its Government and that the personnel of the Society is subject to military law and regulations. Each State must notify to the other, either in time of peace or at the commencement, or during the course, of hostilities, but in every case before actually employing them, the names of societies which it has authorised to render assistance to the regular medical service of its armies. A recognised Voluntary Aid Society of a _neutral_ country cannot, according to article 11, afford the assistance of its personnel and units to a belligerent unless it has previously received the consent of its own Government and of the belligerent concerned. And a belligerent who accepts such assistance from a Voluntary Aid Society of a neutral country is bound, before making any use of it, to notify the fact to the enemy. [Sidenote: Convoys of Evacuation.] § 122. Convoys used for evacuating the wounded and sick must, as regards their personnel and material, be treated in the same way as mobile medical units, but subject to the following special provisions enacted by article 17:-- A belligerent intercepting a convoy may, if military exigencies demand, break it up, provided he takes charge of the sick and wounded who are in it. In this case, the obligation to send back the medical personnel, provided for in article 12, must be extended to the whole of the military personnel detailed for the transport or the protection of the convoy and furnished with an authority in due form to that effect. The obligation to restore the medical material, provided for in article 14, must apply to railway trains and boats used in internal navigation, which are specially arranged for evacuation, as well as to the material belonging to the medical service for fitting up ordinary vehicles, trains, and boats. Military vehicles, other than those of the medical service, however, may be captured with their teams; and the civilian personnel and the various means of transport obtained by requisition, including railway material and boats used for convoys, are subject to the general rules of International Law concerning war. [Sidenote: Distinctive Emblem.] § 123. According to article 18 the Swiss heraldic device of the red cross on a white ground, formed by reversing the federal colours, is adopted as the emblem and distinctive sign of the medical service of armies, but there is no objection to the adoption of another emblem on the part of such non-Christian States as object to the cross on religious grounds. Thus Turkey has substituted a red crescent, and Persia a red sun for the cross.[251] The following are the rules concerning the use of this emblem:--