38. The matériel of military hospitals remains subject to the laws of war; persons attached to the hospitals can only, therefore, carry away their private property on leaving. Ambulances, on the other hand, preserve their matériel.
39. Under the circumstances contemplated in the foregoing paragraph, the term "ambulance" is applicable to field hospitals and other temporary establishments which follow the troops to the field of battle for the purpose of receiving sick and wounded.
40. A distinctive flag and uniform, bearing a red cross upon a white ground, is adopted for hospitals, ambulances, and things and persons connected with the movement of sick and wounded. It must always be accompanied by the national flag.
II. Of Occupied Territory
A. DEFINITION
41. A territory is considered to be occupied when, as the result of its invasion by an enemy's force, the State to which it belongs has ceased, in fact, to exercise its ordinary authority within it, and the invading State is alone in a position to maintain order. The extent and duration of the occupation are determined by the limits of space and time within which this state of things exists.
B. RULES OF CONDUCT WITH REGARD TO PERSONS
Since new relations arise from the provisional change of government,
42. It is the duty of the occupying military authority to inform the inhabitants of the occupied territory as soon as possible of the powers which it exercises, as well as of the local extent of the occupation.
43. The occupier must take all measures in his power to reëstablish and to preserve public order.