The proverb dates very far back in the history of warfare. It originated and found recognition in those times when warfare was not regulated by laws of war--that is universally binding customs and international treaties, but only by usages (_Manier, i.e. Brauch_), and it says that necessity in war overrules usages of warfare. In our days, however, warfare is no longer regulated by usages only, but to a greater extent by laws, firm rules recognised either by international treaties or by universal custom.[88] These conventional and customary rules cannot be overruled by necessity, unless they are framed in such a way as not to apply to a case of necessity in self-preservation. Thus, for instance, the rules that poisoned arms and poison are forbidden, and that it is not allowed treacherously to kill or wound individuals belonging to the hostile army, do not lose their binding force even if escape from extreme danger or the realisation of the purpose of war would result from an act of this kind. Article 22 of the Hague Rules stipulates distinctly that the right of belligerents to adopt means of injuring the enemy is not unlimited, and this rule does not lose its binding force in a case of necessity. What may be ignored in case of military necessity are not the laws of war, but only the usages of war. _Kriegsraeson geht vor Kriegsmanier_, but not _vor Kriegsrecht_! [Footnote 88: Concerning the distinction between usage and custom, see above, vol. I. § 17.] IV THE REGION OF WAR Taylor, §§ 471 and 498--Heffter, § 118--Lueder in Holtzendorff, IV. pp. 362-364--Klüber, § 242--Liszt, § 40, I.--Ullmann, § 174--Pradier-Fodéré, VI. No. 2733, and VIII. Nos. 3104-3106--Rivier, II. pp. 216-219--Boeck, Nos. 214-230--Longuet, §§ 18-25--Perels, § 33--Rettich, _Zur Theorie und Geschichte des Rechts zum Kriege_ (1888), pp. 174-213. [Sidenote: Region of War in contradistinction to Theatre of War.] § 70. Region of war is that part of the surface of the earth in which the belligerents may prepare and execute hostilities against each other. In this meaning region of war ought[89] to be distinguished from theatre of war. The latter is that part of a territory or the Open Sea on which hostilities actually take place. Legally no part of the earth which is not region of war may be made the theatre of war, but not every section of the whole region of war is necessarily theatre of war. Thus, in the war between Great Britain and the two South African Republics the whole of the territory of the British Empire and the Open Sea, as well as the territory of the Republics, was the region of war, but the theatre of war was in South Africa only. On the other hand, in a war between Great Britain and another great naval Power it might well happen that the region of war is in many of its sections made the theatre of war. [Footnote 89: This distinction, although of considerable importance, does not appear to have been made by any other publicist.]