But it is a fundamental condition of this procedure:
1. That the envoy be quite distinguishable as such by means of universally recognized and well-known marks; distinguishable both by sight and by hearing (flags of truce, white flags, or, if need be, white pocket-handkerchiefs) and signals (horns or bugles).
3. That he does not abuse his position in order to commit any unlawful act.
Of course any contravention of the last two conditions puts an end to his inviolability; it may justify his immediate capture, and, in extreme cases (espionage, hatching of plots), his condemnation by military law. Should the envoy abuse his mission for purposes of observation, whereby the army he is visiting is imperiled, then also he may be detained, but not longer than is necessary. In all cases of this kind it is recommended that prompt and detailed information be furnished to the head of the other army.
1. To accept, or to refuse such envoys. An envoy who is not received must immediately rejoin his own army; he must not, of course, be shot at on his way.
2. To declare that it will not during a fixed period entertain any envoys. Should any appear in spite of this declaration; they cannot claim to be inviolable.
3. To determine in what forms and under what precautions envoys shall be received. The envoys have to submit to any commands even though entailing personal inconvenience such as blindfolding or going out of their way on coming or returning, and such like.
[Sidenote: The Etiquette of Flags of Truce.]
The observance of certain forms in the reception of envoys is of the greatest importance, as a parley may serve as a cloak for obtaining information or for the temporary interruption of hostilities and the like. Such a danger is particularly likely to occur if the combatants have been facing one another, as in the case of a war of positions, for a long time without any particular result. These forms are also important because their non-observance, as experience shows, gives rise to recrimination and charges of violation of the usages of war. The following may, therefore, be put forward as the chief rules for the behavior of an envoy and as the forms to be observed in his reception.
1. The envoy (who is usually selected as being a man skilled in languages and the rules, and is mounted on horseback) makes for the enemy’s outpost or their nearest detachment, furnished with the necessary authorization, in the company of a trumpeter and a flag-bearer on horseback. If the distance between the two outposts of the respective lines is very small, then the envoy may go on foot in the company of a bugler or a drummer.