Related Rule
Germany
Practice Relating to Rule 109. Search for, Collection and Evacuation of the Wounded, Sick and Shipwrecked
Germany’s Military Manual (1992) states that a cease-fire may be concluded for “humanitarian purposes, in particular searching and collecting the wounded and the shipwrecked”. 
Germany, Humanitarian Law in Armed Conflicts – Manual, DSK VV207320067, edited by The Federal Ministry of Defence of the Federal Republic of Germany, VR II 3, August 1992, English translation of ZDv 15/2, Humanitäres Völkerrecht in bewaffneten KonfliktenHandbuch, August 1992, § 233.
The manual adds: “At all times, all possible measures shall be taken to collect the wounded and sick and shipwrecked”. 
Germany, Humanitarian Law in Armed Conflicts – Manual, DSK VV207320067, edited by The Federal Ministry of Defence of the Federal Republic of Germany, VR II 3, August 1992, English translation of ZDv 15/2, Humanitäres Völkerrecht in bewaffneten KonfliktenHandbuch, August 1992, § 605.