Endurance for four days or for 220 days, the ability to walk back after the battle or the inability to move at all due to exhaustion, seem to be the extremes. Of course, for the purpose of this study such a finding is insufficient. Further details are required regarding the meaning of endurance and, in particular, a differentiation is necessary between the factors which finally lead to exhaustion. W. Noyce deals with the subject and examines a number of individual cases.1 He analyses the behaviour of a miner buried underground, of trapped polar explorers, of shipwrecked sailors, of lost mountaineers, of a hermit and of a cancer patient, all of whom willed their bodies to superhuman efforts. This cannot be applied directly to military situations, because more than mere survival is involved. In addition the soldier is supposed to take part in active combat. Moreover, the behaviour of individual personalities cannot be applied to large armies. Nevertheless, Noyce's book provides some answers.