but glorious thrusts at Arras and in Champagne in 1915, the British at Loos. From Switzerland to the North Sea there ran two continuous lines of entrenchment, sometimes at a distance of a mile or more, sometimes at a distance of a few feet (at Arras, e.g.), and in and behind these lines of trenches millions of men toiled, raided their enemies, and prepared for sanguinary and foredoomed offensives. In any preceding age these stagnant masses of men would have engendered a pestilence inevitably, but here again modern science had altered the conditions of warfare. Certain novel diseases appeared, trench feet for instance, caused by prolonged standing in cold water, new forms of dysentery, and the like, but none developed to an extent to disable either combatant