except such as contributed to military operations. All the able-bodied manhood of Europe was drawn into the armies or navies or into the improvised factories that served them. There was an enormous replacement of men by women in industry. Probably more than half the people in the belligerent countries of Europe changed their employment altogether during this stupendous struggle. They were socially uprooted and transplanted. Education and normal scientific work were restricted or diverted to immediate military ends, and the distribution of news was crippled and corrupted by military control and “propaganda” activities.
The phase of military deadlock passed slowly into one of aggression upon the combatant populations behind the fronts by the destruction of food supplies and by attacks through the air. And also there was a steady improvement in the size and range of the guns employed and of such ingenious devices as poison-gas shells and the small mobile forts known as tanks, to break down the resistance of troops in the trenches. The air offensive was the most revolutionary of all the new methods. It carried warfare from two dimensions into three. Hitherto in the history of mankind war had gone on only where the armies marched and met. Now it went on everywhere. First the Zeppelin and then the bombing aeroplane carried war over and past the front to an ever- increasing area of civilian activities beyond. The old distinction maintained in civilized warfare between the civilian and combatant population disappeared. Everyone who grew food, or who sewed a garment, everyone who felled a tree or repaired a house, every railway station and every warehouse was held to be fair game for destruction. The air offensive increased in range and terror with every month in the war. At last great areas of Europe were in a state of siege and subject to nightly raids. Such exposed cities as London and Paris passed sleepless night after sleepless night while the bombs burst, the anti-aircraft guns maintained an intolerable racket, and the fire engines and ambulances rattled headlong through the darkened and deserted streets. The effects upon the minds and health of old people and of young children were particularly distressing and destructive.