It is impossible within the space at our command here to trace the intricate details of the war. Within a few months it became apparent that the progress of modern technical science had changed the nature of warfare very profoundly. Physical science gives power, power over steel, over distance, over disease; whether that power is used well or ill depends upon the moral and political intelligence of the world. The governments of Europe, inspired by antiquated policies of hate and suspicion, found themselves with unexampled powers both of destruction and resistance in their hands. The war became a consuming fire round and about the world, causing losses both to victors and vanquished out of all proportion to the issues involved. The first phase of the war was a tremendous rush of the Germans upon Paris and an invasion of East Prussia by the Russians. Both attacks were held and turned. Then the power of the defensive developed; there was a rapid elaboration of trench warfare until for a time the opposing armies lay entrenched in long lines right across Europe, unable to make any advance without enormous losses. The armies were millions strong, and behind them entire populations were organized for the supply of food and munitions to the front. Then was a cessation of nearly every sort of productive activity 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.