By this I do not mean to imply that the changed conditions brought about by the Great War made the army signaler a good life-insurance risk. Far from it! But they did have the effect of making him a trifle less dashing and picturesque. Instead of recklessly exposing himself on the parapet of a trench in order to dash-dot a message which the enemy could have read with the greatest ease, he dragged himself, foot by foot, across the steel-swept terrain, a mud-caked and disreputable figure, on his task of repairing the tangle of copper strands which linked the infantrymen in the front-line trenches with the eager guns; crouching in the meagre shelter afforded by a shell-hole, with receivers strapped to his ears, he sent his radio messages into space; carrying on his back a wicker hamper filled with pigeons, he went forward with the second wave of an attack; or, by means of a military edition of the dictaphone device so familiar to readers of detective stories, he eavesdropped on the enemy’s strictly private conversations. Even though he had no opportunity to wave his little flags, the Signal Corps man never lacked for action and excitement. If the Air Service is, as it has frequently been termed, “the eyes of the army,” then the Signal Corps constitutes the army’s entire nerve-system. Under the conditions imposed by modern warfare, an army without aviators would be at least partially blind, but without signalers it would be bereft of touch, speech, and hearing. It is the business of the Signal Corps to operate and maintain all the various systems of message transmission—telegraphs, telephones, radios, buzzers, Fullerphones, flags, lamps, panels, heliographs, pyrotechnics, despatch-riders, pigeons, even dogs—which enable the Commander-in-Chief to keep in constant communication with the various units of his army and which permit of those units keeping in touch with each other. It was imperative that General Pershing should be able to pick up his telephone-receiver in his private car, sidetracked hundreds of miles away from the battle-front, perhaps, and talk, if he so desired, with a subaltern of infantry crouching in his dugout on the edge of No Man’s Land. The Secretary of War, seated at his desk in Washington, must be enabled to talk to the commander of a camp on the Rio Grande or of a cantonment in the Far Northwest. Though every strand of wire leading to the advanced positions was cut by the periodic shell-storms, means had to be provided for the commanders of the troops holding those positions to call for artillery support, for reinforcements, for ammunition, or for food. It was essential to the proper working of the great war-machine that the chiefs of the Services of Supply at Tours should be in constant telegraphic and telephonic communication with the officers in charge of the unloading of troops and supplies at Bordeaux and Marseilles, at Brest and St. Nazaire. It was vital that the Chief of Staff should be kept