I may add two stories of how real spies were detected--and this owing to the neglect of the merest trifle. The bridge over the Rhine at Bonn is very carefully watched, and every vehicle must be accompanied across by a soldier. A motor-car was once being thus conveyed, with two officers in it, when something unfamiliar about them attracted the attention of the guard. He looked at them more closely, and discovered that with the uniform of the artillery they were wearing the spiked helmets of the infantry. (Artillery helmets end in a ball.) He had the car stopped, and it transpired that the two men were officers in the French Army on a special mission to the interior of Germany. They were tried and shot the same day. The other instance is of an oversight equally trivial. A lady was travelling in the train from Aix-la-Chapelle to Cologne, when her attention was caught by the label of a London tailor sewn in another lady’s jacket which was dangling from the rack. The owner of the jacket was continually running into the next compartment to have a talk with a wounded officer, whose arm was in a sling. “She was like a nervous rabbit,” my informant said. When the train pulled up in Cologne station a detachment of soldiers was waiting on the platform, and they at once arrested the wounded officer. He was an English spy, and his bandages were full of maps and other incriminating documents. (The names of all persons in uniform who board a train are registered, and by the time they reach their destination it is known whether they are _bona fide_ travellers or not. A telegram does the rest.) It was obvious that the wearer of the English jacket was also a spy working together with the man who had been arrested. At first the German lady could not bring herself to give information which must inevitably cost the life of a woman. She hesitated a long time, but in the end duty to the Vaterland prevailed, and she told the authorities. Meanwhile, however, the Englishwoman had left the station and was speeding away in a taxi. But the soldiers rushed out and sounded a peculiar signal, at which every vehicle within hearing is bound to stop and wait further orders. The Englishwoman had not got far enough away, she was arrested, and she, no doubt, suffered the extreme penalty.