I was at one time watched by a detective who one day was a soldierly-looking fellow and the next an invalid with a patch over his eye. I could not believe it was the same man until I watched him from behind and saw him walking, when at once his individuality was apparent.
For mannerisms, a spy has by practice to be able to show an impediment in his speech one day, whereas the next a wiggle of an eyelid or a snuffling at the nose will make him appear a totally different being.
For a quick change, it is wonderful what difference is made by merely altering your hat and necktie. It is usual for a person addressing another to take note of his necktie, and probably of his hat, if of nothing else, and thus it is often useful to carry a necktie and a cap of totally different hue from that which you are wearing, ready to change immediately in order to escape recognition a few minutes later.
This illustration shows how the writer was able to disguise himself at very short notice when he observed that he was recognised on a railway station. The first sketch shows him as he entered a waiting-room shortly after his suspicions were aroused. The second depicts him on his exit a few minutes later. The disguise, simple though it may seem, was entirely successful.
I learnt this incidentally through being interviewed some years ago at a railway station. A few minutes after the ordeal I found myself close up to my interviewer, when he was re-telling the incident to a brother journalist, who was also eager to find me. "He is down there, in one of the last carriages of the train. You will know him at once; he is wearing a green Homburg hat and a red tie, and a black coat."
Fortunately I had a grey overcoat on my arm, in which was a travelling cap and a comforter. Diving into the waiting-room, I effected a "quick change" into these, crammed my hat into my pocket, and tottered back, with an invalid shuffle, to my carriage. I re-entered it under the nose of the waiting reporter without being suspected, and presently had the pleasure of being carried away before him unassailed.
On a recent occasion in my knowledge a man was hunted down into a back street which was a cul-de-sac, with no exit from it. He turned into the door of a warehouse and went up some flights of stairs, hoping to find a refuge, but, finding none, he turned back and came down again and faced the crowd which was waiting outside, uncertain which house he had entered.
By assuming extreme lameness in one leg, hunching up one shoulder, and jamming his hat down over a distorted-looking face, he was able to limp boldly down among them without one of them suspecting his individuality.
In regard to disguises, hair on the face—such as moustache or beard—are very usually resorted to for altering a man's appearance but these are perfectly useless in the eye of a trained detective unless the eyebrows also are changed in some way.