He laughed at things like dyed hair and false beards and such childish follies.

The only thing that mattered was what Peter called 'atmosphere'.
If a man could get into perfectly different surroundings from those in which he had been first observed, and--this is the important part--really play up to these surroundings and behave as if he had never been out of them, he would puzzle the cleverest detectives on earth.

And he used to tell a story of how he once borrowed a black coat and went to church and shared the same hymn-book with the man that was looking for him.

If that man had seen him in decent company before he would have recognized him; but he had only seen him snuffing the lights in a public-house with a revolver.
The recollection of Peter's talk gave me the first real comfort that I had had that day.

Peter had been a wise old bird, and these fellows I was after were about the pick of the aviary.