A certain unexpected vein of pawky humour…
"You have heard me speak of Professor Moriarty?”
“The famous scientific criminal, as famous among crooks as–”
“My blushes, Watson!” Holmes murmured in a deprecating voice.
“I was about to say, as he is unknown to the public.”
“A touch! A distinct touch!” cried Holmes. “You are developing a certain unexpected vein of pawky humour, Watson, against which I must learn to guard myself.“
Arthur Conan Doyle, The Valley of Fear

