As he spoke there was the sharp sound of horses' hoofs and grating wheels against the curb, followed by a sharp pull at the bell. Holmes whistled.

"A pair, by the sound," said he. "Yes," he continued, glancing out of the window. "A nice little brougham and a pair of beauties. A hundred and fifty guineas apiece. There's money in this case, Watson, if there is nothing else."

"I think that I had better go, Holmes."

"Not a bit, Doctor. Stay where you are. I am lost without my Boswell. And this promises to be interesting. It would be a pity to miss it."