"You are clever, Wigan, very clever. You have shown it in this case. But you lack imagination to step out as far as you ought to do. Cultivate imagination, and don't be too bound up by common sense. Common sense is merely the knowledge with which fools on the dead level are content. Imagination carries one to the hills, and shows something of that truth which lies behind what we call truth."
I found him ready and waiting for me next morning, as eager to be on the trail as a dog in leash.
"We are going to call on Dr. Tresman, in Montagu Street," he said, stopping a taxi. "You will tell him that you have reason to believe that his house is being watched, and will be burgled on the first opportunity. If the opportunity is given, it may happen to-night, which will suit us admirably, because we have got to keep watch every night in his room until it is burgled. Of course, you will tell him who you are, and get his permission. We don't want to have to commit burglary ourselves in order to catch the thief."
"Why do you expect this particular doctor will be visited?" I asked.
"It is part of my theory," was all the explanation I could get out of him.
Dr. Tresman was a man in the prime of life, and evidently believed himself capable of dealing with any thieves who visited him. I told him that the man we expected was no ordinary thief.
"A gang at work, eh? I have been out of town for a little while holiday-making, and part of my holiday consists in not reading the papers. Of course you may keep watch, and I shall be within call should you want help."
"You had better leave it to us, doctor," said Quarles, who, for the purpose of this interview, posed as my assistant.
"Come, now, if it means a rough-and-tumble, I should back myself against you," laughed Tresman, drawing himself up to his full inches.
"No lack of muscle, I can see, doctor, but then there is my experience."