“Well, good night, Mr. Copperdock,” he said abruptly. “It’s a pity you didn’t catch your man. I’d better get back to the station and warn my people to look out for him.”

As he left the shop, he noticed that Mr. Ludgrove’s door stood open, and as he crossed the road, the herbalist himself appeared in the entrance. “Good evening, Inspector,” he said politely.

Obeying a sudden impulse, Whyland stopped and returned the greeting. “Good evening, Mr. Ludgrove,” he replied. “May I come in for a moment?”

“By all means, come along,” replied the herbalist, leading the way into his sanctum. “I do not drink much myself, but perhaps you will take some refreshment yourself?”