Powers of Darkness by Fred M. White

The strolling player stood till his hat fell over his eyes and dropped to the floor. His jaunty impudence had gone as clean as if it had been wiped out with a sponge. Grenfell might have been some horrible shade from the nether world from the way that Partridge glared at him. The unexpectedness of it all paralysed him completely. The onlookers began to jeer, being ready, with wonted fickleness, to jostle the dejected cheat on the slightest provocation. This mild-eyed, middle-aged stranger had in some way got the better of Partridge, and that was sufficient.

One or two were shrewd enough to see that there was something beneath the surface. They sufficed to sober the rest. They were looking for something in the way of a dramatic development. But Grenfell gave no further sign. He would have been more than human had he not been pleased with the success of his shot, but in spite of the thrill of triumph he kept his head. He had to remember that he was not Hugh Grenfell, but the grave and learned Dr. Blaydes.