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shirt, once white, but now of an unsavoury grey.

"I want to know what this is," said Miller, exhibiting a brownish-red stain on one sleeve. "Just look at that, sir, and tell me if it is blood, and, if so, is it human blood?"

"Really, Miller," said Thorndyke, with a smile, "you flatter me; but I am not like the wise woman of Bagdad who could tell you how many stairs the patient had tumbled down by merely looking at his tongue. I must examine this very thoroughly. When do you want to know?"

"I should like to know to-night," replied the detective.

"Can I cut a piece out to put under the microscope?"

"I would rather you did not," was the reply.

"Very well; you shall have the information in about an hour."

"It's very good of you, doctor," said the detective; and he was taking up his hat preparatory to departing, when Thorndyke said suddenly—

"By the way, there is a little matter that I was going to speak to you about. It refers to this Camberwell murder case. I understand you have a clue to the identity of the murderer?"

"Clue!" exclaimed the superintendent contemptuously. "