"Who the deuce can that be?" muttered Thorndyke, replacing the microscope on the table. He strode across to the door and opened it somewhat brusquely, but immediately whisked his hat off, and I then perceived a lady standing on the threshold.

"Dr. Thorndyke?" she inquired, and as my colleague bowed, she continued, "I ought to have written to ask for an appointment but the matter is rather urgent—it concerns Mr. Reuben Hornby and I only learned from him this morning that he had consulted you."

"Pray come in," said Thorndyke. "Dr. Jervis and I were just setting out for Scotland Yard on this very business. Let me present you to my colleague, who is working up the case with me."

Our visitor, a tall handsome girl of twenty or thereabouts, returned my bow and remarked with perfect self-possession, "My name is Gibson—Miss Juliet Gibson. My business is of a very simple character and need not detain you many minutes."

She seated herself in the chair that Thorndyke placed for her, and continued in a brisk and business-like manner—

"I must tell you who I am in order to explain my visit to you. For the last six years I have lived with Mr. and Mrs. Hornby, although I am no relation to them. I first came to the house as a sort of companion to Mrs. Hornby, though, as I was only fifteen at the time, I need hardly say that my duties were not very onerous; in fact, I think Mrs. Hornby took me because I was an orphan without the proper means of getting a livelihood, and she had no children of her own.

"Three years ago I came into a little fortune which rendered me independent; but I had been so happy with my kind friends that I asked to be allowed to remain with them, and there I have been ever since in the position of an adopted daughter. Naturally, I have seen a great deal of their nephews, who spend a good part of their time at the house, and I need not tell you that the horrible charge against Reuben has fallen upon us like a thunderbolt. Now, what I have come to say to you is this: I do not believe that Reuben stole those diamonds. It is entirely out of character with all my previous experience of him. I am convinced that he is innocent, and I am prepared to back my opinion."

"In what way?" asked Thorndyke.

"By supplying the sinews of war," replied Miss Gibson. "I understand that legal advice and assistance involves considerable expense."

"I am afraid you are quite correctly informed," said Thorndyke.