"It was a pity you wasted so much time," said Merrick, "for Felix took advantage of your negligence to slip over to Paris, and lay a trap for you. In plain words, he disappeared from Marshminster as Francis, and reappeared in Paris as Felix." "He might have done so! But don't you think I would have guessed the identity of the one with the other?" "How could you," said the doctor, "when the twins are alike in every respect? And, moreover, you firmly believed Olivia Bellin's lover was in Marshminster." "But if I go down at once to Marshminster, I'll detect the absence of Felix, and so guess what has taken place." "If you go down to Marshminster, you'll find Felix back again in his old place." "Then Paris?" I queried uneasily. I was beginning to see I had been duped. "You forget Mr. Felix of Paris has gone to Italy and left no address. It's all safe there, and, as he said he was going to the East for six months or so, there will be plenty of time for the pretended Francis to marry Olivia." "You don't believe that Felix of Paris has gone to Italy or the East?" "Of course not! I believe he arranged all these matters to baffle your prying, and then calmly returned to Marshminster." "But the manager of the hotel?" "He is in the pay of Felix. You'll get nothing out of him. Now, I am certain that is the explanation. Are you not surprised at its simplicity?" "Yes, I am! It is astonishing I never thought of it before." "Columbus and his egg once again," said Merrick grimly. "Well, what are you going to do next?" "To drive to Marshminster, and find out the movements of Felix on the night after the murder." "Quite so; but first satisfy yourself on the subject of Francis." "What do you mean?" I asked. "What day of the month were you at the Fen Inn?" continued Merrick. "On the 10th of June." "Good! Francis there told you that he had just arrived from Chili. Now, find out what boat he came by, look up his name in the passenger list, and ascertain the date on which the true Francis arrived in England. That point established, you can prove the false Francis to be an impostor." "An excellent idea," said I, starting to my feet. "I'll see about it at once." "And mind," said Merrick, raising his forefinger, "I expect to be kept fully advised of the case." "Never fear, doctor. You are excellent at solving puzzles. When I find another nut, I'll bring it to you to crack." "Do! I take a great interest in this sort of cases. I ought to have been a lawyer instead of a doctor." "I'm thankful for my own sake you are the latter," said I, shaking his hand. "Good-by, doctor; I am greatly obliged for the kind interest you have taken in this case." "Pure selfishness, I assure you," replied Merrick; and so I took my leave.