"The snake's fangs are drawn," said Quarles. "Now you can let it be known through the press that the necklace lost at the Duchess of Exmoor's has been returned. It is the exact truth. The real diamonds you may redeem as soon as you like, and I think this letter insures that no lies will be told about your wife in future." "But my son is----" "He is your son, Lord Leconbridge, and our word is pledged not to make the person who returned the necklace suffer." Leconbridge held out his hand. "May I give one other word of advice?" said Quarles. "This must have been a terrible ordeal to Lady Leconbridge. If I were you I should go to Grasslands to-day." And the professor and I went out of the room, closing the door gently behind us. CHAPTER XI THE DISAPPEARANCE OF DR. SMITH Zena had been away visiting friends and on the very day of her return I was obliged to leave London, much to my annoyance. The case came into my hands only because the detective who would have done the work in the ordinary way was ill. Had he been well, little might have been heard of the affair; but through me it came under the notice of Christopher Quarles, and it was he who suggested that there was a mystery. Anyone who cares to turn up the files of the newspapers of that date will find that the police methods, and some commercial methods, too, came in for rather drastic criticism. Dr. Richmond Smith had a house on the outskirts of Riversmouth, where he looked after three or four weak-minded patients. One afternoon in late September he went out, saying he would not be long. His wife was able to fix the time at half-past four. By dinner time he had not returned and she became alarmed. He was a man of methodical, even eccentric, habits; he seldom went outside his own grounds--the fact had caused people in the neighborhood to consider him peculiar--and his wife had no reason to suppose he had gone outside the grounds on this occasion. Dr. Smith's assistant, Patrick Evans, who was a male attendant, not a medical man, said he searched the house and grounds, expecting to find that the doctor had been taken suddenly ill; but the doctor was nowhere to be found. Later in the evening Mrs. Smith communicated with the police. This man Evans was an intelligent fellow, and when I took up the case I found him extremely useful. He wasn't too full of his own ideas, and answered my questions definitely. So far as he knew, Dr. Smith had nothing on his mind. He was not the kind of man to commit suicide. "Having to deal constantly with weak-minded people might have an effect upon him," I suggested. "It might, of course," Evans answered; "but it hasn't had any effect upon me, and, in a way, I should say the doctor was a more phlegmatic person than I am. Nothing moved him very much." "Had he enemies?" "I have no reason to think so." "No money worries?"