The old dame shuffled off for the key, and I gave Doris a special hint to keep her eyes wide open. When the old woman returned she led us directly to Cauvin's private room, a good-sized apartment, furnished something after the pattern of the library of the ordinary English house. I noticed immediately that it had double doors; evidently Cauvin had good reasons for making sure that there should be no eavesdropping when he was at home. Leading from it was a large salon, upholstered in pale blue silk, and the old woman passed into this in order to open the sun-shutters and admit the light. In the window of the library was a big American roll-top desk, which stood open and was rather dusty. The green blotting-pad remained just as the master of the house had left it, and near it lay a pile of miscellaneous and dusty-looking papers. I was glancing round when I was startled by a faint, gasping sob, and, looking round, saw with alarm that Doris had dropped into a chair, apparently faint. The old woman had rushed to her assistance. "It is nothing--only the heat," murmured Doris faintly. "Please get me a glass of water." The old woman hurried away, and, much concerned, I bent over Doris. I had no idea that her illness was anything but real, and I was surprised when she said crisply but quietly, "Now is your chance." Then I realised her purpose and began a hurried examination of the desk, keeping my ears open for any sound of the old woman's return. But I could find nothing. Evidently Cauvin left little to chance. The drawers of the desk were not even locked, and I soon concluded that I had drawn a blank, and that the key to the mystery I was bent on solving must be sought elsewhere. Of course I was not surprised. It was not in the least likely that Cauvin would leave incriminating documents in his winter quarters, but in the work upon which I was engaged it would never do to miss the opportunity that might be afforded by the momentary carelessness which is the ever-besetting peril of even the cleverest of rogues. As events proved, we were to learn once again the truth of the old adage that no man can be wise at all times. When the old lady returned with water Doris soon "recovered," and assured the volubly sympathetic dame that she was quite herself again. As we stood for a moment saying farewell, her quick eye caught something which I had overlooked. "Why," she said, "here is an invitation to a wedding in England!" And she picked up from a small side table, where it lay in a china bowl, a card printed in silver ink--an invitation, as she said, to a wedding, and printed in English. "Has Monsieur Cauvin many English friends?" I asked the old Frenchwoman, hoping that something useful might slip out. "_Non, monsieur_," she replied. "I do not think so; I have never seen English letters come, and you are the first Englishman who has ever been here."