John sat in his room, absorbed in contemplation of a tiny lace-edged pocket-handkerchief. He spread it out upon his knee, and laughed. He crumpled it up in his palm, and pressed it to his face, and drank deep of its faint perfume,--faint, but powerfully provocative of visions and emotions. He had found it during the night on the floor of the sick-room, and had captured and borne it away like a treasure. He spread it out on his knee again, and was again about to laugh at its small size and gauzy texture, when his eye was caught by something in its corner. He held it nearer to the window. The thing that had caught his eye was a cypher surmounted by a crown, embroidered so minutely as almost to call for a magnifying glass. But without a glass he could see that the cypher was composed of the initials M and D, and that the crown was not a coronet, but a closed crown, of the pattern worn by mediatised princes. "What on earth can be the meaning of this?" he wondered, frowning, and breathing quick. But he was stopped from further speculation for the moment by a knock at the door. The postman entered with two letters, for one of which, as it was registered, John had to sign. When he had tipped the postman and was alone again, he put his registered letter on the dressing-table (with a view to disciplining curiosity and exercising patience, possibly) and turned his attention to the other. In a handsome, high old hand, that somehow reminded him of the writer's voice, it ran as follows:-- "DEAR JOHN,