On the third morning, shortly before midday, just as I was thinking of going out to make my round of visits, an unusual incident occurred. I heard a cab stop outside, and a moment later the surgery bell was violently rung. I started, for that sound was synonymous with half a crown. A middle-aged woman, in black, evidently a domestic servant, stood in the surgery, and, as I confronted her, asked breathlessly-- "Are you the doctor, sir?" I replied in the affirmative, and asked her to be seated. "I'm sorry to trouble you, sir," she said, "but would you come round with me? My mistress has been taken worse." "What's the matter with her?" I inquired. "I don't know, sir," answered the woman, in deep distress, "But I do beg of you to come at once." "Certainly I will," I said. And leaving her, ascended, put on my boots, and placing my case of instruments in my pocket, quickly rejoined her, and entered the cab in waiting. On our drive along Hammersmith Road, and through several thoroughfares lying on the right, I endeavoured to obtain from her some idea of the nature of the lady's ailment; but she was either stupidly ignorant, or else had received instructions to remain silent. The cab at last pulled up before a fine grey house with a wide portico, supported by four immense columns, before which we alighted. The place, standing close to the entrance to a large square, was a handsome one, with bright flowers in boxes before the windows, and a striped sun-blind over the balcony formed by the roof of the portico. The quilted blinds were down because of the strong sun, but our ring was instantly answered by a grave-looking footman, who showed me into a cosy library at the end of the hall. "I'll tell my master at once that you are here, sir," the man said. And he closed the door, leaving me alone. CHAPTER TWO. THE THIRD FINGER. The house was one of no mean order, and a glance at the rows of books showed them to be well chosen--evidently the valued treasures of a studious man. Upon the writing-table was an electric reading-lamp with green shade, and a fine, pale photograph of a handsome woman in a heavy silver frame. In the stationery rack upon the table the note-paper bore an embossed cipher surmounted by a coronet. After a few moments the door re-opened, and there entered a very thin, pale-faced, slightly-built man of perhaps sixty, carefully dressed in clothes of rather antique cut. He threw out his chest in walking, and carried himself with stiff, unbending hauteur. His dark eyes were small and sharp, and his clean-shaven face rendered his aquiline features the more pronounced. "Good morning," he said, greeting me in a thin, squeaky voice. "I am very glad my servant found you at home." "And I, too, am glad to be of service, if possible," I responded.