The coachman, at her request, drove out to Fifth Avenue, then down that avenue to Tenth Street, where he opened the door and set her down, receiving orders to wait there for her return. The young girl tripped up from the corner, a few doors on the left hand side, past a church, and entered the front-yard railing of one of two or three unpretending three-story brick-houses standing together. It was now past dusk and the street-lamps were lighted; and looking in at the basement windows of this house, Joe saw that no curtains were drawn, that the gas was burning within, over a table and under a shade; and that at the table sat a man with head bent down and fingers busy at some kind of mechanical contrivance. "That will do," she muttered to herself. "The Doctor _is_ in, as I believed he might be at this hour, and I shall have no occasion to disturb the people up-stairs." Passing under the steps she reached the closed door, and instead of ringing, banged half a dozen times against the panels with her hand, very slowly and tragically, as the ghost in "Don Giovanni" might ask to be admitted, provided it had any occasion for using the door. Immediately there was a shuffle inside, and directly the door opened and a tall figure stood in the doorway. There was enough light from the street-lamp to make the young girl's face and figure pretty plainly visible, and the moment he saw her the occupant said: "I thought so--mischief! I thought I knew that knock! No one else ever takes such liberties with my office-door. What do you want now? But come in, before you forget it!" and seizing both her hands with a playful gesture, he dragged her within the door, closed it, pulled her through the side-door into the front basement which formed the office, drew up a clumsy cushioned operating-chair near the table, sat her down in it, then cast himself into a chair immediately in front of her, threw one leg over the other and his hands behind his head, and said: "Now I am resigned and prepared. Out with it!"