Patsy Garvan arrived at the Osgood Hospital soon after six o’clock that evening, more than two hours before Chick encountered the masked man in Gaston Todd’s apartments.

It then was dark, the sky clouded, with no stars to reveal his stealthy movements to chance observers. Only the scattered street lamps and the numerous lighted windows of the great building, with those of a few more distant dwellings, relieved the prevailing gloom. It was even darker in the deserted grounds, and Patsy took advantage of the trees and shrubbery, entering the extensive estate near one corner, and stealing quickly around the west wing toward a rear part of the main building in which the private room of Doctor David Devoll was located.

Patsy knew from Carter’s description, nevertheless, where to find him, and he presently paused near the rear door and the gravel walk leading out to the back street.

“I must find out, to begin with, whether the blooming sawbones is here,” he said to himself. “There are the two windows of his room, all right, but there’s no sign of a light. It looks very much as if he were absent.”

Hugging the wall, and stealing closer, nevertheless, he cautiously crouched under the nearer of the two windows and tried to peer into the room. He then found that the roller shade was lowered and an interior shutter carefully closed, but through a chink below them he could see the reflection of a dim light on the varnished sill.

“Gee whiz! he makes dead sure that no outsider can see what’s doing in there,” thought Patsy. “He may be in some other part of the hospital, since only a dim light is burning. I’ll have to stick round till I can get an eye on him.”

As a matter of fact, however, Patsy had arrived there in the nick of time. The light in the room was suddenly extinguished. Half a minute later the sound of a turning knob, that of the rear door, broke the outside stillness, and, as quick as a flash, Patsy dropped flat on the ground close to the building.

He scarce had taken this precaution when the door was opened and the physician came out. Though Patsy never had seen him, Nick Carter had described him carefully and there was no mistaking him. His slender figure, invariably clad in a black frock coat, which accentuated his leanness, was one very easily identified. His smooth-shaven face was dimly discernible through the darkness, while a considerable portion of his bald, white skull could be seen in vivid contrast under his tall, black hat.

“Gee! I’m playing lucky, after all,” thought Patsy, cautiously watching him. “That’s my man, all right, and he’s bound off. The chief was right in thinking he would make a move of some kind.”

Doctor Devoll had paused to lock the door with a key taken from his pocket. He did not so much as glance toward the window under which Patsy was lying, as flat as he could make himself on the damp greensward. With his head and shoulders thrust forward and his hands clasped behind him, an habitual attitude when he was walking, Doctor Devoll proceeded down the gravel walk toward the rear gate.