In a moment the purr of the motors cut the air. The machines ran swiftly, steadily, down the field and swept upward. Havens stood watching them for a long time. The planes glistened like silver in the moonlight, and the song of the motors came to his ears like sweet music. The millionaire loved a flying machine as track-men love a swift and beautiful horse. He finally turned away to find a uniformed messenger boy standing by his side, presenting a yellow envelope. “What is it, kid?” he asked. “Message from the hospital,” was the answer. “Who sent it?” asked the millionaire, taking the envelope into his hands and tearing off the end. “The night matron,” was the reply. “She said I had to hump myself.” “That’s wrong!” laughed Havens. “She shouldn’t expect a messenger boy to hump himself! In fact,” he went on, whimsically, “the only time a messenger boy is permitted to make haste is when he is on his way to a baseball game. That’s right, sonny!” he continued. The boy grinned and made trenches in the smooth earth of the field with the toe of a broken shoe. Havens glanced casually at the message at first, thinking that perhaps the surgeon might have taken it into his head to report progress in the case of the man so recently placed in his charge. He knew very well that the surgeon would manage to prevent the escape of the prisoner should he regain consciousness, so he had put that phase of the case entirely from his mind. However, his eyes widened and an exclamation of astonishment came from his lips as he read the note which had been written by the night matron, and not by the surgeon at all. “Mason, the injured man recently sent here on your order,” the note read, “has most mysteriously disappeared from the hospital. Doctor Bolt, the surgeon detailed, at your request, to take charge of the case, decided to watch the man for the night, and so my attendants were withdrawn. The surgeon must have fallen asleep, for in half an hour’s time he came running to my door shouting that Mason had escaped. As soon as possible I visited the room from which the man had disappeared and found the window sash raised. “There were many footprints in the soft earth under the window—the footprints of men in coarse shoes—and a smear of blood on the window casing disclosed the fact that the injured man had been drawn through the opening. It is quite evident to me, therefore, that the man was carried from the room by some one interested in the case, to which Doctor Bolt only indirectly referred when talking with me. Your presence at the hospital is earnestly requested.” The note was signed, as stated, by the night matron. Scarcely had Havens finished the reading of it when he heard some one stumbling through the darkness, and the next moment Surgeon Bolt, looking crestfallen and excited, stood before him, like a schoolboy anticipating censure. “Well?” asked Havens rather angrily.