All this Jack explained hastily as they retraced their way down the corridor to Colonel Minturn’s cabin. The panic had died down, and the passengers, reassured now, were making their divers ways back to their cabins. Some tried to turn the whole matter into a joke. Others looked sheepish over the panic-stricken way in which they had behaved.

But when the two entered the colonel’s cabin a surprise awaited them.

Jarrold was not there.

Jack rubbed his mental eyes. He could have sworn he had left the man lying across the lounge, to all appearances stunned. Now, in the brief interval that the boy had been out of the cabin, the man had gone.

“He must have been playing ’possum,” said the surgeon, when Jack had briefly explained the circumstances; “but now let us see to Colonel Minturn.”

The doctor bent over the officer’s form as it lay in the bunk. The colonel was breathing heavily, his pulse was slow, his face gray.

“Run to my cabin for my medicine bag,” ordered the doctor to Jack. “You will find it on my lounge. Hurry back.”

Jack waited to ask no questions but sped off. The corridors were still choked with passengers discussing the fire scare. Most of them appeared to think it had been a grim and criminal form of joke on somebody’s part. There was talk of offering a reward for the discovery of the culprit.

But Jack, knowing what he did, placed, as we know, a more sinister construction on the midnight alarm. He was soon back with the doctor’s bag. The surgeon took out of it a small syringe and injected some sort of solution into the unconscious man’s arm.

“What is the matter with him, sir, do you think?” ventured Jack, as the doctor, his hand on Minturn’s pulse, sat by the side of the bunk.