"Not half so bad as I expected," said a guttural voice. The smell of the anæsthetic had almost dispersed. "Where is the switch?"
"Here, Herr Doktor," replied a petty officer.
The next instant the cabin was bathed in brilliant light. In spite of their efforts to the contrary the three supposed sleepers twitched their eyelids.
The ship's surgeon bent over O'Hara. A short scrutiny confirmed his suspicions. He turned to the bunk on which Stirling was lying, and, lifting the sub's eyelid, placed the tip of his forefinger upon the eyeball.
"Ach, is it so?" ejaculated the German, for Stirling had been compelled to contract his eyelids.
A similar test bore the same result in Denbigh's case; then, without another word, the doctor hurried from the cabin.
"The old pillbox has tumbled to it," muttered Denbigh. "Now what will their little game be?"
The sub was not left long in doubt. Ober-leutnant von Langer, who had followed the doctor into the cabin, made his presence known by bawling out an order to half a dozen of the crew who were waiting without:
"Come! Out mit you!" he exclaimed, addressing the sham sleepers. "It is that I know your little pretend. Ach! you tink you smart?"
Yet Denbigh and his companions kept still, half-hoping that the doctor's test had not been successful and von Langer was trying his hand.