"She nearly fainted in the ball-room," replied the Colonel. "Her mother took her home half an hour ago. I looked for you everywhere, but couldn't find you."

"Quite a number have succumbed," said Sime.

"Eileen seemed to be slightly hysterical," continued the Colonel. "She persisted that someone wearing a crocodile mask had been standing beside her at the moment that she was taken ill."

Sime started; perhaps Cairn's story was not a matter of imagination after all.

"There is someone here, dressed like that, I believe," he replied, with affected carelessness. "He seems to have frightened several people. Any idea who he is?"

"My dear chap!" cried the Colonel, "I have been searching the place for him! But I have never once set eyes upon him. I was about to ask if you knew anything about it!"

Sime returned to the table where Cairn was sitting. The latter seemed to have recovered somewhat; but he looked far from well. Sime stared at him critically.

"I should turn in," he said, "if I were you. Khamsîn is playing the deuce with people. I only hope it does not justify its name and blow for fifty days."

"Have you seen the man in the mask!" asked Cairn.

"No," replied Sime, "but he's here alright; others have seen him."