Swiftly the expression of the girl's face changed. Her dark eyes glowed with an internal fire and the immobility of her face vanished as if by magic to be replaced by an expression of fierce hatred. Her lips drew back, exposing her strong white teeth and she literally spat out her words.
"That swine, Saranoff!" she hissed.
Carnes sprang to his feet.
"Why, it's Feodrovna Androvitch!" he cried in astonishment.
In an instant the rage faded from her face and the calm, immobility which had marked it reappeared. Through the silence Dr. Bird's voice cut like a whip.
"Miss Andrews," he said sternly, "I thought that I had impressed on you the fact that even a momentary lapse from the character which you have assumed may easily be fatal to both of us. Unless you can learn to control your emotions, your usefulness to me is at an end."
Although Carnes watched closely he could not detect the slightest change of expression in the girl's face as the doctor spoke.
"I am very sorry, Doctor," she said evenly. "We were alone and I allowed the mask to slip for an instant. It will not happen again."
"It must not," said the doctor curtly. "Carry out your instructions."
"Yes, Doctor."