Stephen Follansbee’s loss of nerve was only momentary, however, and, after their looks had met, Nick quietly closed the door behind him, and, striding forward, dropped into a chair.  
Follansbee looked at him with half-closed eyes and tapped on the desk with his long fingers. “This is an unexpected pleasure, Mr. Carter,” he said, in his high, thin voice. “Of course I’m always glad to see such a distinguished visitor as yourself.”
 
Nick’s smile was grim. He rated his antagonist’s recovered coolness and quiet irony at their true value. Physically, Follansbee was beneath contempt, but Nick was well aware that he represented an infinitely more dangerous type of criminal than any hulking, broad-shouldered ruffian who ever swaggered through the world.
 
“You did not come to see me on professional business, I take it?” Follansbee went on, a quiet smile lifting the corners of his mouth. “You don’t look as if you needed medical attention.”
 
“No, I’m quite well, thank you,” was the calm response. “I have come to see you concerning a certain case I have taken up.”
 
“Indeed?”
 
The doctor’s voice was mildly curious, but there was a perceptible tightening of his fingers which told Nick that the man was holding himself in by sheer force of will.
 
“Yes,” the detective continued; “recently I’ve had cause to play the part of a sort of bodyguard to a man who has just returned to this country from South America. His name is Winthrop Crawford.”
 
Follansbee’s performance was improving, in spite of the increasing strain under which he was laboring.
 
“That doesn’t sound like a very important task for one of your abilities,” remarked the physician. “What were your duties, may I ask?”
 
They were fencing with each other—fencing with the skill of masters—and Nick set himself to his task with keen zest.
 
“I undertook the part of bodyguard to Crawford,” he explained, “in order that he might be safe from the murderous attacks of his former friend and partner, James Stone.”
 
“Oh!” Follansbee played with the pen on his desk. “All this may be very interesting to you,” he said presently, “but I can’t imagine what it has to do with me. If you can enlighten me as to that, perhaps I shall prove a better listener.”
 
Nick leaned forward quickly, and his clean-cut face was grave and hard. “On second thoughts, I suggest that we throw aside our masks, and go at it face to face,” he said. “I’m telling you this for the very good reason that to my personal knowledge you had a hand in the last fiendish attack which Stone made on Crawford.”
 
F............