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.”

follansbee raised his vulturelike face and shot a keen glance at the detective.

“i suppose you’re quite sane,” he said slowly, “although your statements sound curiously wild. you deliberately accuse me of having connived with some man of whose identity i am ignorant, to murder some one?”

“i do!” nick rapped out. “and the reason i accuse you of it is that i saw you—and heard you—conspiring with stone last night in his room at the hotel windermere.”

“good lord!”

stephen follansbee had betrayed himself. his icy self-command had cracked for a moment, and through the fissure nick saw a flicker of fear in the beady eyes.

“ah! i found a joint in your armor that time, didn’t i? shall i tell you what you did at the hotel?”

but the head of st. swithin’s held himself once more with a tight rein. he leaned back in his chair and folded his arms.

“i’m afraid you misinterpreted my exclamation,” he said. “it was called out not by guilt, but by astonishment and concern. my confidence in your sanity has received a big jolt, carter. i’ve been treated to many such flights of the imagination, but i never expected to find you indulging in them. professionally, though, your condition appeals to me, and i’m tempted to humor you; therefore, go on by all means, and tell me what i did at the—what hotel did you say it was?”

“cut it out, follansbee,” the detective advised, ignoring the question. “you’ve given yourself away, and it’s a waste of cleverness to try to cover up the break now. i’ll accept your invitation, though, and tell you what you did. in the first place, you were unconventional enough to choose the fire escape as a means of access to stone’s room.”

he did not look into follansbee’s eyes, but fastened his gaze on the man’s right temple. the eyes would have told him nothing, but there was a blue, distended vein in that temple, and its throbbing was significant.

“you and your patient—your tool—used a painter’s ladder to reach the fire escape,” the detective went on, “and when you had climbed to stone’s room, on the second floor, you neglected to remove a little wedge of wood on the sill which prevented the sash from closing.”

he leaned farther forward, and his voice was the voice of a judge. “thanks to that little oversight, follansbee,” he continued, “i was able to hear all that you said. i heard from your own lips about the hypodermic syringe, and the character of its contents, as well as about the drug which you gave to stone to——

“keep your hands up!”