“It must,” agreed Harley, and his manner was almost fierce; “but when I tell you why I ask these two questions—­and I only do so on the understand ing that my words are to be treated in the strictest confidence—­you may regard the matter in a new light.  ‘Nicol Brinn’ and ‘Fire-Tongue’ were the last words which Sir Charles Abingdon uttered.”

“What!” cried Doctor McMurdoch, displaying a sudden surprising energy.  “What?”

“I solemnly assure you,” declared Harley, “that such is the case.  Benson, the butler, also overheard them.”

Doctor McMurdoch relapsed once more into gloom, gazing at the whiskey in the glass which he held in his hand and slowly shaking his head.  “Poor old Charley Abingdon,” he murmured.  “It’s plain to me, Mr. Harley, that his mind was wandering.  May not we find here an explanation, too, of this idea of his that some danger overhung Phil?  You didn’t chance to notice, I suppose, whether he had a temperature?”

“I did not,” replied Harley, smiling slightly.  But the smile quickly left his face, which became again grim and stern.

A short silence ensued, during which Doctor McMurdoch sat staring moodily down at the carpet and Harley slowly paced up and down the room; then: 

“In view of the fact,” he said, suddenly, “that Sir Charles clearly apprehended an attempt upon his life, are you satisfied professionally that death was due to natural causes?”

“Perfectly satisfied,” replied the physician, looking up with a start:  “perfectly satisfied.  It was unexpected, of course, but such cases are by no means unusual.  He was formerly a keen athlete, remember.  ’Tis often so.  Surely you don’t suspect foul play?  I understood you to mean that his apprehensions were on behalf of Phil.”

Paul Harley stood still, staring meditatively in the other’s direction.  “There is not a scrap of evidence to support such a theory,” he admitted, “but if you knew of the existence of any poisonous agent which would produce effects simulating these familiar symptoms, I should be tempted to take certain steps.”

“If you are talking about poisons,” said the physician, a rather startled look appearing upon his face, “there are several I might mention; but the idea seems preposterous to me.  Why should any one want to harm Charley Abingdon?  When could poison have been administered and by whom?”

“When, indeed?” murmured Harley.  “Yet I am not satisfied.”

“You’re not hinting at—­suicide?”

“Emphatically no.”

“What had he eaten?”

“Nothing but soup, except that he drank a portion of a glass of water.  I am wondering if he took anything at Mr. Wilson’s house.”  He stared hard at Doctor McMurdoch.  “It may surprise you to learn that I have already taken steps to have the remains of the soup from Sir Charles’s plate examined, as well as the water in the glass.  I now propose to call upon Mr. Wilson in order that I may complete this line of enquiry.”