"I gave you a description of the man who had killed Professor McMurray; yet you proceed to build up a fantastical case against this poor devil."

"But----" began the inspector. He was interrupted by the door being burst violently open and Sir John Dene shot into the room.

For a moment he stood staring at the two men, Gladys Norman and William Johnson framed in the doorway behind him.

"Sir Jasper's killed himself," he cried.

"Moses' aunt!" cried the inspector, starting to his feet.

Malcolm Sage sat immovable at his table, his eyes upon his outstretched hands. Slowly looking up he motioned to Miss Norman to close the door, then nodded towards a chair into which Sir John Dene sank. The inspector resumed his own seat. It was obvious that the news had considerably shaken him.

"You knew?" Sir John Dene interrogated, his voice a little unsteady.

"I expected it," said Malcolm Sage quietly. "But how, Mr. Sage?"

enquired Inspector Carfon in a whisper, his throat dry with excitement.

"Because I wrote to him yesterday saying that I could not allow the condemned man to be sacrificed. It was Sir Jasper Chambers who killed Professor McMurray."

For a moment Inspector Carfon's eyes looked as if they would start out of his head. He turned and looked at Sir John Dene, who with unsteady hand was taking a cheroot from his case.

Malcolm Sage drew his pipe from his pocket and proceeded to fill it.

"On the Tuesday night," he began, "it is obvious that Professor McMurray admitted someone to the laboratory. That man was Sir Jasper Chambers.

"When the two had dined together a week before," proceeded Malcolm Sage, "an appointment was obviously made for a week later. The professor's last words were significant: 'Anyway, Chambers, you will be the first to know.' If the experiments had proved fatal, how could Sir Jasper be the first to know unless an appointment had been made for him to call at the laboratory and discover for himself the result?"

The inspector coughed noisily.

"When Sir Jasper learned of the unqualified success of the experiments, and saw by the professor's changed appearance proof of his triumph, he remembered the article in _The Present Century_. He realised that in the lengthening of human life a terrible catastrophe threatened the world. Humanitarianism triumphed over his affection for his friend, and he killed him."

Sir John Dene nodded his head in agreement. The inspector was leaning forward, his arms on the table, staring at Malcolm Sage with gla.s.sy eyes.

"The a.s.sailant was clearly a tall, powerful man and left-handed.

That was shown by the nature of the blow. That he had some knowledge of physiology is obvious from the fact that he made no attempt at a second blow to insure death, as a layman most likely would have done.

He knew that he had smashed the occipital bone right into the brain.

In his early years Sir Jasper studied medicine.

"The crime committed, Sir Jasper proceeded to cover his tracks. With the poker he loosened the sockets of the bolts and that of the lock in order to give an impression that the door had been burst open from without. He then left the place and, to suggest robbery as a motive for the crime, he took with him the professor's gold watch, which he threw away. This was found a few hours later by the tramp whom you, Carfon, want to hang for a crime of which he knows nothing." There was a note of sternness in Malcolm Sage's voice.

"But----" began the inspector.

"I suspect," continued Malcolm Sage, "that after he had left the laboratory, Sir Jasper suddenly realised that the professor had probably recorded in his book all his processes. He returned, discovered the ma.n.u.script, and was for hours absorbed in it, at first smoking continuously, later too interested in his task to think of his pipe. It must be remembered that he had studied medicine."

The inspector glanced across at Sir John Dene, who sat rigidly in his chair, his eyes fixed upon Malcolm Sage.

"I rather think that he was aroused from his preoccupation by the ringing of the bell announcing the arrival of the professor's breakfast. He then realised that he could not leave the place until nightfall. He therefore ate that meal, carefully avoiding the marmalade, which he disliked, and subsequently he consumed the luncheon, and dinner, pa.s.sed through the wicket."

Malcolm Sage paused to press down the tobacco in his pipe.

"He burned the ma.n.u.script, tearing up letters and throwing them into the waste-paper basket to give the appearance of Professor McMurray having had a clearing-up. He then destroyed all the test-tubes he could find. Finally he left the laboratory late on the Wednesday night, or early Thursday morning."

"But how did you find out all this?" It was Sir John Dene who spoke.

"First of all, Sir Jasper and the murderer smoke the same tobacco, 'Ormonde Mixture.' I verified that by picking Inspector Carfon's pocket." Taking a tobacco-pouch from a drawer Malcolm Sage handed it across the table. "You will remember Sir Jasper lent me his pouch. I had picked up some tobacco on the floor and on the hearth.

"Secondly, the murderer was left-handed, and so is Sir Jasper.

"Thirdly, the murderer does not eat marmalade and Sir Jasper had the same distaste."

"But how----?" began the inspector.

"I telephoned to his housekeeper in the name of a local grocer and asked if it would be Sir Jasper who had ordered some marmalade, as an a.s.sistant could not remember the gentleman's name. That grocer, I suspect, got into trouble, as the housekeeper seemed to expect him to know that Sir Jasper disliked marmalade."

"Well, you seem to have got the thing pretty well figured out,"

remarked Sir John Dene grimly.

"Another man's life and liberty were at stake," was the calm reply, "otherwise----" he shrugged his shoulders.

"As Sir Jasper did not come forward I wrote to him yesterday giving him until noon to-day to make a statement," continued Malcolm Sage, "otherwise I should have to take steps to save the man condemned."

Then after a short pause he continued: "In Sir Jasper Chambers you have an ill.u.s.tration of the smallness of a great mind. He has devoted his vast wealth to philanthropy; yet he was willing to allow another man to be hanged for his crime."

"And this, I take it," said Sir John Dene, "is his reply," and he handed a letter across to Malcolm Sage.

"Read it out," he said.

Malcolm Sage glanced swiftly through the pages and then read:--

My Dear Dene,----

By the time you receive this letter I shall be dead. I have just received a letter from Mr. Malcolm Sage, which shows him to be a man of remarkable perception, and possessed of powers of a.n.a.lysis and deduction that I venture to think must be unique. All he says is correct, but for one detail. I left the laboratory in the first instance with the deliberate intention of returning, although I did not realise the significance of the ma.n.u.script until after I had tampered with the fastenings of the doors. Had my servants found that my bed had not been slept in, suspicion might have attached itself to me. I therefore returned to remedy this, and I left a note to say that I had gone out early for a long walk, a thing I frequently do.

In his experiments McMurray had succeeded beyond his wildest imaginings, and I foresaw the horrors that must inevitably follow such a discovery as his. I had to choose between myself and the welfare of the race, and I chose the race.

I did not come forward to save the man condemned for the crime, as I regarded my life of more value to the community than his.

Will you thank Mr. Sage for the very gentle and humane way in which he has written calling upon me to see that justice be not outraged.

I am sending this letter by hand. My body will be found in my study.

I have used morphia as a means of satisfying justice.

Very sincerely yours, Jasper Chambers.

"It was strange I should have made that mistake about the reason for his leaving the laboratory," said Malcolm Sage meditatively. "I made two mistakes, one I corrected; but the other was unpardonable."

And he knocked the ashes from his pipe on to the copper tray before him with the air of a man who is far from satisfied.

"And I might have arrested an O.M.," murmured Inspector Carfon, as he walked down Whitehall. "d.a.m.n."