“Rap, rap—rap. I rapped ’em,” said the rotund gentleman. “I always did hate a knocker.”

With your permission I will here interpolate the remark that the further adventures of the eminent surgeon with the mysterious confederacy that sought his life, bore evidence that these depraved and ruffianly men were not without a certain rude artistic temperament as well as a tinge of romance, and a dramatic sense that many who write for the stage might well envy them.

The elation of the doctor over his escape from the toils of the thieves was not of long duration. His breakfast was interrupted by a call to the telephone and over the wires came to his startled ears a hollow “knock, knock—knock; knock, knock—knock.” At his office door down town softly came “tap, tap—tap; tap, tap—tap,” and snatch the door open as hastily as he might, he saw nothing, heard nothing, heard nothing but the electric bells on the floors above and floors below calling for the elevator: “buzz, buzz—buzz; buzz, buzz—buzz.” He walked along State Street at the busy hour of noon and all about him in the throngs was the dull impact of canes upon the pavement, “thud, thud—thud; thud, thud—thud.” As he rode home in the street car at nightfall, back of him in the train at street corner after corner he heard passengers jingle the bell for stopping, “ding, ding—ding; ding, ding—ding.”

Although Dr. McDill was a man of great native resolution and intrepid in the face of known and seen dangers, the horrors of the invisible forces of death everywhere surrounding him so wore at his soul that he returned down town and spent the night at a hotel. On the morrow, he severely condemned himself for this yielding to fear, for on the front steps of his house lay the dead form of his great watch dog, Jacques. There were evidences of a struggle in which the assailants had not been unscathed. Bits of cloth lay about and examining the stains of blood that plentifully blotched the walk, he discovered that some of it was human blood.

“Ah,” he said, in deep self-reproach, “if I had stayed here as I should, I would have been able to fight with poor Jacques and brought low some of my enemies. How easily I could have fired from the upper windows as Jacques made their presence known. It is evident that the noise of the struggle was so great that the fiends were afraid to continue the attack and ran away.”

Philosophers and poets have found a theme for dissertation in the fact that the dog leaves his own kindred to dwell with man and fights them in behalf of his master. It has ever seemed to me that this were but half of the tale, for full many a man loves his dog better than the rest of mankind, and so the devotion of the race of dogs finds return and recompense. Outside his own family, there was no living thing in the city of Chicago which had so dwelt in the affections of Dr. McDill as the dog Jacques. Of the truth of this, he had had but dim realization until now and he was like to burst with sorrow and with hatred of the vile beings who had marked him and his for slaughter. Lifting the stiff form of his humble comrade, for the first time did he observe a poniard thrust in the poor beast’s throat. The blade impaled a piece of paper and upon it was written the word “Knock.”

“Knock!” cried the doctor: “but henceforth it shall be I that knock. Hasten the time when we may meet, malignant knaves. Never again shall I avoid you. Henceforth, I go about my business as before, for it is thus that I may expect the sooner to encounter you.”

An urgent matter would require the doctor’s presence in the municipality of Evanston that night. He could not expect to return before twelve o’clock in the morning and of this informing the cook, who in the temporary reduction of the family carried on the household without the aid of a second girl, he departed northward. It was past the hour of one when he let himself in the front door of his residence. A pleasant savor of various viands saluted his nostrils and in the drawing-room he observed that the chairs and tables had all been thrust against the wall as if to clear the floor for dancing. In the dining-room, the evidence of recent festivity was complete, for the table was covered with the remnants of a sumptuous repast. No words were needed to tell him that Olga Blomgren, the cook, had taken advantage of the foreknowledge of his absence to entertain a wide circle of friends; but here indeed was a mystery. Why had she not set everything in order and removed all traces of the entertainment? He moved toward the kitchen in wonder and—his heart stood still. The beams of the lamp held above his head were shot back by the gleam of blue and white satin, his wife’s favorite ball dress on the kitchen floor. But it was not his wife’s fair hair and snowy shoulders that, rising out of the glistening blue and white, were striped with a glistening red, but the snowy shoulders and fair hair of poor Olga Blomgren. Thus had she paid for her hour of magnificence. Thus had death cut her down because the maid’s form was of the same statuesque beauty as her mistress’s. Tenderly the doctor stooped to lift up the dead girl, stricken in her mistress’s stead. There was a poniard in her throat, and it impaled a piece of paper upon which was written “Knock.”

“Knock, knock—” the next knock would be upon his own heart.

Whatever design the doctor had held of not appealing to the police for protection against his invisible foes, his affairs had now reached a point where the intervention of the officers of the law could no longer be avoided. Poor Jacques could be consigned to earth without the intervention of priest or police, but the murder of Olga was a matter for official investigation. With that crafty and subtle way the astute sleuths of the Chicago constabulary have of informing the public through the intermediary of the press of all measures projected against evil-doers, of moves to be made, of arrests to be attempted, all citizens were in possession of the fact that owing to the startling plot just brought to light, all gatherings and coteries of men, especially at late hours, were to be watched, investigated, and made to give accounts of themselves. Dr. McDill fumed at the turn affairs had taken. That the confederacy of thieves would abandon their attempts upon his life, was not to be dreamed of. But they would forego the pleasure of witnessing his death in the presence of all assembled together. They would now delegate the attack to a single individual, and in event of his death, he could hope to carry with him but one of his enemies.