A figure suddenly came out of the darkness of the road.  The driver stopped the taxi, and walked around the front, as though to adjust the lamp.  The door opened slowly.  A face covered with a black handkerchief obtruded.  A hand slid up the detective’s knee, along his side toward the abdomen, and a protruding thumb began a singular pressure directly below the criminologist’s heart.  Shirley’s analysis for Dr. MacDonald had been correct!  But jiu-jitsu is essentially a game for two.

Shirley’s left hand suddenly shot forth to the neck of his assailant.  His muscular fingers closed in a deft and vice-like pinch directly below the silk handkerchief.  It was the pneumogastric nerve, which he reached:  a nerve which, when deadened by Oriental skill, paralyzes the vocal chords.  Not a sound emanated from the mysterious man, even when Shirley’s right hand shot forward, under the chin of the other, for a deft blow across the thorax.  The other tumbled backward.

“What’s wrong, Chief?  Too much gas?” cried the chauffeur rushing to the side of the fallen man.  As the driver dropped to his knees, Shirley flung himself like a tiger upon the rascal’s back.  The struggle was brief—­the same silent silencer accomplished its purpose.  Before the man knew what had happened to him, he was dragged inside the car, and another deft pinch sent him to oblivion!

“Hit him over the forehead with the butt of the revolver if he opens his mouth,” grunted Shirley.  “This is the chauffeur, now I’ll get the other one.”

Just then a cry came from the darkness:  it was a passing patrolman.

“What you doing in that auto?”

But Shirley waited for no parley-explanations, showing his hand, laying the whole scandal before the morning edition of the newspapers, were all out of question now.  He must take up the pursuit later.  He caught up, the chauffeur’s cap, sprang into the driver’s seat, and the car shot forward like a race horse as he threw forward the lever.  The astonished policeman was within twenty-five yards of the spot, when the auto disappeared in the darkness.  He pursued it vainly.

A few moments later, a man with a handkerchief across his face, groaned and then raised himself on his elbow, there in the roadway.  He could not remember where he was, nor why.  Slowly he crawled on hands and knees, into the rhododendrons by the roadside, where he again lost consciousness.

A big touring car rounded the curve of the roadway.

“Not a sign of the Chief,” said the driver.  “He must have gone back to the garage with the Monk.  But that’s a fool idea.  Let’s get down there right away.”

The injured man’s memory returned, and he rose stiffly to his feet.  He limped out of the Park, putting away the handkerchief, muttering profanity and trying to fathom the mystery.  As nearly as he could reason it out, he must have been struck by another machine from the rear.