“What do you mean?”

“The most powerful and secret of all the death-strokes of the Japanese art of jiu-jitsu fighting.  I paid two thousand dollars to learn the course from a visiting instructor when I was in college.  It was worth it for this one occasion.”

Shirley arose to his feet, and approached the other, touching his shoulder.

“Stand up, if you please.  Let me ask if this was the location of the mark?”

The physician, interested in this new professional phase, readily obeyed.  One quick movement of Shirley’s muscular hand, the thumb oddly twisted and stiffened, and a sudden jab in the doctor’s abdomen made that gentleman gasp with pain.  Shirley’s expression was triumphant, but the professor regarded him with an expression of terror.

“Oh!  Ugh!—­What-did-you-do-to me?” he murmured thickly, when he was at last able to speak.

“Merely demonstrated the beginning of the death punch which I named.  That pressure if continued for half a minute would have been fatal.”

“I wish you would teach me that,” was the physician’s natural request, as he nodded with a wry face.

“Impossible, my dear sir, for I learned it, according to the Oriental custom under the most sacred obligations of secrecy.  One must advance through the whole course, by initiatory degrees, before learning the final mysteries of the samurais.  Now, we have a working hypothesis.  The girls could never have accomplished this.  One man and one alone must have killed the three, although doubtless with confederates.  Yamashino assured me that there were only six men in this country who knew it beside myself.  We must find an Orientalist!”

Shirley paced the floor, but his meditations were interrupted by the arrival of the Coroner and his physician.  Van Cleft hurried into the room with them, to present the doctor, who exchanged a formal greeting with the men he had met twice before that week.

“A sad affair, Professor,” observed the Coroner nervously, drinking in with profound respect the magnificent surroundings which symbolized the great wealth of which he secretly hoped to gain a tithing.  “I trust that, as usual, in such cases, I may suggest an undertaker?”

“Why—­talk about that at once, sir?” asked Howard with a shudder.

The physician, familiar with the subtleties of coroners, gently placed an arm about the young man’s shoulder.  He nodded, understandingly, to the Coroner, as he turned toward Shirley.

“I must be going now,” the latter interposed.  “Just a word with you, Howard, that I may send a message to your mother and sister.”

The physician led away the two officials as Shirley continued:  “I must go to see Cronin—­deserted there like a run-over mongrel on the street.  Can I leave this house by the rear, so that none shall know of my assistance in the case, or follow me to the hospital?  If you can secure an old hat and coat, I will leave my own, with my stick, to get them some other time.”