Dr. Leslie looked up.  “Then there is no test, none?” he asked.

“There is one that is brand new,” replied Kennedy slowly.  “It is the new starch-grain test just discovered by Professor Reichert, of the University of Pennsylvania.  The peculiarities of the starch grains of various plants are quite as great as those of the blood crystals, which, you will recall, Walter, we used once.

“The starch grains of the poison have remained in the wound.  I have recovered them from the dead man’s blood and have studied them microscopically.  They can be definitely recognized.  This is plainly a case of aconite poisoning—­probably suggested to the Oriental mind by the poison arrows of the Ainus of Northern Japan.”

Dr. Leslie and I both looked through the microscope, comparing the starch grains which Kennedy had discovered with those of scores of micro-photographs which lay scattered over the table.

“There are several treatments for aconite poisoning,” ruminated Kennedy.  “I would say that one of the latest and best is digitalin given hypodermically.”  He took down a bottle of digitalin from a cabinet, adding, “only it was too late in this case.”

. . . . . . .

Just what the relations were between Long Sin and the Chong Wah Tong I have never been able to determine exactly.  But one thing was certain:  Long Sin on his arrival in New York had offended the Tong and now that his master, Wu Fang, was here the offence was even greater, for the criminal society brooked no rival.

In the dark recesses of a poorly furnished cellar, serving as the Tong headquarters, the new leader and several of his most trusted followers were now plotting revenge.  Long Sin, they believed, was responsible for the murder, and, with truly Oriental guile, they had obtained a hold over Wu Fang’s secretary.

Their plan decided on, the Chinamen left the headquarters and made their way separately up-town.  They rejoined one another in the shelter of a rather poor house, before which was a board fence, in the vicinity of a fashionable apartment house.  A moment’s conference followed, and then the secretary glided away.

. . . . . . .

Wu had taken another apartment up-town in one of the large apartment houses near a parkway; for he was far too subtle to operate from his real headquarters back of the squalid exterior of Chinatown.

There Long Sin was now engaged in making all possible provisions for the safety of his master.  Any one who had been walking along the boulevard and had happened to glance up at the roof of the tall apartment building might have seen Long Sin’s figure silhouetted against the sky on the top of the mansard roof near a flagpole.

He had just finished fastening to the flagpole a stout rope which stretched taut across an areaway some twenty or thirty feet wide to the next building, where it was fastened to a chimney.  Again and again he tested it, and finally with a nod of satisfaction descended from the roof and went to the apartment of Wu.