Standing beside her, he breathlessly explained his discovery.  “That wall paper has been loaded down with arsenic, probably Paris green or Schweinfurth green, which is aceto-arsenite of copper.  Every minute you are here, you are breathing arseniuretted hydrogen.  The Clutching Hand has cleverly contrived to introduce the nascent gas into the room.  That acts on the arsenic compounds in the wall paper and hangings and sets free the gas.  I thought I knew the smell the moment I got a whiff of it.  You are slowly being poisoned by minute quantities of the deadly gas.  This Clutching Hand is a diabolical genius.  Think of it—­poisoned wall paper!”

No one said a word.  Kennedy reached down and took the two Clutching Hand messages Elaine had received.  “I shall want to study these notes, more, too,” he said, holding them up to the wall at the head of the bed as he flashed his pocket lens at them.  “You see, Elaine, I may be able to get something from studying the ink, the paper, the handwriting—­”

Suddenly both leaped back, with a cry.

Their faces had been several inches apart.  Something had whizzed between them and literally impaled the two notes on the wall.

Down the street, on the roof of a carriage house, back of a neighbor’s, might have been seen the uncouth figure of the dilapidated South American Indian crouching behind a chimney and gazing intently at the Dodge house.

As Craig had thrown open Elaine’s window and turned to Elaine, the figure had crouched closer to his chimney.

Then with an uncanny determination he slowly raised the blow-gun to his lips.

I jumped forward, followed by Dr. Hayward, Aunt Josephine, and Marie.  Kennedy had a peculiar look as he pulled out from the wall a blow-gun dart similar in every way to that which had killed Michael.

“Craig!” gasped Elaine, reaching up and laying her soft white hand on his arm in undisguised fear for him, “you—­you must give up this chase for the Clutching Hand!”

“Give up the chase for the Clutching Hand?” he repeated in surprise.  “Never!  Not until either he or I is dead!”

There was both fear and admiration mingled in her look, as he reached down and patted her dainty shoulder encouragingly.

CHAPTER VI

THE VAMPIRE

Kennedy went the next day to the Dodge house, and, as usual, Perry Bennett was there in the library with Elaine, still going over the Clutching Hand case, in their endeavor to track down the mysterious master criminal.

Bennett seemed as deeply as ever in love with Elaine.  Still, as Jennings admitted Craig, it was sufficiently evident by the manner in which Elaine left Bennett and ran to meet Craig that she had the highest regard for him.

“I’ve brought you a little document that may interest you,” remarked Kennedy, reaching into his pocket and pulling out an envelope.