Perhaps there is something in nature more agile and dismayingly elusive than a romping young collie. But that "something" is not a mortal man. As the thief sprang, Lad sprang in unison with him; darting to the left and a yard or so backward. He came to an expectant standstill once more; his tail wildly vibrating, his entire furry body tingling with the glad excitement of the game. This sportive visitor of his was a veritable godsend. If only he could be coaxed into coming to play with him every night--! But presently he noted that the other seemed to have wearied of the game. After plunging through the air and landing on all fours with his grasping hands closing on nothingness, the man had remained thus, as if dazed, for a second or so. Then he had felt the ground all about him. Then, bewildered, he had scrambled to his feet. Now he was standing, moveless, his lips working. Yes, he seemed to be tired of the lovely game;--and just when Laddie was beginning to enter into the full spirit of it. Once in a while, the Mistress or the Master stopped playing, during the romps with the flannel doll. And Laddie had long since hit on a trick for reviving their interest. He employed this ruse now. As the man stood, puzzled and scared, something brushed very lightly,-even coquettishly,--against his knuckles. He started in nervous fright. An instant later, the same thing brushed his knuckles again, this time more insistently. The man, in a spurt of fear-driven rage, grabbed at the invisible object. His fingers slipped along the smooth sides of the bewitched bag that Lad was shoving invitingly at him. Brief as was the contact, it was long enough for the thief's sensitive finger tips to recognize what they touched. And both hands were brought suddenly into play, in a mad snatch for the prize. The ten avid fingers missed the bag; and came together with clawing force. But, before they met, the finger tips of the left hand telegraphed to the man's brain that they had had momentary light experience with something hairy and warm,--something that had slipped, eel-like, past them into the night;--something that most assuredly was no satchel, but ALIVE! The man's throat contracted, in gagging fright. And, as before, fear scourged him to feverish rage. Recklessly he pressed the flashlight's button; and swung the muffled bar of light in every direction. In his other hand he leveled the pistol he had drawn. This time the shaded ray revealed to him not only his bag, but,--vaguely,--the Thing that held it. He could not make out what manner of creature it was which gripped the satchel's handle and whose eyes pulsed back greenish flares into the torch's dim glow. But it was an animal of some kind;--distorted and formless in the wavering finger of blunted light; but still an animal. Not a ghost.