Read it through once

“Here, there is one thing which is different from all recorded; here is some dual life that is not as the common. She was bitten by the vampire when she was in a trance, sleep-walking--oh, you start; you do not know that, friend John, but you shall know it all later--and in trance could he best come to take more blood. In trance she died, and in trance she is Un-Dead, too. So it is that she differ from all other. Usually when the Un-Dead sleep at home”--as he spoke he made a comprehensive sweep of his arm to designate what to a vampire was “home”--“their face show what they are, but this so sweet that was when she not Un-Dead she go back to the nothings of the common dead. There is no malign there, see, and so it make hard that I must kill her in her sleep.” This turned my blood cold, and it began to dawn upon me that I was accepting Van Helsing’s theories; but if she were really dead, what was there of terror in the idea of killing her? He looked up at me, and evidently saw the change in my face, for he said almost joyously:--