“Due entirely to the overdose,” Dr. Silence replied emphatically, “to the drug’s direct action upon your psychical being. It rendered you ultra-sensitive and made you respond to an increased rate of vibration. And, let me tell you, Mr. Pender, that your experiment might have had results far more dire. It has brought you into touch with a somewhat singular class of Invisible, but of one, I think, chiefly human in character. You might, however, just as easily have been drawn out of human range altogether, and the results of such a contingency would have been exceedingly terrible. Indeed, you would not now be here to tell the tale. I need not alarm you on that score, but mention it as a warning you will not misunderstand or underrate after what you have been through.