INTRODUCTION
poison of scarlet fever; it is then mere delirium. You may obtain it by gazing into a crystal, or a pool of ink, or any bright surface; and then the resultant appearances will be called clairvoyance. For I am strongly inclined to believe that there is a link between the snakes and rats of the drunkard and the varied appearances in the crystal. The one observer obtains his curious results by operating from within—by poisoning his system with exorbitant alcoholic doses; the other works from without, by dazing his eyes. And then there is the third method: the method of the man who induces the toxic state by being tired to death. [I myself once combined two of these methods. I was wearied almost to stupor, and I gazed—by accident, not design—in a bright surface, and I was duly hallucinated.] And so it is possible that the corporal and the lieutenant-
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