Rather more than a quarter of a century ago two Americans visited London, who called themselves professors of Electro-Biology, and claimed the power of 'subjugating the most determined wills, paralysing the strongest muscles, preventing the evidence of the senses, destroying the memory of the most familiar events or of the most recent occurrences, inducing obedience to any command, and making an individual believe himself transformed into any one else.' All this and more was to be effected, they said, by the action of a small disc of zinc and copper held in the hand of the 'subject,' and steadily gazed at by him, 'so as to concentrate the electro-magnetic action.' The pretensions of these professors received before long a shock as decisive as that which overthrew the credit of the professors of animal magnetism when Haygarth and Falconer successfully substituted wooden tractors for the metallic tractors which had been supposed to convey the magnetic fluid. In 1851, Mr. Braid, a Scotch surgeon, who had witnessed some of the exhibitions of the electro-biologists, conceived the idea that the phenomena were not due to any special qualities possessed by the discs of zinc and copper, but simply to the fixed look of the 'subject' and the entire abstraction of his attention. The same explanation applied to the so-called 'magnetic passes' of the mesmerists. The monotonous manipulation of the operator produced the same effect as the fixed stare of the 'subject.' He showed by his experiments that no magnetiser, with his imaginary secret agents or fluids, is in the least wanted; but that the subjects can place themselves in the same condition as the supposed subjects of electro-biological influences by simply gazing fixedly at some object for a long time with fixed attention.