156 THE POPULAR SCIENCE MONTHLY. 



burned. A man sees an old woman in the woods, and, on turning 

 about, the old woman is gone and a hare flies across his track ; he 

 concludes that she turned herself into a hare, and the witch test 

 is applied. When the personal devil was believed in, he was daily- 

 seen clothed in the garments that imagination had given him, 

 and engaged in mischievous actions of all kinds. When witchery- 

 was the dominant superstition, all things gave evidence of that. 

 With the doctrines of modern spiritualism to be supported, the 

 number of mediums and manifestations will be correspondingly 

 abundant. Create a belief in the theory, and the facts will create 

 themselves. 



In the production of this state of mind a factor as yet unmen- 

 tioned plays a leading role : it is the power of mental contagion. 

 Error, like truth, flourishes in crowds. At the hearth of sympathy 

 each finds a home. The fanatical lead, the saner follow. When 

 a person of nervous temperament, not strongly independent in 

 thought and action, enters a spiritualistic circle, where he is con- 

 stantly surrounded by confident believers, all eager to have him 

 share their sacred visions and profound revelations, where the 

 atmosphere is replete with miracles and every chair and table 

 may at any instant be transformed into a proof of the supernat- 

 ural, is it strange that he soon becomes one of them ? — hesitat- 

 ingly at first, and perhaps yet restorable to his former modes of 

 thought by the fresh air of another and more steadfast mental 

 intercourse, but more and more certainly and ardently convinced 

 the longer he breathes the seance atmosphere. No form of con- 

 tagion is so insidious in its onset, so difficult to check in its 

 advance, so certain to leave germs that may at any moment 

 reveal their pernicious power, as a mental contagion — the con- 

 tagion of fear, of panic, of fanaticism, of lawlessness, of supersti- 

 tion. The story of the witchcraft persecutions, were there no 

 similar records to deface the pages of history, would suffice as a 

 standing illustration of the overwhelming power of psychic con- 

 tagion. To fully illustrate its importance in the production of 

 deception would require an essay in itself. It enters at every 

 stage of the process and in every type of illusion. It has least 

 effect when deception is carried on by external arrangements, by 

 skillful counterfeits of logical inferences ; its power is greatest 

 where the subjective factor in deception is greatest, more particu- 

 larly in such forms of deception as have been last described. 



In this review of the types of deception, I have made no men- 

 tion of such devices as the gaining of one's confidence for selfish 

 ends, preying upon ignorance, upon fear, acting the friend while 

 at heart the enemy, planned connivance and skillful plotting, 

 together with the whole outfit of insincerity, villainy, and crime. 

 It is not that these are without interest or are unrelated to the 



