620 THE POPULAR SCIENCE MONTHLY. 



results of the experiments must be accepted by science. Scientifically 

 it makes no diflFerence whether the subject on whom any such experi- 

 ment is performed is honest or dishonest; the experiments are to be 

 made without any reference to the moral character of the subject. 



Fourth Soubce of Error : Unintentional collusion of third par- 

 ties.— By third parties are meant audiences, witnesses, bystanders, or 

 assistants seen or unseen. 



The best iUustration of error from this source is the aid which audi- 

 ences in the mind-reading experiments give to the performer by their 

 silence, when he wanders away from the object looked for, and by their 

 murmurs and applause when he approaches or reaches it. This is quite 

 analogous to the cry of " hot " or " cold " in the game of " bhnd-man s- 

 bufF." So natural is it for errors from this cause to enter these inves- 

 tigations that I found it necessary, in all my researches in that depart- 

 ment, to send all witnesses from the room, or to insist on then: bemg 

 absolutely sUent, and even motionless, at every stage of the experiments. 



Fifth Source of Error : Intentional collusion of third parties. 

 —Under tHs head comes the aid which assistants, known or unknown, 

 designedly give to the subject experimented on. This, in the abstract, 

 is one of the more readily suspected of all the six sources of error, but 

 in the concrete very difficult to guard against, or even to detect, as is 

 so brilliantly Ulustrated in the conjuring tricks of Houdin and Heller, 

 and it may be added also, in the operations of so-called " confidence- 



men." 



The best and most mystifying tricks of illusionists, and sleight-of- 

 hand performers of all kinds, are almost always done through some form 

 of collusion, the time and method of which are so artfully arranged that 

 only those of unusual acuteness or expert skill can at once detect them. 

 The astounding success of clairvoyants and mediums in telling people 

 what they already know, but which they suppose can not be known to 

 the witch they are consulting, is oftentimes explamed by this fifth 



source of error. , • j v 



Intentional, deliberate deception, where no money is to be gamed by 

 deception, is much more common among the better classes than those 

 who have not specially studied this subject would be willing to believe : 

 it is an instructive fact in the psychology of lying, that some persons 

 —usually, though not always, women— whose general character is of the 

 highest, are in some special direction absolutely systematically untruthful 

 all their lives long. An old merchant of New York once told me that a 

 clerk in his employ, trustworthy in all business affairs, exact, scrupulous, 

 just, had a habit of telling large stories in regard to what he had seen 

 and done so firmly fixed that it was organically impossible for him to 

 restrict himself to the facts, and that his statements in regard to matters 

 outside of business were worthy of absolutely no credence. 



I was once requested by a valued medical friend to aid him in some 

 experiments with a case of alleged sixth sense, or the asserted power of 



