PSYCHICAL RESEAKCH OF THE CENTURY. 681 



anecdote leads to the ditficult topic of -collective hallucination;' a.s 

 when a number of persons similarly situated are similarly and snnul- 

 taneously hallucinated. The causes remain a puzzle. Are all affected 

 by an external cause or does one person "wire on" his hallucinations 

 to the others? 



It will be observed that this theory of hallucination gets rid of the 

 old puzzle: *"How about the clothes of the g-hostT' Clothes have no 

 u-liosts, yet I have heard of only one ghost without clothes (on the evi- 

 dence of the report of a criminal trial in 1753). The new theory 

 simply explains that there is neither ghost nor clothes in the case; the 

 hallucination merely includes clothes for the sake of decency or 

 because the agent, the mind which affects the percipient's mind, thinks 

 of himself as dressed *■' in his habit as he lived.'' 



While the society, advancing from the experimental thought trans- 

 ference to telepathy, has more or less explained "wraiths" and has 

 perhaps suggested a conceivable theory of "ghosts" in the region of 

 spiritualistic material phenomena, as of volatile articles of furniture, 

 it has found no certaint3\ Experiments with paid "mediums" have 

 invariably resulted in the detection of imposture, notably in the case 

 of Slade and of Eusapia Paladino. But it is fair to say that some 

 thinkers even now believe that Eusapia occasionally gets her effects 

 without cheating. In the cases of amateur mediums many things told 

 on evidence unimpeachable in worldly matters are certaiidy hard to 

 explain. For a number of years a Mrs. Piper, a citoyenne of the 

 United States, has been closely studied by the learned, as by Prof. 

 William James, Dr. Hodgson, and Prof. Oliver Lodge. Her specialty 

 is to convey, by writing or word of mouth, " messages from the dead." 

 Vast reports on Mrs. Piper have been edited by Dr. Hodgson, cer- 

 tainly a clear-headed and skeptical observer, who exposed Eusapia 

 Paladino an! Madame Blavatsky. As at present advised, Di-. Hodg- 

 son expresses his belief that the dead do communicate through Mrs. 

 Piper. Others hold that the "communicators" are only "secondary 

 personalities" of the lady, and that when she does hit on facts not 

 normally knowable by her she owes the information to telei)athy. 

 How is the reverse to be proved? How can she comnuu.icat.- matter 

 at once capable of veriiication and yet unknow.i to any bvmg nnnd^ 

 This is the old difficulty which besets spirits of the dead. 



On the whole, psvchical research has, I think, shown that there is a 

 real element of obscure mental facidty involved in the - superstitior.s 

 of the past and present. It has also made some discoveries ot practi- 

 cal value in hvpnotism and the treatment of hysteria. t streng hens 

 the opinion that science has not yet exhausted all attan.able knowledge 

 about the constitution of man. 

 SM 1900 1:7 



