i6 THE POPULAR SCIENCE MONTHLY. 



ous experience. But after some little time the question was raised 

 whether the effect was not really due to action of heat upon the 

 attenuated vapor of which it was impossible entirely to get rid; and 

 the result of a most careful and elaborate experimental inquiry, in 

 which Nature has been put to the question in every conceivable mode, 

 has been to make it, I believe, almost if not quite certain that the first 

 view was incorrect, and that heat is the real moving power, acting 

 under peculiar conditions, but in no new mode. 



No examination of the phenomena of spiritualism can give the least 

 satisfaction to the mind trained in philosophical habits of thought, 

 unless it shall have been, in its way, as searching and complete as this. 

 And when scientific men are invited to dark seances, or admitted only 

 under the condition that they shall merely look on and not inquire 

 too closely, they feel that the matter is one with which they are en- 

 tirely precluded from dealing. When, again, having seen what ap- 

 pears to them to present the character of a very transparent conjuring 

 trick, they ask for a repetition of it under test-conditions admitted to 

 be fair, their usual experience is that they wait in vain (for hours it 

 may be) for such repetition, and are then told that they have brought 

 an "atmosphere of incredulity " with them, which prevents the mani- 

 festation. Now, I by no means affirm that the claims of spiritnalism 

 are c^/sproved by these failures; but I do contend that, until the evi- 

 dence advanced by believers in those claims has stood the test of the 

 same sifting and cross-examination by skeptical experts that would 

 be applied in the case of any other scientific inquiry, it has no claim 

 upon general acceptance; and I shall now proceed to justify that con- 

 tention by an appeal to the history of previous inquiries of the like 

 kind. 



It was about the year 1772 that Mesmer, who had previously pub- 

 lished a dissertation " On the Influence of the Planets on the Human 

 Body," announced his discovery of a universal fluid, " the immediate 

 agent of all the phenomena of Nature, in which life originates, and by 

 which it is preserved ; " and asserted that he had further discovered 

 the power of regulating the operations of this fluid, to guide its cur- 

 rents in healthy channels, and to obliterate by its means the tracks of 

 disease. This power he in the first instance professed to guide by the 

 use of magnets; but having quarreled with Father Hell, a Professor 

 of Astronomy at Vienna, who had furnished him with the magnets 

 with which he made his experiments, and who then claimed the dis- 

 covery of their curative agency, Mesmer went on to assert that he 

 could concentrate the power in and liberate it from any substance he 

 ])leascd, could charge jars with it (as with electricity) and discharge 

 them at his ])leasure, and could cure by its means the most intractable 

 diseases. Having created a gi'eat sensation in Bavaria and Switzer- 

 land by his mysterious manipulations, and by the novel eftects which 

 they often produced, Mesmer returned to Vienna, and undertook to cure 



