SCIENTIFIC STUDY OF HUMAN TESTIMONY. 53 



sensation-waves, which spread from a focus, may be brought again to a 

 focus by condensing them with an ear (Fig. 12). Here, across a little 

 echo-cave, is hung a curtain, Ty. M., which is blown in and out as each 

 air- wave beats against it ; and, though the air- waves vary from 40 feet to 

 4 inches apart, they jump the distance quickly, and this curtain, taking 

 an exact copy of each, in vibrations less than the thousandth part of an 

 inch, sends them, through the tapping bones, Mall., Stp., to an inside cur- 

 tain, F.o., where they are condensed again, and thrown through a liquid 

 which fills the hollow inside of it. Here three thousand tuned nerves 

 take up, each, its own acchording waves, and bear them to the brain ; 

 and thus the wild waves of an emotion passed from one " conscious- 

 ness " to another in less than a second, proving that the " quickness of 

 thought " is no metaphor. Through pipes, the sound of the voice may 

 be heard nearly four miles, and conversation carried on at nearly a 

 mile. Through the wire of the telephone, which has become literally 

 the " thread of a conversation," sound, with all its qualities, is conveyed 

 hundreds of miles, as we have already shown in a former article. 



-- 



THE SCIENTIFIC STUDY OF HUMAN TESTIMONY 



By GEORGE M. BEAED, M. D. 



" Of what account are the most venerated opinions, if they be untrue ? At best they 

 are only venerable delusions." Sir William Hamilton. 



ABOUT two years ago I chanced to call on an educated profes- 

 sional man, who was much interested in the subject of delusions. 

 He said, " I have been long wishing to see you, in order to get an expla- 

 nation of some strange things that have happened under my observa- 

 tion." I inquired what these strange things were. He replied, as usual 

 in such cases, by giving a detailed account of certain performances of a 

 well-known trickster, to which I listened as politely as I could, and he 

 concluded with this conundrum : " Now, how do you explain that ? " 

 I replied : "I do not know what happened, for there was no expert 

 there to report. If I knew what happened, I could very likely explain 

 it, for a knowledge of what happened would itself be the explanation." 

 " But I have just told you what happened," he interposed, some- 

 what excitedly. " My wife and I both were there, and we saw it all, 

 with our own eyes. Can't we trust our senses ? " " Trust our senses ? " 

 I replied ; " not at all. In science we never trust our senses." My 

 friend was as much astonished and indignant as though he had been 

 personally insulted, and I felt it to be prudent to withdraw from the 

 house. 



