172 THE POPULAR SCIENCE MONTHLY. 



bad as this other, but still presented all these phenomena : he jumped 

 when he heard any sound fx'om behind that was sharp and unex- 

 pected, and struck and threw when ordered to do so. The crowd 

 around the hotel, partly for my benefit, kept him constantly teased 

 and annoyed, so that when he approached he had a stealthy, suspicious, 

 and timid look in his eye, as though he expected each moment to be 

 jumped. 



6. This man, while playing with one of his mates, had thrown him to 

 the ground ; some one approached near and commanded " Strike him," 

 and he struck him very hard and explosively, with both hands at a time. 



7. When standing by a window, he was suddenly commanded to 

 "jump" by a person on the other side of the window. He jumped 

 straight up, half a foot off the floor, with a loud cry, repeating the 

 order which had been given to him, 



8. When the two Jumpers were close together, they were com- 

 manded to " strike " : each struck the other simultaneously not mild 

 or polite, but severe and painful blows. I took one of these men to 

 my room and quietly conversed with him, and made the same experi- 

 ments with him as with the other case. I found him much less irri- 

 table than the other, and he needed usually stronger excitation to pro- 

 duce the phenomena. 



I experimented with him in the phenomenon of repeating language 

 that was addressed to him. W hen the command was uttered in a 

 quick, loud voice, he repeated the order as he heard it, at the same 

 time that he executed it. When told to strike, he said " Strike " at 

 the same time that he struck ; when told to throw it, he said " Throw 

 it " at the same time that he threw whatever was in his hand. It made 

 no difference what language was used. I tried him with the first part 

 of the first line of Homer's " Iliad," and with the first part of Virgil's 

 "^neid," languages, of course, of which he knew nothing, and he 

 repeated quickly, almost violently, the sound as it was uttered " Menin 

 Aida," the first part of the first line of the "Iliad," and "Arma-vi," 

 the first part of the first line of Virgil. In order to have it repeated, 

 it was necessary that the command should be very short, as well as 

 quickly and strongly uttered. He would not repeat a whole line, or 

 even half a line, but simply a word or two. In these, as in the mind- 

 reading experiments, I was able to establish ray conclusions by exclu- 

 sion that is, by proving that only the involuntary action of mind 

 on body could produce the phenomena. 



These experiments were repeated again and again, under various 

 conditions at different times, in such a way as to satisfy myself, abso- 

 lutely, that the six elements of error that apply to all experiments 

 with living human beings were all eliminated, and that the facts 

 obtained were the solid residuum of an exact scientific investigation.* 



* The six sources of error in experimenting with living human beings are 1. Uncon- 

 scious deception on the part of the subject experimented on ; 2. Intentional deception on 



