May 22, 1896.] 



SCIENCE. 



763 



on the back of the hand to the sound of the 

 metronome. After a few times it was not 

 necessary to drop the ball. The person 

 would feel the touch by pure hallucination. 



Similar experiments were made on taste. 

 Of six bottles two contained pure water and 

 the other four a series of solutions of pure 

 cane sugar — the first one-half per cent., the 

 second ten per cent, the third two per cent, 

 and the fourth four per cent, sugar, accord- 

 ing to weight. A block was placed in front 

 of them so that the observer could not see 

 them, although he was aware that they 

 stood near him, becavise he saw them when 

 he received his instructions. It was re- 

 quired of him to tell how weak a solution 

 of sugar he could positively detect. 



The experimenter took a glass dropper 

 and deposited drops on his tongue, drawing 

 first from the two water bottles, and then 

 from the sugar solutions, in order of in- 

 creasing strength. The sugar in the solu- 

 tions was detected in the first trial. Pro- 

 posing to repeat the test, the experimenter 

 proceeded as before, but drew from the 

 first water bottle every time. The result 

 was that when the pure water had been 

 tasted from two to ten times the observer 

 almost without exception thought he de- 

 tected sugar. 



A test on olfactory hallucinations was 

 conducted similarly, with the result that 

 about three-fourths of the persons experi- 

 mented upon perceived the smell of oil of 

 cloves from a pure water bottle. 



In another set of experiments the subject 

 was told to walk slowly forward till he 

 could detect a spot within a white ring. 

 As soon as he did so, he read off the dis- 

 tance on a tape measure at his side. The 

 spot was a small blue bead. The experi- 

 ment was repeated a number of times. 

 Thereafter the bead was removed, but the 

 suggestion of having previously traversed a 

 cartain distance was sufficient to produce a 

 hallucination of the bead. 



The investigation was carried out in va- 

 rious problems of hallucination and sugges- 

 tion ; in each problem the work was kept 

 up till the appropriate method of producing 

 hallucinations was found. I cannot here 

 go into the details of Dr. Seashore's experi- 

 ments, but the fundamental idea is, I hope, 

 clear. 



The surrounding and internal conditions 

 P were of a given character in the first ex- 

 periment, namely, definite place, apparatus, 

 expectation, etc. The sensation S resulted 

 from R. Each repetition of the experiment 

 produced a change in the attitude of expec- 

 tation ; P was consequently changing. Fi- 

 nally, the production of a given value of P 

 was sufficient to entirely replace R in pro- 

 ducing the sensation. 



It is to be clearly understood that the 

 persons experimented upon were perfectly 

 sane and normal. Thej"- were friends or 

 students, generally in total ignorance of the 

 subject, who supposed themselves to be 

 undergoing some tests for sensation. One 

 case was found, however, of a suspicious 

 observer who expected deception and who 

 declared that he had waited every time till 

 he was sure of the sensations ; the results 

 were just as hallucinatory as usual. 



The value of the method and the experi- 

 ments lies mainly, I think, 1, in pointing out 

 a method of determining the portion of a 

 sensation due to the suggestion of circum- 

 stances rather than to the stimulus; 2, in ap- 

 plication to mental pathology ; 3, in begin- 

 ning a scientific treatment of hypnotism and 

 suggestion. E. W. Sceiptuee. 



Yale Univeesity. 



LIFE EABITS OF PHBTN0S03IA. 



In a recent number of the ' Zo51ogischen 

 Anzeiger' Prof. Charles L. Edwards, of the 

 University of Cincinnati, gives the follow- 

 ing interesting notes upon the habits of the 

 horned lizard of Texas: 



While living in Austin, Texas, from 



