128 PSYCHOLOGY. 



We seem herewith to have an explanation for a certain 

 number of hallucinations. Whenever the normal forivard 

 irradiation of intra-cortical excitement through association-paths 

 is checked, any accidental spontaneous activity or any peripheral 

 stimulation [hoivever inadequate at other times) by ivhich a brain- 

 centre may be visited, sets up a process of full sensational inten- 

 sity therein. 



In the hallucinations artificially produced in hypnotic 

 subjects, some degree of peripheral excitement seems usu- 

 ally to be required. The brain is asleep as far as its own 

 spontaneous thinking goes, and the words of the * magneti- 

 zer ' then awaken a cortical process which drafts off into 

 itself any currents of a related sort which may come in 

 from the periphery, resulting in a vivid objective percep- 

 tion of the suggested thing. Thus, point to a dot on a 

 sheet of paper, and call it ' General Grant's photograph,' 

 and your subject will see a photograph of the General 

 there instead of the dot. The dot gives objectivity to the 

 appearance, and the suggested notion of the General gives 

 it form. Then magnify the dot by a lens ; double it by a 

 prism or by nudging the eyeball ; reflect it in a mirror ; 

 turn it upside down ; or wipe it out ; and the subject will 

 tell you that the ' photograph ' has been enlarged, doubled, 

 reflected, turned about, or made to disappear. In M. Binet's 

 language, * the dot is the outward point de repere which is 

 needed to give objectivity to your suggestion, and without 

 which the latter will only produce a conception in the 

 subject's mind.f M. Binet has shown that such a periphe- 



* M. Bluet's highly important experiments, which were first published 

 in vol. XVII of the Revue Philosophiiiue (1884), are also given in full in 

 chapter ix of his and Fere's work on ' Animal Magnetism ' in the Inter- 

 national Scientific Series. Wliere there is no dot on the paper, nor any 

 other visible mark, the subject's judgment about the ' portrait ' would 

 seem to be guided by what he sees happening to the entire sheet. 



t It is a difficult thing to distinguish in a hypnotic patient between a 

 genuine sensoi-ial hallucination of something suggested and a conception 

 of it merely, coupled with belief that it is there. I have been surprised at the 

 vagueness with which such subjects will often trace upon blank paper the 

 outlines of the pictures which they say they ' see ' thereupon. On the other 



