370 HYPNOTISM. 



" after-image." This class of hallucinations has other 

 characteristics, differing from those of the hallucinations to 

 be immediately described, but which need not be further 

 insisted on here {vide note at end of paper). 



The origin of visual hallucinations other than these may, 

 in the first place, be auto-suggestion. Thus a visual recol- 

 lection may arise in the mind. This may remain subjective. 

 If, however, its origin is not recognised, it is generally 

 " projected," i.e. supposed to be due to some external 

 object, and is called an hallucination. (It may be remarked, 

 in passing, that, by persons of great visualising powers, 

 visual recollections may be voluntarily projected ; these 

 would not come under the definition of hallucinations.) In 

 the second place, such a visual hallucination may have its 

 origin in suggestion from without, as in the instances given 

 in the first part of this paper, where the hallucination of a 

 mouse was due in the first case to a verbal suggestion, in 

 the second to a misinterpreted noise. 



We may define, then, a visual hallucination as a visual 

 image which is believed to be due, though it really is not, 

 to a corresponding external object, and which has its origin 

 in auto-suggestion or in suggestion from without. 



This " projection " of an hallucination may take place 

 in either of two ways. Thus if a hypnotised person was 

 told, " Look, there is a dog," he might say he saw it running 

 about the room, or he might think that some piece of furni- 

 ture, e.g. a footstool, was the dog, erroneously interpreting 

 the visual sensations due to the footstool. In the latter 

 case, then, the hallucination is " projected " upon the foot- 

 stool, which is called the point cle repere. In the latter case 

 it will be evident that the hallucination will obey all tests 

 of visual perception of a real object ; e.g. if he look at the 

 imagined dog, with a prism placed before one eye, he will 



