THE PERCEPTION OF THINGS. 115 



dinary parlance hallucination is held to differ from illusion in 

 that, whilst there is an object really there in illusion, inhcdlu^ 

 cination there is no objective stimulus at all. We shall presently 

 see that this supposed absence of objective stimulus in hal- 

 lucination is a mistake, and that hallucinations are often 

 only extremes of the perception process, in which the secon- 

 dary cerebral reaction is out of all normal proportion to the 

 peripheral stimulus which occasions the activity. Hallu- 

 cinations usually appear abruptly and have the character of 

 being forced upon the subject. But they possess various 

 degrees of apparent objectivity. One mistake in limine must 

 be guarded against. They are often talked of as mental 

 images projected outwards by mistake. But where an hallu- 

 cination is complete, it is much more than a mental image. 

 An hallucination is a strictly sensational form of consciousness, 

 as good and true a sensation as if there ivere a real object there. 

 The object happens not to be there, that is all. 



The milder degrees of hallucination have been desig- 

 nated as pseudo-hallucinations. Pseudo-hallucinations and 

 hallucinations have been sharply distinguished from each 



having a bone in the throat; having neither stomach nor brains; 



having lost much money; being covered with vermin; 



being unlit to live; letters being written about her; 



that she will not recover; property being stolen; 



that she is to be murdered; her children being killed; 



that she is to be boiled alive; having committed theft; 



that she is to be starved; the legs being made of glass; 



that the tlesh is boiling; having horns on the head; * 



that the head is severed from the being chloroformed; 



body; having committed murder; 



that children are burning; fear of being hanged; 



that murders take place aroimd; being called names by persons; 



that it is wrong to take food; being acted on by spirits; 



beiaginhell; being a man; 



being tempted of the devil; the body being transformed; 



being possessed of the devil; insects coming from the body; 

 having committed an unpardon- rape being practised on her; 



able sin; having a venereal disease; 



unseen agencies working, being a fish; 



her own identity; being dead; 



being on fire; having committed 'suicide of the soul. 



