AND BODILY STATES UPON THE IMAGINATION. 225 



tioned, or so intimate a knowledge of the nature of the Imagination 

 as to foresee that, in certain conditions, it must produce illusions of 

 this character, though none had fallen under his own observation. 

 If this latter were the case, how correct a metaphysician must the 

 novelist have been ; since we find in the Letters on Demonology 

 and Witchcraft a narration so similar in all its points, that one 

 appears a counterpart of the other. 



The causes of hallucination which I have enumerated, are de- 

 pendant altogether, as we have seen, upon morbid states of the mind; 

 our next division includes those which are the result of diseased 

 conditions of body. These morbid states are so extremely variable, 

 and so numerous, that it would require many lectures to illustrate, 

 even in a general manner, the relations of those conditions of body 

 and mind, which are likely to be attended by hallucinations of the 

 senses. There is one remark, however, which will apply generally 

 to all these, namely, that hallucination never takes place (except 

 where the organs of sense and perception, the brain and senses are 

 the subjects of complaint) without powerful predisposition in the 

 constitution of the mind, which might have produced hallucinations 

 from moral causes, without the occurrence of bodily complaint. 

 This predisposition to hallucination may be almost exclusively 

 limited to persons of extreme nervous irritability, to those whose 

 profession or occupation favours the development of the functions of 

 the mind at the expense of those of the body ; these are chiefly, as 

 we saw in the last lecture when speaking of the predisposition to 

 mania, divines, poets, metaphysicians, and literary or sedentary per- 

 sons in general. The case of Nicolai naturally occurs to us here. 

 Before entering into the detail of one of the most remarkable cases 

 on record, I wish to say that the previous state of Nicolai's mind 

 was one of naturally great power ; he was highly imaginative, took 

 great pleasure in inventing ideal scenes and mental pictures — com- 

 posed on his bed novels, dramas, and fictions of all kinds, and was 

 most happy when he threw the reins from his guidance, and left his 

 fancy to wander unrestrained through the flowery meads of the lighter 

 branches of literature. In addition to this predisposed condition of 

 mind, he had been greatly excited by a concurrence of unpleasant 

 circumstances, which had been followed by violent mental excite- 

 ment, and were enough in themselves to have produced hallucina- 

 tions of the senses in a character of his temperament. Further, he 

 had neglected his usual periodical blood-letting, which had produced 

 some indisposition of body, the particulars of which it is not neces- 

 sary here to mention. " On a sudden/' writes he, <f whilst reclining 

 vol. v. — no. XVIII. 2p 



