AND BODILY STATES UPON THE IMAGINATION. 219 



They create, and are charmed with the productions of their power, 

 and are so lost in admiration of the beauties of their mental visions, 

 or so occupied in their arrangement, that they lose all controul over 

 their senses, which thus become liable to hallucination. When the 

 mind is exclusively concentrated on one absorbing desire or fear, 

 hallucination frequently takes place, and relates directly to some 

 thing connected with the ideas upon which the mind is occupied. 

 Of this character was the appearance of the ghost of Caesar to Bru- 

 tus, on the eve of the battle of Pharsalia. 



Here we see intense occupation upon one subject, from which the 

 mind had acquired a high degree of excitement, exalting the Imagi- 

 nation to the highest degree of which it is capable — that of giving 

 form and colour to its productions, and stamping upon its waking 

 delusions all the vividness of the fancies of our dreams. There is a 

 strict analogy between the vision of the waking and sleeping states; 

 since blind persons are as liable to hallucination, or rather to the 

 appearance of visions, as those whose sight is unimpaired. This at 

 once proves that the hallucination is not caused by an actual im- 

 pression upon the sensitive organs, but by a creation of the Imagi- 

 nation presented to the sense of vision.* No one believes that 

 they actually see the scenes which are presented to them in dreams. 

 The illusions of wakefulness are precisely of the same character, 

 though, perhaps, dependent upon a more exalted or active state of 

 the Imagination than that which produces the incongruities of the 

 illusions of our sleep. There was in Paris, in 1816, a blind Jew, 

 whose visions were of the most extraordinary character. There 

 were likewise two deaf women who continually heard persons ad- 

 dressing them, and held disputes with them incessantly, both day 

 and night. The habitual activity and concentration of some minds 

 produces constant hallucination. The case of Cardan, professor of 

 mathematics at Milan in 1801, is a remarkable instance of this. 

 " I descried," says he, " the shapes of castles, of houses, of animals, 

 of horses with their riders, of herbs, of hills, of musical instruments, 

 of the different features of men, and of their different garments. 



* It will be recollected that in my first lecture I traced the influence of 

 solitude upon the Imagination, and we found it to be a powerful exciting 

 cause to the activity of this faculty of the mind. The same remark applies 

 to hallucinations, which are always more frequent in solitude, in silence, 

 and in darkness, than at other times. The impressions upon the senses made 

 by surrounding objects are, in these situations, weakened ; the mind retires, 

 as it were, upon itself, and in its seclusion creates visions which only deceive 

 the judgment. 



