DEEAMS AND ILLUSIONS. 261 



not only consists in the transition from our waking 

 thoughts to the image of our dreams, but it takes 

 place in the act of dreaming; such is the power of 

 the faculty of perception, in which we find the first 

 origin of myth in man, and its roots also in the 

 animal kingdom. Thus the. genesis of myth, as far 

 as the entification of the image is concerned, is the 

 same as that of dreams. 



The normal illusions .of the senses, which are 

 believed to be real by primitive men, and by those 

 ignorant of physical laws, have a similar origin. The 

 objection of such phenomena as a mirage, or the 

 tremulous effect produced in tropical regions by the 

 refraction and reflection of light on trees, rocks, and 

 mountains, so well described by Humboldt, is due to 

 ignorance of the laws of nature, and this is in fact 

 an entification of the phenomenon, occasioned by the 

 innate tendency to animation which is proper to 

 the perception. In this it is easy to trace the genesis 

 both of myth and dreams. The fact of hallucination 

 is more complex, even in its normal state, that is, in 

 those general conditions of mind and body in which 

 reason has complete command over us. 



Without entering into any analysis of the various 

 forms of hallucination of which many able psycho- 

 logists and physicians of the insane have treated, let 

 us turn to the more ordinary cases in which an image 

 of the mind is projected on the external world so 

 as to appear real. The roots of such a phenomenon 



