DREAMS AND DELUSIONS. 105 



authors to usher in the more dangerous symptoms of rabies 

 to constitute one of its marked features and stages. 



A she-ape suffering from sunstroke is similarly described 

 by Pierquin as terror-struck by imaginary foes or sights 

 and as snapping at imaginary objects. She acted as if she 

 had been watching and catching insects on the wing. 



Auditory delusions occur under similar circumstances to, 

 and, indeed, they usually accompany, visual ones. Thus in 

 rabies a dog 'would throw itself against the wall, yelling 

 furiously as if there were a noise on the other side ' (Fleming) ; 

 while the ape above mentioned behaved as if she heard fami- 

 liar or strange, attractive or repulsive, sounds (Pierquin). 



In man very great difficulty is experienced in distinguish- 

 ing sensorial delusions, which are supposed to originate ab 

 extra in some impression from without, from those which 

 are not connected with the senses, that originate, or are 

 believed to do so, ab intra, and that are distinctively called 

 intellectual. The distinction between false notions, ideas, or 

 conceptions, not involving the special senses, and those 

 others that do implicate more or less these senses, is not 

 always either proper or practicable. It is arbitrary and in- 

 sufficient, because all sensorial delusion must involve false 

 ideas morbid ideation ; while the most purely intellectual 

 delusion seldom leaves sensation uninvolved. In other words, 

 both in man and other animals, disordered sensation must 

 lead to disordered ideation, so that whether or not there be 

 such a thing as intellectual or ideational disturbance inde- 

 pendent of sensational, sensorial necessarily leads to ideational, 

 disorder. 



Naturally, however, we have less clue to the ideas, normal 

 or abnormal, of other animals than to those of man ; and, 

 therefore, we have not the same means, or at least the same 

 variety of means, of judging of the presence in the former of 

 delusion, even of the sensorial kind. We are destitute of the 

 proofs, or at least of the aid, furnished by man's speech, 

 writing and printing by his power of describing, in one 

 or another, his ideas or sensations. 



We have, however, the same kind of phenomena of action, 

 look, voice, of attitude or gesture, from which we infer the 



