106 DREAMS AND DELUSIONS. 



presence of delusion, sensorial or other, in certain forms of 

 human insanity ; and it is clear that if such phenomena are 

 to be accepted as conclusive in the case of man and they are 

 so they cannot be less so in the case of other animals. In 

 man, indeed, these phenomena of action afford a guide which 

 speech and writing fail to give us ; and there is nothing 

 remarkable in this if we bear in mind that the phenomena in 

 question constitute the natural language of man and other 

 animals, and that the expression of ideas and feelings by such 

 means may be involuntary and spontaneous ; while speech 

 and writing are eminently artificial, and may be used with 

 effect to conceal, instead of making evident, real thought or 

 emotion. 



Of the waking delusions of the lower animals, none are 

 so common or so obvious as those connected with fear or sus- 

 picion. They occur equally in domestic and wild animals, es- 

 pecially, perhaps, in those habitually subjected to persecution 

 or other forms of ill-usage by man. Hence we find them 

 equally in the dog and horse, and in the fox and wolf. They 

 are not necessarily connected with the senses, though pro- 

 bably they are usually associated with visual or auditory im- 

 pressions. They take their genesis in morbid fear, morbid 

 fancy, and morbid suspicion. 



The early stage is usually mere unreasonable, unfounded 

 dread, leading probably to excessive or unnecessary caution 

 in such animals as the hunted or baited fox, wolf, or wol- 

 verene. The development of such delusions the liability to 

 delusion stand intimately related to the constitutional timi- 

 dity or nervousness of an animal, and to the nature of its 

 struggle for life. They occur most frequently and readily in 

 animals that are habitually easily startled and frightened, 

 constitutionally timorous and nervous, and living under con- 

 ditions that give rise to perpetual dread of peril to life. 



Fish are startled, we are told, at shadows on water 

 (Watson) ; and a recent describer of the habits of the Nor- 

 wegian lemming speaks of them as ' self-haunted fugitives ' 

 in their migrations, and asserts that ' a mere cloud rapidly 

 passing over the sun affrighted them ' (Crotch). 



Nor must we lose sight of the importance of the degree 



