CHAPTER XVII. 



MORAL CAUSES OP MENTAL DIFFERENCE AND DISORDER. 



BELONGING chiefly to the so-called moral ' or mental group 

 of the causes of mental derangement in the lower animals 

 are the following : 



I. All excess or exuberance of emotion or passion 

 including 



Mental shock. 



Wounded feelings of all kinds. 



Anxiety or worry of every sort and degree. 



Anger in all its degrees. 



Grief. 



Fright and fear. 



Love in all its forms. 



Joy. 



Envy, jealousy, rivalry and hatred. 



Despair. 

 II. Imitation and sympathy. 



III. Novelty : the unfamiliarity of objects, especially if 



suddenly presented. 



IV. Imagination. 



The influence of certain of the commoner passions or 

 emotions in producing mental excitement or depression of a 

 morbid kind is quite as obvious when looked for among 

 other animals, as in man. The dog and certain other ani- 

 mals frequently exhibit in as marked excess, as in man, 

 such feelings or passions as anger, grief or joy. Youatt 

 speaks of c excess or derangement of fondness ' in the dog, 

 while other authors refer to an 'overflow of love' on the 



