INSANITY IN THE LOWER ANIMALS. 31 



2. The reverse condition of morbid drowsiness or somno- 

 lence at unusual times, or excessive in amount or degree, is 

 far less frequent. 



3. Morbid taciturnity or silence, or the reverse states of 

 unusual noisiness or boisterousness. 



4. Desire for isolation. 



5. Irritability, or other infirmities of temper, including 

 passionateness, causeless passion, or anger aroused by the 

 most trivial causes. 



6. Low or bad spirits, moroseness, sadness, or melancholy ; 

 or 



7. The reverse condition of superfluity or exuberance of 

 good spirits, extreme vivacity a common precursor of insanity 

 also in man. 



8. Loss partial or total of memory, which becomes more 

 marked in proportion as dementia or other forms of insanity 

 are developed. It is naturally most familiar in senile forms 

 of mental decay or degeneration. 



9. Loss partial or total of the power of will, which is 

 in itself a state of mental deficiency, if not of alienation. 

 Infirmity of purpose is commonly associated with weakness 

 of mind, or weakening of the mind, for instance in age. The 

 movements then want aim, object, design, definite idea or 

 method. 



10. Alterations in the emotional state, including patho- 

 logical perversions of the natural affections. 



1 1 . Confusion of ideas exists in many of the minor forms 

 of insanity. Derangement of the ideas, and of the process of 

 ideation, the development of morbid ideas occur both in 

 dreams and delusions. 



12. Perversion or destruction of the moral sense. 



13. Loss of self-possession, leading frequently to panic and 

 precipitate flight. 



14. Loss of normal virtues, such as docility, mildness, 

 benevolence, caution. 



15. c Silliness ' of behaviour, such as to attract the notice 

 of by no means specially observant human onlookers. 



As might be expected, the symptomatology of insanity in 

 the lower animals most closely resembles that of human in- 



