INSANITY IN THE LOWER ANIMALS. 39 



zoological scale insanity reaches. Dunne goes the length of 

 asserting incautiously and probably much too sweepingly 

 that it affects, or may affect, all animals. This may be, and 

 probably is, going too far. There may be nothing analogous 

 to human insanity in the lowest animal organisms. And yet 

 it is an obvious inference, from all that has already been de- 

 termined regarding insanity and other diseases in the lower 

 animals, that wherever there is healthy, there may also be 

 morbid, sensation, emotion, memory or volition. We cannot 

 conceive the existence of the physiological without the 

 pathological condition also. We must hold then that feeling 

 and thought, wherever they can be shown to exist, are as 

 liable to be deranged in other animals as in man. 



At present morbid mental phenomena have been mostly 

 observed if properly observed at all among the domestic 

 vertebrata or mammalia. But their study in other and lower 

 animals by the physician or veterinarian, naturalist or com- 

 parative psychologist, cannot fail to bring to light many data 

 of the highest interest in relation to man's knowledge of 

 human insanity. 



The alleged greater prevalence of insanity in the Middle 

 Ages, which has already been adverted to, was no doubt attri- 

 butable to such facts as the following : 



1. That 'madness' then included rabies, distemper, and 

 other diseases, attended with striking morbid mental phe- 

 nomena of the delirium type. 



2. That it probably included also forms of mere eccentri- 

 city or marked individuality. 



3. That man's superstition attributed c possession' to 

 certain animals for no other reason sometimes or perhaps 

 than the blackness of their skin, fur, feathers or hair. 



Formerly, for instance, madness is said to have been com- 

 mon in the Scotch Highlands, whereas now it is stated to be 

 rare, the difference being not one of fact, but of opinion, the 

 apparent or real rarity now-a-days being ascribable to the 

 greater freedom from superstition among the peasantry, 

 (McDowall). 



The duration of insanity in the lower animals is extremely 

 variable. It may be 



