414 THE HUMAN SPECIES 



This question is but little discussed in pathological literature. 

 As regards the more highly gifted vertebrates, a partial affirma- 

 tive cannot be denied offhand. If the disturbances set up by 

 morphia and alcohol are to be included in the organic psychoses 

 of man, then we may correctly speak of psychoses in animals 

 due to the ingesta ; thus the swallowing of belladonna, hyoscy- 

 amus, datura strammonium, allium, cannabis and poisonous 

 fungi produces severe disturbances going on to delirium ; Pteris 

 aquilina (bracken) produces unconsciousness ; the administration 

 of melampyrum is followed by depression. 



Rabies is a remarkable psychosis due to the poisonous action 

 of some infective material on the cerebral cortex, and may be 

 communicated to dogs and other animals by mad wolves and 

 foxes. The clinical picture is well known from cases in man ; 

 it begins with peevishness and anxiety, and goes on to the most 

 violent psychical excitement, with furious delirium and violent 

 convulsions. We must conclude from the behaviour of the 

 rabid animals that similar processes take place in their cerebral 

 cortex. It still remains to ask whether it is possible for a 

 psychosis to develop in animals, with or without recognisable 

 pathological or auatomical changes, quite apart from any 

 poisoning or infection ? I have ransacked the literature in 

 order to obtain some light upon this question, and have only 

 been able to find a reference to it in the work of Lindsay (Journal 

 of Mental Science, July, 1871). He begins by drawing a dis- 

 tinction between " insanity," which is applied to man, and de- 

 notes very various mental disturbances, and " madness," which is 

 applied to animals, and denotes, more or less vaguely, a number 

 of very heterogeneous diseases. He is quite aware that veterin- 

 ary surgeons deny that any parallel exists in the region of 

 psychology between man and animals ; in their view animals 

 have no true intellect, and so cannot lose it ; that is to say, it 

 cannot be damaged by any morbid changes. Lindsay, however, 

 rightly disputes this point of view, and holds that the higher 

 animals, whose intelligence stands so near to that of man, must 

 suffer from similar mental disturbances. Insanity in man and 

 madness in animals convey the same idea to him, and he re- 

 solutely opposes the foolish view held by many other veterinary 

 surgeons that all madness in animals is a kind of hydrophobia, 



