450 DISEASES OF THE NERVOUS SYSTEM. 



is a much shorter one than the list of primary affections 

 implicating any of the other organs of the body. The his- 

 tory of nervous diseases in the lower animals has yet to be 

 written, and I cannot hope to do more than furnish a 

 sketch of the knowledge hitherto acquired on this very 

 important subject. 



It may be well to enter, in the first place, on the con- 

 sideration of a very important group of diseases which im- 

 plicate the nervous system generally, but which are not 

 usually characterised by any marked organic changes, If 

 the limits of this work permitted, much could be said on 

 the subject of morbid mental conditions in animals. Are 

 horses, oxen, dogs, and other animals ever mad ? Are they 

 liable to aberrations of intellect, and to morbid fancies or 

 hallucinations ? The ferocity suddenly manifested by ani- 

 mals which, early in life, have been very docile ; the 

 extreme irritability of some, and the apparently gross stu- 

 pidity and listlessness of others, often indicate deviations 

 from the normal state of either instinctive or reasoning 

 faculties. There are singular instances noticed of animals 

 acquiring peculiar morbid tastes, which can only be ex- 

 plained as due to nervous disease, and there can be no 

 doubt that just as we find the greatest diversity in the 

 amount of intelligence possessed by different individuals of 

 the same species, so may we have perversions of instinct 

 or mind similar to those which are manifested by the 

 human idiot or lunatic. The disease commonly termed 

 madness in the lower animals is not of the class included 

 under the general term madness in man. It is altogether a 

 specific contagious malady, which we may at once describe 

 under the usually accepted names 



