242 NOTES ON THE NATURE OF INSANITY. 



Insanity. Insanity then is that unusual stale wherein an Individual 

 persists in expressing unreasonable thoughts or attempting improper 

 actions, having a tendency to injure himself or others, with or with- 

 out discernible disease of the cerebral structure. 



Quite clear it is, moreover, that if we can show an intimate con- 

 nexion between any part of the human body and the mental mani- 

 festations in human conduct which are the subjects of the alteration 

 uniformly found in concomitance with insanity ; and if we can also 

 show that, where this injurious alteration prevails, there is at the 

 same time diseased organization or diseased action in such part ; we 

 shall then have done much towards arriving at a right conclusion 

 on the nature of insanity. Now, let us put the same question es- 

 sentially altered — Can we trace such a connexion between our 

 mental manifestations and the brain and nervous system ? We 

 have seen that, in animals where the mental powers are in low 

 endowment, there is a proportionate absence of cerebral organiza- 

 tion ; and that, in man, where the mental powers have the highest 

 development, the cerebral organization is the most elaborate. — 

 When the whole human brain has been rendered torpid by chronic 

 inflammation, by gradual pressure from the slow effusion of a fluid, 

 or by any other cause, an alteration is effected and it reduces the 

 cleverest man to the level of the lowest animal, in point of moral 

 and intellectual capacity : his appetite remains and he takes ali- 

 ment ; but, as the cerebral pressure and disease advance, so he loses 

 the ability to perform all other voluntary actions. When the brain 

 is excited to an unusual degree of activity, this is always accompa- 

 nied with a corresponding increase of activity in the mental mani- 

 festations. Thus, when fermented liquors are taken to excess, 

 their abuse creates an exaltation of the cerebral energies, and then 

 the mind's operations, in feeling and sentiment and intellect, are 

 quickened in a degree proportionate to that of the excitement which 

 increases the brain's activity. In brain-fever with acute inflamma- 

 tion, the violence of the mental manifestations corresponds with the 

 violence of the disease ; and when, by cold applications with proper 

 medical treatment, the inflammatory action is subdued, the mind 

 then recovers its natural tone ; but, the feelings and intellectual 

 powers are never completely regained, if this action is left to pro- 

 ceed insidiously until the brain itself and its membranes have be- 

 come permanently injured. That this is found to be the case in 

 all instances where insanity resulted from brain-fever, a superfluity 

 of evidences has been furnished by dissection. It is quite certain, 

 also, that any other part of the body may be diseased or even 



