SECT. XXXiV.2. DISEASES OF VOLITION. 493 



tion of it, and is hence derived with greater cafe or 

 in greater abundance into the limbs, which remain 

 unaffected. 



II. i. Theexcefsor defect of voluntary exertion 

 produces fimilar effects upon the fenfual motions, or 

 ideas of the mind, as thofe already mentioned up- 

 on the mufcular fibres. Thus when any violent 

 pain, ariiing from the defect of fome peculiar fli- 

 mulus, exiils either in the mufcular or fenfual fyf- 

 tems of fibres, and which cannot be removed by 

 acquiring the defective ftimulus } as in fome confti- 

 tutions convulfions of the mufcles are produced to 

 procure a temporary relief, fo in other conftitutions 

 vehement voluntary exertions of the ideas of the 

 mind are produced for the fame purpofe; for dur- 

 ing this exertion, like that of the mufcles, the pain 

 either vanifhes or is diminifhed : this violent exer- 

 tion conflitutes madnefs ; and in many cafes I have 

 ieen the madnefs take place, and the convulfions 

 ceafe, and reciprocally the madnefs ceafe, and the 

 convulfions fupervene. See Sect. III. 5. 8. 



2. Madnefs is diftiuguifhable from delirium, as 

 in the latter the patient knows not the place where 

 he refides, nor the perfons of his friends or attend- 

 ants, nor is confcious of any external objects, ex- 

 cept when fpoken to with a louder voice, or Simu- 

 lated with unufual force, and even then he foon 

 relapfes into a ftate of inattention to every thing 

 about him. VVhilit in the former he is perfectly 

 ienlible to every thing external, but has the volun- 

 tary powers of his mind intenfely exerted n fome 

 particular object of his defire or averfion, he har- 

 bours in his thoughts a fufpicion of all mankind, 

 left they mould counteract his defigns ; and while 

 he keeps his intentions and the motives of his ac- 

 tions profoundly fecret ; he is perpetually (tudying 

 the means of acquiring the object of his wifh, or of 

 preventing or revenging the injuries hefufpedts. 



Kk 2 3. A 



