Sect. XXXIV. 2. 2. OF VOLITION. 337 



fimilaf effects upon the fenfual motions, or ideas of the mind, aa 

 thofe already mentioned upon the mufcular fibres. Thus when 

 any violent pain, arifing from the defect of fome peculiar hamu- 

 lus, exifts either in the mufcular or fenfual fy items of fibres, and 

 which cannot be removed by acquiring the defective ftimulus ; 

 as in fome confcitutions cotivulfiorfs of the mufeles are produced 

 to procure a temporary relief, fo in other constitutions vehement 

 voluntary exertions of the ideas of the mind are produced for 

 the fame piirpofe ; for during this exertion, like that of the mui- 

 cles, the pain either vanifhes or is dirmfiifh'ed : this violent ex- 

 ertion co'hititu'tes madnefs *, a*id in many cafes I have ieen the 

 madnefs take place, and the convulfions ceafe, and reciprocally 

 the madnefs ceafe, and the convulfions fupervene. See Section 

 III. 5. 8. 



2. Madnefs is diftinguilhable from delirium, as in the latter 

 the patient knows not the place where he refides, nor the per- 

 sons of his friends or attendants, nor is confcious of any external 

 objects* except when fpoken to with a louder voice, or ftUnu- 

 lated with unufual force, and even then he foon relapfes into a 

 Hate of inattention to every tiling about him. Whilft in the 

 former he is perfectly fenfible to every thing external, but has 

 the voluntary powers of his mind intenfeiy exerted on fome par- 

 ticular obiect of his deilre or averfio'n, he harbours in his 

 thoughts a fufpicion of all mankind, left they fhouLi counteract 

 his defigns ; and while he keeps his intentions, and the motives 

 of his actions profoundly fecret ; he is perpetually ftudying the 

 means of acquiring the object of his wifli, or of preventing or 

 revenging the injuries he fufpects. 



3. A late French philoibpher, Mr. Kelvetius, has deduced al- 

 moit all our actions from this principle of their relieving us 

 from the ennui or tccdium vitse \ and true it is, that our defiles 

 or averfions are the motives of all our voluntary actions ; and 

 human nature feems to excel other animals in the more facile 

 ufe of this voluntary power, and on that account is more liable 

 to infanity than other animals. But in mania this violent exer- 

 tion of volition is expended en miltaken objects, and would not 

 be relieved, though we were to gain or efcape the objects, that 

 excite it. Thus I have feen two inftances of madmen, who con- 

 ceived that they had the itch, and fever.il have believed they had 

 the venereal infection, without in reality having a fymptom of 

 either of them. They have been perpetually chinking upon this 

 fubject, and fome of them were in vain fahvated with deuVn of 

 convincing them to the contrary. 



4. In the minds of mad people thofe volitions alone cxift, 

 which are unmixed with fenfation ; immoderate fufmcion is 



Vol. I. Uu generally 



