SECT. XXXIV. 2. 2. OF VOLITION. 337 



fimilar effects upon the fenfual motions, or ideas of the mind, as 

 thole already mentioned upon the mufcular fibres. Thus when 

 any violent pain, arifmg from the defect of fome peculiar ftimu- 

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

 which cannot be removed by acquiring the defective (limulus ; 

 as in fome conftitutions 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 during this exertion, like that of the muf- 

 cles, the pain either vaniflies or is diminifhed : this violent ex- 

 ertion conftitutes madnefs ; and in many cafes I have feen 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 diftinguifhable from delirium, as in the latter 

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

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

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

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

 date of inattention to every thing about him. Whilft in the 

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

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

 ticular object of his defire or averfion, he harbours in his 

 thoughts a fufpicion of all mankind, left they ftiould 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 wifh, or of preventing or 

 revenging the injuries he fufpects. 



3 A late French phtlofopher, Mr. Helvetius, has deduced al- 

 moft all our actions from this principle of their relieving us 

 from the ennui or tedium vitse ; and true it is, that our defires 

 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 on miftaken objefts, 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 feveral have believed they had 

 the venereal infection, without in reality having a fymptom of 

 cither of them. They have been perpetually thinking upon this 

 fubject, and fome of them were in vain falivated with defign of 

 convincing them to the contrary. 



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

 which are unmixed with fenfation ; immoderate fufpicion is 



VOL. I. 1 T T generally 



