SECT. XXXIV. 2. DISEASES OF VOLITION. 495 



exertions of their voluntary powers of mind prevent 

 their perception of almoft every other object, either 

 of irritation or of fenfation. Hence it is that they 

 bear cold, hunger, and fatigue, with much greater 

 pertinacity than in their fober hours, and are left* 

 injured by them in refpect to their general health. 

 Thus it is afierted by hiftoiians, that Charles the 

 Twelfth of Sweden flept on the fnow, wrapped only 

 in his cloak, at the liege of Frederick ft ad, and bore 

 extremes of cold, and hunger, and fatigue, under 

 which numbers of his foldiers perimed; becaufe the 

 king was infane with ambition, but the foldier had 

 no fuch powerful ftimulus to preferve his fyftem 

 from debility and death. 



6. Befides the infanities arifing from exertions in 

 ronfequence of pain, there is alfo a pleafurable in- 

 fanity, as well as a pleafurable delirium ; as the in* 

 fanity of perfonal vanity, and that of religious fana- 

 ticifm. When agreeable ideas excite into motion 

 the fenforial power of fenfation, and this again 

 caufes other trains of agreeable ideas, a conftant 

 ftream of pleafurable ideas fucceeds, and produces 

 pleafurable delirium. So when the fenforial power 

 of volition excites agreeable ideas, and the pleafure 

 thus produced excites more volition in its turn, a 

 conftant flow of agreeable voluntary ideas fucceeds ; 

 which when thus exerted in the extreme conftitutes 

 infanity. 



Thus when our mufcular a&ions are excited by 

 our fenfations of pleafure, it is termed play; when 

 they are excited by our volition, it is termed work ; 

 and the former of thefe is attended with lefs fa- 

 tigue, becaufe the mufcular actions in play produce 

 in their turn more pleafurable fenfation ; which 

 again has the property of producing more mufcular 

 acuon. An agreeable inftance of this I faw this 

 morning. A little boy, who was tifed with walk- 

 ing, begged of his papa to carry him. " Here," 



fays 



