CLASS III. 2.1. OF VOLITION. 3 3 ' 



ORDO II. 



Decreafed Volition. 



GENUS I. 

 With decreafed AElions of the Mufcles. 



OUR mufcles become fatigued by long contra&ion, and ceafc 

 for a time to be excitable by the will ; owing to exhauftion of 

 the fenforial power, which refides in them. After a fhort inter- 

 val of relaxation the mufcle regains its power of voluntary con- 

 traction 5 which is probably occafioned by a new fupply of the 

 fpirit of animation. In weaker people thefe contractions ceafe 

 fooner, and therefore recur more frequently, and are attended 

 with fliorter intervals of relaxation, as exemplified in the quick- 

 nefs of the pulfe in fevers with debility, and in the tremors of 

 the hands of aged or feeble people. 



After a common degree of exhauftion of the fenforial power 

 in a mufcle, it becomes again gradually reftored by the reft of 

 the mufcle, and even accumulated in thofe mufcles, which are 

 moft frequently ufed ; as in thofe which conftitute the capilla- 

 ries of the fkin after having been rendered torpid by cold. But 

 in thofe mufcles, which are generally obedient to volition, as 

 thofe of locomotion, though their ufual quantity of fenforial 

 power is reftored by their quiefcence, or in fleep (for ileep af- 

 fecls thefe parts of the fyftem only), yet but little accumulation 

 of it fucceeds. And this want of accumulation of the fenforial 

 power in thefe mufcles, which are chiefly fubfervient to voli- 

 tion, explains to us one caufe of their greater tendency to para- 

 lytic affection. 



It muft be obferved, that thofe parts of the fyftem, which 

 have been for a time quiefcent from want of ftimulus, as the 

 veflels of the fkin, when expofed to cold, acquire an accumula- 

 tion of fenforial power during their inactivity ; but this does 

 not happen at all, or in much lefs quantity, from their quief- 

 cence after great expenditure of fenforial power by a previous 

 exceflive ftimulus, as after intoxication. In this cafe the muf- 

 cles or organs of fenfe gradually acquire their natural quantity 

 of fenforial power, as after fleep ; but not an accumulation or 

 iuperabundance of it. And by frequent repetitions of exhauf- 

 tion by great ftimulus, thefe veflels ceafe to acquire their whole 

 natural quantity of fenforial power ; as in the fcirrhous ftom- 

 ach, and fcirrhous liver, occafioned by the great and frequent 



ftimulus 



