CLASS. HI, 2. 1. F VOLITION, 33J 



ORDO II. 



Increased Volition. 



GENUS I. 

 With decreased Actions of the Muscles. 



OUR muscles become fatigued by long contraction, and ceaste 

 ibr a time to be excitable by the will; owing to exhaustion of 

 the sensorial power, which resides in them After a short inter- 

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

 traction; which is probably occasioned by a new supply of the 

 spirit of animation. In weaker people these contractions cease 

 sooner, and therefore recur more frequently, and are attended 

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

 ness of the pulse in fevers with debility, and in the tremors of 

 the hands of aged or feeble people. 



After a common degree of exhaustion of the sensorial power 

 in a muscle, it becomes again gradually restored by the rest of 

 the muscle, and even accumulated in those muscles, which are 

 most frequently used; as in those which constitute the capilla- 

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

 in those muscles, which are generally obedient to volition, as 

 those of locomotion, though their usual quantity of sensorial 

 power is restored by their quiescence, or in sleep (for sleep af- 

 fects these parts of the system only,) yet but little accumulation 

 of it succeeds. And this want of accumulation of the sensorial 

 power in these muscles, which are chiefly subservient to voli- 

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

 lytic affection. 



It must be observed, that those parts of the system, which 

 have been for a time quiescent from want of stimulus, as the; 

 vessels of the skin, when exposed to cold, acquire an accumula- 

 tion of sensorial power during their inactivity; but this does 

 not happen at all, or in much less quantity, from their quies- 

 cence after great expenditure of sensorial power by a previous, 

 excessive stimulus, as after intoxication. In this case the mus- 

 cles or organs of sense gradually acquire their natural quantity 

 of sensorial power, as after sleep; but not an accumulation or 

 superabundance of it. And by frequent repetitions of exhaus- 

 tion by great stimulus, these vessels cease to acquire their whole 

 natural quantity of sensorial power; as in the scirrhous sto- 

 mach, and scirrhous liver, occasioned by the great and frequent 



